The spatial consistency of summer rainfall variability between the Mongolian Plateau and North China
The Mongolian Plateau (MP) is located in the eastern part of arid Central Asia (ACA). Climatically, much of the MP is dominated by the westerly circulation and has an arid and semi-arid climate; however, the eastern part of the MP is also influenced by the East Asian summer monsoon (EASM) and has a humid and semi-humid climate. Recently, several studies have shown that precipitation variability in the MP differs from that in western ACA but is consistent with that in the EASM region.
To find out the accurate spatial scope of this precipitation consistency, Professor Huang Wei and Dr. Jie Chen in the Key Laboratory of Western China's Environmental Systems at Lanzhou University used reanalysis data to characterize and determine this spatial consistency of summer precipitation variability.
They found that this consistent pattern shows in MP and North and Northeast China.
The Eurasian mid-latitude teleconnection wave train, with negative (positive) anomalies in the North Atlantic and ACA and positive (negative) anomalies in the MP and mid-latitude EASM region, is largely responsible for the consistency of precipitation variability in the MP and North and Northeast China. The positive anomalies over the North Atlantic and ACA and negative anomalies over Europe and the MP would enhance the transport of westerly and monsoon moisture to the MP and North and Northeast China. They could also strengthen the Northeast Asian low, enhance the EASM, and trigger the anomalous ascending motion over the MP, which promotes precipitation in the MP and Northeast and North China.
Additionally, they also found the decadal variability of the precipitation in the MP and ACA exhibits an out-of-phase pattern, due to the Eurasian mid-latitude teleconnection wave train. These results would help explain the spatial variations of paleo-precipitation/humidity reconstructions in East Asia and clarify the reasons for the consistency of the regional climate.