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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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Schoeberl MR, Jensen EJ, Pfister L, Ueyama R, Wang T, Selkirk H, Avery M, Thornberry T, Dessler AE. Water Vapor, Clouds, and Saturation in the Tropical Tropopause Layer. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:3984-4003. [PMID: 33868885 PMCID: PMC8051107 DOI: 10.1029/2018jd029849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 03/06/2019] [Indexed: 06/12/2023]
Abstract
The goal of this investigation is to understand the mechanism behind the observed high relative humidity with respect to ice (RHi) in the tropical region between ~14 km (150 hPa) and the tropopause, often referred to as the tropical tropopause layer (TTL). As shown by satellite, aircraft and balloon observations, high (>80%) RHi regions are widespread within the TTL. Regions with the highest RHi are co-located with extensive cirrus. During boreal winter, the TTL RHi is highest over the Tropical Western Pacific (TWP) with a weaker maximum over South America and Africa. In the winter, TTL temperatures are coldest and upward motion is the greatest in the TWP. It is this upward motion, driving humid air into the colder upper troposphere that produces the persistent high RHi and cirrus formation. Back trajectory calculations show that comparable adiabatic and diabatic processes contribute to this upward motion. We construct a bulk model of TWP TTL water vapor transport that includes cloud nucleation and ice microphysics that quantifies how upward motion drives the persistent high RHi in the TTL region. We find that atmospheric waves triggering cloud formation regulate the RHi, and that convection dehydrates the TTL. Our forward domain-filling trajectory (FDF) model is used to more precisely simulate the TTL spatial and vertical distribution of RHi. The observed RHi distribution is reproduced by the model and we show that convection increases RHi below the base of the TTL with little impact on the RHi in the TTL region.
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Affiliation(s)
| | - E. J. Jensen
- NASA Ames Research Center, Moffett Field, CA, USA
| | - L. Pfister
- NASA Ames Research Center, Moffett Field, CA, USA
| | - R. Ueyama
- NASA Ames Research Center, Moffett Field, CA, USA
| | - T. Wang
- Goddard Space Flight Center, Greenbelt, MD, USA
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | - H. Selkirk
- Goddard Space Flight Center, Greenbelt, MD, USA
- Universities Space Research Association, Columbia, MD, USA
| | | | - T. Thornberry
- NOAA Earth System Research Laboratory, and Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, Boulder, CO, USA
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Hossaini R, Atlas E, Dhomse SS, Chipperfield MP, Bernath PF, Fernando AM, Mühle J, Leeson AA, Montzka SA, Feng W, Harrison JJ, Krummel P, Vollmer MK, Reimann S, O'Doherty S, Young D, Maione M, Arduini J, Lunder CR. Recent Trends in Stratospheric Chlorine From Very Short-Lived Substances. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:2318-2335. [PMID: 30984484 PMCID: PMC6446807 DOI: 10.1029/2018jd029400] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 05/15/2023]
Abstract
Very short-lived substances (VSLS), including dichloromethane (CH2Cl2), chloroform (CHCl3), perchloroethylene (C2Cl4), and 1,2-dichloroethane (C2H4Cl2), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCltot) using a chemical transport model and atmospheric measurements, including novel high-altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCltot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to the stratosphere through source gas injection, and the remainder from product gases. The modeled evolution of chlorine source gas injection agrees well with historical aircraft data, which corroborate reported surface CH2Cl2 increases since the mid-2000s. The relative contribution of VSLS to total stratospheric chlorine increased from ~2% in 2000 to ~3.4% in 2017, reflecting both VSLS growth and decreases in long-lived halocarbons. We derive a mean VSLCltot growth rate of 3.8 (±0.3) ppt Cl/year between 2004 and 2017, though year-to-year growth rates are variable and were small or negative in the period 2015-2017. Whether this is a transient effect, or longer-term stabilization, requires monitoring. In the upper stratosphere, the modeled rate of HCl decline (2004-2017) is -5.2% per decade with VSLS included, in good agreement to ACE satellite data (-4.8% per decade), and 15% slower than a model simulation without VSLS. Thus, VSLS have offset a portion of stratospheric chlorine reductions since the mid-2000s.
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Affiliation(s)
- Ryan Hossaini
- Lancaster Environment CentreLancaster UniversityLancasterUK
| | - Elliot Atlas
- Rosenstiel School of Marine and Atmospheric Science (RSMAS)University of MiamiCoral GablesFLUSA
| | | | | | - Peter F. Bernath
- Department of Chemistry and BiochemistryOld Dominion UniversityNorfolkVAUSA
- Department of ChemistryUniversity of WaterlooWaterlooONCanada
| | | | - Jens Mühle
- Scripps Institution of OceanographyUniversity of California San DiegoLa JollaCAUSA
| | | | | | - Wuhu Feng
- School of Earth and EnvironmentUniversity of LeedsLeedsUK
- NCASUniversity of LeedsLeedsUK
| | - Jeremy J. Harrison
- Department of Physics and AstronomyUniversity of LeicesterLeicesterUK
- National Centre for Earth ObservationUniversity of LeicesterLeicesterUK
| | - Paul Krummel
- Climate Science CentreCSIRO Oceans and AtmosphereAspendaleVictoriaAustralia
| | - Martin K. Vollmer
- Laboratory for Air Pollution and Environmental TechnologyEmpa, Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfSwitzerland
| | - Stefan Reimann
- Laboratory for Air Pollution and Environmental TechnologyEmpa, Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfSwitzerland
| | | | - Dickon Young
- School of ChemistryUniversity of BristolBristolUK
| | - Michela Maione
- Department of Pure and Applied SciencesUniversity of UrbinoUrbinoItaly
| | - Jgor Arduini
- Department of Pure and Applied SciencesUniversity of UrbinoUrbinoItaly
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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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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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Pan LL, Atlas EL, Salawitch RJ, Honomichl SB, Bresch JF, Randel WJ, Apel EC, Hornbrook RS, Weinheimer AJ, Anderson DC, Andrews SJ, Baidar S, Beaton SP, Campos TL, Carpenter LJ, Chen D, Dix B, Donets V, Hall SR, Hanisco TF, Homeyer CR, Huey LG, Jensen JB, Kaser L, Kinnison DE, Koenig TK, Lamarque JF, Liu C, Luo J, Luo ZJ, Montzka DD, Nicely JM, Pierce RB, Riemer DD, Robinson T, Romashkin P, Saiz-Lopez A, Schauffler S, Shieh O, Stell MH, Ullmann K, Vaughan G, Volkamer R, Wolfe G. The Convective Transport of Active Species in the Tropics (CONTRAST) Experiment. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 2017; 98:106-128. [PMID: 29636590 PMCID: PMC5889942 DOI: 10.1175/bams-d-14-00272.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5° N, 144.8° E) during January-February 2014. Using the NSF/NCAR Gulfstream V research aircraft, the experiment investigated the photochemical environment over the tropical western Pacific (TWP) warm pool, a region of massive deep convection and the major pathway for air to enter the stratosphere during Northern Hemisphere (NH) winter. The new observations provide a wealth of information for quantifying the influence of convection on the vertical distributions of active species. The airborne in situ measurements up to 15 km altitude fill a significant gap by characterizing the abundance and altitude variation of a wide suite of trace gases. These measurements, together with observations of dynamical and microphysical parameters, provide significant new data for constraining and evaluating global chemistry climate models. Measurements include precursor and product gas species of reactive halogen compounds that impact ozone in the upper troposphere/lower stratosphere. High accuracy, in-situ measurements of ozone obtained during CONTRAST quantify ozone concentration profiles in the UT, where previous observations from balloon-borne ozonesondes were often near or below the limit of detection. CONTRAST was one of the three coordinated experiments to observe the TWP during January-February 2014. Together, CONTRAST, ATTREX and CAST, using complementary capabilities of the three aircraft platforms as well as ground-based instrumentation, provide a comprehensive quantification of the regional distribution and vertical structure of natural and pollutant trace gases in the TWP during NH winter, from the oceanic boundary to the lower stratosphere.
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Affiliation(s)
- L L Pan
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | | | | | - S B Honomichl
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - J F Bresch
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - W J Randel
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - E C Apel
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - R S Hornbrook
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - A J Weinheimer
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - D C Anderson
- University of Maryland, College Park, Maryland, USA
| | | | - S Baidar
- University of Colorado Boulder, Boulder, Colorado, USA
| | - S P Beaton
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T L Campos
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | | | - D Chen
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | - B Dix
- University of Colorado Boulder, Boulder, Colorado, USA
| | - V Donets
- University of Miami, Florida, USA
| | - S R Hall
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T F Hanisco
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
| | - C R Homeyer
- University of Oklahoma, Norman, Oklahoma, USA
| | - L G Huey
- Georgia Institute of Technology, Atlanta, Georgia, USA
| | - J B Jensen
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - L Kaser
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - D E Kinnison
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - T K Koenig
- University of Colorado Boulder, Boulder, Colorado, USA
| | - J-F Lamarque
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - C Liu
- Texas A&M University at Corpus Christi, Texas, USA
| | - J Luo
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - Z J Luo
- City College of New York, New York, New York, USA
| | - D D Montzka
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - J M Nicely
- University of Maryland, College Park, Maryland, USA
| | - R B Pierce
- NOAA Satellite and Information Service (NESDIS) Center for Satellite Applications and Research (STAR), Madison Wisconsin, USA
| | | | - T Robinson
- University of Hawaii at Mānoa, Hawaii, USA
| | - P Romashkin
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - A Saiz-Lopez
- Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain
| | - S Schauffler
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - O Shieh
- University of Hawaii at Mānoa, Hawaii, USA
| | - M H Stell
- National Center for Atmospheric Research, Boulder, Colorado, USA
- Metropolitan State University, Denver, Colorado, USA
| | - K Ullmann
- National Center for Atmospheric Research, Boulder, Colorado, USA
| | - G Vaughan
- University of Manchester, Manchester, UK
| | - R Volkamer
- University of Colorado Boulder, Boulder, Colorado, USA
| | - G Wolfe
- NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
- University of Maryland Baltimore County, Baltimore, Maryland, USA
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