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三江源地区草地植被生长状况不仅关系着当地的生态环境和牧畜业生产,而且对中国和亚洲的生态环境都有重要的影响.但以往的研究集中于年、季尺度降水和气温的变化趋势分析上,很少研究草地植被生长季的气候变化以及草地植被的响应.为此,本文利用三江源地区1961～2007年气温、降水、日照时数和1982年以来NOAA/AVHRR植被指数以及牧业气象站1994年有完整观测以来围封草地的牧草高度、生物量和草层覆盖度等资料,构建气候变化评价模型和草地植被生长气候适宜度模型,综合分析了三江源地区生长季气候变化趋势、草地植被生长气候适宜度变化趋势以及草地植被对气候变化的响应.结果表明,1961年以来三江源地区生长季4～8月平均气温、降水量和日照时数均呈增加趋势,增加幅度分别为每10年0.24℃,2.32mm和2.81h;4～5和6～8月平均气温分别增高0.17和0.30℃,降水量增幅分别为2.80和?0.38mm,日照时数分别增加2.15和1.2h.三江源地区草地植被生长气候适宜度呈上升趋势,其中4～5月上升的速度快于6～8月,整体气候朝着有利于草地植被生长的方向变化.三江源地区1982年以来植被指数整体呈弱的增加趋势,2004年以来草地植被变好趋势明显,草地植被的生长对气候已呈现出正响应的变化.为此,建议三江源地区应充分利用气温升高、降水增加,有利于草地植被生长的暖湿化趋势,加大草地保护力度,促进草地生态环境尽快恢复.
The growth of grassland vegetation in the Three River Source Region is not only related to the local ecological environment and animal husbandry production, but also has an important impact on the ecological environment in China and Asia. However, previous studies focused on the analysis of the trend of annual and seasonal precipitation and temperature Seldom studied the climate change of grassland vegetation season and the response of grassland vegetation.Therefore, this paper makes use of the temperature, precipitation, sunshine hours from 1961 to 2007 and the NOAA / AVHRR vegetation index since 1982, Based on the data of pasture height, biomass and coverage of grassland enclosed by grassland since 1994, a climate change assessment model and grassland vegetation climate suitability model were constructed. The climate change trends in the growing season of the Three River Source Region were comprehensively analyzed. The change trend of grassland vegetation climate suitability and the response of grassland vegetation to climate change showed that the average temperature, precipitation and sunshine duration increased from April to August in Sanjiangyuan region since 1961, Every 10 years 0.24 ℃, 2.32mm and 2.81h; 4 ~ 5 and 6 ~ August the average temperature increased by 0.17 and 0.30 ℃, precipitation With the width of 2.80 and 0.38 mm respectively, and the sunshine hours increased by 2.15 and 1.2 h respectively. The climate suitability of grassland vegetation in the Three River Source Region was on an upward trend, of which the increase in April-May was faster than that in June-August, Which is in favor of the change of grassland vegetation.The vegetation index in Sanjiangyuan area tends to increase weakly since 1982, and the grassland vegetation has a good trend since 2004. The growth of grassland vegetation has shown a positive response to climate change. Therefore, it is suggested that the Three River Source Region should make full use of the temperature increase and precipitation increase, which is conducive to the warm-humid trend of grassland vegetation growth, increase the grassland protection and promote the restoration of grassland ecological environment as soon as possible.