 |
| Titel |
Simulation of stratospheric water vapor and trends using three reanalyses |
| VerfasserIn |
M. R. Schoeberl, A. E. Dessler, T. Wang |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 14 ; Nr. 12, no. 14 (2012-07-24), S.6475-6487 |
| Datensatznummer |
250011338
|
| Publikation (Nr.) |
 copernicus.org/acp-12-6475-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| The domain-filling, forward trajectory calculation model developed by
Schoeberl and Dessler (2011) is extended to the 1979–2010 period. We compare
results from NASA's MERRA, NCEP's CFSR, and ECMWF's ERAi reanalyses with
HALOE, MLS, and balloon observations. The CFSR based simulation produces a
wetter stratosphere than MERRA, and ERAi produces a drier stratosphere than
MERRA. We find that ERAi 100 hPa temperatures are cold biased compared to
Singapore sondes and MERRA, which explains the ERAi result, and the CFSR
grid does not resolve the cold point tropopause, which explains its
relatively higher water vapor concentration. The pattern of dehydration
locations is also different among the three reanalyses. ERAi dehydration
pattern stretches across the Pacific while CFSR and MERRA concentrate
dehydration activity in the West Pacific. CSFR and ERAi also show less
dehydration activity in the West Pacific Southern Hemisphere than MERRA. The
trajectory models' lower northern high latitude stratosphere tends to be dry
because too little methane-derived water descends from the middle
stratosphere. Using the MLS tropical tape recorder signal, we find that
MERRA vertical ascent is 15% too weak while ERAi is 30% too strong.
The trajectory model reproduces the observed reduction in the amplitude of
the 100-hPa annual cycle in zonal mean water vapor as it propagates to
middle latitudes. Finally, consistent with the observations, the models show
less than 0.2 ppm decade−1 trend in water vapor both at mid-latitudes and in
the tropics. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|