Acta Geographica Sinica, Volume. 75, Issue 1, 41(2020)
The precipitation distribution has obvious intraseasonal variation characteristics in the Haihe River Basin (HRB) during summer. In this paper, intraseasonal evolution of the key areas of precipitation in the HRB and its associated atmospheric circulation pattern have been investigated, and the relative contributions of different atmospheric circulation factors to precipitation in the key areas are quantitatively calculated, by using daily precipitation data of 148 meteorological stations over the HRB and NCEP/NCAR reanalysis data. The results present a prominent intraseasonal variation of the key areas of summer precipitation in the HRB. The key areas move clockwise around the lower reaches of the Luanhe River and Beisan River located in the northeastern HRB, which are the maximum contribution areas of station precipitation to the HRB total amount, from early summer (June) to midsummer (July and August). The key areas are distributed in northeast HRB, east and south HRB, east and central HRB along with the movement. During early summer, the activities of the Northeast Cold Vortex (NECV) play a dominant role (relative contribution is 69.6%) in precipitation in the key areas; in July, the anomalous precipitation in the key areas is mainly affected by the ridge line of the Western Pacific Subtropical High (WPSH), with a relative contribution of more than 60%; in August, the ridge line of the WPSH and the East Asian summer monsoon index (EASMI) has an equivalent contribution to precipitation in the key areas. In addition, the monthly significant correlation areas relating to these atmospheric circulation factors for precipitation, are found at the same location as the key areas of precipitation in the HRB, and their intraseasonal changing paths are both accordant with the position changes of the associated atmospheric circulation systems in summer.
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Liye HE, Shanjun CHENG, Ning MA, Jun GUO.
Received: Apr. 10, 2018
Accepted: --
Published Online: Oct. 16, 2020
The Author Email: GUO Jun (guojun@cma.gov.cn)