عنوان مقاله [English]
Changing climate is one of the most important issues in the present age. Heavy rainfall is the prominent clue of it that sometimes is destructive and harmful and has some awkward effects on human being’s environment. It does not seem to be from the same source and each part of Iran has its special sources (Ghaur and coligues 27-11 1391). Iran is one of those regions which has experienced irregular and climatic abnormalities (Mohamadi and Masodian 70-47 1389). for having Topographic has the heavy and sever rainfall which is in one of the climates raucousness which faces the global with different crises such as severe floods, damage in agricultural sectors, transportations and human death .because of this, recognizing the methods and studding of these occurrences to exact prognosticate and an alert before the incident has an important role in the management of preventing the events .the place and time of raining changes in the mountainous region of Iran’s North west is a lot.( khorshiddoost and coligues 1395 82- 53) . The Iranian west vast part not only depends on local conditions, but on out regional and itinerant systems in weather circular conditions. These specifics cause our study to be affected by rare annual raining, the shortness of rain period and severity of the raining in the shower forms. (Banfshe and coligues 1394 117-135).
Methodology and data
The severe rainfall in Kermanshah province has been studied in this research and to obtain the aim, Data of 92 synoptics and hydro graphing stations has been gathered during 1970, 2018. The Data produced in two parts, the first part with 1434 stations until 2004 and the second with 1036 stations from 2005 to 2018. After the Data being prepared to determine rainfall limitation, heavy and dangerous ones the most important is to choose the suitable threshold. From the 90 decades most researcher sources have been used for studding the hard raining in fact using decades for heavy rain in each point is on the basis on its raining behavior, thus the 90 decades has been applied in the research. Man, Kendal Analysis method has been used for studding the situation and heavy rain changes.
The results show that the severe rainfalls include most of Kermanshah province annual precipitation, the conditions are more observed in the North West parts such as Javanrood and Pave cities and in the South east gets to the least point. Most heavy rain occurrence expansion includes a tow- day continue and the least includes a five- day one. The heavy rain changes coefficient on the other hand had increased terribly as a result of its continuance, so that the situation in the east of province was more prominent. the heavy rain limit over the province was different and the most limitation with heavy one with 20 mm was observed in some parts in west of the province , especially in Gillan e Gharb and the least with 9MM in the east part .But on the contrary the least ones had more continuance with 2 or 5 days of training and has been observed as nuclear in some parts of Kermanshah such a Ravansar and Javanrood .Man Kendal Graphic tests also revealed that the 2 and 3 days raining continuance in after 2000 got a leaping .while the 4 and 5 days has been observed during the beginning of period of research .
The aim is to study the analyzing and studding of Kermanshah heavy rains and for this the data of 92 synoptic and water gauge stations from Esfazari stations were gathered .the term decade is used to determine the limitation of heavy rainfalls in each point and Man Kendall test is used to scrutinize more in the province rainfalls , results revealed that heavy rainfalls in Kermanshah province form the huge parts of the province and the limitations over the province has been different me the most occurred in the Northwest part and the least in the half Eastern part. And the most part of the under study on heavy rainfall limitation was between 11 to 15 MM, the rainfall process over the province expansion in 2 to 5 days of continuance has experienced a decrease one and this also includes for the 2 days rainfall continuance .and also Man Kendall Graphic test reveals a meaningful leap for 2 and 3 days of continuance in the recent years and has experienced a 4 and 5 ones from the beginning of the research.