Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer
An abrupt drop in tropical tropopause layer (TTL) water vapor, similar to that observed in 2000, recently occurred in 2011, and was concurrent with reductions in TTL temperature and ozone. Previous studies have indicated that such large water vapor variability can have significant radiative impacts....
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Meteorological Society
2017
|
| Online Access: | http://hdl.handle.net/1721.1/108125 https://orcid.org/0000-0003-2422-0887 https://orcid.org/0000-0002-2020-7581 |
| _version_ | 1826205092275027968 |
|---|---|
| author | Portmann, Robert W. Gilford, Daniel Michael Solomon, Susan |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Portmann, Robert W. Gilford, Daniel Michael Solomon, Susan |
| author_sort | Portmann, Robert W. |
| collection | MIT |
| description | An abrupt drop in tropical tropopause layer (TTL) water vapor, similar to that observed in 2000, recently occurred in 2011, and was concurrent with reductions in TTL temperature and ozone. Previous studies have indicated that such large water vapor variability can have significant radiative impacts. This study uses Aura Microwave Limb Sounder observations, the Stratospheric Water Vapor and Ozone Satellite Homogenized dataset, and two radiative transfer models to examine the radiative effects of the observed changes in TTL water vapor and ozone on TTL temperatures and global radiative forcing (RF). The analyses herein suggest that quasi-isentropic poleward propagation of TTL water vapor reductions results in a zonal-mean structure with “wings” of extratropical water vapor reductions, which account for about half of the 2011 abrupt drop global radiative impact. RF values associated with the mean water vapor concentrations differences between 2012/13 and 2010/11 are between −0.01 and −0.09 W m⁻², depending upon the altitude above which perturbations are considered. TTL water vapor and ozone variability during this period jointly lead to a transient radiative cooling of ~0.25–0.5 K in layers below the tropopause. The 2011 abrupt drop also prolonged the reduction in stratospheric water vapor that followed the 2000 abrupt drop, providing a longer-term radiative forcing of climate. Water vapor concentrations from 2005 to 2013 are lower than those from 1990 to 1999, resulting in a RF between these periods of about −0.045 W m⁻², approximately 12% as large as, but of opposite sign to, the concurrent estimated CO[subscript 2] forcing. |
| first_indexed | 2024-09-23T13:06:37Z |
| format | Article |
| id | mit-1721.1/108125 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:06:37Z |
| publishDate | 2017 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1081252022-10-01T13:08:13Z Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer Portmann, Robert W. Gilford, Daniel Michael Solomon, Susan Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Gilford, Daniel Michael Solomon, Susan An abrupt drop in tropical tropopause layer (TTL) water vapor, similar to that observed in 2000, recently occurred in 2011, and was concurrent with reductions in TTL temperature and ozone. Previous studies have indicated that such large water vapor variability can have significant radiative impacts. This study uses Aura Microwave Limb Sounder observations, the Stratospheric Water Vapor and Ozone Satellite Homogenized dataset, and two radiative transfer models to examine the radiative effects of the observed changes in TTL water vapor and ozone on TTL temperatures and global radiative forcing (RF). The analyses herein suggest that quasi-isentropic poleward propagation of TTL water vapor reductions results in a zonal-mean structure with “wings” of extratropical water vapor reductions, which account for about half of the 2011 abrupt drop global radiative impact. RF values associated with the mean water vapor concentrations differences between 2012/13 and 2010/11 are between −0.01 and −0.09 W m⁻², depending upon the altitude above which perturbations are considered. TTL water vapor and ozone variability during this period jointly lead to a transient radiative cooling of ~0.25–0.5 K in layers below the tropopause. The 2011 abrupt drop also prolonged the reduction in stratospheric water vapor that followed the 2000 abrupt drop, providing a longer-term radiative forcing of climate. Water vapor concentrations from 2005 to 2013 are lower than those from 1990 to 1999, resulting in a RF between these periods of about −0.045 W m⁻², approximately 12% as large as, but of opposite sign to, the concurrent estimated CO[subscript 2] forcing. United States. National Aeronautics and Space Administration (NNX14AK83H) National Science Foundation (U.S.) (AGS-1342810) National Science Foundation (U.S.) (AGS-1461517) 2017-04-13T18:13:14Z 2017-04-13T18:13:14Z 2016-01 2015-10 Article http://purl.org/eprint/type/JournalArticle 0894-8755 1520-0442 http://hdl.handle.net/1721.1/108125 Gilford, Daniel M., Susan Solomon, and Robert W. Portmann. “Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer.” J. Climate 29, no. 2 (January 2016): 595–612. © 2016 American Meteorological Society https://orcid.org/0000-0003-2422-0887 https://orcid.org/0000-0002-2020-7581 en_US http://dx.doi.org/10.1175/jcli-d-15-0167.1 Journal of Climate Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society |
| spellingShingle | Portmann, Robert W. Gilford, Daniel Michael Solomon, Susan Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title | Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title_full | Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title_fullStr | Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title_full_unstemmed | Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title_short | Radiative Impacts of the 2011 Abrupt Drops in Water Vapor and Ozone in the Tropical Tropopause Layer |
| title_sort | radiative impacts of the 2011 abrupt drops in water vapor and ozone in the tropical tropopause layer |
| url | http://hdl.handle.net/1721.1/108125 https://orcid.org/0000-0003-2422-0887 https://orcid.org/0000-0002-2020-7581 |
| work_keys_str_mv | AT portmannrobertw radiativeimpactsofthe2011abruptdropsinwatervaporandozoneinthetropicaltropopauselayer AT gilforddanielmichael radiativeimpactsofthe2011abruptdropsinwatervaporandozoneinthetropicaltropopauselayer AT solomonsusan radiativeimpactsofthe2011abruptdropsinwatervaporandozoneinthetropicaltropopauselayer |