Abstract
One of the factors that sometimes leads to the complete destruction of vineyards is the danger of temperatures below zero degrees Celsius. The purpose of this study was to investigate the effect of temperature hazards on the destruction of the western and northwestern vineyards of Iran.The results show that the most frequent days with a devastating cold wave in the region's vineyards occur on average on January 14 (January 25th). The lowest critical temperature among meteorological stations is related to Saghez weather station in Kurdistan province with negative 33 ° C and afterwards, Hamadan, Bostanabad and Sarab cities with record temperatures below 30 ° C. The cities of the study area are. The results showed that 60% of the studied cities with all available Iranian and foreign cultivars could survive the cold season without the threat of severe winter cold conditions. Key words: Grapes, winter cold, west and northwest
Introduction:
Grapes are warm and resistant to temperate zone plants, but despite the resistance of different grape varieties to cold, the resistance to cold in the hair is the same ability of the grape's sleeping tissues to survive under freezing stress conditions. It is autumn and winter, sometimes due to temperature stresses and unexpected damages(Jalili Marandi, R, 2010: 918).Rezazadeh and Alijani (2017), Synoptic analysis of the damaging cold waves of northwestern Iran. The results of this study showed that their monthly abundance is in the transition months of November and April and these two months have experienced more severe and pervasive cold waves than the other months. Mahmoudi (2016), A study of the mean atmospheric circulation leading to widespread glaciation in Iran showed that in the circulation pattern of sea level pressure, the spatial arrangement of the Siberian high-pressure system and its interactions with the two polar low pressure systems (low pressure Iceland) and low pressure Sudanese monsoon is the most important push players in the maximum and minimum incidence of frosts in Iran.
Material & Methods
The study area includes West Azarbaijan, East Azarbaijan, Qazvin, Hamadan, Zanjan, Markazi and Kurdistan provinces. The climate of this region is mostly from the semi-arid climates and other climates in the region. The data used in this study include the minimum temperature parameter of 85 synoptic stations in the west and northwest of Iran during the period 1996 to 2014. It is also used to identify synoptic patterns (low and high pressure) and effective factor. The extreme cold and the time of its occurrence in the region have been analyzed by synoptic (synoptic) cold wave on January 14th. For this purpose, three hourly statistics of 85 synoptic stations during the period 1996 to 2014 were studied to determine the frost occurrence in the region and then the most frequent day, and the most frequent minimum temperature below 15 ° C, were determined. Discussion & Result
Statistical analysis of minimum temperatures below -15 ° C that showed destructive temperatures in grape cultivars in western and northwestern Iran after Saghez in Kurdistan province with negative 33 ° C, Hamadan, Bostanabad and Hamadan Mirages are at temperatures below 30 degrees Celsius. Bostanabad, Kheirabad, Sarab; Zarineh Abatoo, Kamijan and Hamadan stations with mean of 15.8, 14.2, 11.3, 9.4, 8.7 and 8.4 days in one year, respectively, with the most days with Negative temperatures are 15 ° C and lower.Khendab stations with a temperature of 24.8 ° C and the cities of Bostanabad, Khoy and Hamadan with temperatures below 20 ° C have the most frequent temperatures below 15 ° C. Khandab city, in addition to its higher altitude, due to the dry and semi-arid climate and lack of sufficient humidity to reduce the effect of cold air transmitted along with the entry of cold-glacial waves from all stations in more critical condition contract .The analysis of the synoptic maps of January 14, as the average of the most frequent day of the lowest minimum temperature in the region, indicates that the orbital component is positive and the meridional component negative. Such conditions increase the intensity and magnitude of the extremely cold winter time in the region. Conclusion:
Examination of the 500 hPa surface pressure map on high cold days such as January 21, 2007 shows that by observing the status of Azores tropical high pressure, Siberian surface thermal high pressure, and Iceland polar low pressure In addition, observations of 1022 hPa at ground level and 5520 hPa at 500 hPa can be predicted at least 1 to 3 days before the cold wave transporting critical temperatures to northwest, western and central parts of Iran. It provides farmers with the opportunity to prepare and provide the equipment needed to prevent and deal with the damaging cold wave.From a temporal point of view, the mean temperature distribution map for the late cultivar can be seen as a result of the close proximity of the phenological stages of fruit formation to the arrival and harvesting of cooler months (especially at lower temperatures at night). It is not suitable for the growth of diseases such as fungal infections of superficial white matter.
Ebrahimi M, Ildoromi A, Sabzi parvar A A, Gholami M, Nouri H. Investigating the effect of critical minimum temperatures and destructive cold waves in the western and northwestern vineyards of the country. جغرافیایی 2023; 22 (80) :47-65 URL: http://geographical-space.iau-ahar.ac.ir/article-1-3563-en.html