Features of Annual Temperature and Precipitation Variety with the Effects on NPP in Chongqing

In terms of mean temperature and precipitation data of 34 observation stations in Chongqing from 1959 to 2001 the NPP is calculated using Leith's famous Thornthwaite Memoriae model. Based on EOF and MHF wavelet the variations of temperature, precipitation, NPP and their relations are analyzed. The effects of temperature and precipitation on NPP are discussed and the prediction results in the future and possible increase extent of the NPP in Chongqing are discovered. Results show that there are consistent distributing characters among annual temperature, precipitation and NPP in Chongqing. The variation tendency of annual temperature is descend, that of precipitation is unconspicuous, and that of NPP is descend slightly during the whole times. But they all have their own obvious staggered change features, and the variation tendency of precipitation and NPP are approximate. The variation tendency of climatic productivity strongly resembles that of rainfall in multi-time scales, but it is not consanguineous to that of temperature in less than 10 years scales. The quasi-period of temperature series is main about 10 years and those of precipitation and NPP series is main about 2 years from 1959 to 2003. The interannual oscillations of precipitation and NPP are strong, and interdecadal oscillations of temperature are strong. The increase or decrease of mean temperature or precipitation result in corresponding change of the NPP. The NPP increase by degrees while only temperature or precipitation raises. The warm-wet type climate is most advantageous for NPP but cold-dry type one is most disadvantageous. The NPP will increase 11.2% or so controlled by the former climate type but lessen 12.5% or so controlled by the latter climate type. Correlative climate prediction results show that the temperature and precipitation will both increase little and so the increase scope of the NPP in Chongqing will be 0.3%—3.9% in 2010, but 6.7%—10.0% in 2030 because the temperature and precipitation will both increase much, and 4.4%—8.4% in 2050 while the temperature will continue increase but the precipitation will increase indistinctively. In the coming 50 years the climatic variation tendency will be propitious to increase of NPP and the NPP will be top in 2030 or so.