| 摘要: |
| 在最近的30a里,中国长江流域夏季洪水频繁,直接影响该流域经济发展和生态环境在致力于解决洪水灾害和努力减轻其影响的同时,我们常面临如下三个问题:洪水频繁发生的原因,将来几十年的洪水频率将如何变化,还会这样频繁吗?本文将从局部气候的自然变化规律中来试图回答这三个问题.文中报告主要结果指出:长江流域夏季降水具有一个明显的自然尺度的变化,且该变化最近由一个偏干的气候态(从1910年到(30年代末期)转化为一个偏湿的气候态(自60年代末以来).伴随着这种变化,长江流域夏季降水表现出增加趋势(平均增加率为30mm/10a),夏季地表水蒸发呈现出减少趋势(平均减少率为10mm/10a),以及这两种作用共同造成的地表水增加和洪水频繁.由于目前偏湿的气候态将持续,预计在今后10-20a里这些变化以及相联系的频繁洪水的趋势将在长江流域持续. |
| 关键词: 世纪尺度 气候变化 趋势 地表蒸发 径流 洪水 长江流域 |
| DOI：10.18307/2003.sup12 |
| 分类号: |
| 基金项目: |
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| Centennial Variations and Recent Trends in Summer Rainfall and Runoff in the Yangtze Rive Basin, China |
|
Qi HU
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Climate & Bio-Atmospheric Sciences Group, School of Natural Resources, University of Nebraska-Lincoln, U. S. A
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| Abstract: |
| In recent decades, summer floods in China's Yangtze River basin have become more frequent and severer, threatening the economic development and ecosystem environment in the basin. While great efforts and a large amount of resources have been devoted to minimizing damages and mitigating consequences of floods, several scientific questions are raised:what may have attributed to the increase of the floods, and what may be anticipated of future floods? These questions are addressed in this note from a perspective of natural variability of the region's climate. Major results show that a centennial scale variation of the region's climate has shifted from a dry epoch, from 1910 to the late 1960s, to a wet epoch after the 1960s. Associate with this change are 1) a trend of increase in summer rainfall at an average rate of 30mm per ten years in the eastern portion of the basin, 2) a trend of decrease in summer season surface evaporation at an average rate of 10mm per ten years in the same region, and 3) a combined result of rising surface runoff and flood potential. These trends are speculated to continue because the current wet epoch in the centennial variation will persist in the next few decades. |
| Key words: Centennial scale climate variation trend surface evaporation runoff floods Yangtze River basin |
