Impacts of Tibetan Plateau Spring Snowmelt on Spring and Summer Precipitation in Northwest China
Zhilan Wang,
Kai Yang,
Feimin Zhang,
Jinyu Zhang,
Xuying Sun
Affiliations
Zhilan Wang
Key Laboratory of Climate Resources Development and Disaster Prevention and Reduction of Gansu Province/College of Atmospheric Sciences, Lanzhou University, No. 222 Tianshui South Road, Chengguan District, Lanzhou 730000, China
Kai Yang
Key Laboratory of Climate Resources Development and Disaster Prevention and Reduction of Gansu Province/College of Atmospheric Sciences, Lanzhou University, No. 222 Tianshui South Road, Chengguan District, Lanzhou 730000, China
Feimin Zhang
Key Laboratory of Climate Resources Development and Disaster Prevention and Reduction of Gansu Province/College of Atmospheric Sciences, Lanzhou University, No. 222 Tianshui South Road, Chengguan District, Lanzhou 730000, China
Jinyu Zhang
Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province/Key Laboratory of Arid Climatic Change and Disaster Reduction, Institute of Arid Meteorology, China Meteorological Administration, No. 2070 Donggang East Road, Chengguan District, Lanzhou 730020, China
Xuying Sun
Key Laboratory of Arid Climatic Change and Reducing Disaster of Gansu Province/Key Laboratory of Arid Climatic Change and Disaster Reduction, Institute of Arid Meteorology, China Meteorological Administration, No. 2070 Donggang East Road, Chengguan District, Lanzhou 730020, China
Snow on the Tibetan Plateau (TP) is an important signal for the prediction of East Asian climate. In this study, the relationship between the TP spring snowmelt and spring and summer precipitation in Northwest China (NWC) was investigated, along with the possible mechanisms linked to the impacts of snowmelt on precipitation. The results showed that the TP spring snowmelt had significant impacts on spring and summer precipitation in NWC. For example, when there was a large spring snowmelt in the central- eastern TP, the spring and summer precipitation in the Hexi Corridor and southeast NWC was excessive, especially in summer; when there was a large spring snowmelt in the northern TP, the spring and summer precipitation was deficient across the whole of NWC, while a large spring snowmelt in the western TP led to deficient spring and summer precipitation in eastern NWC but excessive precipitation in western NWC. The possible mechanisms for this included the fact that more spring snowmelt over the TP led to higher soil moisture contents, which further resulted in weakened subtropical westerly and enhanced ridge over Xinjiang. By changing the TP thermal forcing, these anomalous atmospheric circulation conditions transported water vapor into NWC, thus creating excessive summer precipitation in that region.
