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Schwarz JP, Gao RS, Thornberry TD, Rollins AW, Rosenlof KH, Portmann RW, Bui T, Jensen EJ, Ray EA. Considering intentional stratospheric dehydration for climate benefits. SCIENCE ADVANCES 2024; 10:eadk0593. [PMID: 38416836 DOI: 10.1126/sciadv.adk0593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/25/2024] [Indexed: 03/01/2024]
Abstract
We introduce a climate intervention strategy focused on decreasing water vapor (WV) concentrations near the tropopause and in the stratosphere to increase outbound longwave radiation. The mechanism is the targeted injection of ice-nucleating particles (INP) in air supersaturated with respect to ice at high altitudes in the tropical entryway to the stratosphere. Ice formation in this region is a critical control of stratospheric WV. Recent airborne in situ data indicate that targeting only a small fraction of air parcels in the region would be sufficient to achieve substantial removal of water. This "intentional stratospheric dehydration" (ISD) strategy would not counteract a large fraction of the forcing from carbon dioxide but may contribute to a portfolio of climate interventions by acting with different time and length scales of impact and risk than other interventions that are already under consideration. We outline the idea, its plausibility, technical hurdles, and side effects to be considered.
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Affiliation(s)
| | - Ru-Shan Gao
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
| | | | | | | | | | - ThaoPaul Bui
- NASA Ames Research Center, Moffett Field, CA, USA
| | - Eric J Jensen
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, Boulder, CO, USA
| | - Eric A Ray
- NOAA Chemical Sciences Laboratory, Boulder, CO, USA
- Cooperative Institute for Research in Environmental Sciences, Boulder, CO, USA
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2
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Gao RS, Rosenlof KH, Kärcher B, Tilmes S, Toon OB, Maloney C, Yu P. Toward practical stratospheric aerosol albedo modification: Solar-powered lofting. SCIENCE ADVANCES 2021; 7:7/20/eabe3416. [PMID: 33990319 PMCID: PMC8121417 DOI: 10.1126/sciadv.abe3416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 03/24/2021] [Indexed: 06/12/2023]
Abstract
Many climate intervention (CI) methods have been proposed to offset greenhouse gas-induced global warming, but the practicalities regarding implementation have not received sufficient attention. Stratospheric aerosol injection (SAI) involves introducing large amounts of CI material well within the stratosphere to enhance the aerosol loading, thereby increasing reflection of solar radiation. We explore a delivery method termed solar-powered lofting (SPL) that uses solar energy to loft CI material injected at lower altitudes accessible by conventional aircraft. Particles that absorb solar radiation are dispersed with the CI material and heat the surrounding air. The heated air rises, carrying the CI material to the stratosphere. Global model simulations show that black carbon aerosol (10 microgram per cubic meter) is sufficient to quickly loft CI material well into the stratosphere. SPL could make SAI viable at present, is also more energy efficient, and disperses CI material faster than direct stratospheric injection.
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Affiliation(s)
- Ru-Shan Gao
- National Oceanic and Atmospheric Administration Chemical Sciences Laboratory, Boulder, CO 80305, USA
| | - Karen H Rosenlof
- National Oceanic and Atmospheric Administration Chemical Sciences Laboratory, Boulder, CO 80305, USA.
| | - Bernd Kärcher
- Insititut für Physik der Atmosphäre, DLR Oberpfaffenhofen, Wessling, Germany
| | - Simone Tilmes
- National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Owen B Toon
- Department of Atmospheric and Oceanic Sciences, Laboratory for Atmospheric and Space Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Christopher Maloney
- National Oceanic and Atmospheric Administration Chemical Sciences Laboratory, Boulder, CO 80305, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Pengfei Yu
- Institute for Environmental and Climate Research, Jinan University, Guangzhou, China.
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3
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Bellouin N, Quaas J, Gryspeerdt E, Kinne S, Stier P, Watson‐Parris D, Boucher O, Carslaw KS, Christensen M, Daniau A, Dufresne J, Feingold G, Fiedler S, Forster P, Gettelman A, Haywood JM, Lohmann U, Malavelle F, Mauritsen T, McCoy DT, Myhre G, Mülmenstädt J, Neubauer D, Possner A, Rugenstein M, Sato Y, Schulz M, Schwartz SE, Sourdeval O, Storelvmo T, Toll V, Winker D, Stevens B. Bounding Global Aerosol Radiative Forcing of Climate Change. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2020; 58:e2019RG000660. [PMID: 32734279 PMCID: PMC7384191 DOI: 10.1029/2019rg000660] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/30/2019] [Accepted: 10/03/2019] [Indexed: 05/04/2023]
Abstract
Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol-radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol-driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed-phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of -1.6 to -0.6 W m-2, or -2.0 to -0.4 W m-2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial-era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.
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Affiliation(s)
- N. Bellouin
- Department of MeteorologyUniversity of ReadingReadingUK
| | - J. Quaas
- Institute for MeteorologyUniversität LeipzigLeipzigGermany
| | - E. Gryspeerdt
- Space and Atmospheric Physics GroupImperial College LondonLondonUK
| | - S. Kinne
- Max Planck Institute for MeteorologyHamburgGermany
| | - P. Stier
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
| | - D. Watson‐Parris
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
| | - O. Boucher
- Institut Pierre‐Simon Laplace, Sorbonne Université/CNRSParisFrance
| | - K. S. Carslaw
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
| | - M. Christensen
- Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
| | - A.‐L. Daniau
- EPOC, UMR 5805, CNRS‐Université de BordeauxPessacFrance
| | - J.‐L. Dufresne
- Laboratoire de Météorologie Dynamique/IPSL, CNRS, Sorbonne Université, Ecole Normale Supérieure, PSL Research University, Ecole PolytechniqueParisFrance
| | - G. Feingold
- NOAA ESRL Chemical Sciences DivisionBoulderCOUSA
| | - S. Fiedler
- Max Planck Institute for MeteorologyHamburgGermany
- Now at Institut für Geophysik und MeteorologieUniversität zu KölnKölnGermany
| | - P. Forster
- Priestley International Centre for ClimateUniversity of LeedsLeedsUK
| | - A. Gettelman
- National Center for Atmospheric ResearchBoulderCOUSA
| | - J. M. Haywood
- CEMPSUniversity of ExeterExeterUK
- UK Met Office Hadley CentreExeterUK
| | - U. Lohmann
- Institute for Atmospheric and Climate ScienceETH ZürichZürichSwitzerland
| | | | - T. Mauritsen
- Department of MeteorologyStockholm UniversityStockholmSweden
| | - D. T. McCoy
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
| | - G. Myhre
- Center for International Climate and Environmental Research‐Oslo (CICERO)OsloNorway
| | - J. Mülmenstädt
- Institute for MeteorologyUniversität LeipzigLeipzigGermany
| | - D. Neubauer
- Institute for Atmospheric and Climate ScienceETH ZürichZürichSwitzerland
| | - A. Possner
- Department of Global EcologyCarnegie Institution for ScienceStanfordCAUSA
- Now at Institute for Atmospheric and Environmental SciencesGoethe UniversityFrankfurtGermany
| | | | - Y. Sato
- Department of Applied Energy, Graduate School of Engineering, Nagoya UniversityNagoyaJapan
- Now at Faculty of Science, Department of Earth and Planetary SciencesHokkaido UniversitySapporoJapan
| | - M. Schulz
- Climate Modelling and Air Pollution Section, Research and Development DepartmentNorwegian Meteorological InstituteOsloNorway
| | - S. E. Schwartz
- Brookhaven National Laboratory Environmental and Climate Sciences DepartmentUptonNYUSA
| | - O. Sourdeval
- Institute for MeteorologyUniversität LeipzigLeipzigGermany
- Laboratoire d'Optique AtmosphériqueUniversité de LilleVilleneuve d'AscqFrance
| | - T. Storelvmo
- Department of GeosciencesUniversity of OsloOsloNorway
| | - V. Toll
- Department of MeteorologyUniversity of ReadingReadingUK
- Now at Institute of PhysicsUniversity of TartuTartuEstonia
| | - D. Winker
- NASA Langley Research CenterHamptonVAUSA
| | - B. Stevens
- Max Planck Institute for MeteorologyHamburgGermany
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Mitchell DL, Garnier A, Pelon J, Erfani E. CALIPSO (IIR-CALIOP) Retrievals of Cirrus Cloud Ice Particle Concentrations. ATMOSPHERIC CHEMISTRY AND PHYSICS 2018; 18:17325-17354. [PMID: 31662738 PMCID: PMC6818510 DOI: 10.5194/acp-18-17325-2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A new satellite remote sensing method is described whereby the sensitivity of thermal infrared wave resonance absorption to small ice crystals is exploited to estimate cirrus cloud ice particle number concentration N, effective diameter De, and ice water content IWC. This method uses co-located observations from the Infrared Imaging Radiometer (IIR) and from the CALIOP (Cloud and Aerosol Lidar with Orthogonal Polarization) lidar aboard the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) polar orbiting satellite, employing IIR channels at 10.6 μm and 12.05 μm. Using particle size distributions measured over several flights of the TC4 (Tropical Composition, Cloud and Climate Coupling) and the mid-latitudes SPARTICUS (Small Particles in Cirrus) field campaigns, we show for the first time that N/IWC is tightly related to βeff; the ratio of effective absorption optical depths at 12.05 μm and 10.6 μm. Relationships developed from in situ aircraft measurements are applied to βeff derived from IIR measurements to retrieve N. This satellite remote sensing method is constrained by measurements of βeff from the IIR and is by essence sensitive to the smallest ice crystals. Retrieval uncertainties are discussed, including uncertainties related to in situ measurement of small ice crystals (D < 15 µm), which are studied through comparisons with IIR βeff. The method is applied here to single-layered semi-transparent clouds having a visible optical depth between about 0.3 and 3, where cloud base temperature is ≤ 235 K. Two years of CALIPSO data have been analyzed for the years 2008 and 2013, with the dependence of cirrus cloud N and De on altitude, temperature, latitude, season (winter vs. summer) and topography (land vs. ocean) described. The results for the mid-latitudes show a considerable dependence on season. In the high latitudes, N tends to be highest and De smallest, whereas the opposite is true for the tropics. The frequency of occurrence of these relatively thick cirrus clouds exhibited a strong seasonal dependence in the high latitudes, with the occurrence frequency during Arctic winter being at least twice that of any other season. Processes that could potentially explain some of these micro-and macroscopic cloud phenomena are discussed.
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Affiliation(s)
| | - Anne Garnier
- Science Systems and Applications, Inc., Hampton, Virginia, USA
- NASA Langley Research Center, Hampton, Virginia, USA
| | - Jacques Pelon
- Laboratoire Atmosphères, Milieux, Observations Spatiales, Sorbonne Université, CNRS, Paris, France
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5
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Penner JE, Zhou C, Garnier A, Mitchell DL. Anthropogenic Aerosol Indirect Effects in Cirrus Clouds. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2018; 123:11652-11677. [PMID: 30775191 PMCID: PMC6360521 DOI: 10.1029/2018jd029204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 05/04/2023]
Abstract
We have implemented a parameterization for forming ice in large-scale cirrus clouds that accounts for the changes in updrafts associated with a spectrum of waves acting within each time step in the model. This allows us to account for the frequency of homogeneous and heterogeneous freezing events that occur within each time step of the model and helps to determine more realistic ice number concentrations as well as changes to ice number concentrations. The model is able to fit observations of ice number at the lowest temperatures in the tropical tropopause but is still somewhat high in tropical latitudes with temperatures between 195°K and 215°K. The climate forcings associated with different representations of heterogeneous ice nuclei (IN or INPs) are primarily negative unless large additions of IN are made, such as when we assumed that all aircraft soot acts as an IN. However, they can be close to zero if it is assumed that all background dust can act as an INP irrespective of how much sulfate is deposited on these particles. Our best estimate for the forcing of anthropogenic aircraft soot in this model is -0.2 ± 0.06 W/m2, while that from anthropogenic fossil/biofuel soot is -0.093 ± 0.033 W/m2. Natural and anthropogenic open biomass burning leads to a net forcing of -0.057 ± 0.05 W/m2.
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Affiliation(s)
- Joyce E. Penner
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - Cheng Zhou
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - Anne Garnier
- Science Systems and Applications, Inc.HamptonVAUSA
- NASA Langley Research CenterHamptonVAUSA
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6
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Woods S, Lawson RP, Jensen E, Bui TP, Thornberry T, Rollins A, Pfister L, Avery M. Microphysical Properties of Tropical Tropopause Layer Cirrus. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2018; 123:6053-6069. [PMID: 31832294 PMCID: PMC6907018 DOI: 10.1029/2017jd028068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/23/2018] [Indexed: 05/13/2023]
Abstract
Pervasive cirrus clouds in the tropical tropopause layer (TTL) play an important role in determining the composition of stratospheric air through dehydration of tropospheric air entering the stratosphere. This dehydration affects Earth's energy budget and climate, yet uncertainties remain regarding the microphysical processes that govern TTL cirrus. TTL cirrus were sampled with the NASA Global Hawk UAV for over 30 hr in the Western Pacific in 2014 during the Airborne Tropical TRopopause EXperiment. In situ measurements by a Fast Cloud Droplet Probe and Hawkeye probe (combination Fast Cloud Droplet Probe, Two-Dimensional Stereo optical array probe, and Cloud Particle Imager) provided particle concentrations and sizing between 1- and 1,280-μm diameter and high resolution images for habit identification. We present the variability in ice concentrations, size distributions, and habits as functions of temperature, altitude, and time since convective influence. Observed ice particles were predominantly small and quasi-spheroidal in shape, with the percentage of quasi-spheroids increasing with decreasing temperature. In comparison to the large fraction of the population consisting of quasi-spheroids, faceted habits (columns, plates, rosettes, and budding rosettes) constituted a smaller percentage of the overall population and exhibited the opposite correlation with temperature. The trend of higher percentages of faceted crystals occurring at warmer temperatures may be due to diffusional growth or aggregation as particles descend through cloud, and/or the more rapid diffusional growth rate at warmer temperatures. Sampling was typically well away from deep convection, however, and very few aggregates were observed, so the trend of higher percentages of faceted habits is likely attributable to diffusional growth.
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Affiliation(s)
| | | | - Eric Jensen
- NASA Ames Research Center, Moffet Field, CA, USA
| | - T P Bui
- NASA Ames Research Center, Moffet Field, CA, USA
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7
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Rivera-Valentín EG, Gough RV, Chevrier VF, Primm KM, Martínez GM, Tolbert M. Constraining the Potential Liquid Water Environment at Gale Crater, Mars. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2018; 123:1156-1167. [PMID: 33294305 PMCID: PMC7720553 DOI: 10.1002/2018je005558] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/26/2018] [Indexed: 05/28/2023]
Abstract
The Mars Science Laboratory (MSL) Rover Environmental Monitoring Station (REMS) has now made continuous in situ meteorological measurements for several Martian years at Gale crater, Mars. Of importance in the search for liquid formation are REMS' measurements of ground temperature and in-air measurements of temperature and relative humidity, which is with respect to ice. Such data can constrain the surface and subsurface stability of brines. Here we use updated calibrations to REMS data and consistent relative humidity comparisons (i.e., with respect to liquid versus with respect to ice) to investigate the potential formation of surface and subsurface liquids throughout MSL's traverse. We specifically study the potential for the deliquescence of calcium perchlorate. Our data analysis suggests that surface brine formation is not favored within the first 1648 sols as there are only two times (sols 1232 and 1311) when humidity-temperature conditions were within error consistent with a liquid phase. On the other hand, modeling of the subsurface environment would support brine production in the shallow subsurface. Indeed, we find that the shallow subsurface for terrains with low thermal inertia (Γ ≲ 300 J m-2 K-1 s-1/2) may be occasionally favorable to brine formation through deliquescence. Terrains with Γ ≲ 175 J m-2 K-1 s-1/2 and albedos of ≳0.25 are the most apt to subsurface brine formation. Should brines form, they would occur around Ls 100°. Their predicted properties would not meet the Special nor Uncertain Region requirements, as such they would not be potential habitable environments to life as we know it.
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Affiliation(s)
- Edgard G Rivera-Valentín
- Arecibo Observatory, Universities Space Research Association, Arecibo, PR, USA
- Lunar and Planetary Institute, Universities Space Research Association, Houston, TX, USA
| | - Raina V Gough
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Vincent F Chevrier
- Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Katherine M Primm
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - German M Martínez
- Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Margaret Tolbert
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO, USA
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Zhao B, Gu Y, Liou KN, Wang Y, Liu X, Huang L, Jiang JH, Su H. Type-Dependent Responses of Ice Cloud Properties to Aerosols From Satellite Retrievals. GEOPHYSICAL RESEARCH LETTERS 2018; 45:3297-3306. [PMID: 31631917 PMCID: PMC6800730 DOI: 10.1002/2018gl077261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/24/2018] [Indexed: 05/25/2023]
Abstract
Aerosol-cloud interactions represent one of the largest uncertainties in external forcings on our climate system. Compared with liquid clouds, the observational evidence for the aerosol impact on ice clouds is much more limited and shows conflicting results, partly because the distinct features of different ice cloud and aerosol types were seldom considered. Using 9-year satellite retrievals, we find that, for convection-generated (anvil) ice clouds, cloud optical thickness, cloud thickness, and cloud fraction increase with small-to-moderate aerosol loadings (<0.3 aerosol optical depth) and decrease with further aerosol increase. For in situ formed ice clouds, however, these cloud properties increase monotonically and more sharply with aerosol loadings. An increase in loading of smoke aerosols generally reduces cloud optical thickness of convection-generated ice clouds, while the reverse is true for dust and anthropogenic pollution aerosols. These relationships between different cloud/aerosol types provide valuable constraints on the modeling assessment of aerosol-ice cloud radiative forcing.
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Affiliation(s)
- Bin Zhao
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
- Jet propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Yu Gu
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
| | - Kuo-Nan Liou
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
| | - Yuan Wang
- Jet propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
| | - Xiaohong Liu
- Department of Atmospheric Science, University of Wyoming, Laramie, WY, USA
| | - Lei Huang
- Joint Institute for Regional Earth System Science and Engineering and Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
- Jet propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Jonathan H Jiang
- Jet propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Hui Su
- Jet propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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Barahona D, Molod A, Kalesse H. Direct estimation of the global distribution of vertical velocity within cirrus clouds. Sci Rep 2017; 7:6840. [PMID: 28754986 PMCID: PMC5533806 DOI: 10.1038/s41598-017-07038-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 06/21/2017] [Indexed: 12/03/2022] Open
Abstract
Cirrus clouds determine the radiative balance of the upper troposphere and the transport of water vapor across the tropopause. The representation of vertical wind velocity, W, in atmospheric models constitutes the largest source of uncertainty in the calculation of the cirrus formation rate. Using global atmospheric simulations with a spatial resolution of 7 km we obtain for the first time a direct estimate of the distribution of W at the scale relevant for cirrus formation, validated against long-term observations at two different ground sites. The standard deviation in W, σw, varies widely over the globe with the highest values resulting from orographic uplift and convection, and the lowest occurring in the Arctic. Globally about 90% of the simulated σw values are below 0.1 m s−1 and about one in 104 cloud formation events occur in environments with σw > 0.8 m s−1. Combining our estimate with reanalysis products and an advanced cloud formation scheme results in lower homogeneous ice nucleation frequency than previously reported, and a decreasing average ice crystal concentration with decreasing temperature. These features are in agreement with observations and suggest that the correct parameterization of σw is critical to simulate realistic cirrus properties.
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Affiliation(s)
- Donifan Barahona
- Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA.
| | - Andrea Molod
- Global Modeling and Assimilation Office, NASA Goddard Space Flight Center, Greenbelt, MD, USA
| | - Heike Kalesse
- Leibniz Institute for Tropospheric Research, Leipzig, Germany
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10
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Jensen EJ, Thornberry T, Rollins A, Ueyama R, Pfister L, Bui TV, Diskin GS, DiGangi JP, Hintsa E, Gao RS, Woods S, Lawson RP, Pittman J. Physical Processes Controlling the Vertical and Longitudinal Distributions of Relative Humidity in the Tropical Tropopause Layer Over the Pacific. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2017; 122:6094-6107. [PMID: 31534878 PMCID: PMC6749611 DOI: 10.1002/2017jd026632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The vertical distribution of relative humidity with respect to ice (RHI) in the Boreal wintertime Tropical Tropopause Layer (TTL, ≃14-18 km) over the Pacific is examined with the extensive dataset of measurements from the NASA Airborne Tropical TRopopause EXperiment (ATTREX). Multiple deployments of the Global Hawk during ATTREX provided hundreds of vertical profiles spanning the longitudinal extent of the Pacific with accurate measurements of temperature, pressure, water vapor concentration, ozone concentration, and cloud properties. We also compare the measured RHI distributions with results from a transport and microphysical model driven by meteorological analysis fields. Notable features in the distribution of RHI versus temperature and longitude include (1) the common occurrence of RHI values near ice saturation over the western Pacific in the lower-middle TTL (temperatures greater than 195 K); (2) low RHI values in the lower TTL over the central and eastern Pacific; (3) common occurrence of RHI values following a constant mixing ratio in the middle-to-upper TTL (temperatures between about 190 and 200 K), particularly for samples with ozone greater than about 50-100 ppbv indicating mixtures of tropospheric and stratospheric air; (4) RHI values typically near ice saturation in the coldest airmasses sampled (temperatures less than about 190 K); and (5) common occurrence of RHI values near 100% across the TTL temperature range in air parcels with low ozone mixing ratio (O3 < 50 ppbv) indicative of recent uplift by deep convection. We suggest that the typically saturated air in the lower TTL over the western Pacific is likely driven by a combination of the frequent occurrence of deep convection and the predominance of radiative heating (rising motion) in this region. The low relative humidities in the central/eastern Pacific lower TTL result from the lack of convective influence, the predominance of subsidence, and the relatively warm temperatures in the region. The nearly-constant water vapor mixing ratios in the middle-to-upper TTL likely result from the combination of slow ascent (resulting in long residence times) and wave driven temperature variability on a range of time scales (resulting in most air parcels having experienced low temperature and dehydration). The numerical simulations generally reproduce the observed RHI distribution features and sensitivity tests further emphasize the strong sensitivities of TTL relative humidity to convective input and vertical motions.
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Affiliation(s)
- Eric J Jensen
- NASA Ames Research Center, Moffett Field, California, USA
| | | | | | - Rei Ueyama
- NASA Ames Research Center, Moffett Field, California, USA
| | | | - Theopaul V Bui
- NASA Ames Research Center, Moffett Field, California, USA
| | - Glenn S Diskin
- NOAA Earth Science Research Laboratory and Cooperative Institute for Research in Environmental Science, Boulder, Colorado, USA
| | - Joshua P DiGangi
- NOAA Earth Science Research Laboratory and Cooperative Institute for Research in Environmental Science, Boulder, Colorado, USA
| | - Eric Hintsa
- NASA Langley Research Center, Hampton, Virginia, USA
| | - Ru-Shan Gao
- NOAA Earth Science Research Laboratory, Boulder, Colorado, USA
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Jensen EJ, Pfister L, Jordan DE, Bui TV, Ueyama R, Singh HB, Thornberry TD, Rollins AW, Gao RS, Fahey DW, Rosenlof KH, Elkins JW, Diskin GS, DiGangi JP, Lawson RP, Woods S, Atlas EL, Navarro Rodriguez MA, Wofsy SC, Pittman J, Bardeen CG, Toon OB, Kindel BC, Newman PA, McGill MJ, Hlavka DL, Lait LR, Schoeberl MR, Bergman JW, Selkirk HB, Alexander MJ, Kim JE, Lim BH, Stutz J, Pfeilsticker K. THE NASA AIRBORNE TROPICAL TROPOPAUSE EXPERIMENT: High-Altitude Aircraft Measurements in the Tropical Western Pacific. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 2017; 98:129-143. [PMID: 32699427 PMCID: PMC7375333 DOI: 10.1175/bams-d-14-00263.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Abstract
The February–March 2014 deployment of the National Aeronautics and Space Administration (NASA) Airborne Tropical Tropopause Experiment (ATTREX) provided unique in situ measurements in the western Pacific tropical tropopause layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the Convective Transport of Active Species in the Tropics (CONTRAST) and the Coordinated Airborne Studies in the Tropics (CAST) airborne campaigns based in Guam using lower-altitude aircraft (see companion articles in this issue). The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes, as well as for evaluation and improvement of global-model representations of TTL processes. The ATTREX data are publicly available online (at https://espoarchive.nasa.gov/).
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Affiliation(s)
- Eric J Jensen
- NASA Ames Research Center, Moffett Field, California
| | | | | | | | - Rei Ueyama
- NASA Ames Research Center, Moffett Field, California
| | | | - Troy D Thornberry
- NOAA/Earth System Research Laboratory, and Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado
| | - Andrew W Rollins
- NOAA/Earth System Research Laboratory, and Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado
| | - Ru-Shan Gao
- NOAA/Earth System Research Laboratory, Boulder, Colorado
| | - David W Fahey
- NOAA/Earth System Research Laboratory, Boulder, Colorado
| | | | - James W Elkins
- NOAA/Earth System Research Laboratory, Boulder, Colorado
| | | | | | | | | | | | | | | | | | | | - Owen B Toon
- University of Colorado Boulder, Boulder, Colorado
| | | | - Paul A Newman
- NASA Goddard Space Flight Center, Greenbelt, Maryland
| | | | | | | | | | - John W Bergman
- Bay Area Environmental Research Institute, Sonoma, California
| | | | - M Joan Alexander
- NorthWest Research Associates, Colorado Research Associates Office, Boulder, Colorado
| | - Ji-Eun Kim
- NorthWest Research Associates, Colorado Research Associates Office, Boulder, Colorado
| | - Boon H Lim
- Jet Propulsion Laboratory, Pasadena, California
| | - Jochen Stutz
- University of California, Los Angeles, Los Angeles, California
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12
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Hegglin MI, Plummer DA, Shepherd TG, Scinocca JF, Anderson J, Froidevaux L, Funke B, Hurst D, Rozanov A, Urban J, von Clarmann T, Walker KA, Wang HJ, Tegtmeier S, Weigel K. Vertical structure of stratospheric water vapour trends derived from merged satellite data. NATURE GEOSCIENCE 2014; 7:768-776. [PMID: 29263751 PMCID: PMC5734650 DOI: 10.1038/ngeo2236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/29/2014] [Indexed: 05/25/2023]
Abstract
Stratospheric water vapour is a powerful greenhouse gas. The longest available record from balloon observations over Boulder, Colorado, USA shows increases in stratospheric water vapour concentrations that cannot be fully explained by observed changes in the main drivers, tropical tropopause temperatures and methane. Satellite observations could help resolve the issue, but constructing a reliable long-term data record from individual short satellite records is challenging. Here we present an approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology. We use the models' water vapour as a transfer function between data sets that overcomes issues arising from instrument drift and short overlap periods. In the lower stratosphere, our water vapour record extends back to 1988 and water vapour concentrations largely follow tropical tropopause temperatures. Lower and mid-stratospheric long-term trends are negative, and the trends from Boulder are shown not to be globally representative. In the upper stratosphere, our record extends back to 1986 and shows positive long-term trends. The altitudinal differences in the trends are explained by methane oxidation together with a strengthened lower-stratospheric and a weakened upper-stratospheric circulation inferred by this analysis. Our results call into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere.
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Affiliation(s)
- M I Hegglin
- University of Reading, Department of Meteorology, Reading RG6 6BB, UK
| | - D A Plummer
- Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia V8W 3V6, Canada
| | - T G Shepherd
- University of Reading, Department of Meteorology, Reading RG6 6BB, UK
| | - J F Scinocca
- Canadian Centre for Climate Modelling and Analysis, Victoria, British Columbia V8W 3V6, Canada
| | - J Anderson
- Hampton University, Atmospheric and Planetary Science, Hampton, Virginia 23668, USA
| | - L Froidevaux
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91020, USA
| | - B Funke
- Instituto de Astrofisica de Andalucia, Granada 18008, Spain
| | - D Hurst
- NOAA Earth System Research Laboratory, Global Monitoring Divison, Boulder, Colorado 80305, USA
| | - A Rozanov
- University of Bremen, Institute of Environmental Physics, Bremen 28334, Germany
| | - J Urban
- Chalmers University of Technology, Department of Earth and Space Sciences, Gothenburg, 412 96, Sweden
| | - T von Clarmann
- Karlsruhe Institute of Technology, Karlsruhe 76021, Germany
| | - K A Walker
- University of Toronto, Toronto M5S 1A7, Canada
| | - H J Wang
- Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, Georgia 30332-0340, USA
| | | | - K Weigel
- University of Bremen, Institute of Environmental Physics, Bremen 28334, Germany
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