摘要
为了深入研究西藏高寒草甸气候湿润度的时空变化规律,根据西藏地区及其周边38个气象观测站1971—2010年的日均平均温度、降水量资料,采用草原湿润度(K)指标,并利用Arc GIS软件分析西藏高寒草甸40年来气候湿润度的时空变化规律。结果表明:(1)西藏高寒草甸平均湿润度呈条带状由东北部和西南部向西藏中部逐渐减小。(2)湿润度变化趋势的区域特征比较明显,昌都市、日喀则市局部区域湿润度指数呈增加趋势,气候趋于湿润化,其他地区湿润度呈减少趋势,气候干旱化趋势明显。(3)湿润度表现为先升高后降低的趋势。西藏高寒草甸湿区面积由1990s占总面积94.61%,到21世纪初减少至83.24%,从另一个侧面说明研究区域气候干旱化趋势显著。(4)湿润度1.2等值线的位置发生了明显的位移,位置向西北方向推进,逐渐向高寒草甸草原和高寒草原入侵。对于西藏高寒草甸分布地区,在未来的气候变化过程中,对气候干旱现象应给予高度重视。
To study the spatio-temporal variation laws of moisture index of alpine meadow in Tibet, according to the data of average daily temperature and precipitation from 38 meteorological stations in Tibet Autonomous Region and surroundings in 1971-2010, the author adopted the moisture index （K） and the ArcGIS software to analyze the spatio-temporal variation laws of moisture index of alpine meadow in Tibet for nearly 40 years. The results showed that： （1） the average moisture index decreased from northeast and southwest to central Tibet, which appeared to be stripped; （2） the variation trends of moisture index had regional characteristics, some areas of Changdu and Rikaze had an increasing trend, conversely, other regions had a downward trend and obvious aridification; （3） the moisture index presented a trend of ＂increase-decrease＂, resulted in the decrease of alpine meadow area from 94.61% in 1990s to 83.24% in the beginning of 21st century, this also proved that the aridification was significant in the research regions; （4） the location of 1.2 contour of moisture index had a clear displacement, invaded to the northeast and into alpine meadow and alpine steppes. As to the distribution of alpine meadow in Tibet, high attention should be paid to the drought phenomenon during the climate change in the future.
出处
《农学学报》
2017年第1期46-51,共6页
Journal of Agriculture
基金
农业部公益性科研行业(农业)专项"青藏高原羊八井社区天然草地保护与合理利用技术研究与示范"(201203006)
西藏自治区科技厅科技支撑计划"西藏主要气象灾害对农业的影响与数据库建设"
关键词
高寒草甸
湿润度
时空格局
干旱化
西藏
Alpine Meadow
Moisture Index
Spatial-temporal Pattern
Aridification
Tibet
