Acta Geographica Sinica ›› 2010, Vol. 65 ›› Issue (9): 1069-1078.doi: 10.11821/xb201009004

Previous Articles     Next Articles

Variations of Winter Snow Concentration Degree and Snow Concentration Period in Northeast China

WANG Ji1, ZHAO Chunyu2, LOU Dejun3   

  1. 1. Beijing Climate Center, Beijing 100089, China;
    2. Liaoning Climate Center, Shenyang 110014, China;
    3. Qiqihar Meteorological Bureau, Qiqihar 161006, Heilongjiang, China
  • Received:2009-12-08 Revised:2010-07-03 Online:2010-09-20 Published:2010-11-19
  • Supported by:

    Foundation: Climate Change Special Fund of CMA, No.CCSF-09-01; New Technology Popularizing Project of CMA, No.CMATG2008M19; Study on Time-spatial Variation and Forecasting Methods of High-impact Climate Events over Beijing and Its Surrounding, No.Z07050600680701

Abstract:

Based on 1961-2005 observed winter precipitation data in Northeast China, the temporal and spatial variations of precipitation concentration degree (PCD) and precipitation concentration period (PCP) are computed and analyzed, together with the circulation characteristics when there is a higher PCD. Results show that the PCD in Northeast China presents a yearly rising tendency and the PCP decreases obviously. In terms of decadal variation, there is a 12-year periodic variation in PCP, and since the mid-1970s there has been an 8-year short periodic variation. As to spatial variation, the PCD in winter of Northeast China has increased gradually from the eastern to western part, and the minimum value of PCD occurs in the east of Jilin Province, while the high value center is observed in the central part of the province. For the whole Northeast China, the variation tendencies are consistent in the eastern and central parts. The PCD presents a rising tendency and the PCP shows a decreasing tendency. The PCD in the southwestern and northern parts has a slight rising tendency, with the PCD in the southwestern part having the slightest increasing tendency, and the PCP in the northern part showing the slightest decreasing tendency. When a high PCD value is observed, the areas are controlled by the East Asian deep trough at 500 hPa, and the trough becomes deeper in the western part, while a high pressure, which is easily formed and intensified in the eastern part, makes the East Asia deep trough move eastward slowly. Upper-level jet stream and low-level jet stream co-exist, and the former is stronger and takes more of a southwestward position than the latter. Over the Pacific the high value extent of water vapor transport is intensified obviously, and the extent also increases. Northeast China is influenced by the water vapor transported to the northwest along the north of the high value center.

Key words: Northeast China, precipitation concentration degree, precipitation concentration period, circulation characteristics