نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی دکتری آب و هواشناسی دانشگاه زنجان، زنجان، ایران
2 دانشیار و عضو هیات علمی دانشگاه زنجان
3 استاد و عضو هیات علمی دانشگاه زنجان، زنجان، ایران
4 استادیار و عضو هیات علمی دانشگاه زنجان، زنجان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Examining temporal and spatial changes of snow melting is very important in various fields including water resource management. Therefore, the current research was conducted with the aim of investigating the temporal and spatial changes as well as the spatial autocorrelation of the amount of snow melting in the northwest of Iran for the months of the cold seasons. For this purpose, snowmelt data from the European Center for Medium-Range Weather Forecasts (ECMWF), version (ERA5) with a spatial resolution of 0.25 x 0.25 degrees for the cold season months during the statistical period from 1982 to 2022 received and then divided into four periods of ten years. In order to analyze spatial autocorrelation changes, global Moran indices and hot spot analysis (Gettis-ORDJ) were used at the significance level of 90, 95 and 99%. Also, in order to determine the effect of temperature on the amount of snow melting, the trend of changes in the average minimum monthly temperature of 20 synoptic stations in the northwest region was investigated. The results of the present research showed that in the studied area, snow melting has spatial autocorrelation and a strong cluster pattern. During the first decade to the end of the fourth decade, the amount of snow melting in the months of October, November and December was between 0 and 5.27 mm per day, and especially in the month of December, which is accompanied by a negative minimum temperature anomaly the area (number of pixels) and the amount of snowmelt in the northwest have been reduced. The results of the analysis of the amount of snow melting changes in the winter months also showed that both the amount and the area of snow melting have increased during the study period. Thus, the range of snow melting threshold changes in January, February and March has increased between 0.95 and 19.27 mm per day from the first decade to the end of the fourth decade. Among the months of the winter season, February is associated with a strong positive minimum temperature anomaly (significant increase in minimum temperature), and accordingly, the area (number of pixels) and the amount of snow melting in the northwest have been increased.
کلیدواژهها [English]