近40年青藏高原主要生物温度指标的变化趋势

以最热月均温、最冷月均温、≥0℃积温及其日数、≥5℃积温及其日数和≥10℃积温及其日数作为生物温度指标的代表,应用青藏高原地区1966~2005年共87个气象站点逐日观测资料,分析其变化趋势。结果显示:最热月均温与最冷月均温整体均呈上升趋势,而最冷月均温的上升幅度明显大于最热月均温的上升幅度,空间上两者呈非对称变化。≥10℃积温、≥5℃积温和≥0℃积温增幅依次增大,其日数的变化是,≥5℃积温日数增幅最大,≥10℃积温日数次之,≥0℃积温日数最小。总体而言,近40年来青藏高原温度变化为增加趋势,植被的最佳生态空间及生态地理区域界线可能会发生不同程度的变动,生态系统的结构和功能可能也需要进行相应的调整来适应温度的变化。

Variation of bio-temperature indexes on the Tibetan Plateau in the past 40 years

The Tibetan Plateau is sensitive to climate change,and its detailed trend of climate change is highly interesting.Temperature change is a key content of climate change.Currently,more studies focused on statistical meaning of temperature change,but ignored its biological meaning.In this study,mean temperature of the warmest month (TWM),mean temperature of the coldest month (TCM),accumulated temperature of duration temperature ≥10℃ (AT_(10)),duration with mean daily temperature≥10℃ (DT_(10)),accumulated temperature of duration temperature ≥5℃ (AT_5),duration with mean daily temperature≥5℃ (DT_5),accumulated temperature of duration temperature ≥0℃ (AT_0) and duration with mean daily temperature ≥0℃ (DT_0) were selected as representative bio-temperature indexes due to clear biological meaning,and their changing tendencies were analyzed based on observation data of 87 stations on the Tibetan Plateau during 1966-2005.The result indicated that TWM and TCM increased significantly with different velocities,arid that also it slowed down with different variation tendencies on the spatial distribution.Even contrary variation tendency between TWM and TCM was found at some stations,but its significance level is lower.AT_(10),AT_5 and AT_0 were ascending with high significance level,with the largest increase in AT_(10),followed by AT_5 and AT_0.Differences with variation tendency of AT_(10),AT_5 and AT_0,DT_5 had been greatly rising,followed by DT_(10) and DT_0.As far as significance level was concerned,DT_(10) was the highest,followed by DT_(10) and DT_0.In general,air temperature of the Tibetan Plateau is rising,which can affect ecological niche and eco-geographical boundary,and make structures and functions of ecosystem modified adaptive to temperature change.