The Trend Analysis of NDVI index in the elevation Class of Iran

As vegetation and its variations have an effective influence, it is indispensable to be aware of the vegetation changes for each of the given geographic territory. The aim of this study is to examine trends in the NDVI index over Iran's elevation class. For this purpose, the MODIS Aqua Satellite NDVI data were obtained from July 4th 2002 to March 14th 2015. The 16 days long term mean of NDVI was computed based on the analysis of 10 billion pixels and, at the next step, a matrix was constructed in 111*293, which the rows were the representatives of the elevation class from -50 to 5500m in 50 meter steps and the columns showed the long term mean of the NDVI in the 16 days temporal resolution. The trend investigation using Mann-Kendall trend test revealed a positive trend for 400-450, 450-500, 500-550, 700-750 and 1250-1300 m elevation class at 0.95 level of significance, the other remaining elevation class showed no significant trend.