地理学报 ›› 2004, Vol. 59 ›› Issue (2): 230-238.doi: 10.11821/xb200402009

• 气候变化与水环境 • 上一篇    下一篇

华北农牧交错带夏季极端气候的趋势分析

龚道溢,韩晖   

  1. 北京师范大学资源学院,环境演变与自然灾害教育部重点实验室,北京 100875
  • 收稿日期:2003-07-08 修回日期:2003-10-20 出版日期:2004-03-25 发布日期:2004-03-25
  • 作者简介:龚道溢 (1969-), 男, 土家族, 博士,教授, 主要从事气候变化研究。E-mail:gdy@ires.cn
  • 基金资助:

    霍英东教育基金资助 (81014)

Extreme Climate Events in Northern China over the Last 50 Years

GONG Daoyi, HAN Hui   

  1. Laboratory of Environmental Change and Natural Disaster, Institute of Resources Science, Beijing Normal University, Beijing 100875, China
  • Received:2003-07-08 Revised:2003-10-20 Online:2004-03-25 Published:2004-03-25
  • Supported by:

    Huo Yingdong Education Foundation, No.81014

摘要:

利用1956~2001年日降水量及日平均气温资料,分析华北农牧交错带极端气候事件的长期变化趋势。对降水极端事件的分析季节为5~9月,温度为6~8月。结果发现暴雨 (日降水 ≥50 mm) 频数没有显著的线性变化趋势,但1980年前后发生了明显的年代际尺度变化,1980年代到1990年代初,频次显著减少,此期间暴雨发生的时间更加分散。定义连续无雨的天数为干燥事件。发现虽然降水量没有显著的变化,但是严重干燥事件 (连续0降水日 ≥10天) 的频数却呈显著增加趋势 (+8.3%/10a), 超过99%信度水平。最高和最低的10%温度分别定义异常高温和异常低温,则异常高温的频数有显著增加趋势 (+20.9%/10a),特别是1990年代后期以来增加非常突出。异常低温频次有减少的趋势 (-15.1%/10a),超过99%信度水平。严重干燥事件及异常高温事件的强烈增加,可能是造成近来北方干旱频繁发生的重要原因。

关键词: 农牧交错带;极端气候;趋势;华北

Abstract:

Climate in the agri-pasture transition zone, northern China is analyzed on the basis of daily mean temperature and precipitation observations for 31 stations during 1956-2001. Analysis season for precipitation is May-September, and for temperature is the hottest three months, i.e., June through August. Heavy rain events, defined as those with daily precipitation equal to or larger than 50 mm, show no significant secular trend. A jump-like change, however, is found occurring in about 1980. For the period 1980-1993, the frequency of heavy rain events is significantly lower than the previous periods. Simultaneously, the occurring time of heavy rains expanded, commencing about one month early and ending one month later. Long dry spells are defined as those with longer than 10 days without rainfall. The frequency of long dry spells displays a significant (at 99% confidence level) trend at the value of +8.3%/10a. That may be one of the major causes for the frequent droughts emerging over northern China during the last decades. The frequency of hot days is increasing, while the low temperatures are significantly decreasing.

Key words: agriculture-pasture transition zone, climate extremes, trends