Analyzing the temporal and spatial distribution of the start and end of the frost is necessary along with examining its trend to reveal the characteristics, behavior, effects, and predictability of changes in this climatic phenomenon. Thus, in this study, the distribution of early fall and late spring frost and the trend of its changes in 1987–2019 were investigated in a network consisting of 82 consolidation stations in Iran. For this purpose, spatial scattering methods, Mann-Kendall nonparametric test, and Sen’s slope estimator were used. The results of the spatiotemporal distribution of the start and end of the frost showed that in the northern and semi-western half of Iran, the frost begins earlier and ends later. Also, the frost period, as well as the frequency of its occurrence, is longer compared to the southern and eastern hemispheres. The trend of changes in the start of frost in Iran has a significant increase. The end of the frost in most parts of the country is declining, which is significant in most parts of the country. In the central and southern regions of Iran, especially in the foothills of the Zagros, the frost begins earlier and ends later, and the frost period has become longer. However, these changes are not significant and are due to short-term fluctuations in climatic conditions. In other parts of the country, the frost begins later and ends sooner. In most stations, these changes are significant due to rising temperatures, global warming, and the effect of climate change in these areas.
کلید واژگان :Spatiotemporal distribution . Sen’s slope estimator . Mann-Kendall test . Frost . Iran
ارزش ریالی : 600000 ریال
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