Analyzing Changes in Frozen Soil in the Source Region of the Yellow River Using the MODIS Land Surface Temperature Products

Abstract

The degradation of the frozen soil in the Qinghai–Tibetan Plateau (QTP) caused by climate warming has attracted extensive worldwide attention due to its significant effects on the ecosystem and hydrological processes. In this study, we propose an effective approach to estimate the spatial distribution and changes in the frozen soil using the moderate-resolution imaging spectroradiometer (MODIS) land surface temperature products as inputs. A comparison with in-situ observations suggests that this method can accurately estimate the mean daily land surface temperature, the spatial distribution of the permafrost, and the maximum thickness of the seasonally-frozen ground in the source region of the Yellow River, located in the northeastern area of the QTP. The results of The Temperature at the Top of the Permafrost model indicates that the area of permafrost in the source region of the Yellow River decreased by 4.82% in the period from 2003 to 2019, with an increase in the areal mean air temperature of 0.35 °C/10 years. A high spatial heterogeneity in the frozen soil changes was revealed. The basin-averaged active layer thickness of the permafrost increased at a rate of 5.46 cm/10 years, and the basin-averaged maximum thickness of the seasonally-frozen ground decreased at a rate of 3.66 cm/10 years. The uncertainties in calculating the mean daily land surface temperature and the soil’s thermal conductivity were likely to influence the accuracy of the estimation of the spatial distribution of the permafrost and the maximum thickness of the seasonally-frozen ground, which highlight the importance of the better integration of field observations and multi-source remote sensing data in order to improve the modelling of frozen soil in the future. Overall, the approach proposed in this study may contribute to the improvement of the application of the MODIS land surface temperature data in the study of frozen soil changes in large catchments with limited in-situ observations in the QTP.

Spatial–Temporal Correlations between Soil pH and NPP of Grassland Ecosystems in the Yellow River Source Area, China

“…Rising temperatures caused by global warming have degraded the permafrost in the Yellow River source area, having a profound impact on the vegetation and soil conditions [ 39 , 40 , 41 ]. Because soil pH has a significant impact on plant growth [ 42 ], soil microbial changes [ 43 ], as well as soil nutrients [ 44 ], it has emerged as an important soil variable [ 23 ].…”

Assessing the State of Structural Foundations in Permafrost Regions by Means of Acoustic Testing

“…There are two key approaches to how data is obtained on permafrost temperature: measuring soil temperature profiles, using sensors installed in boreholes [5,8,9], and satellite remote sensing of the earth's surface [10,11]. There are a lot of mathematical models that have been developed to assess temperature distribution in soils [10,[12][13][14]. Regardless of the approach chosen, the criterion for assessing the state is the soil freezing temperature.…”

Quantifying the Cooling Effect and Scale of Large Inner-City Lakes Based on Landscape Patterns: A Case Study of Hangzhou and Nanjing

“…UHI represents the temperature difference between urban and suburban areas [10]. There are mainly three ways to measure the temperature for UHI studies, including meteorological station observation records [11,12], thermometers mounted on vehicles [13], and remote sensing observation of the surface temperature [14][15][16]. Among them, the meteorological stations provide detailed records but fail to show the spatial distribution characteristics of the temperature on a large scale.…”