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Bonsoms J, Oliva M, Alonso-González E, Revuelto J, López-Moreno JI. Impact of climate change on snowpack dynamics in coastal Central-Western Greenland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169616. [PMID: 38159743 DOI: 10.1016/j.scitotenv.2023.169616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/06/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
Snow patterns in ice-free areas of Greenland play important roles in ecosystems. Within a changing climate, a comprehensive understanding of the snow responses to climate change is of interest to anticipate forthcoming dynamics in these areas. In this study, we analyze the future snowpack evolution of a polar maritime Arctic location, Qeqertarsuaq (Disko Island, Central-Western Greenland). A physically-based snow model (FSM2) is validated and forced with CMIP6 projections for SSP2-4.5 and SSP5-8.5 greenhouse gasses emission scenarios, using two models: CanESM5 and MIROC6. The future snowpack evolution is assessed through four key seasonal (October to May) snow climate indicators: snow depth, snow days, snowfall fraction and ablation rate. Comparison against the observed air temperature for the reference climate period demonstrates superior accuracies for MIROC6 SSP2.4-5, with anomalies at 19 %, compared to CanESM5 SSP5.8-5 (25 %) and CanESM5 SSP2.4-5 (78 %). In terms of precipitation, CanESM5 SSP2.4-5 and SSP2.4-5 exhibit smaller anomalies against the observed data (5 %) in contrast to MIROC6 SSP2.4-5 (15 %) and MIROC6 SSP2.8-5 (17 %). Results demonstrate distinct snowpack responses to climate change depending on the model and emission scenario. For CanESM5, seasonal snow depth anomalies with respect to the reference period range from - 38 % (SSP2-4.5, 2040-2050 period) to - 74 % (SSP5-8.5, 2090-2100 period). MIROC6 projects lower snowpack reductions, with a decrease ranging from - 38 % (SSP2-4.5, 2040-2050 period) to - 57 % (SSP5-8.5, 2090-2100 period). Similar reductions are anticipated for snowfall and snow days. Changes in the snowpack evolution are primarily driven by positive trends in downwelling longwave radiation and air temperature. The projected increase in precipitation by the mid to late 21st century will lead to more frequent rain-on-snow events, intensifying snowpack melting. These findings help enhance the comprehension of future snow dynamics in the ice-free zones of Greenland, as well as the associated hydrological and ecological changes.
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Affiliation(s)
- Josep Bonsoms
- Department of Geography, Universitat de Barcelona, Barcelona, Spain.
| | - Marc Oliva
- Department of Geography, Universitat de Barcelona, Barcelona, Spain
| | - Esteban Alonso-González
- Centre d'Etudes Spatiales de la Biosphère (CESBIO), Université de Toulouse, CNES/CNRS/IRD/UPS, Toulouse, France
| | - Jesús Revuelto
- Instituto Pirenaico de Ecología (IPE-CSIC), Campus de Aula Dei, Zaragoza, Spain
| | - Juan I López-Moreno
- Instituto Pirenaico de Ecología (IPE-CSIC), Campus de Aula Dei, Zaragoza, Spain
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2
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Ndah FA, Maljanen M, Kasurinen A, Rinnan R, Michelsen A, Kotilainen T, Kivimäenpää M. Acclimation of subarctic vegetation to warming and increased cloudiness. PLANT-ENVIRONMENT INTERACTIONS (HOBOKEN, N.J.) 2024; 5:e10130. [PMID: 38323130 PMCID: PMC10840376 DOI: 10.1002/pei3.10130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 11/03/2023] [Accepted: 11/08/2023] [Indexed: 02/08/2024]
Abstract
Subarctic ecosystems are exposed to elevated temperatures and increased cloudiness in a changing climate with potentially important effects on vegetation structure, composition, and ecosystem functioning. We investigated the individual and combined effects of warming and increased cloudiness on vegetation greenness and cover in mesocosms from two tundra and one palsa mire ecosystems kept under strict environmental control in climate chambers. We also investigated leaf anatomical and biochemical traits of four dominant vascular plant species (Empetrum hermaphroditum, Vaccinium myrtillus, Vaccinium vitis-idaea, and Rubus chamaemorus). Vegetation greenness increased in response to warming in all sites and in response to increased cloudiness in the tundra sites but without associated increases in vegetation cover or biomass, except that E. hermaphroditum biomass increased under warming. The combined warming and increased cloudiness treatment had an additive effect on vegetation greenness in all sites. It also increased the cover of graminoids and forbs in one of the tundra sites. Warming increased leaf dry mass per area of V. myrtillus and R. chamaemorus, and glandular trichome density of V. myrtillus and decreased spongy intercellular space of E. hermaphroditum and V. vitis-idaea. Increased cloudiness decreased leaf dry mass per area of V. myrtillus, palisade thickness of E. hermaphroditum, and stomata density of E. hermaphroditum and V. vitis-idaea, and increased leaf area and epidermis thickness of V. myrtillus, leaf shape index and nitrogen of E. hermaphroditum, and palisade intercellular space of V. vitis-idaea. The combined treatment caused thinner leaves and decreased leaf carbon for V. myrtillus, and increased leaf chlorophyll of E. hermaphroditum. We show that under future warmer increased cloudiness conditions in the Subarctic (as simulated in our experiment), vegetation composition and distribution will change, mostly dominated by graminoids and forbs. These changes will depend on the responses of leaf anatomical and biochemical traits and will likely impact carbon gain and primary productivity and abiotic and biotic stress tolerance.
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Affiliation(s)
- Flobert A. Ndah
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Marja Maljanen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Anne Kasurinen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
| | - Riikka Rinnan
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagen ØDenmark
- Center for Volatile Interactions (VOLT), Department of BiologyUniversity of CopenhagenCopenhagen ØDenmark
| | - Anders Michelsen
- Terrestrial Ecology Section, Department of BiologyUniversity of CopenhagenCopenhagen ØDenmark
- Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource ManagementUniversity of CopenhagenCopenhagen KDenmark
| | | | - Minna Kivimäenpää
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandKuopioFinland
- Natural Resources Institute FinlandSuonenjokiFinland
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Kecorius S, Hoffmann EH, Tilgner A, Barrientos-Velasco C, van Pinxteren M, Zeppenfeld S, Vogl T, Madueño L, Lovrić M, Wiedensohler A, Kulmala M, Paasonen P, Herrmann H. Rapid growth of Aitken-mode particles during Arctic summer by fog chemical processing and its implication. PNAS NEXUS 2023; 2:pgad124. [PMID: 37152675 PMCID: PMC10156171 DOI: 10.1093/pnasnexus/pgad124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 03/21/2023] [Accepted: 04/03/2023] [Indexed: 05/09/2023]
Abstract
In the Arctic, new particle formation (NPF) and subsequent growth processes are the keys to produce Aitken-mode particles, which under certain conditions can act as cloud condensation nuclei (CCNs). The activation of Aitken-mode particles increases the CCN budget of Arctic low-level clouds and, accordingly, affects Arctic climate forcing. However, the growth mechanism of Aitken-mode particles from NPF into CCN range in the summertime Arctic boundary layer remains a subject of current research. In this combined Arctic cruise field and modeling study, we investigated Aitken-mode particle growth to sizes above 80 nm. A mechanism is suggested that explains how Aitken-mode particles can become CCN without requiring high water vapor supersaturation. Model simulations suggest the formation of semivolatile compounds, such as methanesulfonic acid (MSA) in fog droplets. When the fog droplets evaporate, these compounds repartition from CCNs into the gas phase and into the condensed phase of nonactivated Aitken-mode particles. For MSA, a mass increase factor of 18 is modeled. The postfog redistribution mechanism of semivolatile acidic and basic compounds could explain the observed growth of >20 nm h-1 for 60-nm particles to sizes above 100 nm. Overall, this study implies that the increasing frequency of NPF and fog-related particle processing can affect Arctic cloud properties in the summertime boundary layer.
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Affiliation(s)
| | - Erik H Hoffmann
- Atmospheric Chemistry Department, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Andreas Tilgner
- Atmospheric Chemistry Department, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Carola Barrientos-Velasco
- Department of Remote Sensing of Atmospheric Processes, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Manuela van Pinxteren
- Atmospheric Chemistry Department, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Sebastian Zeppenfeld
- Atmospheric Chemistry Department, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Teresa Vogl
- Institute of Meteorology, Universität Leipzig, Leipzig 04103, Germany
| | - Leizel Madueño
- Atmospheric Microphysics, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Mario Lovrić
- Department of Methods and Algorithms for AI, Know-Center, Graz 8010, Austria
| | - Alfred Wiedensohler
- Atmospheric Microphysics, Leibniz Institute for Tropospheric Research (TROPOS), Leipzig 04318, Germany
| | - Markku Kulmala
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
| | - Pauli Paasonen
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki 00014, Finland
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4
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Topál D, Ding Q, Ballinger TJ, Hanna E, Fettweis X, Li Z, Pieczka I. Discrepancies between observations and climate models of large-scale wind-driven Greenland melt influence sea-level rise projections. Nat Commun 2022; 13:6833. [PMID: 36376292 PMCID: PMC9663692 DOI: 10.1038/s41467-022-34414-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 10/25/2022] [Indexed: 11/16/2022] Open
Abstract
While climate models project that Greenland ice sheet (GrIS) melt will continue to accelerate with climate change, models exhibit limitations in capturing observed connections between GrIS melt and changes in high-latitude atmospheric circulation. Here we impose observed Arctic winds in a fully-coupled climate model with fixed anthropogenic forcing to quantify the influence of the rotational component of large-scale atmospheric circulation variability over the Arctic on the temperature field and the surface mass/energy balances through adiabatic processes. We show that recent changes involving mid-to-upper-tropospheric anticyclonic wind anomalies – linked with tropical forcing – explain half of the observed Greenland surface warming and ice loss acceleration since 1990, suggesting a pathway for large-scale winds to potentially enhance sea-level rise by ~0.2 mm/year per decade. We further reveal fingerprints of this observed teleconnection in paleo-reanalyses spanning the past 400 years, which heightens concern about model limitations to capture wind-driven adiabatic processes associated with GrIS melt. Here, the authors highlight that a better representation of large-scale wind-driven warming processes in climate models has potential for lessening sea-level rise projection uncertainties associated with Greenland ice sheet melt.
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5
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Ryan JC, Smith LC, Cooley SW, Pearson B, Wever N, Keenan E, Lenaerts JTM. Decreasing surface albedo signifies a growing importance of clouds for Greenland Ice Sheet meltwater production. Nat Commun 2022; 13:4205. [PMID: 35864084 PMCID: PMC9304359 DOI: 10.1038/s41467-022-31434-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/17/2022] [Indexed: 12/04/2022] Open
Abstract
Clouds regulate the Greenland Ice Sheet’s surface energy balance through the competing effects of shortwave radiation shading and longwave radiation trapping. However, the relative importance of these effects within Greenland’s narrow ablation zone, where nearly all meltwater runoff is produced, remains poorly quantified. Here we use machine learning to merge MODIS, CloudSat, and CALIPSO satellite observations to produce a high-resolution cloud radiative effect product. For the period 2003–2020, we find that a 1% change in cloudiness has little effect (±0.16 W m−2) on summer net radiative fluxes in the ablation zone because the warming and cooling effects of clouds compensate. However, by 2100 (SSP5-8.5 scenario), radiative fluxes in the ablation zone will become more than twice as sensitive (±0.39 W m−2) to changes in cloudiness due to reduced surface albedo. Accurate representation of clouds will therefore become increasingly important for forecasting the Greenland Ice Sheet’s contribution to global sea-level rise. Here the authors use remote sensing observations and machine learning to show that clouds will become increasingly important for determining the Greenland Ice Sheet’s contribution to global sea levels due to decreasing albedo in the ablation zone.
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Affiliation(s)
- J C Ryan
- Department of Geography, University of Oregon, Eugene, OR, USA.
| | - L C Smith
- Institute at Brown for Environment and Society, Brown University, Providence, RI, USA.,Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, USA
| | - S W Cooley
- Department of Geography, University of Oregon, Eugene, OR, USA
| | - B Pearson
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - N Wever
- Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA
| | - E Keenan
- Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA
| | - J T M Lenaerts
- Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO, USA
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6
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Assessment of MODIS Surface Temperature Products of Greenland Ice Sheet Using In-Situ Measurements. LAND 2022. [DOI: 10.3390/land11050593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Satellite-based data have promoted the research progress in polar regions under global climate change, meanwhile the uncertainties and limitations of satellite-derived surface temperatures are widely discussed over Greenland. This study validated the accuracy of ice surface temperature (IST) from the moderate-resolution imaging spectroradiometer (MODIS) over the Greenland ice sheet (GrIS). Daily MODIS IST was validated against the observational surface temperature from 24 automatic weather stations (AWSs) using the mean bias (MB), the root mean square (RMSE), and the correlation coefficient (R). The temporal and spatial variability over the GrIS spanning from March 2000 to December 2019 and the IST melt threshold (−1 °C) were analyzed. Generally, the MODIS IST was underestimated by an average of −2.68 °C compared to AWSs, with cold bias mainly occurring in winter. Spatially, the R and RMSE performed the better accuracy of MODIS IST on the northwest, northeast, and central part of the GrIS. Furthermore, the mean IST is mainly concentrated between −20 °C and −10 °C in summer while between −50 °C and −30 °C in winter. The largest positive IST anomalies (exceeds 3 °C) occurred in southwestern GrIS during 2010. IST shows the positive trends mainly in spring and summer and negative in autumn and winter.
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7
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Moschos V, Dzepina K, Bhattu D, Lamkaddam H, Casotto R, Daellenbach KR, Canonaco F, Rai P, Aas W, Becagli S, Calzolai G, Eleftheriadis K, Moffett CE, Schnelle-Kreis J, Severi M, Sharma S, Skov H, Vestenius M, Zhang W, Hakola H, Hellén H, Huang L, Jaffrezo JL, Massling A, Nøjgaard JK, Petäjä T, Popovicheva O, Sheesley RJ, Traversi R, Yttri KE, Schmale J, Prévôt ASH, Baltensperger U, El Haddad I. Equal abundance of summertime natural and wintertime anthropogenic Arctic organic aerosols. NATURE GEOSCIENCE 2022; 15:196-202. [PMID: 35341076 PMCID: PMC8916957 DOI: 10.1038/s41561-021-00891-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 12/27/2021] [Indexed: 05/22/2023]
Abstract
Aerosols play an important yet uncertain role in modulating the radiation balance of the sensitive Arctic atmosphere. Organic aerosol is one of the most abundant, yet least understood, fractions of the Arctic aerosol mass. Here we use data from eight observatories that represent the entire Arctic to reveal the annual cycles in anthropogenic and biogenic sources of organic aerosol. We show that during winter, the organic aerosol in the Arctic is dominated by anthropogenic emissions, mainly from Eurasia, which consist of both direct combustion emissions and long-range transported, aged pollution. In summer, the decreasing anthropogenic pollution is replaced by natural emissions. These include marine secondary, biogenic secondary and primary biological emissions, which have the potential to be important to Arctic climate by modifying the cloud condensation nuclei properties and acting as ice-nucleating particles. Their source strength or atmospheric processing is sensitive to nutrient availability, solar radiation, temperature and snow cover. Our results provide a comprehensive understanding of the current pan-Arctic organic aerosol, which can be used to support modelling efforts that aim to quantify the climate impacts of emissions in this sensitive region.
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Affiliation(s)
- Vaios Moschos
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Katja Dzepina
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
- Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
- Center for Atmospheric Research, University of Nova Gorica, Ajdovščina, Slovenia
| | - Deepika Bhattu
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
- Department of Civil and Infrastructure Engineering, Indian Institute of Technology Jodhpur, Jodhpur, India
| | - Houssni Lamkaddam
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Roberto Casotto
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | | | - Francesco Canonaco
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
- Datalystica Ltd, Villigen, Switzerland
| | - Pragati Rai
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Wenche Aas
- Norwegian Institute for Air Research (NILU), Kjeller, Norway
| | - Silvia Becagli
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Florence, Italy
- Institute of Polar Sciences, ISP-CNR, Venice-Mestre, Italy
| | - Giulia Calzolai
- National Institute for Nuclear Physics (INFN), Florence Division, Florence, Italy
| | | | - Claire E. Moffett
- Department of Environmental Science, Baylor University, Waco, TX USA
| | | | - Mirko Severi
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Florence, Italy
- Institute of Polar Sciences, ISP-CNR, Venice-Mestre, Italy
| | - Sangeeta Sharma
- Climate Research Division, Environment and Climate Change Canada, Toronto, Canada
| | - Henrik Skov
- Department of Environmental Science, iClimate, Aarhus University, Roskilde, Denmark
| | - Mika Vestenius
- Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Wendy Zhang
- Climate Research Division, Environment and Climate Change Canada, Toronto, Canada
| | - Hannele Hakola
- Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Heidi Hellén
- Atmospheric Composition Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Lin Huang
- Climate Research Division, Environment and Climate Change Canada, Toronto, Canada
| | - Jean-Luc Jaffrezo
- Institute of Environmental Geosciences, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Andreas Massling
- Department of Environmental Science, iClimate, Aarhus University, Roskilde, Denmark
| | - Jakob K. Nøjgaard
- The National Research Centre for the Working Environment, Copenhagen, Denmark
| | - Tuukka Petäjä
- Institute for Atmospheric and Earth System Research/Physics, University of Helsinki, Helsinki, Finland
| | - Olga Popovicheva
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
| | | | - Rita Traversi
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Florence, Italy
- Institute of Polar Sciences, ISP-CNR, Venice-Mestre, Italy
| | | | - Julia Schmale
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
- Extreme Environments Research Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - André S. H. Prévôt
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Urs Baltensperger
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Imad El Haddad
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, Switzerland
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8
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Supercooled Liquid Water Detection Capabilities from Ka-Band Doppler Profiling Radars: Moment-Based Algorithm Formulation and Assessment. REMOTE SENSING 2021. [DOI: 10.3390/rs13152891] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The occurrence of supercooled liquid water in mixed-phase cloud (MPC) affects their cloud microphysical and radiative properties. The prevalence of MPCs in the mid- and high latitudes translates these effects to significant contributions to Earth’s radiative balance and hydrological cycle. The current study develops and assesses a radar-only, moment-based phase partition technique for the demarcation of supercooled liquid water volumes in arctic, MPC conditions. The study utilizes observations from the Ka band profiling radar, the collocated high spectral resolution lidar, and ambient temperature profiles from radio sounding deployments following a statistical analysis of 5.5 years of data (January 2014–May 2019) from the Atmospheric Radiation Measurement observatory at the North Slope of Alaska. The ice/liquid phase partition occurs via a per-pixel, neighborhood-dependent algorithm based on the premise that the partitioning can be deduced by examining the mean values of locally sampled probability distributions of radar-based observables and then compare those against the means of climatologically derived, per-phase probability distributions. Analyzed radar observables include linear depolarization ratio (LDR), spectral width, and vertical gradients of reflectivity factor and radial velocity corrected for vertical air motion. Results highlight that the optimal supercooled liquid water detection skill levels are realized for the radar variable combination of spectral width and reflectivity vertical gradient, suggesting that radar-based polarimetry, in the absence of full LDR spectra, is not as critical as Doppler capabilities. The cloud phase masking technique is proven particularly reliable when applied to cloud tops with an Equitable Threat Score (ETS) of 65%; the detection of embedded supercooled layers remains much more uncertain (ETS = 27%).
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9
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McIlhattan EA, Kay JE, L'Ecuyer TS. Arctic Clouds and Precipitation in the Community Earth System Model Version 2. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2020; 125:e2020JD032521. [PMID: 33381360 PMCID: PMC7757258 DOI: 10.1029/2020jd032521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 09/01/2020] [Accepted: 10/08/2020] [Indexed: 06/12/2023]
Abstract
The Arctic climate is changing rapidly, warming at about twice the rate of the planet. Global climate models (GCMs) are invaluable tools both for understanding the drivers of these changes and predicting future Arctic climate evolution. While GCMs are continually improving, there remain difficulties in representing cloud processes which occur on scales smaller than GCM resolution. Since clouds influence the Arctic energy and water cycles, their accurate representation in models is critical for robust future projections. In this work, we examine the representation of Arctic clouds and precipitation in the Community Earth System Model (CESM) with the Community Atmosphere Model (CAM), comparing the newly released version (CESM2 with CAM6) with its predecessor (CESM1 with CAM5). To isolate changes in the Arctic mean state, we compare preindustrial control runs. Arctic cloud ice has decreased slightly, while cloud water has increased dramatically in CESM2. Annual mean liquid-containing cloud (LCC) frequency has increased from 19% in CESM1 to 51% in CESM2. Since LCCs strongly modulate downwelling radiation at the surface, their increase has led to an increase in mean downwelling longwave (+22 W m-2) and corresponding decrease in downwelling shortwave (-23 W m-2) radiation. The mean Arctic surface temperature increased from 257 K in CESM1 to 260 K in CESM2, with the largest seasonal difference in winter (+6 K). Annual average snowfall has decreased slightly (-1 mm month-1), while rainfall has increased (+5 mm month-1).
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Affiliation(s)
- Elin A. McIlhattan
- Department of Atmospheric and Oceanic SciencesUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Jennifer E. Kay
- Department of Atmospheric and Oceanic SciencesUniversity of ColoradoBoulderCOUSA
- Cooperative Institute for Research in Environmental SciencesUniversity of ColoradoBoulderCOUSA
| | - Tristan S. L'Ecuyer
- Department of Atmospheric and Oceanic SciencesUniversity of Wisconsin‐MadisonMadisonWIUSA
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10
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Sanchez-Marroquin A, Arnalds O, Baustian-Dorsi KJ, Browse J, Dagsson-Waldhauserova P, Harrison AD, Maters EC, Pringle KJ, Vergara-Temprado J, Burke IT, McQuaid JB, Carslaw KS, Murray BJ. Iceland is an episodic source of atmospheric ice-nucleating particles relevant for mixed-phase clouds. SCIENCE ADVANCES 2020; 6:eaba8137. [PMID: 32637618 PMCID: PMC7314534 DOI: 10.1126/sciadv.aba8137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/14/2020] [Indexed: 05/26/2023]
Abstract
Ice-nucleating particles (INPs) have the potential to remove much of the liquid water in climatically important mid- to high-latitude shallow supercooled clouds, markedly reducing their albedo. The INP sources at these latitudes are very poorly defined, but it is known that there are substantial dust sources across the high latitudes, such as Iceland. Here, we show that Icelandic dust emissions are sporadically an important source of INPs at mid to high latitudes by combining ice-nucleating active site density measurements of aircraft-collected Icelandic dust samples with a global aerosol model. Because Iceland is only one of many high-latitude dust sources, we anticipate that the combined effect of all these sources may strongly contribute to the INP population in the mid- and high-latitude northern hemisphere. This is important because these emissions are directly relevant for the cloud-phase climate feedback and because high-latitude dust emissions are expected to increase in a warmer climate.
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Affiliation(s)
- A. Sanchez-Marroquin
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - O. Arnalds
- Agricultural University of Iceland, Hvanneyrabraut, 311 Hvanneyri, Iceland
| | - K. J. Baustian-Dorsi
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
- Bison Engineering Inc., Helena, MT 59601, USA
| | - J. Browse
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
- Center for Geography and Environmental Science, University of Exeter, Penryn Campus, Penryn, Cornwall TR10 8FE, UK
| | - P. Dagsson-Waldhauserova
- Agricultural University of Iceland, Hvanneyrabraut, 311 Hvanneyri, Iceland
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycka 126, Prague 6, 16000, Czech Republic
| | - A. D. Harrison
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - E. C. Maters
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
- Department of Chemistry, University of Cambridge, The Old Schools, Trinity Lane, Cambridge CB2 1TN, UK
| | - K. J. Pringle
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - J. Vergara-Temprado
- Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland
| | - I. T. Burke
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - J. B. McQuaid
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - K. S. Carslaw
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - B. J. Murray
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
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11
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Stephens GL, Slingo JM, Rignot E, Reager JT, Hakuba MZ, Durack PJ, Worden J, Rocca R. Earth's water reservoirs in a changing climate. Proc Math Phys Eng Sci 2020; 476:20190458. [PMID: 32398926 PMCID: PMC7209137 DOI: 10.1098/rspa.2019.0458] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 02/26/2020] [Indexed: 11/12/2022] Open
Abstract
Progress towards achieving a quantitative understanding of the exchanges of water between Earth's main water reservoirs is reviewed with emphasis on advances accrued from the latest advances in Earth Observation from space. These exchanges of water between the reservoirs are a result of processes that are at the core of important physical Earth-system feedbacks, which fundamentally control the response of Earth's climate to the greenhouse gas forcing it is now experiencing, and are therefore vital to understanding the future evolution of Earth's climate. The changing nature of global mean sea level (GMSL) is the context for discussion of these exchanges. Different sources of satellite observations that are used to quantify ice mass loss and water storage over continents, how water can be tracked to its source using water isotope information and how the waters in different reservoirs influence the fluxes of water between reservoirs are described. The profound influence of Earth's hydrological cycle, including human influences on it, on the rate of GMSL rise is emphasized. The many intricate ways water cycle processes influence water exchanges between reservoirs and thus sea-level rise, including disproportionate influences by the tiniest water reservoirs, are emphasized.
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Affiliation(s)
- Graeme L. Stephens
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | | | - Eric Rignot
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
- Department of Earth System Science, University of California, Irvine, CA 92697, USA
| | - John T. Reager
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Maria Z. Hakuba
- Department of Atmospheric Science, Colorado State University, Ft Collins, CO 80525, USA
| | - Paul J. Durack
- Atmospheric, Earth and Energy Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - John Worden
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Remy Rocca
- Observatoire Midi-Pyrénées, LEGOS, Toulouse, France
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12
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Noël B, van de Berg WJ, Lhermitte S, van den Broeke MR. Rapid ablation zone expansion amplifies north Greenland mass loss. SCIENCE ADVANCES 2019; 5:eaaw0123. [PMID: 31517042 PMCID: PMC6726448 DOI: 10.1126/sciadv.aaw0123] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 08/06/2019] [Indexed: 05/02/2023]
Abstract
Since the early 1990s, the Greenland ice sheet (GrIS) has been losing mass at an accelerating rate, primarily due to enhanced meltwater runoff following atmospheric warming. Here, we show that a pronounced latitudinal contrast exists in the GrIS response to recent warming. The ablation area in north Greenland expanded by 46%, almost twice as much as in the south (+25%), significantly increasing the relative contribution of the north to total GrIS mass loss. This latitudinal contrast originates from a different response to the recent change in large-scale Arctic summertime atmospheric circulation, promoting southwesterly advection of warm air toward the GrIS. In the southwest, persistent high atmospheric pressure reduced cloudiness, increasing runoff through enhanced absorption of solar radiation; in contrast, increased early-summer cloudiness in north Greenland enhanced atmospheric warming through decreased longwave heat loss. This triggered a rapid snowline retreat, causing early bare ice exposure, amplifying northern runoff.
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Affiliation(s)
- Brice Noël
- Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands
| | | | - Stef Lhermitte
- Department of Geoscience and Remote Sensing, Delft University of Technology, Delft, Netherlands
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13
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Cloud-driven modulations of Greenland ice sheet surface melt. Sci Rep 2019; 9:10380. [PMID: 31316097 PMCID: PMC6637179 DOI: 10.1038/s41598-019-46152-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 06/24/2019] [Indexed: 11/08/2022] Open
Abstract
Clouds have been recognized to enhance surface melt on the Greenland Ice Sheet (GrIS). However, quantitative estimates of the effects of clouds on the GrIS melt area and ice-sheet-wide surface mass balance are still lacking. Here we assess the effects of clouds with a state-of-the-art regional climate model, conducting a numerical sensitivity test in which adiabatic atmospheric conditions as well as zero cloud water/ice amounts are assumed (i.e., clear-sky conditions), although the precipitation rate is the same as in the control all-sky simulation. By including or excluding clouds, we quantify time-integrated feedbacks for the first time. We find that clouds were responsible for a 3.1%, 0.3%, and 0.7% increase in surface melt extent (of the total GrIS area) in 2012, 2013, and 2014, respectively. During the same periods, clouds reduced solar heating and thus daily runoff by 1.6, 0.8, and 1.0 Gt day-1, respectively: clouds did not enhance surface mass loss. In the ablation areas, the presence of clouds results in a reduction of downward latent heat flux at the snow/ice surface so that much less energy is available for surface melt, which highlights the importance of indirect time-integrated feedbacks of cloud radiative effects.
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14
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Trusel LD, Das SB, Osman MB, Evans MJ, Smith BE, Fettweis X, McConnell JR, Noël BPY, van den Broeke MR. Nonlinear rise in Greenland runoff in response to post-industrial Arctic warming. Nature 2018; 564:104-108. [PMID: 30518887 DOI: 10.1038/s41586-018-0752-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 09/18/2018] [Indexed: 11/09/2022]
Abstract
The Greenland ice sheet (GrIS) is a growing contributor to global sea-level rise1, with recent ice mass loss dominated by surface meltwater runoff2,3. Satellite observations reveal positive trends in GrIS surface melt extent4, but melt variability, intensity and runoff remain uncertain before the satellite era. Here we present the first continuous, multi-century and observationally constrained record of GrIS surface melt intensity and runoff, revealing that the magnitude of recent GrIS melting is exceptional over at least the last 350 years. We develop this record through stratigraphic analysis of central west Greenland ice cores, and demonstrate that measurements of refrozen melt layers in percolation zone ice cores can be used to quantifiably, and reproducibly, reconstruct past melt rates. We show significant (P < 0.01) and spatially extensive correlations between these ice-core-derived melt records and modelled melt rates5,6 and satellite-derived melt duration4 across Greenland more broadly, enabling the reconstruction of past ice-sheet-scale surface melt intensity and runoff. We find that the initiation of increases in GrIS melting closely follow the onset of industrial-era Arctic warming in the mid-1800s, but that the magnitude of GrIS melting has only recently emerged beyond the range of natural variability. Owing to a nonlinear response of surface melting to increasing summer air temperatures, continued atmospheric warming will lead to rapid increases in GrIS runoff and sea-level contributions.
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Affiliation(s)
- Luke D Trusel
- Department of Geology, Rowan University, Glassboro, NJ, USA. .,Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
| | - Sarah B Das
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - Matthew B Osman
- Joint Program in Oceanography, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - Ben E Smith
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA, USA
| | - Xavier Fettweis
- Department of Geography, University of Liège, Liège, Belgium
| | - Joseph R McConnell
- Division of Hydrologic Sciences, Desert Research Institute, Reno, NV, USA
| | - Brice P Y Noël
- Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands
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15
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Redman BJ, Shaw JA, Nugent PW, Clark RT, Piazzolla S. Reflective all-sky thermal infrared cloud imager. OPTICS EXPRESS 2018; 26:11276-11283. [PMID: 29716051 DOI: 10.1364/oe.26.011276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 03/28/2018] [Indexed: 06/08/2023]
Abstract
A reflective all-sky imaging system has been built using a long-wave infrared microbolometer camera and a reflective metal sphere. This compact system was developed for measuring spatial and temporal patterns of clouds and their optical depth in support of applications including Earth-space optical communications. The camera is mounted to the side of the reflective sphere to leave the zenith sky unobstructed. The resulting geometric distortion is removed through an angular map derived from a combination of checkerboard-target imaging, geometric ray tracing, and sun-location-based alignment. A tape of high-emissivity material on the side of the reflector acts as a reference that is used to estimate and remove thermal emission from the metal sphere. Once a bias that is under continuing study was removed, sky radiance measurements from the all-sky imager in the 8-14 μm wavelength range agreed to within 0.91 W/(m2 sr) of measurements from a previously calibrated, lens-based infrared cloud imager over its 110° field of view.
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16
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Abstract
Meltwater runoff is an important hydrological process operating on the Greenland ice sheet surface that is rarely studied directly. By combining satellite and drone remote sensing with continuous field measurements of discharge in a large supraglacial river, we obtained 72 h of runoff observations suitable for comparison with climate model predictions. The field observations quantify how a large, fluvial supraglacial catchment attenuates the magnitude and timing of runoff delivered to its terminal moulin and hence the bed. The data are used to calibrate classical fluvial hydrology equations to improve meltwater runoff models and to demonstrate that broad-scale surface water drainage patterns that form on the ice surface powerfully alter the timing, magnitude, and locations of meltwater penetrating into the ice sheet. Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland’s midelevation (1,207–1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems.
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17
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Enhanced MODIS Atmospheric Total Water Vapour Content Trends in Response to Arctic Amplification. ATMOSPHERE 2017. [DOI: 10.3390/atmos8120241] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Nicolas JP, Vogelmann AM, Scott RC, Wilson AB, Cadeddu MP, Bromwich DH, Verlinde J, Lubin D, Russell LM, Jenkinson C, Powers HH, Ryczek M, Stone G, Wille JD. January 2016 extensive summer melt in West Antarctica favoured by strong El Niño. Nat Commun 2017. [PMID: 28643801 PMCID: PMC5481731 DOI: 10.1038/ncomms15799] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Over the past two decades the primary driver of mass loss from the West Antarctic Ice Sheet (WAIS) has been warm ocean water underneath coastal ice shelves, not a warmer atmosphere. Yet, surface melt occurs sporadically over low-lying areas of the WAIS and is not fully understood. Here we report on an episode of extensive and prolonged surface melting observed in the Ross Sea sector of the WAIS in January 2016. A comprehensive cloud and radiation experiment at the WAIS ice divide, downwind of the melt region, provided detailed insight into the physical processes at play during the event. The unusual extent and duration of the melting are linked to strong and sustained advection of warm marine air toward the area, likely favoured by the concurrent strong El Niño event. The increase in the number of extreme El Niño events projected for the twenty-first century could expose the WAIS to more frequent major melt events. Sporadic surface melt over the West Antarctic Ice Sheet is not fully understood. Here, the authors report on an extensive melting episode in the Ross Ice Shelf area in 2016 and use comprehensive in situ observations and model simulations to highlight the role of the strong El Niño event.
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Affiliation(s)
- Julien P Nicolas
- Byrd Polar and Climate Research Center, The Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210, USA
| | - Andrew M Vogelmann
- Brookhaven National Laboratory, Building 490D, PO Box 5000, Upton, New York 11973, USA
| | - Ryan C Scott
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Aaron B Wilson
- Byrd Polar and Climate Research Center, The Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210, USA
| | - Maria P Cadeddu
- Argonne National Laboratory, 9700 South Cass Avenue, EVS/Building 240, Argonne, Illinois 60439, USA
| | - David H Bromwich
- Byrd Polar and Climate Research Center, The Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210, USA.,Department of Geography, The Ohio State University, 1036 Derby Hall, 154 North Oval Mall, Columbus, Ohio 43210, USA
| | - Johannes Verlinde
- Department of Meteorology and Atmospheric Science, The Pennsylvania State University, 605A Walker Building, University Park, Pennsylvania 16802, USA
| | - Dan Lubin
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Lynn M Russell
- Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Colin Jenkinson
- Australian Bureau of Meteorology, GPO Box 1289, Melbourne, Victoria 3001, Australia
| | - Heath H Powers
- Los Alamos National Laboratory, PO Box 1663, Los Alamos, New Mexico 87545, USA
| | - Maciej Ryczek
- Los Alamos National Laboratory, PO Box 1663, Los Alamos, New Mexico 87545, USA
| | - Gregory Stone
- Australian Bureau of Meteorology, GPO Box 1289, Melbourne, Victoria 3001, Australia
| | - Jonathan D Wille
- Byrd Polar and Climate Research Center, The Ohio State University, 1090 Carmack Road, Columbus, Ohio 43210, USA
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19
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Zamora LM, Kahn RA, Eckhardt S, McComiskey A, Sawamura P, Moore R, Stohl A. Aerosol indirect effects on the nighttime Arctic Ocean surface from thin, predominantly liquid clouds. ATMOSPHERIC CHEMISTRY AND PHYSICS 2017; 17:7311-7332. [PMID: 32849860 PMCID: PMC7447155 DOI: 10.5194/acp-17-7311-2017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Aerosol indirect effects have potentially large impacts on the Arctic Ocean surface energy budget, but model estimates of regional-scale aerosol indirect effects are highly uncertain and poorly validated by observations. Here we demonstrate a new way to quantitatively estimate aerosol indirect effects on a regional scale from remote sensing observations. In this study, we focus on nighttime, optically thin, predominantly liquid clouds. The method is based on differences in cloud physical and microphysical characteristics in carefully selected clean, average and aerosol-impacted conditions. The cloud subset of focus covers just ~5% of cloudy Arctic Ocean regions, warming the Arctic Ocean surface by ~1-1.4 W m-2 regionally during polar night. However, within this cloud subset, aerosol and cloud conditions can be determined with high confidence using CALIPSO and CloudSat data and model output. This cloud subset is generally susceptible to aerosols, with a polar nighttime estimated maximum regionally integrated indirect cooling effect of ~ -0.11 W m-2 at the Arctic sea ice surface (~10% of the clean background cloud effect), excluding cloud fraction changes. Aerosol presence is related to reduced precipitation, cloud thickness, and radar reflectivity, and in some cases, an increased likelihood of cloud presence in the liquid phase. These observations are inconsistent with a glaciation indirect effect and are consistent with either a deactivation effect or less efficient secondary ice formation related to smaller liquid cloud droplets. However, this cloud subset shows large differences in surface and meteorological forcing in shallow and higher altitude clouds and between sea ice and open ocean regions. For example, optically thin, predominantly liquid clouds are much more likely to overlay another cloud over the open ocean, which may reduce aerosol indirect effects on the surface. Also, shallow clouds over open ocean do not appear to respond to aerosols as strongly as over stratified sea ice environments, indicating a larger influence of meteorological forcing over aerosol microphysics in these types of clouds over the rapidly changing Arctic Ocean.
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Affiliation(s)
- Lauren M. Zamora
- former NASA Postdoctoral Program Fellow, Universities Space Research Association; Now at Earth System Science Interdisciplinary Center (ESSIC), University of Maryland, College Park, MD, USA
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Ralph A. Kahn
- NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Sabine Eckhardt
- NILU - Norwegian Institute for Air Research, Kjeller, Norway
| | | | - Patricia Sawamura
- NASA Langley Research Center, Hampton, VA, USA
- Science Systems and Applications, Inc., Greenbelt, MD, USA
| | | | - Andreas Stohl
- NILU - Norwegian Institute for Air Research, Kjeller, Norway
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20
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21
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Lund M, Stiegler C, Abermann J, Citterio M, Hansen BU, van As D. Spatiotemporal variability in surface energy balance across tundra, snow and ice in Greenland. AMBIO 2017; 46:81-93. [PMID: 28116688 PMCID: PMC5258660 DOI: 10.1007/s13280-016-0867-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The surface energy balance (SEB) is essential for understanding the coupled cryosphere-atmosphere system in the Arctic. In this study, we investigate the spatiotemporal variability in SEB across tundra, snow and ice. During the snow-free period, the main energy sink for ice sites is surface melt. For tundra, energy is used for sensible and latent heat flux and soil heat flux leading to permafrost thaw. Longer snow-free period increases melting of the Greenland Ice Sheet and glaciers and may promote tundra permafrost thaw. During winter, clouds have a warming effect across surface types whereas during summer clouds have a cooling effect over tundra and a warming effect over ice, reflecting the spatial variation in albedo. The complex interactions between factors affecting SEB across surface types remain a challenge for understanding current and future conditions. Extended monitoring activities coupled with modelling efforts are essential for assessing the impact of warming in the Arctic.
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Affiliation(s)
- Magnus Lund
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Christian Stiegler
- Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Jakob Abermann
- Asiaq, Greenland Survey, Qatserisut 8, 3900 Nuuk, Greenland
| | - Michele Citterio
- Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350 Copenhagen, Denmark
| | - Birger U. Hansen
- Department of Geosciences and Natural Resource Management, Center for Permafrost (CENPERM), University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark
| | - Dirk van As
- Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350 Copenhagen, Denmark
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22
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Galewsky J, Steen-Larsen HC, Field RD, Worden J, Risi C, Schneider M. Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2016; 54:809-865. [PMID: 32661517 PMCID: PMC7357203 DOI: 10.1002/2015rg000512] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long-term datasets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large-scale mixing, deep convection, and kinetic fractionation. The technologies for in-situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite- and ground-based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope-enabled microphysics schemes using higher-order moments for water- and ice-size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.
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Affiliation(s)
- Joseph Galewsky
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | | | - Robert D Field
- NASA Goddard Institute for Space Studies, New York, New York, USA
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York, USA
| | - John Worden
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Camille Risi
- Laboratoire de Meteorologie Dynamique, Institut Pierre Simon Laplace, Centre National de la Recherche Scientifique, Paris, France
| | - Matthias Schneider
- Institute for Meteorology and Climate Research (IMK-ASF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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23
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Berkelhammer M, Noone DC, Steen-Larsen HC, Bailey A, Cox CJ, O'Neill MS, Schneider D, Steffen K, White JWC. Surface-atmosphere decoupling limits accumulation at Summit, Greenland. SCIENCE ADVANCES 2016; 2:e1501704. [PMID: 27386509 PMCID: PMC4928998 DOI: 10.1126/sciadv.1501704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 03/31/2016] [Indexed: 06/06/2023]
Abstract
Despite rapid melting in the coastal regions of the Greenland Ice Sheet, a significant area (~40%) of the ice sheet rarely experiences surface melting. In these regions, the controls on annual accumulation are poorly constrained owing to surface conditions (for example, surface clouds, blowing snow, and surface inversions), which render moisture flux estimates from myriad approaches (that is, eddy covariance, remote sensing, and direct observations) highly uncertain. Accumulation is partially determined by the temperature dependence of saturation vapor pressure, which influences the maximum humidity of air parcels reaching the ice sheet interior. However, independent proxies for surface temperature and accumulation from ice cores show that the response of accumulation to temperature is variable and not generally consistent with a purely thermodynamic control. Using three years of stable water vapor isotope profiles from a high altitude site on the Greenland Ice Sheet, we show that as the boundary layer becomes increasingly stable, a decoupling between the ice sheet and atmosphere occurs. The limited interaction between the ice sheet surface and free tropospheric air reduces the capacity for surface condensation to achieve the rate set by the humidity of the air parcels reaching interior Greenland. The isolation of the surface also acts to recycle sublimated moisture by recondensing it onto fog particles, which returns the moisture back to the surface through gravitational settling. The observations highlight a unique mechanism by which ice sheet mass is conserved, which has implications for understanding both past and future changes in accumulation rate and the isotopic signal in ice cores from Greenland.
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Affiliation(s)
- Max Berkelhammer
- Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA.; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA
| | - David C Noone
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Hans Christian Steen-Larsen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Laboratoire des Sciences du Climat et de l'Environnement, UMR CEA-CNRS-UVSQ/IPSL 8212, Gif-sur-Yvette, France.; Center for Ice and Climate, University of Copenhagen, Copenhagen, Denmark
| | - Adriana Bailey
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, WA 98195, USA
| | - Christopher J Cox
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Department of Atmospheric and Oceanic Sciences, University of Colorado, Boulder, CO 80309, USA.; National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
| | - Michael S O'Neill
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
| | - David Schneider
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Konrad Steffen
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA.; Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - James W C White
- Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA.; Environmental Studies Program, University of Colorado, Boulder, CO 80309, USA.; Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
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24
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Van Tricht K, Lhermitte S, Lenaerts JTM, Gorodetskaya IV, L'Ecuyer TS, Noël B, van den Broeke MR, Turner DD, van Lipzig NPM. Clouds enhance Greenland ice sheet meltwater runoff. Nat Commun 2016; 7:10266. [PMID: 26756470 PMCID: PMC4729937 DOI: 10.1038/ncomms10266] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 11/23/2015] [Indexed: 11/16/2022] Open
Abstract
The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m(-2). Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise.
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Affiliation(s)
- K. Van Tricht
- KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, Leuven 3001, Belgium
| | - S. Lhermitte
- KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, Leuven 3001, Belgium
| | - J. T. M. Lenaerts
- Institute for Marine and Atmospheric research Utrecht—Utrecht University, Utrecht 3584CC, The Netherlands
| | - I. V. Gorodetskaya
- KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, Leuven 3001, Belgium
| | - T. S. L'Ecuyer
- Atmospheric and Oceanic Sciences, University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
| | - B. Noël
- Institute for Marine and Atmospheric research Utrecht—Utrecht University, Utrecht 3584CC, The Netherlands
| | - M. R. van den Broeke
- Institute for Marine and Atmospheric research Utrecht—Utrecht University, Utrecht 3584CC, The Netherlands
| | - D. D. Turner
- National Severe Storms Laboratory, NOAA, Norman, Oklahoma 73072, USA
| | - N. P. M. van Lipzig
- KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, Leuven 3001, Belgium
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Cox CJ, Walden VP, Rowe PM, Shupe MD. Humidity trends imply increased sensitivity to clouds in a warming Arctic. Nat Commun 2015; 6:10117. [PMID: 26657324 PMCID: PMC4682107 DOI: 10.1038/ncomms10117] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 11/05/2015] [Indexed: 11/09/2022] Open
Abstract
Infrared radiative processes are implicated in Arctic warming and sea-ice decline. The infrared cloud radiative effect (CRE) at the surface is modulated by cloud properties; however, CRE also depends on humidity because clouds emit at wavelengths that are semi-transparent to greenhouse gases, most notably water vapour. Here we show how temperature and humidity control CRE through competing influences between the mid- and far-infrared. At constant relative humidity, CRE does not decrease with increasing temperature/absolute humidity as expected, but rather is found to be approximately constant for temperatures characteristic of the Arctic. This stability is disrupted if relative humidity varies. Our findings explain observed seasonal and regional variability in Arctic CRE of order 10 W m(-2). With the physical properties of Arctic clouds held constant, we calculate recent increases in CRE of 1-5 W m(-2) in autumn and winter, which are projected to reach 5-15 W m(-2) by 2050, implying increased sensitivity of the surface to clouds.
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Affiliation(s)
- Christopher J Cox
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.,NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA
| | - Von P Walden
- Department of Civil and Environmental Engineering, Washington State University, Pullman 99164, Washington, USA
| | - Penny M Rowe
- Department of Geography, University of Idaho, Moscow 83844, Idaho, USA.,Departamento de Física, Universidad de Santiago de Chile, Santiago 9170124, Chile
| | - Matthew D Shupe
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, USA.,NOAA Earth System Research Laboratory, Boulder, Colorado 80305, USA
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Daily Area of Snow Melt Onset on Arctic Sea Ice from Passive Microwave Satellite Observations 1979–2012. REMOTE SENSING 2014. [DOI: 10.3390/rs61111283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Climate change and forest fires synergistically drive widespread melt events of the Greenland Ice Sheet. Proc Natl Acad Sci U S A 2014; 111:7964-7. [PMID: 24843158 DOI: 10.1073/pnas.1405397111] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In July 2012, over 97% of the Greenland Ice Sheet experienced surface melt, the first widespread melt during the era of satellite remote sensing. Analysis of six Greenland shallow firn cores from the dry snow region confirms that the most recent prior widespread melt occurred in 1889. A firn core from the center of the ice sheet demonstrated that exceptionally warm temperatures combined with black carbon sediments from Northern Hemisphere forest fires reduced albedo below a critical threshold in the dry snow region, and caused the melting events in both 1889 and 2012. We use these data to project the frequency of widespread melt into the year 2100. Since Arctic temperatures and the frequency of forest fires are both expected to rise with climate change, our results suggest that widespread melt events on the Greenland Ice Sheet may begin to occur almost annually by the end of century. These events are likely to alter the surface mass balance of the ice sheet, leaving the surface susceptible to further melting.
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28
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Greenland ice sheet motion insensitive to exceptional meltwater forcing. Proc Natl Acad Sci U S A 2013; 110:19719-24. [PMID: 24248343 DOI: 10.1073/pnas.1315843110] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Changes to the dynamics of the Greenland ice sheet can be forced by various mechanisms including surface-melt-induced ice acceleration and oceanic forcing of marine-terminating glaciers. We use observations of ice motion to examine the surface melt-induced dynamic response of a land-terminating outlet glacier in southwest Greenland to the exceptional melting observed in 2012. During summer, meltwater generated on the Greenland ice sheet surface accesses the ice sheet bed, lubricating basal motion and resulting in periods of faster ice flow. However, the net impact of varying meltwater volumes upon seasonal and annual ice flow, and thus sea level rise, remains unclear. We show that two extreme melt events (98.6% of the Greenland ice sheet surface experienced melting on July 12, the most significant melt event since 1889, and 79.2% on July 29) and summer ice sheet runoff ~3.9 σ above the 1958-2011 mean resulted in enhanced summer ice motion relative to the average melt year of 2009. However, despite record summer melting, subsequent reduced winter ice motion resulted in 6% less net annual ice motion in 2012 than in 2009. Our findings suggest that surface melt-induced acceleration of land-terminating regions of the ice sheet will remain insignificant even under extreme melting scenarios.
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Failure and Redemption of Multifilter Rotating Shadowband Radiometer (MFRSR)/Normal Incidence Multifilter Radiometer (NIMFR) Cloud Screening: Contrasting Algorithm Performance at Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) and Southern Great Plains (SGP) Sites. ATMOSPHERE 2013. [DOI: 10.3390/atmos4030299] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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