1- Research institute of Forests and Rangelands 2- University of Sistan and Baluchistan 3- etc.
Abstract: (2548 Views)
The purpose of this study is to analyze the winter temperature status of Iran during the Siberian High Rule in Iran. For this purpose, daily winter temperature data of 283 ynoptic stations of the country were extracted from the Meteorological Organization during the period of 1341 to 2011. Then, to extract the Siberian high-pressure model, ground-level pressure data were extracted from the US National Oceanic and Oceanographic Database. Then, by performing cluster analysis, the Siberian high pressure pattern is identified and extracted. In order to evaluate and validate the identification of Siberian High Pressure Pattern, Davis-Bouldin Validity Index (DBI), Silhouette Index (SI), Diagnostic Function Analysis (DFA), Cummins Analysis (k-M) have been used. The results of this study indicate that the spatial distribution of mean daily temperature is strongly influenced by the Siberian high pressure system, so that during the dominance of this system over the Iranian climate, the temperature in most parts of Iran has declined sharply, which is a higher share of December. This system enters Iran in the east-west direction more than northeast and west of the Caspian Sea and causes cold air to fall on the Iranian climate, so that in addition to the thickness of the atmosphere, cold air circulation almost dominates all over Iran. Along the Zagros Mountains and the northwestern highlands, these spatial variations in temperature are more pronounced.