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DOI	10.1029/2023JD038617
	Observation and Process Understanding of Typical Cloud Holes Above Lakes Over the Tibetan Plateau
	Yao, Xiangnan; Yang, Kun; Letu, Husi; Zhou, Xu; Wang, Yan; Ma, Xiaogang; Lu, Hui; La, Zhu
发表日期	2023
ISSN	2169-897X
EISSN	2169-8996
卷号	128 期号:13
英文摘要	Understanding cloud distribution over lakes is crucial to determine input radiation and precipitation for lake thermal and water balance processes. Based on Himawari-8 satellite observation and Weather Research and Forecasting model results, this study examines the influences of lakes on daytime cloud cover during warm seasons over the Tibetan Plateau (TP), which is home to thousands of lakes. Observation shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported and is considered typical to TP by comparison with lakes outside of TP. The threshold size of lakes that can produce the shoreline cloud ring is identified to be about 300 km(2), as a conservative estimate. We further highlight the importance of atmosphere advection/background wind in the formation of lake-associated clouds. Lake breeze forms under weak background winds and the downdraft branch inhibits cloud formation over the lakes; while the updraft branch causes convection to form clouds over lakeshores. However, strong background winds do not favor lake breeze formation, changing cloud distribution over the lakes. Fewer clouds are also found in the downwind regions, and this influence is at a distance comparable to the lake scale. Due to fewer clouds over lakes, shortwave radiation is significantly larger (similar to 100 W/m(2)) and longwave radiation is smaller (similar to a few W/m(2)) than that of the further land region. Therefore, the above observational facts provide a new perspective to advance the understanding of lake-air interactions. Plain Language Summary There are lots of lakes over the Tibetan Plateau (TP), but the influence of these lakes on cloud during warm seasons remain unclear. Satellite data shows the existence of cloud holes and narrow cloud rings around the lakes, that is, fewer clouds over the lakes and more clouds along the shoreline, which has rarely been reported before. Simulation results demonstrate that the lake breeze accounts for this phenomenon: air descends over the lake, which inhibits cloud formation, while ascending branch over the shoreline favors cloud formation. Lakes over 300 km(2) can yield these cloud influences, so this area is thought as the threshold area that lakes can have influence on atmosphere. Clouds in the downwind regions are also fewer under the influence of background wind, and this influencing distance is almost equal to the lake scale itself. Due to less block by clouds, solar radiation is much higher over the lake than surrounding land, but downward longwave radiation is a little lower because of less emission from the cloud bottom, resulting an increase of net radiation in total at the lake surface. The conclusions of this study can help understand energy and hydrology processes of lakes better over the TP.
关键词	cloud cover lake breeze Tibetan Plateau radiation warm season
英文关键词	EFFECT PRECIPITATION; CONVECTION; MODEL; DYNAMICS; ASIA
WOS研究方向	Meteorology & Atmospheric Sciences
WOS记录号	WOS:001040712000001
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/283915
作者单位	Tsinghua University; Chinese Academy of Sciences; Institute of Tibetan Plateau Research, CAS; Chinese Academy of Sciences; Chinese Academy of Sciences; Institute of Geographic Sciences & Natural Resources Research, CAS; Tibet University
推荐引用方式 GB/T 7714	Yao, Xiangnan,Yang, Kun,Letu, Husi,et al. Observation and Process Understanding of Typical Cloud Holes Above Lakes Over the Tibetan Plateau[J]. 中国科学院青藏高原研究所,2023,128(13).
APA	Yao, Xiangnan.,Yang, Kun.,Letu, Husi.,Zhou, Xu.,Wang, Yan.,...&La, Zhu.(2023).Observation and Process Understanding of Typical Cloud Holes Above Lakes Over the Tibetan Plateau.JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES,128(13).
MLA	Yao, Xiangnan,et al."Observation and Process Understanding of Typical Cloud Holes Above Lakes Over the Tibetan Plateau".JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 128.13(2023).