The Potential of GRASP/GARRLiC Retrievals for Dust Aerosol Model Evaluation: Case Study during the PreTECT Campaign

Abstract

We use the Generalized Retrieval of Aerosol Surface Properties algorithm (GRASP) to compare with dust concentration profiles derived from the NMME-DREAM model for a specific dust episode. The GRASP algorithm provides the possibility of deriving columnar and vertically-resolved aerosol properties from a combination of lidar and sun-photometer observations. Herein, we apply GRASP for analysis of a Saharan dust outburst observed during the “PREparatory: does dust TriboElectrification affect our ClimaTe” campaign (PreTECT) that took place at the North coast of Crete, at the Finokalia ACTRIS station. GRASP provides column-averaged and vertically resolved microphysical and optical properties of the particles. The retrieved dust concentration profiles are compared with modeled concentration profiles derived from the NMME-DREAM dust model. To strengthen the results, we use dust concentration profiles from the POlarization-LIdar PHOtometer Networking method (POLIPHON). A strong underestimation of the maximum dust concentration is observed from the NMME-DREAM model. The reported differences between the retrievals and the model indicate a high potential of the GRASP algorithm for future studies of dust model evaluation.

Aeolus winds impact on volcanic ash early warning systems for aviation

“…For FLEXPART, the size range of volcanic ash particles is between 5 and 21 µm diameter, which is within a range that is detectable from Polly XT . The POLIPHON technique for the retrieval of the concentrations has been validated against synergistic retrievals that combine multi-wavelength lidar and sun/sky-radiometer observations (sensitive up to 15 μm in particle radius 60 , 61 ) for dust and volcanic ash particles and has been found to perform well 62 , 63 . To separate the contribution of the depolarizing ( and the non-depolarizing ( component to the particle backscatter, we apply the following equations: …”

Retrievals of dust-related particle mass and ice-nucleating particle concentration profiles with ground-based polarization lidar and sun photometer over a megacity in central China

“…It detects the direct solar irradiance at eight wavelengths (340, 380, 440, 500, 675, 870, 1020, and 1246 nm) for every 15 min; the AOD at each wavelength can then be calculated following the Beer-Lambert law. The uncertainties of AOD are ∼ 0.015 at 440-1020 nm and ∼ 0.035 at 340-380 nm under the optical air mass of 1.0 (Zhang et al, 2021), which corresponds to the summer solstice in the Northern Hemisphere. Considering that transported dust plumes generally intrude into Wuhan in spring and winter, these AOD uncertainties should be divided by a factor of 1.6 and 2.4, respectively.…”

“…A sun-and sky-scanning spectral photometer (CE-318) was installed at our observatory in April 2008 and operated until August 2013 (Zhang et al, 2021). It detects the direct solar irradiance at eight wavelengths (340, 380, 440, 500, 675, 870, 1020, and 1246 nm) for every 15 min; the AOD at each wavelength can then be calculated following the Beer-Lambert law.…”

“…This is caused by plenty of local aerosol emissions (especially within the boundary layer), which cause the column-integrated aerosol properties observed to generally reflect characteristics of mixed dust (dust 5944 Y. He et al: Particle mass and INP concentration for mixed dust particles mixed with other urban aerosols) (Shao et al, 2020;Liu et al, 2021;Yin et al, 2021b). It is also worth noting that the previous gravitational sedimentation and wet deposition of dust particles during transport may modify the dust optical and microphysical properties above Wuhan.…”

A Comprehensive Description of Multi-Term LSM for Applying Multiple a Priori Constraints in Problems of Atmospheric Remote Sensing: GRASP Algorithm, Concept, and Applications

“…Using this synergy, GARRLiC/GRASP retrieves improved aerosol columnar properties together with details about vertical aerosol variability including profiles of fine and coarse aerosol mode concentrations and vertical profiles of ω 0 (λ), as will be illustrated below. GARRLiC/GRASP has been used in a number of studies and employed in routine processing within Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS) (Tsekeri, et al, 2013;Bovchaliuk, et al, 2016;Benavent-Oltra et al, 2017;Tsekeri, et al, 2017;Román et al, 2018;Benavent-Oltra et al, 2019;Hu et al, 2019;Herreras et al, 2019;Titos et al, 2019;Konsta, et al, 2021). The evolution of the GARRLiC/GRASP branch, its applications to more complex lidar systems and more complex synergy processing is discussed by Lopatin et al (2021).…”