Analysis of the Spatial and Temporal Trend of Annual Rainfall in Iran during 1950-2007

One of the ways to assess the rainfall trends in the past and present is through trend analysis of time series of rainfall at different scales of time. The aim of this study was to analyze the spatial and temporal trend of annual rainfall in Iran using Aphrodite's database. In this study, using the quality- controlled resulting outputs of Aphrodite cell precipitation database in order to assess the trend of the country's Iran's annual rainfall. The base data for the period of 1950 to 2007, and with the spatial resolution is of 0.25 × 0.25 and 0.5 × 0.5 degrees were used. Iran's annual precipitation trend was calculated using non-parametric Mann-Kendall method and in order to estimate the slope of trend the age line slope method was conducted. The results of the analysis of these data showed that in the time series of mean cell and Iran precipitation stations of Iran precipitation, there is was no significant increasing or decreasing trend at confidence levels of 99 and 95%. Age test statistics at the assessed confidence levels showed that the average rainfall of Iran has increased by about 0.439 mm/yr per year. In addition, the minimum and maximum decrease in rainfall at 99% level was -0.476 and 1.321 mm respectively. While the minimum and maximum Iran cellular precipitation at 95% level was estimated to be -0.221 and 1.088 mm respectively

Spatiotemporal changes of forest fire in vegetation areas of Iran based on MODIS sensor

The increase in fire activity in many regions of Iran in recent decades has raised concerns about the short-term and long-term consequences. Forest and pasture fires will affect the quantity, quality, and health of natural ecosystems. The first step in controlling and preventing forest fires is monitoring. Therefore, this study was conducted to estimate ​​fire areas and identify the spatial-temporal changes of these events in the vegetation areas of Iran. To achieve this goal, TERRA satellite MODIS sensor data including active fire products (MOD14A1) and burned areas (MCD64A1) for 20 years (2001-2020) have been used. The results showed that the maximum extent of fires in the vegetation areas of Iran is related to July, which covers about 4100 hectares. This month, a large part of the country's forests, especially in the northwestern parts of the Arasbaran vegetation area, has caught fire. In contrast, the minimum amount of fire areas in the vegetation areas of Iran is related to April, which was observed as two limited zones in the northwest and west of the country. Due to the maximum time of forest fires in the hot and dry months of the year, including June, July, August, and September in the western part of the country in the Zagros. The linear correlation between the burned areas and the areas with active fires in Iran showed that there is a significant relationship between these two satellite products. This connection shows that the burned areas in the vegetation areas of Iran are among the active centers of forest fires