喜马拉雅山北坡典型高山流域水文过程与气候变化研究（本站推荐）

第一篇：喜马拉雅山北坡典型高山流域水文过程与气候变化研究（本站推荐）

喜马拉雅山北坡典型高山流域水文过程与气候变化研究

摘要：全球变暖的大环境下，作为淡水最大储存的冰川日益退缩，以冰川融水补给为主的河流直接受到影响，尤其在中国等亚洲地区。这类河流在我国主要分布在西部地区，冰川水资源是下游，尤其是干旱与半干旱区人民赖以生存和社会经济可持续发展的生命线。喜马拉雅山是我国以及印度、东南亚很多河流的发源地，由于冰雪融水占很大比重，所以对气候变化比较敏感；同时这个区域广泛分布着岛状多年冻土，冻土对径流过程也有着不可忽视的影响，但在我国喜马拉雅山一侧冰川冻土水文对气候变化响应的研究却很少。本文选取我国喜马拉雅山一侧唯一具有长期水文气象观测资料的卡鲁雄曲为典型区域，通过Mann-Kendall趋势检验法，Sen坡度估计以及相关统计分析方法，分析了近20年河流水情，并与气候特征结合来探讨径流变化的原因，所得结果对研究青藏高原水文气象过程与我国东南亚乃至全球的天气、气候变化都有一定的指导意义。（1）卡鲁雄曲流域近40年平均气温以0.38℃/10a的趋势上升，高于西藏年均温0.26℃/10a的增长率，更是明显高于同期全国气温增长率（0.40℃/100a）和全球气温增长率（0.3~0.6℃/100a），且极端最高温都出现在20世纪90年代。后十年气温（1994~2003年）比前十年（1983~1993年）升高0.5℃。（2）径流对气候变化的响应最灵敏（一年有8个月的增加趋势通过α=0.05的显著性检验），尤其是秋冬季的径流（α=0.01）。后10年与前10年比较，径流量增加了26%；不同月份径流增加强度不同，10~2月增加了44%，7~9月增加了27%，3~6月增加了24%。（3）受冰川消融和季风降水的影响，不同月份的径流受到的影响因素不同；但存在共性，即气温对径流起着积极主导作用，而降水对径流的影响则具有不确定性；根据已有资料建立了消融期（4~10月）置信度超过95%的径流与气候要素的统计方程，可进行未来情景预测。并采用未来不同气候情景（α=0.02℃/a或α=0.052℃/a），根据已建立的统计方程，得出2050年和2100年可能的径流变化，发现5月和10月的径流增加最多。（4）非消融期（11~3月）径流有不同程度的涨幅，突变发生在1990年左右。1月份增加最明显，后10年比前10年增加了67%。遥相关分析表明1月份径流与7~12月径流有通过95%显著性检验的相关性，前期月份共同作用使径流变化更显著，这是冻土区所特有的。（5）SRM在卡鲁雄曲流域的模拟结果比较理想，说明SRM融雪径流模型在冰川区域同样适用；并且通过情景预测，在气温上升1℃的情况下，模拟的径流没有明显提前，但流域径流量整体明显增大。

Abstract：The Karuxung catchment is a typical area and unique with a long term observations in the Tibet-Himalayas since 1983.The altitude of the basin varies widely from about 4,550 m to 7,200 m.Owing to high elevation, the alpine permafrost covers about 60% of the drainage area, which limit line is 5,100 m, above which underlay permafrost and below is seasonally frozen ground.Water supply of the Karuxung watershed is mainly from melt water and rainfall;therefore climate warming and precipitation increasing both have positive impacts to runoff.Mann-Kendall trend analysis, the Sen’s slope estimate and correlation analysis were employed to analyze data from Wengguo hydrometric station and Langkazi meteorological station.The results indicated that runoff, air temperature, precipitation and evaporation all have pictured significantly upward trends.Of which runoff change was the most sensitive to climate change, especially during fall and winter.It was concluded that a great number of trends were observed than were expected to occur by chance.In recent 20 years, the annual mean temperature has increased dramatically with a speed of 0.34℃ every 10 years, which was higher than the speed of Tibet region which was 0.26℃ every 10 year, and the extremely high temperature all appeared in the 1990s.For the air temperature, it in the pre-10 years was higher with 0.5℃ than that of the post-10 years, whereas the runoff has increased 26%.Different periods have different growth extent, it during October to February has increased 44%, July to September has increased 27%, and March to June has increased 24%.During ablation period, the runoff change was affected mostly by climate change from April to June, whereas the runoff was affected by air temperature and precipitation jointly when monsoon came, and the precipitation influenced the runoff with uncertainty.During non-ablation period, runoff change was more obviously as it was influenced by former months;the key supply was baseflow.The results indicated that the runoff in cold season all have figured out significantly increasing extents, of which runoff change in January was the greatest about 67%.Furthermore, the runoff in January had close correlations with the runoff from July to December at a significance level of 95%.Therefore, the runoff change in cold season was caused by the former months jointly, which was a characteristic of the permafrost effect.SRM was applied to the Karuxung watershed, and showed a very good result.In a warmer scenario with 1℃ increased daily air temperature, the runoff peak did not move forward, but the mount was enlarged.