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- Title
Temporal and Spatial Soil Moisture–Precipitation Coupling Relationships Over the Tibetan Plateau.
- Authors
Zan, Beilei; Wang, Huimin; Wei, Jiangfeng; Song, Yuanyuan
- Abstract
Soil moisture can significantly influence weather and climate via land‒atmosphere interactions over the Tibetan Plateau. However, the temporal and spatial preferences of precipitation for soil moisture anomalies and the underlying mechanisms over the plateau have not been determined. Using multiple satellite data sets (including Global Precipitation Measurement precipitation data and Soil Moisture Active Passive and Advanced SCATterometer soil moisture data) and ERA5 reanalysis data, the temporal and spatial soil moisture–precipitation coupling (SMPC) relationships in seven summers during 2015–2021 over the plateau are quantified based on a percentile‐based method. The satellite observations show prevalent positive temporal SMPC across the plateau, indicating that wetter‐than‐normal soil conditions tend to lead to more afternoon precipitation. While ERA5 generally aligns with satellite findings, it underestimates areas with positive temporal SMPC. Both the satellite and ERA5 data show that spatial SMPC relationships are usually statistically insignificant, but a few regions show significant positive relationships, that is, precipitation is more likely to occur over soils wetter than the surrounding soils. Moreover, the satellite observations suggest an inter‐event positive correlation between the temporal and spatial SMPC relationships. ERA5 agrees with the satellite‐based results over the western plateau but shows discrepancies over the eastern plateau. The temporal and spatial variations in soil moisture modulate the partitioning of surface heat fluxes, planetary boundary layer height, and lifting condensation level, promoting moist convection and afternoon precipitation. The findings from this study shed new light on SMPC and have important implications for precipitation forecasting over the plateau. Plain Language Summary: Soil moisture can influence precipitation via land–atmosphere water and energy exchanges over the Tibetan Plateau. Such impacts manifest itself in different ways. Temporally, precipitation could preferentially occur on antecedent soils that are either wetter or drier than normal. Spatially, precipitation could preferentially occur on antecedent soils that are either wetter or drier than the surrounding soils. In this study, we investigate the effects of soil moisture on precipitation in summer over the plateau from separate temporal and spatial perspectives using satellite and reanalysis data sets. Satellite data suggest that wetter‐than‐normal soil conditions often lead to more afternoon precipitation. While the ERA5 generally supports satellite findings, they underestimate areas with a positive temporal relationship. Both the satellite and ERA5 data show that in many areas, the spatial relationship between soil moisture and precipitation is not statistically significant. However, in a few regions, precipitation is more likely to occur over soils wetter than the surrounding soils. Soil moisture‐induced changes in surface energy and water fluxes influence the atmospheric boundary layer, leading to the spatiotemporal preference of afternoon precipitation over soil moisture anomalies. This work helps improve our understanding of the effects of soil moisture on precipitation over the plateau. Key Points: The temporal and spatial preferences of afternoon precipitation over soil moisture anomalies over the Tibetan Plateau are investigatedPrecipitation preferentially occurs over antecedent soil that is wetter than normal and wetter than the surrounding soilsSoil moisture changes the surface energy partitioning and affects subsequent precipitation by adjusting the atmospheric boundary layer
- Subjects
TIBETAN Plateau; PLATEAUS; ATMOSPHERIC boundary layer; LAND-atmosphere interactions; SOIL moisture; PRECIPITATION forecasting; SOILS
- Publication
Journal of Geophysical Research. Atmospheres, 2024, Vol 129, Issue 11, p1
- ISSN
2169-897X
- Publication type
Article
- DOI
10.1029/2023JD040621