Ice nucleation and dehydration in the Tropical Tropopause Layer
Eric J. Jensen,Glenn S. Diskin,R. Paul Lawson,Sara Lance,T. Paul Bui,Dennis L. Hlavka,Matthew J. McGill,Leonhard Pfister,Owen B. Toon,Ru-Shan Gao +9 more
TLDR
Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth’s radiation budget and climate.Abstract:
Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to ∼70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L(-1) (often less than 20 L(-1)), whereas the high ice concentration layers (with concentrations up to 10,000 L(-1)) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as ∼1.7 times the ice saturation mixing ratio.read more
Citations
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Bounding global aerosol radiative forcing of climate change
Nicolas Bellouin,Johannes Quaas,Edward Gryspeerdt,Stefan Kinne,Philip Stier,Duncan Watson-Parris,Olivier Boucher,Kenneth S. Carslaw,Matthew Christensen,Anne-Laure Daniau,Jean-Louis Dufresne,Graham Feingold,Stephanie Fiedler,Stephanie Fiedler,Piers M. Forster,Andrew Gettelman,Jim Haywood,Jim Haywood,Ulrike Lohmann,Florent Malavelle,Thorsten Mauritsen,Daniel T. McCoy,G. Myhre,Johannes Mülmenstädt,David Neubauer,Anna Possner,Anna Possner,Maria Rugenstein,Yousuke Sato,Yousuke Sato,Michael Schulz,Stephen E. Schwartz,Odran Sourdeval,Odran Sourdeval,Trude Storelvmo,Velle Toll,Velle Toll,David M. Winker,Bjorn Stevens +38 more
TL;DR: A new range of aerosol radiative forcing over the industrial era is provided based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations, to constrain the forcing from aerosol‐radiation interactions.
Journal ArticleDOI
Physical processes in the tropical tropopause layer and their roles in a changing climate
William J. Randel,Eric J. Jensen +1 more
TL;DR: In this article, a synthesis report concludes that transport and mixing in the tropopause region are closely linked with the Asian monsoon and other tropical circulation systems, with possible implications for the impacts of climate change on this important layer.
Journal ArticleDOI
A microphysics guide to cirrus clouds – Part 1: Cirrus types
Martina Krämer,Christian Rolf,Anna Luebke,Armin Afchine,Nicole Spelten,Anja Costa,Jessica Meyer,Martin Zöger,Jessica Smith,Robert L. Herman,Bernhard Buchholz,Bernhard Buchholz,Volker Ebert,Darrel Baumgardner,Stephan Borrmann,Marcus Klingebiel,Marcus Klingebiel,L. Avallone,L. Avallone +18 more
TL;DR: In this paper, an extensive set of model simulations, covering the broad range of atmospheric conditions for cirrus formation and evolution, are presented in the same parameter space as field measurements, i.e., in the Ice Water Content-Temperature (IWC-T) parameter space.
Journal ArticleDOI
Vertical structure of stratospheric water vapour trends derived from merged satellite data.
Michaela I. Hegglin,David A. Plummer,Theodore G. Shepherd,John F. Scinocca,John Anderson,Lucien Froidevaux,Bernd Funke,Dale F. Hurst,A. Rozanov,Joachim Urban,T. von Clarmann,Kaley A. Walker,H. J. Wang,Susann Tegtmeier,Katja Weigel +14 more
TL;DR: An approach to merge satellite data sets with the help of a chemistry-climate model nudged to observed meteorology is presented, calling into question previous estimates of surface radiative forcing based on presumed global long-term increases in water vapour concentrations in the lower stratosphere.
Journal ArticleDOI
A microphysics guide to cirrus – Part 2: Climatologies of clouds and humidity from observations
Martina Krämer,Christian Rolf,Nicole Spelten,Armin Afchine,David W. Fahey,Eric J. Jensen,Sergey Khaykin,Thomas Kuhn,Paul Lawson,Alexey Lykov,Laura L. Pan,Martin Riese,Andrew W. Rollins,Fred Stroh,Troy Thornberry,Veronika Wolf,Sarah Woods,Peter Spichtinger,Johannes Quaas,Odran Sourdeval +19 more
TL;DR: In this article, an extensive, quality checked data archive, the Cirrus Guide II in-situ data base, is created from airborne in-Situ measurements during 150 flights in 24 campaigns and contains meteorological parameters, IWC, Nice, Rice, RHice and H2O for each of the flights.
References
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Journal ArticleDOI
Evidence for a world circulation provided by the measurements of helium and water vapour distribution in the stratosphere
TL;DR: In this article, the authors studied the vertical distribution of water vapour and helium in the lower stratosphere over southern England and found that the helium content of the air is remarkably constant up to 20 km but the water content is found to fall very rapidly just above the tropopause, and in the lowest 1 km of the stratosphere the humidity mixing ratio falls through a ratio of 10-1.
Journal ArticleDOI
Water activity as the determinant for homogeneous ice nucleation in aqueous solutions
TL;DR: This work shows from experimental data that the homogeneous nucleation of ice from supercooled aqueous solutions is independent of the nature of the solute, but depends only on the water activity of the solution, and presents a thermodynamic theory for homogeneous ice nucleation, which expresses the nucleation rate coefficient as a function of water activity and pressure.
Journal ArticleDOI
Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming
Susan Solomon,Karen H. Rosenlof,Robert W. Portmann,John S. Daniel,Sean M. Davis,Sean M. Davis,Todd Sanford,Todd Sanford,Gian-Kasper Plattner +8 more
TL;DR: It is shown that stratospheric water vapor is an important driver of decadal global surface climate change, by acting to slow the rate of warming by about 25% compared to that which would have occurred due only to carbon dioxide and other greenhouse gases.
Journal ArticleDOI
An atmospheric tape recorder: The imprint of tropical tropopause temperatures on stratospheric water vapor
Philip W. Mote,Karen H. Rosenlof,Michael E. McIntyre,Ewan S. Carr,John C. Gille,James R. Holton,Jonathan S. Kinnersley,Hugh C. Pumphrey,James M. Russell,Joe W. Waters +9 more
TL;DR: In this paper, the authors describe observations of tropical stratospheric water vapor q that show clear evidence of large-scale upward advection of the signal from annual fluctuations in the effective "entry mixing ratio" qE of air entering the tropical stratosphere.
Journal ArticleDOI
Measurements of the concentration and composition of nuclei for cirrus formation
Paul J. DeMott,Daniel J. Cziczo,Anthony J. Prenni,D. M. Murphy,Sonia M. Kreidenweis,David S. Thomson,Randolph D. Borys,D. C. Rogers +7 more
TL;DR: Simultaneous measurements of the concentration and composition of tropospheric aerosol particles capable of initiating ice in cold (cirrus) clouds are reported, suggesting a predominant potential impact of these nuclei on cirrus formed by slow, large-scale lifting or small cooling rates, including subvisual cirrus.