Abstract
A regional climate model, NIES/CCSR RAMS, was used with the ECMWF objective analysis data as boundary conditions to reproduce the precipitation pattern over East Asia in June, including that accompanying the Baiu front. In the control experiment, the simulated precipitation pattern was unrealistic, mainly in two respects: precipitation over the Baiu front was too weak, and strong precipitation was found over the North Pacific subtropical high at around 20°N. According to the ECMWF data, strong potential instability is maintained over the subtropical high, under which condition, the cumulus parameterization used in the model predicts strong precipitation to stabilize the atmosphere. Because the lower free atmosphere is very dry over the subtropical high, it is conjectured that the development of deep cumulus convection is suppressed by this dry air in the real atmosphere. When the cumulus parameterization was modified to include this assumption, the intensity of precipitation over the Baiu front as well as the unrealistic precipitation pattern over the subtropical high was clearly ameliorated. The intensification of precipitation over the Baiu front is considered to be due to the increased water vapor transport to the Baiu front, and the decreased stability with respect to the moist convection around the Baiu front. In semi-prognostic experiments with CCSR/NIES AGCM, this modification was found to be also effective in many other parts of the globe. Because problems in precipitation distribution similar to that discussed in the present study are found in many other climate models, the modification of cumulus parameterization suggested here could also be effective in those models.
| Original language | English |
|---|---|
| Pages (from-to) | 939-947 |
| Number of pages | 9 |
| Journal | Journal of the Meteorological Society of Japan |
| Volume | 79 |
| Issue number | 4 |
| Publication status | Published - Aug 2001 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Atmospheric Science
Cite this
Importance of cumulus parameterization for precipitation simulation over East Asia in June. / Emori, Seita; Nozawa, Toru; Numaguti, Atusi; Uno, Itsushi.
In: Journal of the Meteorological Society of Japan, Vol. 79, No. 4, 08.2001, p. 939-947.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Importance of cumulus parameterization for precipitation simulation over East Asia in June
AU - Emori, Seita
AU - Nozawa, Toru
AU - Numaguti, Atusi
AU - Uno, Itsushi
PY - 2001/8
Y1 - 2001/8
N2 - A regional climate model, NIES/CCSR RAMS, was used with the ECMWF objective analysis data as boundary conditions to reproduce the precipitation pattern over East Asia in June, including that accompanying the Baiu front. In the control experiment, the simulated precipitation pattern was unrealistic, mainly in two respects: precipitation over the Baiu front was too weak, and strong precipitation was found over the North Pacific subtropical high at around 20°N. According to the ECMWF data, strong potential instability is maintained over the subtropical high, under which condition, the cumulus parameterization used in the model predicts strong precipitation to stabilize the atmosphere. Because the lower free atmosphere is very dry over the subtropical high, it is conjectured that the development of deep cumulus convection is suppressed by this dry air in the real atmosphere. When the cumulus parameterization was modified to include this assumption, the intensity of precipitation over the Baiu front as well as the unrealistic precipitation pattern over the subtropical high was clearly ameliorated. The intensification of precipitation over the Baiu front is considered to be due to the increased water vapor transport to the Baiu front, and the decreased stability with respect to the moist convection around the Baiu front. In semi-prognostic experiments with CCSR/NIES AGCM, this modification was found to be also effective in many other parts of the globe. Because problems in precipitation distribution similar to that discussed in the present study are found in many other climate models, the modification of cumulus parameterization suggested here could also be effective in those models.
AB - A regional climate model, NIES/CCSR RAMS, was used with the ECMWF objective analysis data as boundary conditions to reproduce the precipitation pattern over East Asia in June, including that accompanying the Baiu front. In the control experiment, the simulated precipitation pattern was unrealistic, mainly in two respects: precipitation over the Baiu front was too weak, and strong precipitation was found over the North Pacific subtropical high at around 20°N. According to the ECMWF data, strong potential instability is maintained over the subtropical high, under which condition, the cumulus parameterization used in the model predicts strong precipitation to stabilize the atmosphere. Because the lower free atmosphere is very dry over the subtropical high, it is conjectured that the development of deep cumulus convection is suppressed by this dry air in the real atmosphere. When the cumulus parameterization was modified to include this assumption, the intensity of precipitation over the Baiu front as well as the unrealistic precipitation pattern over the subtropical high was clearly ameliorated. The intensification of precipitation over the Baiu front is considered to be due to the increased water vapor transport to the Baiu front, and the decreased stability with respect to the moist convection around the Baiu front. In semi-prognostic experiments with CCSR/NIES AGCM, this modification was found to be also effective in many other parts of the globe. Because problems in precipitation distribution similar to that discussed in the present study are found in many other climate models, the modification of cumulus parameterization suggested here could also be effective in those models.
UR - http://www.scopus.com/inward/record.url?scp=23044528708&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=23044528708&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:23044528708
VL - 79
SP - 939
EP - 947
JO - Journal of the Meteorological Society of Japan
JF - Journal of the Meteorological Society of Japan
SN - 0026-1165
IS - 4
ER -