Analysis of Snowline Altitude Phenology in Northwestern Iran

Articles in Press

Document Type : Original Article

Authors

1 Professor of Climatology, Department of Physical Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran

2 Department of Geography, Payame Noor University, Tehran, Iran

3 Ph. D Student of Climatology, Department of Physical Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran

Abstract

In this study, MODIS daily snow products (MOD10A1 and MYD10A1) were used in the period 2003-2020, and the snow line height in the northwestern territory of Iran (in two ways: 1) the 0˚ isotherm using LST data and 2) for each cell where there is both snow cover and LST is 0˚ or below 0˚) was estimated monthly, seasonally, annually and long-term, and area maps were drawn. Based on the first and second algorithms, the snow line height was in the maximum phase in January and in the minimum phase in July and August. Based on the second algorithm, in January, negative temperature anomalies accompanied by snowfall led to the expansion of the snow line to an altitude of 1974 meters. The increase in air temperature, snow melting and the sharp decrease in snow cover in July and August have caused the regression of this phenological snow characteristic to an altitude of 4811 meters (Sablan Mountain). In the second algorithm, the maximum advance of the snow line height from October to November by 1374 meters towards lower altitude classes has occurred. The snow line height in the winter season (maximum phase) has been moved to an altitude of 2230 meters based on the second algorithm and to an altitude of 4805 meters in the summer pattern (minimum phase). According to the second algorithm, the years 2011 and 2010 have the lowest and highest snow line heights with an altitude of 3408 meters and 3692 meters, respectively.

Keywords

Main Subjects

Journal of Hydrogeomorphology

Articles in Press, Accepted Manuscript
Available Online from 06 October 2025

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History

  • Receive Date: 16 January 2025
  • Revise Date: 04 October 2025
  • Accept Date: 06 October 2025

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