Document Type : Original Article
Authors
1 Teacher
2 Department: Climatology and Geomorphology Faculty: Geography and Environmental Sciences Sabzvar, Iran
3 Department: Climatology and Geomorphology Faculty: Geography and Environmental Sciences, Hakim Sabzevari University Sabzevari, Iran
4 Department of Climatology & Geomorphology Faculty of Geographic & Environmental Sciences Hakim Sabzevari University Sabzevar, Iran
Abstract
storms are a particularly important natural hazard of atmospheric origin. Tropical cyclones are responsible for half of the damage caused by these storms. This study identifies the synoptic patterns governing the tracks of tropical cyclones in the northwestern Indian Ocean basin using a descriptive–analytical approach. First, the basin’s tropical cyclone characteristics, including dates, cyclone intensities, and cyclone positions, were extracted from the Indian Meteorological Department (IMD) website for the latitude–longitude bounds 0–27°N and 53–75°E. Next, 700 hPa geopotential height data with a horizontal resolution of 0.25° from ECMWF ERA5 were obtained for a 41-year period (1982–2022). A total of 169 cyclone-days were selected. A factor analysis with an S-mode configuration was applied. Each cyclone day was represented as an 89×109 matrix, i.e., 9,701 spatial grid cells. This number of cells applies to 169 days. All data-processing steps up to pattern identification were performed in MATLAB. Ten 700 hPa geopotential-height patterns were obtained. These patterns reflect the dominant synoptic configurations shaping the tracks of tropical cyclones in the study region. Finally, maps of these ten patterns were produced using the R programming language. The results indicate that the primary control on cyclone tracks in the study area is an Mid-level high over the Arabian Peninsula. Other influential factors include incursions of mid-latitude lows and Cut-offs into the region thermal lows over Pakistan and northern/northwestern India, the Mid-level high over the over western India, the northward shift of the monsoon trough, and the cyclone’s beta effect.
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