Temporal and Spatial Soil Moisture–Precipitation Coupling Relationships Over the Tibetan Plateau
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...
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Veröffentlicht in: | Journal of geophysical research. Atmospheres 2024-06, Vol.129 (11), p.n/a |
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Sprache: | eng |
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Zusammenfassung: | 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‐t |
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ISSN: | 2169-897X 2169-8996 |
DOI: | 10.1029/2023JD040621 |