Assessment of aerosol optical property and radiative effect for the layer decoupling cases over the northern South China Sea during the 7‐SEAS/Dongsha Experiment

Abstract

The aerosol radiative effect can be modulated by the vertical distribution and optical properties of aerosols, particularly when aerosol layers are decoupled. Direct aerosol radiative effects over the northern South China Sea (SCS) were assessed by incorporating an observed data set of aerosol optical properties obtained from the Seven South East Asian Studies (7‐SEAS)/Dongsha Experiment into a radiative transfer model. Aerosol optical properties for a two‐layer structure of aerosol transport were estimated. In the radiative transfer calculations, aerosol variability (i.e., diversity of source region, aerosol type, and vertical distribution) for the complex aerosol environment was also carefully quantified. The column‐integrated aerosol optical depth (AOD) at 500 nm was 0.1–0.3 for near‐surface aerosols and increased 1–5 times in presence of upper layer biomass‐burning aerosols. A case study showed the strong aerosol absorption (single‐scattering albedo (ω) ≈ 0.92 at 440 nm wavelength) exhibited by the upper layer when associated with predominantly biomass‐burning aerosols, and the ω (≈0.95) of near‐surface aerosols was greater than that of the upper layer aerosols because of the presence of mixed type aerosols. The presence of upper level aerosol transport could enhance the radiative efficiency at the surface (i.e., cooling) and lower atmosphere (i.e., heating) by up to −13.7 and +9.6 W m−2 per AOD, respectively. Such enhancement could potentially modify atmospheric stability, can influence atmospheric circulation, as well as the hydrological cycle over the tropical and low‐latitude marginal northern SCS.

Technical note: Fu–Liou–Gu and Corti–Peter model performance evaluation for radiative retrievals from cirrus clouds

“…Such evaluation, however, can readily be conducted using the unique NASA Micro-Pulse Lidar Network (MPLNET; Welton et al, 2002;Campbell et al, 2002;Lolli et al, 2013Lolli et al, , 2014, established in 1999 to continuously monitor cloud and aerosol physical properties (Wang et al, 2012;Pani et al, 2016).…”

Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS/BASELInE

“…Extending from the optical closure modeling (Bell et al, 2013;Pani et al, 2016a) for regional biomass-burning aerosols, Pani et al (2016b) reported, for the first time, a detailed estimation of direct aerosol radiative effect (DARE) near source regions over northern SAP by using in-situ datasets (i.e., ground-based measurement of aerosol physical, chemical, and optical properties) and a radiative transfer model during the spring of 2013 BASELInE campaign. Their results provided strong evidence that biomass-burning aerosols (mainly water soluble and black carbon) enhance the surface cooling (as high as -33.5 W m -2 in 24-hour mean) as well as atmospheric warming (as high as +24.7 W m -2 ), which could significantly influence the diurnally-averaged radiative energetics.…”

Investigation of Biomass Burning Chemical Components over Northern Southeast Asia during 7-SEAS/BASELInE 2014 Campaign

“…Lulin), due to long-range transport from the Indochina region, has been explained and verified by longterm observations (Chuang et al, 2014) and also by modelsimulated results (Chuang et al, 2016b). Pani et al (2016a) recently investigated the radiative impact of upper-layer BB aerosols from the Indochina region over northern South China Sea. Moreover, Pani et al (2016b) reported a detailed estimation of direct aerosol radiative effect for near source BB aerosols over northern Indochina during the spring of 2013.…”