长江源头湿地消长对气候变化的响应

Response of Wetlands Rise and Fall in the Changjiang River Source Region to Climatic Change

位于青藏高原腹地唐古拉山以北的长江源头区域,由于受直接人类活动的影响程度较小,因此,从气候变化与湿地消长关系的强弱程度上可以看出其中的关键信息,能更真实地反映气候变化对长江源头湿地的影响。据灰色系统理论分析发现,蒸发量对湿地总面积的消长相对其他气候因子更具主导作用,其次为降水量的影响,且夏季各气候因子对湿地面积消长的影响较其他季节更为显著;1990年以来长江源头呈现出气温升高、降水量增加和蒸发量减少的暖湿化趋势,但进入21世纪以来年降水量呈下降以及年蒸发量呈增加的趋势,对于湿地的消长具有明显驱动作用;利用遥感技术分析,1990-2000年长江源头的湿地总面积共增加353.22 km2,年平均增加速率为35.32km2/a,而2000-2004年减少20.57 km2,这两个阶段湿地的消长与相应的气候变化特征有着很好的响应规律。

The Changjiang River Source Region is located in the hinterland of Qinghai-Tibet Plateau and in the north of Tanggula Mountain.Because the direct impact of human activities is limited,critical information can be found from the inter-related climate change and wetlands rise and fall.The impacts of climate change on the wetlands of the Changjiang River can be reflected.According to Gray correlation analysis,it can be found that evaporation plays an dominant role in the rise and fall of the total area of wetlands compared to other climatic factors,followed by the impact of precipitation.Climate in summer affects the rise and fall of wetlands more prominently than that in other seasons.The Changjiang River has a tendency of temperature rise,precipitation increase,and evaporation decrease,and it has a warm and humid trend since 1990.Its annual precipitation has been declining and its annual evaporation has an increasing trend in the 21st century.These are the significant driving forces for the rise and fall of wetlands.According to the remote sensing analysis,the total area of wetlands in the Changjiang River Source Region was increased by 353.22 km2,and the annual average increasing rate was 35.32 km2/a during 1990-2000,while it was reduced by 20.57 km2 during 2000-2004.These two periods showed the close relations between wetlands rise and fall and corresponding climate change.