Analysis of spatial changes of extreme precipitation and temperature in Iran over a <scp>50‐year</scp> period

Alavinia, Seyed Hassan; Zarei, Mahdi

doi:10.1002/joc.6845

Cited by 21 publications

(8 citation statements)

References 58 publications

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“…At the other stations, a negative trend was recognized for the annual maximum 24-h precipitation (statistically significant at Kerman, Bandar Anzali, and Zahedan Stations), showing the lower levels of flash flood risk (Table 3). In this regard, our results are consistent with [38,57,58].…”

Section: Spatiotemporal Precipitation Trend By the Mann-kendall Testsupporting

confidence: 91%

Spatiotemporal Changes in Air Temperature and Precipitation Extremes over Iran

Jamali

Gohari

Motamedi

et al. 2022

Water

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In this study, a comprehensive trend analysis was employed to study the spatiotemporal changes in precipitation characteristics with an increased temperature, as well as over time. The nonparametric Mann–Kendall test and the quantile regression methods were applied to detect the plausible temporal trends in 11 extreme rainfall indices and three temperature indices employed in this study. The results showed there was little evidence to suggest that increases in the maximum of 3-h and 24-h precipitation at higher temperatures resulted in similar increases in the annual precipitation, with most stations throughout Iran showing drying features with higher temperatures. Generally, most regions over Iran scaled negatively, implying a reduction in the annual precipitation ranging from −2.64 to −0.44 mm/°C at higher temperatures. The linear tendencies of the maximum 24-h precipitation ranged from −0.4 to 0.23 mm/°C. The annual precipitation of the stations located at Urmia Lake, Caspian Sea, and the Eastern Border Basins showed a decreasing trend (−3.70 to 1.11 mm/year), while the number of rainy days increased (−2.78 to 4.72), which showed the occurrence of lighter rainfall in these regions. The increasing trend in the maximum 24-h precipitation over Western and Central Iran implied a higher probability of extreme precipitation with a higher intensity. This study revealed that the shift in precipitation extremes shifted from fall to winter by increasing the elevation, but these effects have no statistical significance in Iran.

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Section: Spatiotemporal Precipitation Trend By the Mann-kendall Testsupporting

confidence: 91%

Spatiotemporal Changes in Air Temperature and Precipitation Extremes over Iran

Jamali

Gohari

Motamedi

et al. 2022

Water

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“…In contrast, our results show that the total annual precipitation will decrease by 6.1% K-1 over Iran. While our results are generally consistent with the results of previous studies that have examined the precipitation change in Iran (Javari et al 2016;Khalili et al 2016;Daneshvar et al 2019;Alavinia and Zarei 2020;Sharafi and Mir Karim 2020;Doostan 2020;Sadeghinia et al 2022a), our findings provide a more detailed analysis of precipitation behavior in Iran, because we have examined changes in the characteristics (amount, frequency and intensity) of precipitation events of different intensities (light, moderate, heavy precipitation). The results in this paper indicate that dividing daily precipitation events into several categories is useful for a more detailed analysis of precipitation events.…”

Section: Conclusion and Discussionsupporting

confidence: 92%

“…In general, a decreasing trend in precipitation has been observed in Iran (Khalili et al 2016;Javari et al 2016;Daneshvar et al 2019;Sharifi and Mir Karim 2020). Also, the number of wet days (RR) has decreased in most stations in Iran (Alavinia and Zarei 2020;Doostan 2020;Sadeghinia et al 2022a). It is important to ask whether the previous results regarding daily rainfall change patterns in Iran still hold according to additional observations; and the more important question is which of the types of precipitation events in Iran has changed significantly: light, moderate or heavy events?…”

Section: Introductionmentioning

confidence: 99%

Changes in Classified Precipitation in Iran

Sadeghinia,

Nazaripour,

Rafati

2023

BOGPGS

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Changes in classified precipitation in Iran and its relationship with global mean surface temperature (GMST) have not been comprehensively investigated. Therefore, this study analyzed changes in precipitation of different intensities over Iran for the 1987–2017 period. Results show that the total annual precipitation (PRCPTOT) and the number of wet days (RR) have significantly decreased over Iran. Also, the mean precipitation intensity (SDII) has increased somewhat. There is a non-uniform change for three intensity categories of precipitation. The amounts (frequency) of light, moderate, and heavy precipitation have significantly decreased at 47% (57.9%), 18.7% (15.8%), and 3.94% (7.9%) of stations respectively. Therefore, the decrease in the amount and frequency of light and moderate precipitation is more severe than heavy precipitation and the proportion of heavy precipitation to the total annual precipitation has increased somewhat during 1987-2017. Overall, the result shows that the intensity of decreasing trends of amount and frequency of precipitation has increased from the south (east) to the north (west) of Iran. Also, SDII has increased from the south (east) to the north (west) of Iran. The sensitivity value was obtained by calculating the ratio of linear trends of precipitation indices and GMST. The regional median sensitivity and percentage change in PRCPTOT, RR, and SDII per 1-kelvin increase in GMST are -6.1%, -11.2%, and 12.9% respectively. Considering that Iran is located in the arid subtropical region, a significant decrease in the amount and frequency of precipitation may have destructive effects on water resources.

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“…Some recent studies (e.g., Modarres et al ., 2016; Alavinia and Zarei, 2020) showed that although the overall trend of precipitation has decreased, flood magnitude has increased in western and northwestern Iran. This trend is highly correlated with changes in Mediterranean and Sudanese cyclone intensity (Khoshakhlagh et al ., 2008; Sabziparvar et al ., 2010; Heydari and Khoshakhlag, 2015; Bayat et al ., 2017; Kiani et al ., 2020; Rezaei et al ., 2021; Sherpa and Shirzaei, 2022).…”

Section: Study Areamentioning

confidence: 99%

Climatology of cyclones in western and northwestern Iran using reanalysis and remote sensing data

Ghasemifar

Hardy

Minaei

2022

Intl Journal of Climatology

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Agriculture and hydrological management in western and northwestern Iran is highly sensitive to precipitation associated with Mediterranean and Sudanese cyclones particularly during spring and winter. Although many studies have focused on the theoretical basis of these cyclones, statistical analyses, especially with satellite observations, have not been undertaken. In this study, 40 cyclones during all months of 2015-2021 are characterized using data collected by Global Precipitation Measurement (GPM) dual-frequency precipitation radar (DPR), Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) and ERA5 reanalysis within each cyclone quadrant. The results show that about 45% of cyclones have a lifetime between 1 and 2 days, and approximately 25% occur during April with a secondary peak in March (22.5%). Accordingly, cyclonic rainy days and rainfall amounts peak in April with values of 76.1% and 64.1%, respectively. The lowest (most negative) low-and midtropospheric vertical velocity in the southeast and northeast quadrants indicates upward motion, which leads to the most intense latent heat release within the cyclone. Accordingly, the highest rainfall rates occur in the southeast and northeast quadrants, located within and ahead of the highest specific humidity quadrant (southeast) where the warm conveyor belt plays a significant role for rainfall formation. Maximum stratiform and convective rainfall rates are observed in the southwest and southeast quadrants, respectively. The distribution of rainfall rate is consistent with that of the storm-top height pattern in all quadrants. The maximum percentage of warm rain to the total rain (34.6% on average) for both stratiform and convective precipitation falls in the southeast quadrant. The structure of these analysed cyclones is largely similar to that shown previously in the literature. According to the analysed rainfall in different life cycles, it is expected that the cyclones have the greatest impact (i.e., extreme rainfall) during the developing stage in the northeast and southeast quadrants, and during the mature stage in the southwest quadrant. The lowest influence is during the dissipating stage. The results from this study can help decision makers within the hydrological and risk management industries.

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Analysis of spatial changes of extreme precipitation and temperature in Iran over a 50‐year period

Cited by 21 publications

References 58 publications

Spatiotemporal Changes in Air Temperature and Precipitation Extremes over Iran

Spatiotemporal Changes in Air Temperature and Precipitation Extremes over Iran

Changes in Classified Precipitation in Iran

Climatology of cyclones in western and northwestern Iran using reanalysis and remote sensing data

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