| In this paper, it uses solar energy utilization rate of the CASA model as the foundation, and uses 2000-2013 MODIS NDVI data during the month scale, temperature, precipitation, solar radiation data and different vegetation types, the combination of remote sensing and geographic information system technology, which estimates Inner Mongolia terrestrial vegetation net primary productivity of growing season in recent 14 years(4-10 month).Also, it discuss relation between vegetation net primary productivity and climate. So, it gets the following conclusion:1.During 2000-2013 years, terrestrial net primary productivity of growing season NPP showed an increasing trend in Inner Mongolia, which increased from 250.16 gC/m2/yr in 2000 to 321.03 gC/m2/yr in 2013, the increase rate of 3.78/a. Especially after 2011, NPP increased dramatically, which reached the highest value in 2013. From the seasonal change trend, the mean NPP of spring, summer and autumn increased, the rate of increase in summer NPP maximum(2.51/a). From correlation analyses between NPP and climate factors, changes in the growth season and the season of NPP is mainly affected by precipitation amount and temperature change. The precipitation is the main factor that leads to the Inner Mongolia terrestrial vegetation NPP increases, but the temperature limit the NPP’s increasing to a certain extent.2.During the period time of 2000-2013, different vegetation types NPP means has a larger difference in Inner Mongolia. In the northeast of Inner Mongolia semi humid area of deciduous broadleaf and deciduous coniferous forest area, due to plenty of sunshine and abundant rainfall condition, the two vegetation types of NPP mean value is relatively high. Which were 648.47gC/m2 and 506.59 gC/m2. While the shrub(354.83 gC/m2), crop vegetation(348.43 gC/m2), sparse forests(321.76 gC/m2), grassland(286.86 gC/m2) and desert(49.92 gC/m2) regions in the arid and semi-arid regions is relatively low that is affected by the higher temperature and lower precipitation NPP average. From the change trend of different types of vegetation growing season and seasonal average NPP in Inner Mongolia, the average NPP of 7 different types of vegetation growing season showed an increase trend during 14 years,. The desert area NPP in growing season is the slowest growth rate, increase the rate of 0.75/a. In the seasonal NPP variation trend, in addition to deciduous coniferous forest fall NPP decreasing, other vegetation types showed an increase trend in the spring, summer, autumn.3.From space distribution growing season NPP during 2000-2013 year, the East is High while the West is low. The distribution trend, decreasing from northeast to southwest, consistent with the change trend of temperature and precipitation in this region. The total area of the entire study area accounted for 92.57% showed an increase trend. The extremely increased area mainly distributed in the north of Greater Khingan Range part area, Hulun Buir plateau in western regions, the West Liaohe plain and Horqin Sandy Land and Hunshandake Sandy Land in eastern, southern and central parts of the XilinGol plateau, east central region in Mu Us Sandy land, Southern part of Kubuqi desert, Badan Jilin desert southwest and central part of Gobi area. However, the significantly reduced area is very small, the total area of the study area 0.29%. From the distribution of seasonal trend of NPP spatial variation, the increasing area of seasonal NPP is larger than the decreasing area. Among them, the area of summer NPP, showing a significant increasing trend, is the largest, which account for the total area of the whole study area 7.61%. While the area of autumn NPP, showing a significant decreasing trend, is the largest, which account for the total area of the whole study area 0.81%.From the changes of different types of vegetation spatial trend, during 2000-2013 years, the increased the area of the NPP of different types of vegetation growing season in Inner Mongolia is larger than the decreased area.4.From the terrestrial net primary productivity in response to climate growth analysis in Inner Mongolia, it presents the positive correlation between NPP and precipitation in growing season in most areas of Inner Mongolia, account for the total area of the study area 98.18%. NPP and precipitation showed very significant positive correlation in the central and northern areas of Hulun Buir Grassland of Inner Mongolia. Correlation between NPP and temperature in growing season showed a negative correlation, accounted for 84.7% of the study area, in addition to the north of Hulun Buir plateau and Badan Jilin desert area being positive relationship. From the seasonal scale, the area of the positive correlation between NPP and precipitation in spring, summer and autumn are larger than the area of the positive correlation with temperature. What’s more, at the season scale, the area of the exceedingly negative correlation between NPP and precipitation is special less in spring and summer and autumn, accounting for the total area of the study area 0.01%, 0.02% and 0.05% respectively. This shows that seasonal precipitation is the main factor to improve the seasonal NPP growth in the Inner Mongolia area, which responds to precipitation was more sensitive than the temperature.The correlation between NPP and precipitation in the growing season of different vegetation types are better than the correlation with temperature. The positive relationship with precipitation area is far greater than the positive relationship with temperature area. The area of the positive correlation between NPP and temperature in the growing season of broad-leaved coniferous and deciduous broad-leaved forest is larger than the area of a negative correlation. From correlation between the NPP and climatic factors in different vegetation types in each season, the area of 7 kinds of vegetation NPP, being positively related with precipitation in spring, summer and autumn, are all larger than a negative correlation.5.The analysis of the correlation between terrestrial vegetation’s monthly NPP and the early precipitation and temperature in Inner Mongolia demonstrates that the temperature has noticeable impact on the late NPP but the precipitation, within the period of seeding establishment. However, after June, both the precipitation and temperature have significant influence on the increase of the NPP. The response lag analysis of climate factor due to its NPP of different kinds of vegetation shows a possible correlation between the NPP of all the other kinds of vegetation and the precipitation accumulated in the early stage except the deciduous coniferous forest. Therefore, the early precipitation is of great importance to terrestrial vegetation’s NPP. |
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