Diurnal Variation of Convective Activity and Precipitable Water around Ulaanbaator, Mongolia, and the Impact of Soil Moisture on Convective Activity during NighttimeSource: Monthly Weather Review:;2008:;volume( 136 ):;issue: 004::page 1401Author:Iwasaki, Hiroyuki
,
Nii, Tomoki
,
Sato, Tomonori
,
Kimura, Fujio
,
Nakagawa, Kiyotaka
,
Kaihotsu, Ichirow
,
Koike, Toshio
DOI: 10.1175/2007MWR2062.1Publisher: American Meteorological Society
Abstract: The diurnal variations of convective activity and precipitable water were investigated using a C-band airport radar and GPS receivers around Ulaanbaator (UB), Mongolia; this location was considered as an example of an arid region. The convective activity exhibited a pronounced diurnal cycle; it increased rapidly at 1100 local solar time (LST; 0300 UTC), reached the maximum at 1400 LST, and almost disappeared after 1900 LST. On the other hand, no diurnal variation of precipitable water could be observed, which implied that there was no considerable evapotranspiration, and the diurnal variation of the convective activity was irrelevant to the variation of water vapor. The reason why the deep convection could not develop at night is discussed using numerical modeling from the viewpoint of soil moisture. In the moist soil conditions assumed for humid simulations, an increase in the water vapor in the boundary layer due to evapotranspiration led to a potentially unstable condition that was sustained until night. Deep convection was formed at the southern foot of mountains where topographical convergence was expected. On the other hand, in the dry soil conditions assumed for the arid simulations, deep convection did not occur during nighttime even though topographical convergence was expected over the southern foot of the mountains. These features of dry soil conditions were consistent with the results from radar observations around UB. In other words, since the soil around UB is too dry in practice to sustain an unstable condition until night, the deep convection had to decay by night and could not be initiated at night.
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contributor author | Iwasaki, Hiroyuki | |
contributor author | Nii, Tomoki | |
contributor author | Sato, Tomonori | |
contributor author | Kimura, Fujio | |
contributor author | Nakagawa, Kiyotaka | |
contributor author | Kaihotsu, Ichirow | |
contributor author | Koike, Toshio | |
date accessioned | 2017-06-09T16:21:00Z | |
date available | 2017-06-09T16:21:00Z | |
date copyright | 2008/04/01 | |
date issued | 2008 | |
identifier issn | 0027-0644 | |
identifier other | ams-66246.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4207561 | |
description abstract | The diurnal variations of convective activity and precipitable water were investigated using a C-band airport radar and GPS receivers around Ulaanbaator (UB), Mongolia; this location was considered as an example of an arid region. The convective activity exhibited a pronounced diurnal cycle; it increased rapidly at 1100 local solar time (LST; 0300 UTC), reached the maximum at 1400 LST, and almost disappeared after 1900 LST. On the other hand, no diurnal variation of precipitable water could be observed, which implied that there was no considerable evapotranspiration, and the diurnal variation of the convective activity was irrelevant to the variation of water vapor. The reason why the deep convection could not develop at night is discussed using numerical modeling from the viewpoint of soil moisture. In the moist soil conditions assumed for humid simulations, an increase in the water vapor in the boundary layer due to evapotranspiration led to a potentially unstable condition that was sustained until night. Deep convection was formed at the southern foot of mountains where topographical convergence was expected. On the other hand, in the dry soil conditions assumed for the arid simulations, deep convection did not occur during nighttime even though topographical convergence was expected over the southern foot of the mountains. These features of dry soil conditions were consistent with the results from radar observations around UB. In other words, since the soil around UB is too dry in practice to sustain an unstable condition until night, the deep convection had to decay by night and could not be initiated at night. | |
publisher | American Meteorological Society | |
title | Diurnal Variation of Convective Activity and Precipitable Water around Ulaanbaator, Mongolia, and the Impact of Soil Moisture on Convective Activity during Nighttime | |
type | Journal Paper | |
journal volume | 136 | |
journal issue | 4 | |
journal title | Monthly Weather Review | |
identifier doi | 10.1175/2007MWR2062.1 | |
journal fristpage | 1401 | |
journal lastpage | 1415 | |
tree | Monthly Weather Review:;2008:;volume( 136 ):;issue: 004 | |
contenttype | Fulltext |