Increasing Snow–Soil Interface Temperature in Farmland of Northeast China from 1979 to 2018

Xiuxue Chen,Lei Li,Xingming Zheng,Lingjia Gu,Guangrui Wang,Xiaofeng Li

doi:10.3390/agriculture11090878

Abstract

The presence of seasonal snow cover in the cold season can significantly affect the thermal conditions of the ground. Understanding the change of the snow–soil interface temperature (TSS) and its environmental impact factors is essential for predicting subnivean species changes and carbon balance in future climatic conditions. An improved Snow Thermal Model (SNTHERM) is employed to quantify TSS in farmland of Northeast China (NEC) in a 39-year period (1979–2018) firstly. This study also explored the variation tendency of TSS and its main influencing factors on grid scale. The result shows that annual average TSS and the difference between TSS and air temperature (TDSSA) increased rapidly between 1979 and 2018 in the farmland of NEC, and we used the Mann–Kendall test to further verify the increasing trends of TSS and TDSSA on aggregated farmland of NEC. The correlation analysis showed that mean snow depth (MSD) is the most pivotal control factor in 95% of pixels and TDSSA increases as MSD increases. Snow depth can better predict the change of TSS in deep–snow regions than average winter temperature (TSA). The results of this study are of great significance for understanding the impact of snow cover on the energy exchange between the ground and the atmosphere in the cold climate.

Highlights

Snow cover has a great impact on the thermal conditions of the soil due to its low thermal conductivity and high albedo [1,2]
The single–point Snow Thermal Model (SNTHERM) model was improved according to snow cover and soil characteristics of farmland in Northeast China (NEC)
The interface temperature under snow cover, known as TSS, was extracted, the changes in TSS and TDSSA were quantitatively analyzed, and the specific factors that caused the increase of TSS in farmland in NEC were deeply explored

Summary

Introduction

Snow cover has a great impact on the thermal conditions of the soil due to its low thermal conductivity and high albedo [1,2]. Snow cover in the Northern Hemisphere has significantly changed [10,11]. Surface ground temperature (TSG) is the result of physical and biological couplings between the atmosphere and the ground, and snow cover is an important factor affecting the change of TSG [12,13]. The thermal insulation effect of snow cover can prevent species from being affected by extreme winter temperatures. The change of the snow–soil interface temperature (TSS) affects the severity of soil freezing and the stability of the soil carbon pool [7,16]. Snow cover affects the coupling between the air temperature (TNSA) and TSG due to its insulating effect [17]. Altitude affects the spatial distribution and thickness of snow cover [19,20]

Methods

Results

Discussion

Conclusion