Developing a thermodynamic model to predict minimum temperature due to cold air accumulation over a complex terrain

آب و خاک

Article 14, Volume 22, Issue 2, May 2008   

Document Type: Research Article

DOI: 10.22067/jsw.v0i22.1014

Authors

M.S. Ghazanfari Moghadam^{* 1}; M. Mousavi baygi²; S.H. Sanaei-Nejad³

¹Graduate University of Advanced Technology, Kerman, Iran

²Department of Water Engineering, Faculty of Agriculture, Ferdowsi University of Mashhad

³Ferdowsi University of Mashhad

Abstract

Abstract
Topography is the most important parameter which produces minimum temperatures in complex terrain. Radiative inversion occurs in the mountains and produces radiative freezing. When the land surface is cooled, a boundary layer forms. Since cold air is heavier than warm air, therefore, it flows toward the down slope, which is named Katabolic flow. When Katabolic flows are formed, cold air accumulates in the valleys and thereafter in places which do not have a good drainage of air. Based on thermodynamic equations a model was developed to consider the accumulation of cold air in each point of a complex terrain. Minimum temperature prediction model (MTPM) was developed and used to predict the minimum temperature in complex terrains. This thermodynamic model uses digital elevation model to produce minimum temperature maps. Running MTPM for North Mountains of Tehran showed a good correlation between modeled and actual minimum temperatures.

Key words: Katabolic flow, Minimum temperature, Freezing ponds, Complex terrain, Thermodynamic models