Responses Of ANPP To Climate Change In Inner Mongolia Grassland

Global climate change research has become the largest inter-disciplinary,trans-department, cross-border research activities in international cooperation filed,which represents the development trend of world science, the interactions and feedbackof climate change and terrestrial ecosystems that most closely with human being havebeen known as a hot issue. Inner Mongolia grassland which located in the mid-Eurasiancontinent steppe zone, plays an important role in the study of global change processes forits special geographical location, variables in climatic conditions and the complex naturalenvironment. As an important parts of the terrestrial ecosystem, Aboveground NetPrimary Productivity (ANPP) dynamic determines the environment quality and thecarbon balance of the terrestrial ecosystem, has a direct effect on the grassland animalhusbandry. This paper focused on the spatial and temporal dynamic changes and futuretrends of theANPP under the current situation of global climate change.We has analyzed the spatial and temporal climate variation of Inner Mongoliagrassland by using106automatic weather stations data from1961to2010, evaluated thesimulating ability of the CENTURY model in point and area by using the data collectedfrom39grassland monitored stations and10a satellite remote sensing data, simulated thespatial and temporal dynamic in ANPP by using the data collected from78automaticmeteorological stations in Inner Mongolia grassland, also analyzed the correlationsbetween ANPP and26meteorological factors. Finally, we are simulated the spatial andtemporal patterns, rate of change and the possible variation tendency of Inner Mongoliagrassland based on the SRES B2,A2and A1B scenarios. The results show as follows:1. In the past50years, the annual average air temperature, the average airtemperature of the growing season, the annual extreme maximum air temperature and theminimum air temperature showed an upward trend in Inner Mongolia grassland, with therate are0.39℃/10a,0.33℃/10a,0.24℃/10a and0.54℃/10a, respectively. The warmingmainly occurred in the Northeast of Inner Mongolia grassland. There are no significantchange trends in the annual average precipitation and precipitation during the growingseason; The annual average sunshine hours showed a significant downward trend withrate of14.6h/10a; The average wind speed was decreased obviously with rate of0.2m/s·10a; The relative humidity also showed a significantly decrease, while the annual maximum snow depth was significant increased.2. In the past50years, ANPP of Inner Mongolia grassland has an increase trend.ANPP in the typical steppe has a slight increase trend with the rate of1.04g/m~2·10a;ANPP in the meadow steppe has no a significant increase trend with the rate of just0.41g/m~2·10a；while ANPP in the desert steppe has a significant increase trend with therate of2.57g/m~2·10a. The validate results of CENTURY model showed that most ofsimulation effects were very well; The spatial simulation results of ANPP in InnerMongolia grassland showed a high agreement with NDVI. Spatial distribution of ANPPpresented the obviously zonal distribution, which was gradually dropped form east towest, form south to north.Correlation analysis indicated that the correlation between ANPP and the annualprecipitation was significant, especially with the precipitation during the growing season.Grassland ANPP of Xilinhot has a extremely significant negative correlation withextreme maximum air temperature, average air temperature and average maximum airtemperature. Grassland ANPP of Siziwang Banner has a extremely significant negativecorrelation with extreme maximum air temperature. Grassland ANPP of Eyou Banner hasa significant correlation with the mean minimum air temperature, averaged surface airtemperature and average air temperature, while it has a extremely significant negativecorrelation with the annual average wind speed.3. In three kinds of SRES scenarios, the spatial distribution patterns of ANPP werestill decreased gradually from south to north, from east to west in Inner Mongoliagrassland in2030s. Compared to the base year, the ANPP of most parts of InnerMongolia grassland in2030s is higher than the base year. The spatial distribution ofANPP change rate shows that ANPP will present the increasing trend in most parts ofInner Mongolia grassland in2030s, distribution area of ANPP with greater than251g/m~2is largest in SRES A2scenario, decreasing in SRES A1B scenario, while it is smallest inSRES B2. Distribution area of ANPP less than150g/m~2is largest in SRES B2scenario,decreasing in SRES A2scenario, while it is smallest in SRES A1B.