Effects of Lake Baikal on Summertime Precipitation Climatology Over the Lake Surface

• Published in: Geophysical research letters 2023-05, Vol.50 (10), p.n/a
• Main Authors: Lee, Hyunho, Ganbat, Gantuya, Jin, Han‐Gyul, Seo, Jaemyeong Mango, Moon, Sungju, Bok, Hyejeong, Baik, Jong‐Jin
• Format: Article
• Language: English
• Subjects: Air temperature; Atmosphere; Atmospheric convection; Atmospheric radiation; Climate; Climatology; Convection; Convection cooling; Convective instability; Deforestation; Downward long wave radiation; Freshwater; Freshwater lakes; Geographical distribution; Geographical locations; Heat flux; Heat transfer; Inland water environment; Latent heat; Latent heat flux; Local climates; Local precipitation; Moisture; Moisture effects; Precipitation; Questions; Regional climates; Satellite observation; Simulation; Summer; Surface temperature; Surface-air temperature relationships
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL103426

This study investigates the impacts of Lake Baikal, the largest by volume and the deepest freshwater lake in the world, on its nearby precipitation climate. Satellite observations and a reanalysis data set reveal that summertime precipitation amount is smaller over Lake Baikal than around it. A 15‐year regional climate simulation at a cloud‐resolving scale supports the smaller precipitation, and another simulation in which the lake is replaced by forest shows that the lake reduces summertime precipitation over it by 15%. The lake decreases daytime near‐surface air temperature, resulting in more convectively stable atmosphere over the lake. Latent heat flux is reduced along with the weakened convection, and the lower‐level moisture convergence and upper‐level moisture divergence over the lake are weakened. Plain Language Summary Lakes can have profound impacts on local precipitation, and such impacts are influenced by a variety of factors including the lake's geographical location, its size, and its depth. If only because of its sheer size, the question of how Lake Baikal, the largest and deepest freshwater lake in the world, affects the local climate deserves an in‐depth investigation. The present study aims to tackle this question by simulating the regional climate with and without Lake Baikal present, focusing on the summertime precipitation. The simulation results indicate that Lake Baikal reduces the summertime precipitation by 15%. It turns out that the lake cools down the atmosphere near the surface, which weakens convection. Moisture supply from the surface to the atmosphere is rather reduced due to the lake. This study suggests that the role of a lake, especially that as large as Lake Baikal, in regional climate can be more complicated than previously understood due to the complex interactions among multiple different processes involving convective instability, moisture supply, and atmospheric radiation. Key Points We conducted two 15‐year cloud‐resolving simulations to investigate how Lake Baikal affects summertime surface precipitation over it A decrease in air temperature weakens convection over the lake, reducing precipitation by 15% as well as water vapor amount It is essential to consider complex interactions among clouds, radiation, and lake surfaces to characterize the lake effect