近52年渭河流域气候变化对植被净第一性生产力的影响

Effect of Climate Change on Net Primary Productivity of Vegetation in the Weihe River Basin

利用渭河流域及其周边地区52个气象站1959—2010年的逐日气象资料,采用周广胜-张新时模型、Penman-Monteith模型、气候倾向率、相关分析和Spline插值等方法分析了近52年渭河流域气温、降水、湿润指数的时空变化特征及其对植被净第一性生产力(NPP)的影响,并对其未来变化趋势进行预测。结果表明:(1)在渭河流域,气温呈上升趋势(0.4℃/10a,p<0.001),且北部快于南部,东部快于西部;降水呈减少趋势(-20.1mm/10a,p>0.1),且南部快于北部。(2)湿润指数总体下降,仅关中部分地区微弱变湿。(3)NPP高值区位于秦岭山区、关中部分地区;NPP总体下降,仅个别站点微弱上升。NPP下降速率南部大于北部,空间分布格局与同一时期降水量和湿润指数的变化较为一致。(4)NPP与降水量、相对湿度和湿润指数均呈显著正相关(p<0.01),与潜在蒸散量、日照时数和气温负相关,温度对于NPP累积所起到的作用有限,水分是主要制约因素。(5)不同气候变化情景下对NPP的模拟表明,温度和降水同时上升的情况下,NPP增加15%以上;仅温度升高而降水不变时,NPP增加10%左右;温度上升而降水下降导致NPP不升反降,仅个别地区出现小幅上升。

Based on the temperature and precipitation data got from 52 meteorological stations within and around the Weihe River Basin between 1959 and 2010, Net primary productivity （NPP） was calculated using Zhou Guang-sheng and Zhang Xin-shi Model. The spatial and temporal variation of temperature, precipitation, humid index, NPP and their relations were analyzed by using linear regression, correlation analysis and Spline spatial interpolation method. The possible response of NPP to the variation of temperature and pre-cipitation in the future was discussed. The main results are as follows： （1） Climate became warmer with a trend rate of 0.4 ℃/10a, and the increase in the northern part was larger than in the southern part, eastern part was larger than western part. Precipitation was decreasing with a trend rate of --20.1 mm/10a, which was larger in southern part than in northern part; （2） The humid index was decreasing with a rate of --0.02/10a, but Guanzhong area presented a slight tendency of becoming wetter; （3） The NPP was large in Qin Mountain, Guanzhong area. NPP of the whole basin was decreasing while a few stations presented a slight increasing tendency. The trend rate of NPP in southern part was bigger than in northern part, which was in accordance with the distribution character of precipitation. （4） NPP correlated positively with humid index and precipitation, while correlated negatively with potential evapotranspiration, sunshine duration and temperature. Temperature had limited impact on accumulation of NPP, precipitation was the main limit factor; （5） The result of simulation demonstrated that under the scenario of temperature and precipitation increasing at the same time NPP would increased by approximately 15 % or 10 %. Under the scenario of annual precipitation decreasing by 20 %, NPP would also decrease, only a few stations increase insignificantly.