Influence of lower-tropospheric moisture on local soil moisture-precipitation feedback over the US Southern Great Plains

Wang, Gaoyun1,2,3; Fu, Rong2; Zhuang, Yizhou2; Dirmeyer, Paul A.4; Santanello, Joseph A.5; Wang, Guiling6; Yang, Kun7; McColl, Kaighin8

2024-03-28

10.5194/acp-24-3857-2024

ATMOSPHERIC CHEMISTRY AND PHYSICS   影响因子和分区

1680-7316

1680-7324

Land-atmosphere coupling (LAC) has long been studied, focusing on land surface and atmospheric boundary layer processes. However, the influence of humidity in the lower troposphere (LT), especially that above the planetary boundary layer (PBL), on LAC remains largely unexplored. In this study, we use radiosonde observations from the US Southern Great Plains (SGP) site and an entrained parcel buoyancy model to investigate the impact of LT humidity on LAC there during the warm season (May-September). We quantify the effect of LT humidity on convective buoyancy by measuring the difference between the 2-4 km vertically integrated buoyancy with the influence of background LT humidity and that without it. Our results show that, under dry soil conditions, anomalously high LT humidity is necessary to produce the buoyancy profiles required for afternoon precipitation events (APEs). These APEs under dry soil moisture cannot be explained by commonly used local LAC indices such as the convective triggering potential and low-level humidity index (CTP / HI Low ), which do not account for the influence of the LT humidity. On the other hand, consideration of LT humidity is unnecessary to explain APEs under wet soil moisture conditions, suggesting that the boundary layer moisture alone could be sufficient to generate the required buoyancy profiles. These findings highlight the need to consider the impact of LT humidity, which is often decoupled from the humidity near the surface and is largely controlled by moisture transport, in understanding land-atmospheric feedbacks under dry soil conditions, especially during droughts or dry spells over the SGP.

SCI

英语

其他

Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences

Environmental Sciences ; Meteorology & Atmospheric Sciences

WOS:001192577500001

COPERNICUS GESELLSCHAFT MBH

GEOSCIENCES

Web of Science

1.Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, Beijing, Peoples R China
2.Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA
3.Southern Univ Sci & Technol, High Sch, Shenzhen, Peoples R China
4.George Mason Univ, Dept Atmospher Ocean & Earth Sci, Fairfax, VA USA
5.NASA, Goddard Space Flight Ctr, Greenbelt, MD USA
6.Univ Connecticut, Dept Civil & Environm Engn, Storrs, CT USA
7.Tsinghua Univ, Dept Earth Syst Sci, Beijing, Peoples R China
8.Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA USA

Wang, Gaoyun,Fu, Rong,Zhuang, Yizhou,et al. Influence of lower-tropospheric moisture on local soil moisture-precipitation feedback over the US Southern Great Plains[J]. ATMOSPHERIC CHEMISTRY AND PHYSICS,2024,24(6).

Wang, Gaoyun.,Fu, Rong.,Zhuang, Yizhou.,Dirmeyer, Paul A..,Santanello, Joseph A..,...&McColl, Kaighin.(2024).Influence of lower-tropospheric moisture on local soil moisture-precipitation feedback over the US Southern Great Plains.ATMOSPHERIC CHEMISTRY AND PHYSICS,24(6).

Wang, Gaoyun,et al."Influence of lower-tropospheric moisture on local soil moisture-precipitation feedback over the US Southern Great Plains".ATMOSPHERIC CHEMISTRY AND PHYSICS 24.6(2024).