Investigation of relationship between air and soil temperature at different depths and estimation of the freezing depth (Case study: Khorasan Razavi)

آب و خاک

Article 38, Volume 22, Issue 2, May 2008   

Document Type: Research Article

DOI: 10.22067/jsw.v0i22.1044

Authors

M.H. Najafi mood^{* 1}; A. Alizadeh²; A. Mohamadian³; J. Mousavi¹

¹Ferdowsi University of Mashhad

²Water Resources Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

³Climatological Research Institute, Mashhad, Iran

Abstract

Abstract
In order to estimate the freezing depth and developing a simple and rational relationship between air temperatures at the screen and soil temperature at different depths a study was conducted during 1386. The maximum and minimum daily air temperatures (2 meter above ground) and the soil temperature at 5, 10, 20, 30, 50 and 100 centimeter depths were measured at 12 stations of Khorasan Razavi province. Functional relationships were developed between air and soil temperatures for each station. Also, soil freezing depths were estimated by four standard methods. The estimated depths were compared with actual freezing depths which were measured during the year of observation. The results showed that the Finnish and Norway methods were more reliable than U.S. and SNipll – 15 – 74 methods.

Key words: Air temperature, Soil temperature,Freezing depth