نوع مقاله : پایان نامه و رساله
موضوعات
عنوان مقاله English
نویسندگان English
Heavy rains are one of the main climate hazards that cause enormous damage to the human environment yearly. The identification of this natural hazard is essential. Due to the special topographical and local conditions, heavy rains occur often in the northwest of Iran. The purpose of this study was to extract the dynamic and thermodynamic patterns of heavy and widespread precipitations in the northwest of Iran from 2000 to 2019. An environmental-to-circulation method with emphasis on vorticity was performed. The percentile method was used to determine heavy precipitation. Patterns were identified using the clustering method in the SPSS software environment. After determining the two general patterns, composite climatic maps at 500 hectopascals (hPa) level were drawn and analyzed. The zoning of heavy precipitation was done in a GIS software environment and the Hovmoller diagram for Jetstream was prepared and analyzed. In both patterns, the main factor of ascent was the Sudanese low, and the presence of a short front strengthened the low-level convergence conditions. The establishment of Omega blocking in the middle level of the atmosphere caused the continuation of precipitation. The primary sources of supply moisture for the heavy precipitation were the Black Sea, the Mediterranean Sea, and the Red Sea.
کلیدواژهها English