Aerosol optical properties and radiative effect determined from sky-radiometer over Loess Plateau of Northwest China

Abstract

Abstract. The aerosol optical properties and their associated radiative effects are derived from sky-radiometer and surface solar radiation data collected over the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) for the period of March to May (MAM) 2009. The result shows that the seasonal mean aerosol optical depth (AOD) at 500 nm in MAM is 0.40. The single scattering albedo (SSA) at 500 nm in MAM at SACOL fluctuates significantly ranging from 0.82 to 0.98. The averaged value of SSA there for background aerosol is 0.90 in MAM, while it is smaller (0.87) during the dust event outbreak period. The smaller SSA can be interpreted as the result of larger particles during dust events. The averaged asymmetry factor (ASY) at 500 nm during dust event period is 0.73, which is larger than 0.70 of background aerosols. The averaged shortwave radiative effects of the aerosols during dust event period in MAM are 0.68, −70.02 and 70.70 W m −2 , respectively, at the top of the atmosphere (TOA), surface and in the atmosphere. The aerosols heat the atmosphere during dust event period by up to about 2 K day −1 (daily averaged), which is 60 % larger than the heating (1.25 K day −1 ) of background aerosols. The significant heating effect in the atmosphere of the aerosols during dust event is determined by larger AOD and smaller SSA.

The relationship between anthropogenic dust and population over global semi-arid regions

“…Guan et al (2015a) found that the enhanced warming in drylands was a result of radiativeforced temperature, which has a close relationship with aerosol column burden. The aerosol in drylands has an obvious warming effect (Huang et al, 2006aChen et al, 2010;Ye et al, 2012;Jin et al, 2015), and the aerosol has a wide distribution and tends to have a relatively large optical depth (H. Bi et al, 2011;Liu et al, 2011;, leading to a significant radiative effect in the drylands. According to the results of Tegen and Fung (1995), the existing atmospheric dust load is hard to explain by natural sources alone.…”

Aerosol Optical and Microphysical Properties of Four Typical Sites of SONET in China Based on Remote Sensing Measurements

“…Li et al [34] found the decrease of residual aerosol and an unusual case of residual aerosol increase during the different processes of a haze episode. In addition, some research concentrated on the properties of a single type aerosol, e.g., urban-industrial (e.g., [40]), rural (e.g., [32]), desert dust (e.g., [41]), and oceanic [42].…”

Aerosol Optical Properties over Mount Song, a Rural Site in Central China

“…Values of α greater than 1.6 and α values less than 0.8 accounted respectively for 1.3% and 8.2% of the total. It is reported that the probability distribution of α has a modal value of 1.1 and varies in the range 0 to 1.7 over Loess Plateau of Northwestern China (Bi et al, 2011); values of α greater than 1.8 and less than 0.6 accounted respectively, for 0.3% and 1%, over Shanghai, China (He et al, 2012). Meanwhile, the frequency histogram of WVC shows a maximum around 0.6 cm; 75% lower than 2 cm and 64% in the range 0.3-1.8 cm (Fig.…”

“…The single scattering albedo (SSA) is a common measurement of the relative contribution of scattering to extinction, which is mostly dependent on the chemical composition, matter concentration and size distribution of (Dubovik et al, 2002;Liu et al, 2011). 08.…”