recognition and analysis of agro climatic indices changes in iran

in this study, by using minimum, maximum and mean daily interpolated data from asfazari data base, the changes of agro climatic indices analyzed in iran during 1962-2004. at first, the indices calculated for each pixels and then trend and slope value evaluated by nonparametric mann-kendal and parametric regression method. in total, the results showed that the indices have positive trend on the low elevations region on iran, while on the height elevations the indices have negative trend. the start of growing season length (sgs) start earlier and end of growing season length delay latter. the result of this is the increasing of growing season length in iran. this lengthening of the growing season can mostly be attributed to advances of spring start of growing season length rather than the delay of autumn.