چکیده:
One of the important climatic phenomena is the occurrence of frost, which, depending on its intensity, duration, and extent, has significant impacts on human activities including agriculture, transportation, energy, environmental issues, and the biological activities of plants and animals. Frost has various characteristics such as onset, termination, frost season, duration, etc. Duration refers to the period of time during which a temperature of zero or below prevails in an area. The occurrence of this phenomenon is important in agriculture because every type of plant has a specific temperature threshold above or below which the plant may perish. Therefore, to prevent damage to them, studying frost duration hours is essential and necessary. Also, in the field of civil engineering works (such as dam construction), studying frost duration hours is unavoidable to increase the safety factor. The aim of the present article is to calculate frost duration hours using Delphi programming language. For this purpose, at least hourly daily temperature data from 4 meteorological stations in Lorestan province, namely Khorramabad, Borujerd, Naserodin, and Aligudarz, which had 10-year statistics from 1989 to 1999, were obtained from the national meteorological organization's database. After extracting the frost days at the desired threshold (zero and below) during the statistical period using the intended program algorithm, the calculation and extraction of frost duration hours in each of the stations were carried out. Then, the frost duration hours were divided into 8 selected classes (3-hour intervals) and their frequency percentage charts were drawn. All stations were compared together in three selected classes: 0 to 3 hours, 9 to 12 hours, and 21 to 24 hours. It was found that the highest frost duration hours belong to the Borujerd station; consequently, crop damage in this station is higher than in other stations. Also, the most important influencing factor in the frost duration hours of the region is land surface cover, and altitude factors do not have an effect on frost duration hours.
خلاصه ماشینی:
After extracting the frost days at the desired threshold (zero and below) during the statistical period using the intended program algorithm, the calculation and extraction of frost duration hours in each of the stations were carried out.
Therefore, in this article, for the first time using Delphi programming(1), the frost duration hours for each of the stations during the studied statistical years (1989-1999) have been calculated.
Figure 1 shows the percentage frequency chart of different frost duration hour classes for the Khorramabad station during the statistical period 1989-1999.
Figure 2 shows the percentage frequency chart of different frost duration hour classes for the Borujerd station during the statistical period 1989-1999.
Table 2: Frequency and percentage frequency of different frost duration hour classes at Borujerd station during the statistical period 1989-1999 Endnotes 1.
Figure 3 shows the percentage frequency chart of different frost duration hour classes at Nasreddin station during the statistical period 1989-1999.
Figure 4 shows the percentage frequency chart of different frost duration hour classes at Aligudarz station during the studied statistical period 1989-1999.
Table 4: Frequency and percentage frequency of different frost duration hour classes at Aligudarz station during the statistical period 1989-1999 (Refer to the page image) Nasreddin Station This station is located at an altitude of 1182 meters above sea level in the northeast of Lorestan province.
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