Quantifying the contribution of land use change to surface temperature in the lower reaches of the Yangtze River

Xueqian Wang,Aijun Ding,Ye Liu,Weidong Guo,Bo Qiu,Jianning Sun

doi:10.5194/acp-17-4989-2017

Abstract

Abstract. Anthropogenic land use has a significant impact on climate change. Located in the typical East Asian monsoon region, the land–atmosphere interaction in the lower reaches of the Yangtze River is even more complicated due to intensive human activities and different types of land use in this region. To better understand these effects on microclimate change, we compare differences in land surface temperature (Ts) for three land types around Nanjing from March to August, 2013, and then quantify the contribution of land surface factors to these differences (ΔTs) by considering the effects of surface albedo, roughness length, and evaporation. The atmospheric background contribution to ΔTs is also considered based on differences in air temperature (ΔTa). It is found that the cropland cooling effect decreases Ts by 1.76° and the urban heat island effect increases Ts by 1.25°. They have opposite impacts but are both significant in this region. Various changes in surface factors affect radiation and energy distribution and eventually modify Ts. It is the evaporative cooling effect that plays the most important role in this region and accounts for 1.40° of the crop cooling and 2.29° of the urban warming. Moreover, the background atmospheric circulation is also an indispensable part in land–atmosphere feedback induced by land use change and reinforces both these effects.

Highlights

Land-use–land-cover change (LULCC) has been widely investigated in the past few decades, and it has been found that more than half of the land surface on Earth has been exploited by human (Baldocchi, 2014)
Robust evidence indicates that the impact of LULCC on temperature is obvious, and this impact depends on different types of land surface transformation
Anthropogenic heat (AH) flux is more obvious in urban areas than in rural areas, but it is

Summary

Introduction

Land-use–land-cover change (LULCC) has been widely investigated in the past few decades, and it has been found that more than half of the land surface on Earth has been exploited by human (Baldocchi, 2014). Agriculture often leads to cooling temperature in different patterns, and the cooling effect can usually be magnified when it comes to irrigation (Campra et al, 2008; Kueppers et al, 2007; Lobell et al, 2006; Zhang et al, 2011) For this reason, analyzing different types of land use plays an important role in evaluating climate change on different spatial scales (Alkama and Cescatti, 2016; Baldocchi and Ma, 2013; Huang et al, 2008; Wang et al, 2010; Hari et al, 2016), and in improving the predictive capacity of models (Huang et al, 2015; Niu et al, 2011; Zhang et al, 2015). There have been many studies concentrating on LULCC, they

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Conclusion