Investigating Temporal-Spatial Behavior of Sultry Days in Southern Half of Iran

One of the most important limiting factors of human activities in southern half of Iran, especially coasts, is the climatic sultry. The aim of this study is to determine the first sultry day, the last sultry day, duration of sultry period, duration of non-sultry period, and sultry frequency with 95% probability in southern half of Iran. Therefore, hourly data of vapor pressure for a 15-years term (1995-2009) relating to 13 synoptic stations was used. Its worthy of note that in this study, the sultry day is defined as a day in which in one of the 8 daily scouts’ vapor pressure is about 18.8 Hpa.
Results have indicated that in the southern half of Iran with 95% probability, the earliest sultry day takes place in Chabahar station on January 3rd and the latest one occurs in Kerman station on July 29th. The latest date of the last sultry day is in Chabahar station on December 28th and the earliest one is in Fasa station on August 19th. The longest sultry period belongs to coastal stations in Chabahar (359days), Bandar abbas (353days), Boushehr (298days), and Abadan (260days) and the shortest one with 16, 17, and 29days belongs to Shiraz, Kerman, and Fasa stations, respectively. Spatial frequency distribution of sultry days shows as stations latitude increases, their frequency decrease. In this manner, frequency of sultry days in south-east of Iran is much more than that in south-west.