Research On Inversion Of Snow Water Equivalent By GAMMA In Alpine Region

Snow water equivalent is an important parameter to measure the change of snow water resources.Gamma-ray from soil after the attenuation of snow,can accurately measure the surface snow water equivalent of a wide range,and this method has the advantage of without destroying the surface features.However,the changes in measuring geographical bring a great influence in accuracy of it.In order to improve the precision of snow water equivalent measured by gamma(Gamma),This article select altay and big tree mountain as the study area.The results as following:(1)Analyzed the gamma inversion consume the equivalent of the traditional formula,and the results show that the inversion by 40 K elements and 208 Tl elements consume the equivalent value compared with the measured values have the same trend of fluctuations,but the overall slants small,error is bigger,Nash coefficient was only 0.09,method needs to be improved.(2)The improved method is proposed,namely the introduction of parameter n and F.At first,he soil water content M = 0,and the overall efficiency of Nash coefficient reached 0.92,but in melting snow period,the change trend of the snow water equivalent of both exist completely different phenomenon,therefore,the soil moisture content should not be neglected.Soil moisture content as a variable input inversion formula,validation results show that the improved inversion formula when considering soil moisture content,inversion snow water equivalent value well.At this point,the overall Nash coefficient can reach 0.99.(3)When GAMMA be used in alpine region,can monitor of snow and wind blowing snow very well,humidity of the air has a little effect on the inversion accuracy,can be neglected.(4)Using gamma ray detector,in the absence of a season of snow detecting soil moisture content,the calculation results of Nash coefficient is 0.37;In the earth's surface and freezing and thawing period,no snow,the soil moisture content with gamma good index relationship between particles,the correlation coefficient of 0.84.Gamma ray detector after improved detection methods can accurately measure the snow water equivalent,applied to the wind blowing snow multiple alpine region.Detect the snow water equivalent value,can be used to quantitatively calculate the snowfall in area of qilian mountain snow period,strong winds caused by wind blowing snow,and snow and wind blowing snow under the action of the change of equivalent value.When there is no snow season,detect the soil moisture content.