Empirically derived parameterizations of the direct aerosol radiative effect based on ORACLES aircraft observations

• DOI: 10.5194/amt-14-567-2021
• Publication Date: 2021-01-27T07:23:39Z
• Authors: Sabrina P. Cochrane; K. Sebastian Schmidt; Hong Chen; Peter Pilewskie; Scott Kittelman; Jens Redemann; Samuel LeBlanc; Kristina Pistone; Meloë Kacenelenbogen; Michal Segal Roze...; Yohei Shinozuka; Connor Flynn; Amie Dobracki; Paquita Zuidema; Steven Howell; Steffen Freitag; Sarah Doherty
• Keywords: Single-scattering albedo; Albedo (alchemy); Angstrom exponent; Solar zenith angle; Cloud albedo

Abstract. In this paper, we use observations from the NASA ORACLES (ObseRvations of CLouds above Aerosols and their intEractionS) aircraft campaign to develop a framework by way two parameterizations that establishes regionally representative relationships between aerosol-cloud properties radiative effects. These rely on new spectral aerosol property retrievals single scattering albedo (SSA) asymmetry parameter (ASY). The capture natural variability study region as sampled, both were found be fairly narrowly constrained (SSA: 0.83 ± 0.03 in mid-visible, 532 nm; ASY: 0.54 0.06 at nm). are well suited for calculating direct effect (DARE) since SSA ASY tied directly irradiance measured presence aerosols – one inputs DARE. allows entire campaigns generalized into set parameterizations. For range solar zenith angles, it links broadband DARE mid-visible optical depth (AOD) (α) underlying scene (either clouds or clear sky) first parameterization: P(AOD, α). ORACLES, majority case-to-case is attributable dependence driving parameters A second, extended, parameterization PX(AOD, α, SSA) explains even more introducing third parameter. establish link three (narrowband) DARE, implicitly accounting dependencies its drivers. They circumvent some assumptions when satellite products modeling context. example, microphysical not explicit P PX because varies too little case translate appreciable variability. While these particular only represent data, they raise prospect generalizing other regions.