توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Comparative Study of Multi–Day Intense Precipitations over Iran
نویسنده(ها): ، ،
اطلاعات انتشار: اولین کارگاه مشترک ایران و کره در مدلسازی اقلیم، سال
تعداد صفحات: ۱۴
Precipitation is one of the meteorological variables that have highest spatial and temporal variability. There is increasing attention to variations and trends of extreme values of such a variable in local, regional and global scales. Extreme events of precipitation have caused serious effect on human lives and properties. In this paper, we examine extreme precipitations in view of monthly maximum 1–day (Rxlday) and monthly maximum consecutive 5–day (RxSday) precipitations over those Iranian synoptic stations having reliable data. These indices can also be defined seasonally, but seasonal indices are more spatially coherent than the annual indices, spatial coverage remains generally poor in global scale. We mainly worked on 16 Synoptic stations that are distributed well over the country. Highest 1 day and 5 days precipitations among the stations under study are 353 mm from Bandar Anzali on September 17th, 1962 and 487 mm from Ramsar on 2–6 October of 1993 respectively. Lowest
ones are 41 mm from Bam on January 26, 1991 and 5 1 mm from the same city on 20–24 January of 1957.We got negative trends for Rx5day in NW, West of Zagros mountain ranges, Caspian Sea coastal area, NE, SE and some stations located in the south of Iran. We did not
find a clear pattern for Rxlday over the Country. Whole Country actually showed a mixed pattern. We also got significant negative trends for this index for Shiraz and Zahedan, and a significant positive trend for Abadan at 0.05 significant levels.<\div>

۲Study of Decadal Variations of Warm Days and Nights over Iran
اطلاعات انتشار: اولین کارگاه مشترک ایران و کره در مدلسازی اقلیم، سال
تعداد صفحات: ۱۳
Variations and trends of thermal properties of the living environment have caused too much attention to the public and scientific communities. There is evidence of significant changes in the distribution of maximum and minimum temperatures in many parts of the world especially for minimum temperature during winter. In this paper, we deal with number of warm days and nights over Iran. According to ETCCDMI (Joint World Meteorological Organization Commission for Climatology (CC1) \ World Climate Research Programme (WCRP) project on Climate Variability and Predictability (CLIVAR) Expert Team on Climate Change Detection, Monitoring and Indices), number of warm days (nights) are defined as number of days (nights) that maximum (minimum) temperature passes 9om percentile of the variable for period 1961–90. Based on obtained results of the first attempt on global view of changes of warm days and nights in 2002, all continents except parts of Canada, Iceland, China and Black Sea Area showed a positive trend for warm nights. Above results also shows about 15% increase in the number of warm nights with respect to 1961–90 base periods. Such a study conduced due to expecting more frequent extreme temperature. From greenhouse gas forced warming of climate. We worked on daily extreme temperatures of 20 Iranian synoptic stations for 1951–2003. Although, Islamic Republic of Iranian Meteorological Organization (IRIMO) currently has more than 160 synoptic stations, we only selected that number of them due to their reliable continuous extreme temperatures data We found positive trends for warm nights (Tn90) for most of the stations under study. These
trends are significant except for Arak, Bandar Abbas, Birjand, Ghazvin, and Shahrekd These are almost consistent with many previous findings including our obtained results. We r also found both negative and positive trends for number of warm days (Tx90), which less
j number of them is statistically significant.
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