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1980—2023年西藏高原气候变化特征及其对农业的影响

Characteristics of Climate Change in Xizang Plateau from 1980 to 2023 and Its Impact on Agriculture

  • 摘要: 基于西藏38个气象站点1980—2023年气温、降水量、日照时数的观测数据,采用线性回归、5年滑动平均、M-K突变检验等方法,分析了其关键气候要素的时空变化特征。结果表明:(1)近44年来,西藏年均气温以0.379 ℃/10 a的升温速率极显著上升,2000年发生了气候突变,1997年为显著升温的转折点;空间上呈现西北高海拔区(那曲、阿里)的升温速率高于东南部的特征,作物适生区向高海拔地区扩展。(2)年降水量呈弱增长趋势(4.032 mm/10 a),并于1985年发生了突变,2009年以后降水量呈下降趋势;降水空间分异性显著,东南部(林芝)可达西北部(阿里)的2.8倍。季节上表现为春、夏季增湿而秋、冬季趋干的“暖湿—冷干”格局,降水表现出集中化趋势(5—9月的贡献率增至59%),极端降水事件频发。(3)日照时数以21.18 h/10 a的速率显著递减,在2016年发生了突变,空间分布与降水呈反向变化的特征,西北干旱区“少雨多照”与东南湿润区“多雨少照”分异性显著,其中,冬季微弱增加,夏季显著减少。气候变化对西藏农业产生了双向效应:升温显著延长了生长季、扩展了高海拔适生区、微幅提高了冬季设施光热效率;但降水空间的分异与集中化加剧了东南洪涝与西北干旱风险,日照减少可能影响作物的光合效率,以及显著增加了病虫害的发生频率、范围和极端事件的威胁,而冬季日照增加有利于促进设施农业的发展,并且能为区域农业布局优化、灾害防御和可持续发展提供理论科学依据。

     

    Abstract: Based on the observation data of temperature, precipitation and sunshine hours of 38 meteorological stations in Xizang from 1980 to 2023, the spatial-temporal variation characteristics of key climatic elements were analyzed by using linear regression, five-year moving average, Mann-Kendall (M-K) mutation test and other methods. The results show that: (1) In the past 44 years, the average annual temperature in Xizang has risen very significantly at a rate of 0.379 ℃/10 a, with a sudden climate change in 2000 and a significant warming turning point in 1997. Spatially, the warming rate in the northwest high-altitude areas (Naqu, Ali) is higher than that in the southeast, and the crop suitable areas are expanding towards higher altitudes. (2) The annual precipitation showed a weak increasing trend (4.032 mm/10 a) and underwent a sudden change in 1985. After 2009, the precipitation showed a decreasing trend. The spatial variability of precipitation is significant, with the southeast (Linzhi) reaching 2.8 times that of the northwest (Ali). In terms of seasons, it shows a "warm wet cold dry" pattern of increasing humidity in spring and summer, and drying in autumn and winter, with a trend of precipitation concentration (the contribution rate from May to September increases to 59%), and extreme precipitation events occur frequently. (3) The sunshine hours significantly decreased by 21.2 hours per 10 years, and underwent a sudden change in 2016. The spatial distribution and precipitation changed in reverse, with a significant difference between the“ less rain and more sunshine” in the arid northwest region and the“ more rain and less sunshine” in the humid southeast region. There is a slight increase in winter season and a significant decrease in summer season. Climate change has had a two-way effect on Xizang’s agriculture: warming significantly prolonged the growth season, expanded high-altitude habitat, and slightly improved the light and heat efficiency of winter facilities. However, the differentiation and concentration of precipitation space have intensified the risks of floods in the southeast and droughts in the northwest. The decrease in sunshine may affect photosynthetic efficiency and significantly increase the frequency, scope, and threat of extreme events of pests and diseases. The increase in winter sunshine is conducive to the development of facility agriculture and can provide theoretical and scientific basis for optimizing regional agricultural layout, disaster prevention, and sustainable development.