Dr Dariush Yarahmadi, Dr Amanolah Fathnia, Mehdi Sherafat,
Volume 20, Issue 56 (3-2020)
Abstract
Abstract
The extention of Snow cover and its spatial and temporal changes considered as a basic parameter in climatic and hydrologic studies. Data from satellite images due to the low cost and the large extention of cover are, effectively help the identifying of the snowy basins. Since the satellites are able to imaging a surface at different times, this will allow snow survey studies to investigate the spatial and temporal distribution of snow. In this research, Snow line changes and the surface temperature line in Alborz Mountains using NOAA-AVHRR satellite images since 2006 from 2015 was studied. The results showed that at the study period, maximum area of snow have been observed in April 2015, with the amount of 12051 square kilometers and the minimum area snow have been observed in June 2008, with the amount of 33 square kilometers. The average of the lowest elevation of snow covered areas, have been observed in April 2007, with the amount of 2662 meters and its highest value have been observed in June 2008 with the amount of 3820 meters. Also the most of the snow line change occurred between the years 2007 to 2008. Moreover, in almost of 15 years, the isoterm of zero degrees Celsius, matches with the snow line and its elevation has changed as the snow area is changed.
Abolghasem Amir Ahmadi, Leila Goli Mokhtari, Naemi Tebar Mahnaz,
Volume 23, Issue 70 (9-2023)
Abstract
The purpose of this study was to identify evidence of late Quaternary glaciers in the northern highlands of Binalood. Topographic maps, satellite imagery and climatic data are the tools and data used in this study. Arc gis 10.4 software was used for data analysis. Quaternary glacier evidences were identified based on four types of evidences including morphic indices, climatic evidences, geomorphological evidences and laboratory indices. Using morphic indexes, the curve lines were identified on topographic maps of satellite imagery, ice-dominated areas, and the effects of 28 glacial circuses. Climatic evidence shows that not only was Quaternary at about 7 degrees cooler than the present time, but its precipitation was almost twice as high as at present. On the other hand, glacier circles, moraines, thales and glacial mounds were the most prominent geomorphologic evidence of glaciers in the Binaloud Heights. Finally, granulometric laboratory indices supplementing the evidence of glaciers have confirmed the existence of glacial sediments at the Binaloud Heights. Also, using Wright's method, the permanent snow boundary line during the reign of Binalood Heights Glaciers was estimated at 2600 m.
