西北干旱地区气候变化及其对草地生产潜力的影响

Climate change in arid regions of Northwest China and its impact on potential grassland productivity

依据宁夏各县区24个气象站37年(1981—2017年)间的逐月气温、降水资料,采用Miami模型和Thornthwaite Memorial模型计算宁夏草地生产潜力,分析其时空变化。结果表明:从时间变化来看,宁夏平均气温以0.47℃·(10a)^-1的速度持续上升,降水量呈先下降后上升的趋势,从2010—2017年年降雨量增加了40 mm;从空间变化来看,宁夏气候从西北向东南由“暖干”向“冷湿”逐渐变化;宁夏草地气候生产潜力从西北向东南逐渐递增;草地气候生产潜力变化趋势与降水变化趋势一致,各时间段气候生产潜力与降水呈显著正相关(P<0.01),与温度呈负相关关系。因此,降水是宁夏草地气候生产潜力的限制因素,草地生产潜力较大区域在宁夏中南部,而以温度升高为特征的气候变化,对宁夏草地气候生产潜力影响较小。

Based on the monthly temperature and precipitation data of 24 meteorological stations in Ningxia during the past 37 years(1981-2017),the Miami model and the Thornthwaite Memorial model were used to calculate the potential grassland productivity in Ningxia,and analyzed its spatial and temporal changes.The results showed that from the perspective of time changes,the average temperature in Ningxia continued to rise at a rate of 0.47℃ every 10 years,and the precipitation first decreased and then increased;the annual precipitation increased by 40 mm from 2010 to 2017.From northwest to southeast in Ningxia,the phenology was changed from"warm and dry"to"cold and wet".Meanwhile,the potential climatic productivity of grassland in Ningxia gradually increased from northwest to southeast.The trend of potential climatic productivity of grassland was consistent with the trend of precipitation.There was a significant positive correlation between potential climatic productivity and precipitation(P<0.01)each time period,and a negative correlation between potential climatic productivity and temperature.Therefore,precipitation was the limited factor for the potential climatic productivity of grassland in Ningxia,the largest potential grassland productivity was in the south-central part of Ningxia,and the climate change characterized by rising temperature has a weak impact on the potential climatic productivity of Ningxia grassland.