عنوان مقاله [English]
In this study, using radiosonde data of temperature and altitude relationship networks during 2005 to 2018 statistical period, annual, seasonal, monthly and hourly averages were obtained. Based on the regression equations between temperature changes and altitude the environmental temperature drop rate was calculated and the solidification level height was calculated. The results show that ELR rate is strongly correlated with ground surface temperature in hot and cold seasons, so that ELR increases during warm seasons and decreases in cold seasons.
The ELA survey of the Dena Heights shows that this level is at an average altitude of 5241 meters, while the highest elevation is at the Dena Mountain Range of 4450 meters, as a result, in terms of climatic conditions, it is not possible to create permanent and active glaciers in this mountain range. The percentage of snow cover above the FLH level is about 2 times that of the downstream levels, but this difference can be increased up to 3 times in the cold season. According to the hypsometric profiles of Dena elevations, two elevations of T1 and T2 at 2400 and 3400 m were determined based on curve slope changes, respectively. The crossing and oscillation of the environmental components from these topographic thresholds can lead to exponential responses of the Dena altitude toughness System to the accumulation and density of ice and snow, as well as its hydraulic power and distribution throughout the year and in warm and cold phases.