List of Articles precipitation anomaly

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  1 - Analysis of the effect of precipitation anomalies during the occurrence of severe wet in southern Iran in the last three solar cycles
  FARNAZ mashayekh hassan lashkari Seyed jamaledin Daryabary mohsen Ranjbar
  In this study, the impact of precipitation anomalies during the occurrence of severe and extremely severe Wet in southern Iran has been investigated. The research design involves the following steps. 1- The daily and annual rainfall data of the synoptic stations of the More

  In this study, the impact of precipitation anomalies during the occurrence of severe and extremely severe Wet in southern Iran has been investigated. The research design involves the following steps. 1- The daily and annual rainfall data of the synoptic stations of the study area were extracted from the data of the Meteorological Organization. 2- The statistical base has been chosen to adapt to the solar cycles of a 33-year period corresponding to the years 1986-2019. 3- The number of 19 synoptic stations that had these conditions were selected. 4- Wet years were determined based on standard precipitation indices (SPI), Chinese Z (CZI), Z score (ZSI). 5- To check the anomaly of precipitation RAI index is used. 6- Based on the declared indicators, with the criteria of 30% repetition in selected stations, 6 severe wet and based on 50% repetition in selected stations, three severe wets have occurred in the statistical period of 33 years. 7- In this research, two seasons of 1992-1993 and 1995-1996 have been examined in terms of anomaly indices and other rainfall characteristics. In the wet and extremely severe years, the annual rainfall was more than two and sometimes three times the long-term average in many stations. In terms of the number of rainy days in the years 1993-1992 in 10 stations and in the wet years 1996-1995 in 17 stations, rainy days over 30 days have been recorded. However, the number of rainy days in both wet years does not show a proportional Manuscript profile
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  2 - The analysis of seasonality and seasonal precipitation anomaly changes in Iran during 1977-2006
  S. ZarrinkamarMajd P. S. Katiraie-Boroujerdy
  Rainfall change as a result of climate change is one of the important issues of recent decades. Climate change can be represented as changes in the inter-annual precipitation distribution and seasonality. Furthermore, the seasonality changes and the transposition of the More

  Rainfall change as a result of climate change is one of the important issues of recent decades. Climate change can be represented as changes in the inter-annual precipitation distribution and seasonality. Furthermore, the seasonality changes and the transposition of the seasonal precipitation are very important for agricultural and hydrological domains decision makings. In this paper, in order to quantitatively investigat the inter-annual distribution of precipitation, at first the seasonality index and the normalized seasonal precipitation anomaly are calculated. For this purpose the monthly rainfall of 33 synoptic stations are used over Iran. The spatial distribution of the seasonality index average and also the year occurrence of maximum and minimum index for each station are identified. Then the significant trends of seasonality indices and also the normalized seasonal precipitation anomaly are examined using Mann-Kendall test for the period 1977-2006.The results show the minimum seasonality index for Gorgan station in the south east of the Caspian Sea, and the maximum seasonality index for Bandarabas station in the south of the country (the coast of the Persian Gulf). The precipitation tends to be concentrated in few months of the year in most stations for the study period (only three stations show significant trends). The maximum seasonality index is observed after 1990 in most stations. However, the trends of seasonal rainfall anomalies for all four seasons in the northwest parts of Iran are negative, but in the central and western regions changes in anomaly trends are positive. This means that seasonal rainfall year to year variations are reduced in the northwest of the country. Highest number of significant trends is observed in winter precipitation. Manuscript profile