The goal of this research is studying the effect of recent climate changes, espeeially heat rise on the amount of effective  rainfall in the lorestan peovince. Effective rainfall is the amount of fall which, after evaporation, is absorbed in the ground. in the ground.in USDA method and the us agriculture, the amount of rain abstorbed in a growth perlod of a plant and available for its consumption is called effective raifoll. The results showed that the amouent of rainfall in the first period is more than that of the second. The frequency of raining days got reduced  in the after-climate- change period. Heat got increased in the second period. Evaporation was more in the second period. Relation humidity got decreased in the second compared to the first period, and wind speed increased by studying the process of the data changes, it became evident that climate change leads to the increased inconsistent rainfalls in the studied climate variables indicate that under the effect of climate change , Based on Vibol method, droughts caused by effective rainfalls were calculated, and the probability of effective rainfalls in 5 time periods was accounted for. It was shown that in the years 1369 to 1396, effective rainfall in the region was scarce, so it was very influential. With Dobif Model, effective rainfall was analyzed, and years with the least effective rainfall for dry farming with positive signal, that is, appropriate conditions, and negative, that is, inappropriate conditions were recorded. Based on linear coefficient, rainfall trends in the three stations of Khorramabad, Aligudarz and Borujerd. Geographical distribution analysis of   effective rainfall showed that in the south and south-east of the province, the coefficient of effective rainfall was more than the rest of the province. This coefficient was decreasing when it comes to the south-west of the province. Effective rainfall decrease was more due to increasing evaporation happening in this part. the effective rainfall in the studied region got decreased, therefore, preserving underground water resources, on which natural life depend, should be considered more than ever.

In this research, we are trying to determine the “beginning time” as well as the “end” of the climatic seasons; and we will focus on identifying the displacement of these dates, which is influenced by the “climate changes” and “descriptionAbstract
The purpose of this study is to investigate possible changes and displacements in Iran's climatic seasons due to climate change. To do this, temperature, relative humidity, water vapor, wind and cloud data for 36 stations were received from the Meteorological Agency over 40 years. The data were divided into two 20-year series to allow comparison. Daily temperature data for each clustering time series were determined, then by considering 7-day sequences, the beginning and end of the seasons. The designated times were tested using the Rayman model. The results of comparing the seasons in the two time series indicated that in all stations, changes in climatic seasons occurred from Insignificant to significant. Climatic seasons in Iran do not correspond to calendar seasons, and climate change, especially temperature changes in recent decades, has caused the seasons to shift and shorten and lengthen. Although the beginning and end of the seasons do not generally correspond to their calendar dates, most of the days of these seasons occur in its calendar periods. The changes that have taken place have not only affected the length of the seasons, and these shifts have also changed the quality of the natural seasons.
Keywords: Climate change, natural seasons, cluster analysis, Rayman model of the qualitative conditions” created in them, compared to the past climatic periods. “Meteorological Organization” data has been used in this research. Forty years of received data, was divided into two groups of 20. Applying SPSS, each group was divided into four stages representing each seasons. From these stages, the beginning time and the end of seasons were determined and the accuracy of the obtained dates was controlled with the comfort indicators of the Rayman model. The results of the comparison of seasons in two time series indicated that, the changes occurred in natural seasons from an almost non-existent one in all stations. Climatic seasons in Iran are not compatible with the summer season and climate change, especially the change in temperature in recent decades, has caused changes and shortening of seasons. Most of the days in these seasons occur during its monthly periods, although the beginning and end of the seasons generally do not match their calendar dates. Changes have not only affected the duration of the season, and these changes have also led to a change in the natural quality of the season.