Research On Evolvement And Meteorological Driving Factors Of Vegetation In Ordos Basin Using Remote Sensing Data

The ecology of Ordos Basin, located in arid and semi-arid region, is relativelyfragile environmental change. The environmental problems of the basin have becomemuch more serious than the ever, as that it was projected to be built as the nationalmajor energy base, and much more water resources needed for industry andurbanization development. It is of importance to carry out a research on regionalvegetation variation, and impacts on vegetation.Making use of vegetation remote sensing data GIMMS-NADI from1982to2006,applying software ENVI, ArcGIS, and employ GIS methods and variousmathematical statistics, we study vegetation coverage variation on spatial andtemporal scale. We also analyze the correlation between vegetation coverage changeand meteorological elements on spatial scale, and vegetation sensitivity tometeorological variation on temporal scale. Base of these researches, someconclusions can be reached as the followings:1) The growing period of vegetation in the basin start from April, and end inOctober in a year, and August is most productive time of the vegetation during itsgrowing period. Vegetation in the southeast of the region firstly enters its growingperiod, while vegetation in the southeast first end growing period in September.Vegetation growth have two significant periods1year and6~8year.2) From1982to2006, the area of increasing vegetation occupies a majority ofthe area of the basin, nearly70%area, at the same time vegetation in some placedegraded. Vegetation growing period has been pushed backward.3) From1991to2000, precipitation and air temperature have different trends inthe basin. Precipitation in northwest has increasing trend, meanwhile, temperature risein southern and decrease in the northern of basin.4) The delay period of vegetation growth to precipitation variation is about amonth, and there is no obvious delay time of it to temperature. Vegetation in thenorthwest of the basin has higher correlation with precipitation, but they have smallcorrelations in the southeast of the region. The correlation is higher between vegetation and temperature in the northern of the basin, while their correlationbecome small in the south of the basin.5) When precipitation quantity is smaller and temperature is lower, thevegetation growth is much sensitive to the variation of precipitation and temperature.Along with the precipitation and temperature increase, the sensibility of vegetationgrowth to the climate reduces. The threshold of temperature impacting on vegetationgrowth is22~24℃, and but the threshold of precipitation is should above110mm.