Response Characteristic Analysis of Climate Change of Vegetation Activity in Huanghe-huaihe-haihe Zone Based on Noaa Ndvi Data Set

The article, using the each ten day’s data of NOAA/AVHRR from 1981 to 2000 and adopting the Maximum-Slope Method and Curve-Fitting Method, analyzes the beginning and ending of the growth season of the vegetations in the Huanghe-Huaihe-Haihe (HHH) zone. Meanwhile, the pixel by pixel NDVI map is worked out with typical bands as the sample. The article, through researching on the change of green wave and brown wave, reveals the changing rules of vegetation activities and its response to climate changes in the past 20a. According to the researches, the growth season in the HHH zone starts at the last 10 days of March and ends at the first 10 days of November on average. The average NDVI for the vegetations in the researched area in the past 20 years is generally increasing, especially in Spring. With the time passing by, the green wave of the critical value of the growth season in the area changes from south to north, while the emergence of brown wave prolongs from north to south. As the main response of the vegetation activities in the area to climate changes, the growth season of the vegetation happens ahead in the HHH zone.