Warm Island Effect in the Badain Jaran Desert Lake Group Region Inferred from the Accumulated Temperature

Nan Meng,Nai’Ang Wang,Xingbin Xu,Liqiang Zhao,Zhenmin Niu,Xiaoyan Liang

doi:10.3390/atmos11020153

Abstract

The Badain Jaran Desert (BJD) is characterized by the coexistence of over 110 perennial lakes and thousands of megadunes in its southeast part. Unlike the cold island effect, we found a special phenomenon of the warm island effect in the lake group region of the BJD. However, the concept and formation mechanism remains unclear. In this study, based on observations of land surface processes in the area, we first used the daily mean temperature from 23 automated meteorological stations from 2010 to 2017 to calculate the mean daily temperature (T) ≥ 0 °C, T ≥ 10 °C accumulated temperature and negative accumulated temperature. Furthermore, using the net radiation from two eddy covariance measurement systems, characteristics of the net radiation between the lake and megadunes were analyzed. When comparing observed data in the lake group region to surrounding areas, accumulated temperature from all three meteorological stations in the lake group region were higher; the duration days of T ≥ 0 °C and T ≥ 10 °C were longer, whereas duration days of negative accumulated temperature were shorter. In addition, the initial dates for T ≥ 0 °C and T ≥ 10 °C accumulated temperature were earlier, whereas the end dates were delayed. Variations in heat were observed between stations in the lake group region that may be reflective of microclimate environments between lakes. The authors relate warm island formation in the BJD lake group region to (1) the heat carried by groundwater recharge to the desert lake groups has a great impact on the local temperature. (2) Net heat radiation to the atmosphere through sensible heat flux owing to sparse vegetation in the desert areas. Hence, heat resources are richer in the lake group region. This study aims to improve our understanding of the warm island effect from a comprehensive analysis of its intensity and distribution pattern around the lake group region as compared to its surroundings. In addition, the results from this study will provide a scientific basis for determining the source of lake water in the BJD.

Highlights

Climate and climate variability are determined by the amount of incoming solar radiation, chemical composition and dynamics of the atmosphere, and surface characteristics of the earth [1,2,3].The surface characteristics of the earth often affect the regional and local patterns of climate through the redistribution of energy [4,5,6]
The aim of this paper is to reveal the phenomenon of the warm island effect and its formation mechanism based on the observations of land surface processes
Duration days of T ≥ 0 ◦ C and T ≥ 10 ◦ C were longer in the lake group region than in surrounding areas, while duration days of negative accumulated temperature were shorter than in surrounding areas

Summary

Introduction

Climate and climate variability are determined by the amount of incoming solar radiation, chemical composition and dynamics of the atmosphere, and surface characteristics of the earth [1,2,3]. The surface characteristics of the earth often affect the regional and local patterns of climate through the redistribution of energy [4,5,6]. Great contrasts exist in the climate and surface characteristics from one desert to the [9,10,11,12,13]. Understanding the desert climates is essential because of strong linkages between climate, biological processes, and geomorphology [14,15,16,17,18,19,20]

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