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中国沙漠 ›› 2010, Vol. 30 ›› Issue (4): 946-953.

• 天气与气候 • 上一篇    下一篇

祁连山层状云的时空分布及其环流特征分析

陈少勇1,2, 石光普2, 董安祥1, 张晓芬2   

  1. 1.中国气象局 兰州干旱气象研究所 甘肃省干旱气候变化与减灾重点实验室/中国气象局干旱气候变化与减灾重点开放实验室, 甘肃 兰州 730020; 2.白银市气象局, 甘肃 白银 730900
  • 收稿日期:2009-12-29 修回日期:2010-03-18 出版日期:2010-07-20 发布日期:2010-07-20

Temporal and Spatial Distribution of Stratiform Clouds over Qilian Mountains and Circulation Characteristic

CHEN Shao-yong1,2, SHI Guang-pu2, DONG An-xiang1, ZHANG Xiao-fen2   

  1. 1.Key laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province/Key Open Laboratory of Arid Climatic Change and Disaster Reduction of CMA, Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, Gansu, China; 2.Meteorological Bureau of Baiyin, Baiyin 730900, Gansu, China
  • Received:2009-12-29 Revised:2010-03-18 Online:2010-07-20 Published:2010-07-20

摘要: 利用祁连山区29个测站1961—2001年1—12月云状资料,分析了过去41 a祁连山区层状云的时空分布特征及其与大环流变化的关系。结果表明:①祁连山区层状云从西北向东南递增,祁连山主区层状云出现频次高于周边地区。②大部区域层状云显著减少,其中河西走廊东部减少幅度最大。③层状云年平均和季度的年际变化阶段性基本一致,1990年以前以偏多为主,1990年发生突变性减少,以后一直处于偏少的状态。④层状云出现频率与各月降水正相关显著。⑤层状云偏多年与偏少年差值最大的月份是8月和5月,偏多年和偏少年在亚洲500 hPa高度场上有明显的差异。⑥与层状云频率显著相关的环流特征量主要有:副高面积、强度、极涡强度、青藏高原高度场指数。祁连山层状云的减少趋势主要是副高面积增大和强度增强的结果。最后,用前期环流特征量为因子建立了祁连山主区层状云频率的预测模型。

关键词: 层状云, 时空分布, 大气环流, 预测, 祁连山

Abstract: The temporal and spatial distribution of stratiform clouds over the Qilian Mountains in recent 41 years and its relationship with atmospheric circulation were studied using the cloud data in 1961 2001 obtained from 29 stations in Qilian Mountains. The following results are obtained. (1) The stratiform clouds over the Qilian Mountains increased from northwest to southeast, and the stratiform clouds appeared more frequently over main Qilian Mountain body area than in surrounding areas. (2) Stratiform clouds reduced remarkably in most areas in recent 41 years, especially in east Gansu Corridor. (3) Annual variation of yearly average frequency was basically consistent with the annual variation of seasonal average frequency of stratiform clouds. The frequency of stratiform clouds was relatively high before 1990 and it was relatively low after 1990. (4) The frequency of stratiform clouds was remarkably positive correlative with precipitation of each month. (5) The biggest discrepancy of monthly average frequency of stratiform clouds between the more years and the less years occurred in May and August. The average geo-potential height composites at 500 hPa in the more year and in the less year were different. (6) The main circulation characteristic factors that are remarkable correlative with the frequency of stratiform clouds were area and intensity of subtropical high, intensity of polar vortex, Tibetan Plateau height field index.It was just the enlargement of area and the enhancement of intensity of subtropical high that caused the reduction of frequency of stratiform clouds over Qilian Mountains. Finally, a forecast model of frequency of stratiform clouds in Qilian Mountains was built based on the circulation characteristic factors.

Key words: stratiform cloud, temporal and spatial distribution, atmospheric circulation, forecast, Qilian Mountains

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