Temporal Synoptic Index of Winter Season for Southern Coasts of IRAN

Each place reflects the properties of the air mass dominant on that area based on its geographical, topographical, and environmental characteristics, which can create unique meteorological conditions on station scale. In this research, Temporal Synoptic Index of winter season or according to its localized definition, surface weather types of the Persian Gulf's and the sea of Oman's coastal stations consisting of six stations were examined. For this purpose, identification and categorization of different climatic types on station scale were carried out. This task was perfomed based on nine meteorological variables including sea level pressure, dew point, minimum temperature, maximum temperature, daily minimum and maximum saturation deficit, cloudiness, daily temperature range, and daily dew point range on daily scale during 1961-2004 period using Principal Components Analysis and Cluster Analysis. The meteorological properties of each of the weather types were determined through organizing 40 variables and employing and emphasizing on elements such as precipitation, daily temperature, relative humidity, cloudiness, maximum and minimum daily temperature and the number of rainy days. The results of this investigation showed that the weather types of the Strait of Hormuz's eastern stations including Jask and Chabahar from meteorological conditions and amount of precipitation aspects were distinguishable from the western stations. In addition, a kind of relative homogeneity between station types can be observed considering heat and humidity aspects, by disregarding the precipitation characteristics. If so, this homogeneity could cause error. Therefore, the precipitation element has relative salience in categorization of the types. High-precipitation types in the western stations of the Strait of Hormuz were consistent with moderate and humid type from precipitation aspect while it is consistent with partly warm and humid type in the eastern stations. Furthermore, high-precipitation types in Bandar-Abbas's and Bandar-Lengeh's stations and Bushehr's and Chabahar's stations and Kish's and Jask stations during statistical period of the station had the maximum, middle, and minimum abundance, respectively. Therefore, by considering the number of rainy days and presence frequency of weather types, winter season of Bandar-Abbas's, Bandar-Lengeh's, Bushehr's, Chabahar's, and Kish's and Jask stations can be defined as relatively rainy, semi rainy, low rainy, relatively low rainy, and very low rainy, respectively. Keywords: Iran, Principal Component Analysis, TSI, Weather Types.