| With the society development and industrialization process be accelerated continuously, and natural resources be pillaged excessively and utilized unreasonably by human society, the natural environment has been destroyed, the concentration of greenhouse gases such as CO2has risen, and the speed of climate change has increased. The climate change would have important influence on natural environment which is the foundation of humans’survival and development, and bring serious threats on sustainable development of human society. As an important ecological factor, vegetation is the undertaker of climate change and a natural sensitive indicator to reflect the ecological environment change, and it also produces feedback to the climate variation. Therefore, under the background of climate change, NDVI and climate factors of black soil region in Heilongjiang Province were studied, and relationship between the change of vegetation coverage and main climate factors was discussed, which would provide some reference for protecting natural environment, and have important significance on the effective utilization and sustainable development of natural resources in black soil region. The black soil region in Heilongjiang Province is an important production base of commodity grain, however, because of unreasonable reclamation and cultivation, special geographical position, natural conditions such as climate and landform, soil in the black soil region has been erode seriously, the black soil resource has been degenerated obviously. Based on related domestic and foreign research about influence of climate change on ecological environment of vegetation, and feedback of ecological environment of vegetation to climate change, time series data of SPOT/VGT-NDVI was applied, the change features of vegetation coverage in black soil region were analyzed between1999-2007, relationship between climate factors and vegetation NDVI combined with meteorological data was referred, the following conclusions were reached:1) NDVI in black soil region showed fine stability in average value of each year and growth season, which was rising slightly in small-scope fluctuation, and the maximum appeared in2007, the minimum appeared in2000. NDVI change in black soil region showed a single-peak trend in one year, the maximum appeared in August, values of NDVI in December, January and February were lower, and the change was steady. Average NDVI in those years and the growth period showed high consistency in space distribution, which presented an gradually increasing trend from northwest to southeast on the whole. By the differential analysis of NDVI from1999to2007, vegetation in the middle and south of the part A (focused in the black soil area in middle of Heilongjiang Province) and most in part B (focused in the black soil area in northeast of Heilongjiang Province) in study area presented an improved trend, number of grids in the coverage area was60288, which accounted for52.2percent in the whole number, the north of area A presented a degenerate trend, and seriously degenerate area distributed fragmentarily.2) The meteorological factors in black soil region had larger fluctuate on the change of average value of each year and growth season, temperature and precipitation had an increasing trend, while the relative humidity had a declining trend. From the change comparison between temperature and relative humidity, we could see that variation tendencies of them were at opposite state, which would have an enlightening effect on the dependency study of both them and NDVI. The average temperature of the black soil area in area A distributed obviously by latitude, the temperature rose from north to south, and the isotherm distributed from northwest to southeast. In area B, the temperature reduced gradually from west to east, yearly relative humidity and precipitation in average distributed obviously by longitude, values were increasing gradually from west to east. However number of area B in the east was not more than that of area A, average relative humidity in black soil region was between61-71%, of which above on64%in area B, average annual rainfall amount was400-550mm, of which above on460mm in area B.3) The relevance between NDVI and temperature was mainly in positive correlation, especially in the central and south of area A, and the south of area B. The negative correlation in spring and autumn existed sporadically, which showed that positive correlation of NDVI and temperature was better, and the whole area had better consistency. The main relationship between NDVI and relative humidity was negative correlation, especially clear in the south of Wuchang and north of Nenjiang County. Among studies on all the changing scale, only area covered with positive correlation in the scale of growing season was larger than that of negative correlation. In spring, the negative correlation between NDVI and relative humidity generally covered in the whole black soil area, and area of notable negative correlation was very wide, which showed that negative correlation between NDVI and relative humidity was strongest in spring, of which had better consistency in black soil region. The main relationship between NDVI and precipitation was mainly negative correlation, the same as that of NDVI and relative humidity, especially in Nenjiang County and other districts. Among all studies in every change scale, area covered with positive correlation was larger than that of negative correlation only in scale of the autumn season, and the negative correlation between NDVI and rainfall was strongest in summer. |
PDF Full Text Request