Impact of Seasonal Snowmelt on Snowpack at Woodland, Grassland and Bare Land in North Slope of Tian Mountain

Abstract

【Background】Snowfall on the north face of the Tian mountain in Xinjiang is seasonal and how seasonal snowmelt affects the snowpack has been well documented at watershed scale but not at slope scale. Understanding the change in snowpack in areas under different vegetations is crucial to accurately quantifying snow ablation and provide bassline for predicting surface runoff into rivers. 【Objective】The overall objective of this paper is to analyze and compare the changes in snowpack traits, including its depth, density, liquid water content, and temperature, in areas with different vegetations at north slope of the Tian mountain, as well as their determinants. 【Method】Snowpack traits, meteorological factors - including temperature, solar radiation, relative air humidity, and edaphic factors - including soil moisture content and temperature, in woodland, grassland and bare land were monitored in real-time during snowmelt season. Pearson correlation analysis method was used to calculate the correlation between the meteorological factors, edaphic factors and snowpack traits in three areas. 【Result】The average depth of the snowpack in woodland, grassland and bare land in snowmelt season was 8.06, 18.67, and 16.34 cm, respectively, and the density and liquid water content in the snowpack in the woodland were 0.48 g/cm3 and 0.66%, respectively, higher than those in grassland and bare land. Average snow temperature in the woodland was -0.032 ℃, lower than that in the grassland and bare land. The snowpack depth in the bare land was negatively correlated with solar radiation at significant level with a correlation coefficient of -0.960. The snow density in the grassland was positively correlated with solar radiation at significant level. The density, liquid moisture content and temperature of the snowpack in the bare land were all positively correlated with ambient air temperature at very significant level. Snow density in the woodland was positively correlated with soil temperature and moisture content in the 0~10 cm layer at significant level. The snow depth in the grassland was negatively correlated with soil temperature at depths of 40, 50, and 60 cm at very significant level, and with soil moisture at depths of 20 and 30 cm at significant level. The snow density in grassland was positively correlated with soil temperature at depths of 20, 30, 40, 50 and 60 cm. Snow depth in the bare land was negatively correlated with soil temperature at depth of 10 cm at significant level, and snow temperature was positively correlated with soil moisture at depths of 20 and 30 cm at significant level. 【Conclusion】On average, the snow in the grassland is thickest, and the average snow temperature in the woodland was the lowest; the average density and liquid water content of the snow in the woodland were higher than that in the grassland and the bare land. Ambient air temperature and solar radiation affect the snowpack in all three areas the most. Soil moisture and temperature were negatively correlated with snow depth, while positively correlated with snow density and temperature as well as liquid moisture content.

Keywords

• snow characteristics
• meteorological factors
• soil temperature
• soil moisture content
• northern slope of tianshan