| Vegetation as an important part of the geographical environment, is an indicator of environmental change. In recently decades, environmental problems have become an increasingly prominent points in Upstream of Zhanghe River Basin, with influenced by multiple factors, such as natural and human factors. Vegetation cover change is better for protecting regional vegetation and ecological environment. The study area is located in Eastern Taihang Mountains, west of the Taiyue Mountain, includes Changzhi basin, which is the main farming areas. This area has complex terrain and diverse types of vegetation. It is not only according to vegetation protecting and basin reasonably constructing in tai-hang and tai-yue mountains, but also playing a crucial role in cycling of regional energy, at the same time, research of vegetation is viatal for stabling of regional climate, including its main driving factors.In this paper, meteorological data, SPOT5 data, social economic data, TM/ETM+ data, GDP data, MODIS NDVI data, land cover data, would be used to study the characteristics of vegetation cover and, analyses the main driving factors which causing vegetation cover change. Furthermore, it can forecast the trend of vegetation change in Upstream of Zhanghe River Basin, based on the processing and analysis software ENVI/ArcGis/Spss during 2000-2014 years. The empirical model decomposition and wavelet model noise reduction(EMD-wavelet noise reduction mode)was introduced to remove the imagery data noise and error, and then reconstruct the sequence data of NDVI which is in different groups from 2000 to 2014. Traditionally, the change of NDVI in whole region is very significance, rarely focusing on the perspective of different vegetation. In order to further explore tendency of NDVI in different land cover types, this paper analyzed the change of different vegetation with EMD-wavelet noise reduction model. Finally, the analysis results reveal the evolution of different vegetation groups in the region. Here are the main conclusions:(1) The value of NDVI has progressively increasing from 2000 to 2014 in Upstream of Zhanghe River Basin, and the growth rate of NDVI is 2.3%/10 a. Vegetation cover has keep increased trend over 15 years, and the improved area accounted for 31.40%, the former is larger than the latter, the percentage of degraded area is coverged on the urban area, accounted for 15.12%. The value of NDVI is reduced after the first rise regularity, the condition of vegetation cover is good from 2000 to 2014 in Upstream of Zhanghe River Basin, the value of NDVI is highest in taihang and taiyue mountains, lowest in urban area. The value of NDVI has a progressively decreasing from centre to rim.(2) Tendency of NDVI in different land cover types is various, causing different effectiveness. The NDVI values of woodland, cultivated land, no-use land, urban areas and water areas have a periodical change in Upstream of Zhanghe River Basin. The constant cycle is one year, but the volatility cycle has different dynamic evolution laws. The value of NDVI were increased for no-use land, woodland and water. The cultivated land and urban-land keep steady trend. Water land has a certain periodicity, with obviously fluctuating. The NDVI value of water increased first, then remained stable trend.(3) On entirely, the temperature in the Upstream of Zhanghe River Basin is decreasing over the past 15 years, the temperature decreased at a rate of 0.12°C/10 a, by the inspection of the important level of 0.01. In general, the trend of precipitation was rising, the precipitation increased at rate of 15.75mm/10 a, and the value of precipitation is largest in 2003.(4) The value of NDVI has a positive correlation with temperature from 2000 to 2014 in the Upstream of Zhanghe River Basin. On the whole, NDVI and precipitation presenting a positive relationship, too. The correlation coefficient between the temperature is much larger than the precipitation of, it indicated that the influence of temperature is much larger than the precipitation. Through the inspection of the significant level of 0.01, vegetation was influenced by temperature and precipitation in this area.(5) Vegetation coverage has a negative correlation with the distribution of population in the Upstream of Zhanghe River Basin, and the value decreased with the increased population in this area, the value of NDVI is 0.521 at population 0-100, when the populations over 5000, the value of NDVI is the least.(6) Vegetation coverage has a negative correlation with the GDP in the Upstream of Zhanghe River Basin, Vegetation cover was influenced by the development of the economy. In mountains, the development of GDP is lowest, vegetation cover better, but highest GDP in urban area, NDVI decreases when GDP increase. |
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