Global large-scale stratosphere–troposphere exchange in modern reanalyses
Stratosphere–troposphere exchange (STE) has important impacts on the chemical and radiative properties of the upper troposphere and lower stratosphere. This study presents a 15-year climatology of global large-scale STE from four modern reanalyses: ERA-Interim, JRA-55, MERRA-2, and MERRA. STE is sep...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/17/5537/2017/acp-17-5537-2017.pdf |
| _version_ | 1811317657070206976 |
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| author | A. C. Boothe C. R. Homeyer |
| author_facet | A. C. Boothe C. R. Homeyer |
| author_sort | A. C. Boothe |
| collection | DOAJ |
| description | Stratosphere–troposphere exchange (STE) has important impacts on the
chemical and radiative properties of the upper troposphere and lower
stratosphere. This study presents a 15-year climatology of global large-scale
STE from four modern reanalyses: ERA-Interim, JRA-55, MERRA-2, and MERRA. STE
is separated into three regions (tropics, subtropics, and extratropics) and
two transport directions (stratosphere-to-troposphere transport or STT and
troposphere-to-stratosphere transport or TST) in an attempt to identify the
significance of known transport mechanisms. The extratropics and tropics are
separated by the tropopause <q>break</q>. Any STE occurring between the tropics
and the extratropics through the tropopause break is considered subtropical
exchange (i.e., in the vicinity of the subtropical jet).
<br><br>
In addition, this study employs a method to identify STE as that which
crosses the lapse-rate tropopause (LRT), while most previous studies have
used a potential vorticity (PV) isosurface as the troposphere–stratosphere
boundary. PV-based and LRT-based STE climatologies are compared using the
ERA-Interim reanalysis output. The comparison reveals quantitative and
qualitative differences, particularly for TST in the polar regions.
<br><br>
Based upon spatiotemporal integrations, we find STE to be STT dominant in
ERA-Interim and JRA-55 and TST dominant in MERRA and MERRA-2. The sources of
the differences are mainly attributed to inconsistencies in the
representation of STE in the subtropics and extratropics. Time series during
the 15-year analysis period show long-term changes that are argued to
correspond with changes in the Brewer–Dobson circulation. |
| first_indexed | 2024-04-13T12:12:05Z |
| format | Article |
| id | doaj.art-dbfa8abe75fe48e883ba6bbb125220a7 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-04-13T12:12:05Z |
| publishDate | 2017-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-dbfa8abe75fe48e883ba6bbb125220a72022-12-22T02:47:28ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242017-05-011795537555910.5194/acp-17-5537-2017Global large-scale stratosphere–troposphere exchange in modern reanalysesA. C. Boothe0C. R. Homeyer1School of Meteorology, University of Oklahoma, Norman, OK, USASchool of Meteorology, University of Oklahoma, Norman, OK, USAStratosphere–troposphere exchange (STE) has important impacts on the chemical and radiative properties of the upper troposphere and lower stratosphere. This study presents a 15-year climatology of global large-scale STE from four modern reanalyses: ERA-Interim, JRA-55, MERRA-2, and MERRA. STE is separated into three regions (tropics, subtropics, and extratropics) and two transport directions (stratosphere-to-troposphere transport or STT and troposphere-to-stratosphere transport or TST) in an attempt to identify the significance of known transport mechanisms. The extratropics and tropics are separated by the tropopause <q>break</q>. Any STE occurring between the tropics and the extratropics through the tropopause break is considered subtropical exchange (i.e., in the vicinity of the subtropical jet). <br><br> In addition, this study employs a method to identify STE as that which crosses the lapse-rate tropopause (LRT), while most previous studies have used a potential vorticity (PV) isosurface as the troposphere–stratosphere boundary. PV-based and LRT-based STE climatologies are compared using the ERA-Interim reanalysis output. The comparison reveals quantitative and qualitative differences, particularly for TST in the polar regions. <br><br> Based upon spatiotemporal integrations, we find STE to be STT dominant in ERA-Interim and JRA-55 and TST dominant in MERRA and MERRA-2. The sources of the differences are mainly attributed to inconsistencies in the representation of STE in the subtropics and extratropics. Time series during the 15-year analysis period show long-term changes that are argued to correspond with changes in the Brewer–Dobson circulation.http://www.atmos-chem-phys.net/17/5537/2017/acp-17-5537-2017.pdf |
| spellingShingle | A. C. Boothe C. R. Homeyer Global large-scale stratosphere–troposphere exchange in modern reanalyses Atmospheric Chemistry and Physics |
| title | Global large-scale stratosphere–troposphere exchange in modern reanalyses |
| title_full | Global large-scale stratosphere–troposphere exchange in modern reanalyses |
| title_fullStr | Global large-scale stratosphere–troposphere exchange in modern reanalyses |
| title_full_unstemmed | Global large-scale stratosphere–troposphere exchange in modern reanalyses |
| title_short | Global large-scale stratosphere–troposphere exchange in modern reanalyses |
| title_sort | global large scale stratosphere troposphere exchange in modern reanalyses |
| url | http://www.atmos-chem-phys.net/17/5537/2017/acp-17-5537-2017.pdf |
| work_keys_str_mv | AT acboothe globallargescalestratospheretroposphereexchangeinmodernreanalyses AT crhomeyer globallargescalestratospheretroposphereexchangeinmodernreanalyses |