open access

https://hdl.handle.net/2115/75178

Observed Evidence of Enhanced Probability of Mesoscale Convective System Initiations due to Land Surface Heterogeneity in Semiarid East Asia

英語

2019-06-27

Meteorological society of Japan

SOLA (Scientific Online Letters on the Atmosphere)

15

143-148

This study investigated the impact of land surface heterogeneity on Mesoscale Convective System (MCS) initiations in East Asia, using geostationary satellite data during June-August from 1996 through 2018. The detected MCSs over land exhibited clear diurnal variation with the lowest existence frequency at 10:00 and highest initiation frequency during 12:00-17:00 local time. To quantify land surface heterogeneity, the spatial standard deviation of equivalent Black-Body Temperature (TBB) within a cloud-free 0.35 degrees x 0.35 degrees box (sigma LSTBB:Land Surface TBB) was computed for 10:00 each day. A comparison of the sigma LSTBB and MCS databases revealed that the probability of MCS initiations increased with increasing sigma LSTBB in East Mongolia while the probability was not sensitive to sigma LSTBB in East China. This indicated that MCSs tend to form over heterogeneous land surface conditions in the semiarid region. We found that the impact of land surface heterogeneity on MCS initiations was highest over flat terrain in East Mongolia, where the convection trigger due to topographically-induced circulation was absent. These results suggest that the impact of land surface heterogeneity on MCS initiations during the warm season varies with climate zones and terrain complexities in East Asia, with strongest impact in semiarid and flat regions.

学術雑誌論文

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Creative Commons Attribution 4.0 International

1349-6476