Clear-Sky Surface Solar Radiation and the Radiative Effect of Aerosol and Water Vapor Based on Simulations and Satellite Observations over Northern China

Guang Zhang,Yingying Ma

doi:10.3390/rs12121931

Abstract

The distribution and trend of clear-sky surface solar radiation (SSR) and the quantitative effects of aerosol and water vapor are investigated in northern China during 2001–2015 using radiation simulations and satellite observations. Clear-sky SSR in northern China is high in summer and low in winter, which is dominated by astronomical factors and strongly modulated by the seasonal variations of radiative effects of aerosol (ARE) and water vapor (WVRE). The larger variation of WVRE than ARE indicates that water vapor plays a more important role in moderating the seasonal variation of clear-sky SSR. Clear-sky SSR shows an overall decreasing trend of –0.12 W/m2 per year, with decrease more strongly than –0.60 W/m2 per year in west-central Shandong and increase (about 0.40 W/m2) in south-central Inner Mongolia. The consistency of spatial distribution and high correlation between clear-sky SSR and ARE trend indicate that the clear-sky SSR trend is mainly determined by aerosol variation. Dust mass concentration decreases about 16% in south-central Inner Mongolia from 2001 to 2015, resulting in the increase in clear-sky SSR. In contrast, sulfate aerosol increases about 92% in west-central Shandong, leading to the decreasing trend of clear-sky SSR.

Highlights

Solar radiation reaching the Earth’s surface, known as the surface solar radiation (SSR), is the primary energy source for life on the planet [1,2]
Solar radiation is modulated by atmospheric constituents as it passes through the atmosphere
We analyzed the distribution and trend of clear-sky SSR and the quantitative effects of aerosol and water vapor over northern China based on clear-sky SSR, aerosol direct radiative effect (ARE), and water vapor radiative effect (WVRE) simulated by the Mesoscale Atmospheric Global Irradiance Code (MAGIC)

Summary

Introduction

Solar radiation reaching the Earth’s surface, known as the surface solar radiation (SSR), is the primary energy source for life on the planet [1,2] It drives the majority of the terrestrial processes (e.g., the carbon cycle and hydrological cycle) and plays a crucial role in a large number of sectors (e.g., agriculture and solar energy production) [3,4,5]. Some important efforts have been made to separate SSR variation into cloudy-sky and clear-sky conditions to exclude effects of cloud cover and cloud properties on solar radiation and highlight the effects of other atmospheric constituents [15,16]. The roles that aerosol and water vapor play in the seasonal and inter-annual variations of SSR are still uncertain, considering the huge disparities of spatial and temporal distributions of aerosol and water vapor among regions

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Conclusion