Analysis of the trend of time-series changes in the maximum daily and annual rainfall of Karkheh and Dez catchment
Precipitation is the most important climatic characteristic of any region. This climatic characteristic is one of the most fluctuating climatic variables that seriously affect the water resources of the region. This issue is important in Iran, where the average rainfall is over 250 mm. The purpose o...
| Main Authors: | , , |
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| Format: | Article |
| Language: | fas |
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University of Sistan and Baluchestan
2022-08-01
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| Series: | مخاطرات محیط طبیعی |
| Subjects: | |
| Online Access: | https://jneh.usb.ac.ir/article_6693_e3ebc04d12aaf94ae6c97efae36cbe43.pdf |
| Summary: | Precipitation is the most important climatic characteristic of any region. This climatic characteristic is one of the most fluctuating climatic variables that seriously affect the water resources of the region. This issue is important in Iran, where the average rainfall is over 250 mm. The purpose of this study is to analyze and explain the heavy rainfall Karkheh and Dez using statistical methods. For this purpose, precipitation data from 14 synoptic stations and a rain gauge period of 60 years (1959-2019) were used. To achieve the objectives of the research used the probabilistic distribution function the final limit type 1 Gumble, and the heavy rain threshold of each station were determined. Then to identify the uniform and non-uniform discharges in the time series maximum daily precipitation and total annual precipitation the ITA method and Man – Kendall non-parametric test were used. The results were obtained from heavy rainfall thresholds, The average rainfall of more than 40/7 mm in Karkheh and the average rainfall of more than 47 mm in Daz are considered heavy rainfall. The average rainfall in Karkheh is 118 days and the dose is 81 days. The flood threshold of Karkheh is less than the Dez catchment. Therefore Karkheh rains occur more suddenly and irregularly while Dez has a more normal time series. As a result, Karkheh is more vulnerable to floods than Dez in terms of increased heavy rainfall. The results of using the Man – Kendal, and ITA test showed that Man – the Kendal test can only detect uniform trends in time series as the advantage ITA method is that in addition to uniform trends. It can detect hidden trends and internal in identify time series. For example, although the man – Kendal test did not show a specific trend for maximum rainfall at Khorramabad station, The ITA test detected hidden and non-uniform trends for this station. |
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| ISSN: | 2676-4377 2676-4385 |