TY - JOUR T1 - Investigating the 15-year-old seasonal variations in leaf area index using MODIS sensors in Iran TT - بررسی تغییرات فصلی 15 ساله نمایه‌ی گستره‌ی برگ با استفاده از سنجنده‌ی مودیس در گستره‌ی ایران JF - gnbd-pec JO - gnbd-pec VL - 7 IS - 14 UR - http://pec.gonbad.ac.ir/article-1-360-en.html Y1 - 2019 SP - 189 EP - 208 KW - seasonal study KW - temporal behavior KW - modis KW - leaf area index KW - Iran. N2 - Today, it is widely used satellite imagery to monitor vegetation cover. The aim of this study is to analyses the leaf area in the period of 1395-1381 with the spatial resolution of a kilometer using the data of two remote sensing products of MODIS Terra and Aqua and seasonally. For this purpose, data were analyzed and statistical-mathematical compilation, coding and database creation were done in the software and then prepared the seasonal average map. These maps indicate that the centers of the center, east, and south-east are almost empty of leaf and / or leaf area. The area of the leaf is very thin in some areas and there is no vegetation cover 58.26 percentage of Iran. In contrast, they have a good leaf area, the northern slopes of the Alborz, the North-West highlands and the middle Zagros domains whit 41.74 percentage, which generally include the fields, with the exception of the Hyrcanian forests and Arasbaran. In terms of time, the highest mean leaf area was in spring and summer with an average of 0.47 and 0.36, and the lowest mean were autumn and winter. In the next stage, the leaf area index was prepared. The cells were then placed in four chapters and finally in two groups. These two groups include the cold season with the autumn and winter season, and the hot season group with spring and summer. M3 ER -