the rate at which temperature changes with depth below earth's surface is called geothermal gradient.
the rate at which temperature changes with depth below earth's surface is called?
geothermal gradient
section::::manifestations.









































section::::manifestations.:base depth.









































permafrost extends to a base depth where geothermal heat from the earth and the mean annual temperature at the surface achieve an equilibrium temperature of 0 °c. the base depth of permafrost reaches in the northern lena and yana river basins in siberia. the geothermal gradient is the rate of increasing temperature with respect to increasing depth in the earth's interior. away from tectonic plate boundaries, it is about 25–30 °c/km (72–87 °f/mi) near the surface in most of the world. it varies with the thermal conductivity of geologic material and is less for permafrost in soil than in bedrock.
permafrost
in dashkasan locale the temperature changes from -5 c to -20 c in winter and from +20 c to +35 c in summer. the average annual temperature is 0-100 in dashkaran. the average monthly temperature in january is -2-140, the average monthly temperature of july is + 5-200. sometimes the absolute maximum temperature of air is higher than + 20-310, the absolute minimum temperature of air is lower than 20-300 in summer. in the middle mountain range, the average absolute minimum air temperature changes from +50 to +70 during the year. the average annual soil surface temperature is + 80, the average temperature of january is -50, the average monthly july temperature is 210. the average annual relative humidity of the air is 75% and changes between 67-82% per year. the annual rainfalls in the area are 600–900 mm. most of the rainfalls fall in the spring. the possible evaporation is 300–800 mm from the soil surface in a year.
dashkasan district