Abstract
Abstract. We present LIVAS (LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies), a 3-D multi-wavelength global aerosol and cloud optical database, optimized to be used for future space-based lidar end-to-end simulations of realistic atmospheric scenarios as well as retrieval algorithm testing activities. The LIVAS database provides averaged profiles of aerosol optical properties for the potential spaceborne laser operating wavelengths of 355, 532, 1064, 1570 and 2050 nm and of cloud optical properties at the wavelength of 532 nm. The global database is based on CALIPSO observations at 532 and 1064 nm and on aerosol-type-dependent backscatter- and extinction-related Ångström exponents, derived from EARLINET (European Aerosol Research Lidar Network) ground-based measurements for the UV and scattering calculations for the IR wavelengths, using a combination of input data from AERONET, suitable aerosol models and recent literature. The required spectral conversions are calculated for each of the CALIPSO aerosol types and are applied to CALIPSO backscatter and extinction data corresponding to the aerosol type retrieved by the CALIPSO aerosol classification scheme. A cloud optical database based on CALIPSO measurements at 532 nm is also provided, neglecting wavelength conversion due to approximately neutral scattering behavior of clouds along the spectral range of LIVAS. Averages of particle linear depolarization ratio profiles at 532 nm are provided as well. Finally, vertical distributions for a set of selected scenes of specific atmospheric phenomena (e.g., dust outbreaks, volcanic eruptions, wild fires, polar stratospheric clouds) are analyzed and spectrally converted so as to be used as case studies for spaceborne lidar performance assessments. The final global data set includes 4-year (1 January 2008–31 December 2011) time-averaged CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) data on a uniform grid of 1° × 1° with the original high vertical resolution of CALIPSO in order to ensure realistic simulations of the atmospheric variability in lidar end-to-end simulations.
Highlights
A general methodology to test the ability of candidate future spaceborne remote-sensing instruments to observe atmospheric quantities is the application of their processing algorithms on simulated data sets
The number of observations is presented in the right panel for each plot in order to have a measure of the representativeness of the mean aerosol extinction for each cell, which depends on the available CloudAerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) overpasses and corresponding samples
We presented LIVAS, a 4-year multi-wavelength global aerosol and cloud optical database that has been developed to complement existing data sets used by the ESA for instrument performance simulation of current and future spaceborne lidars as well as retrieval algorithm testing activities based on realistic atmospheric scenarios
Summary
A general methodology to test the ability of candidate future spaceborne remote-sensing instruments to observe atmospheric quantities is the application of their processing algorithms on simulated data sets. For active remote sensors as lidars, the vertical dimension should be included in the simulations Global distributions of such data are available today due to the launch of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on board the CloudAerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission of NASA/CNES in June 2006 (Winker et al, 2009). The technique of active remote sensing of the atmosphere by lidar has been chosen for two of the future ESA Earth Explorer Missions, namely the Atmospheric Dynamics Mission Aeolus (ADM-Aeolus; Stoffelen et al, 2005) and the Earth Clouds, Aerosols and Radiation Explorer (EarthCARE; ESA, 2004; Illingworth et al, 2014), and was further proposed for the Advanced Space Carbon and Climate Observation of Planet Earth (A-SCOPE), one of the candidates for the 7th Earth Explorer mission. The instrument design proposed for the A-SCOPE mission is an integrated path differential absorption (IPDA) lidar, aiming at measuring column-averaged dryair CO2 mixing ratios with high precision and low bias error, based on short-wave infrared (SWIR) (1570 or 2050 nm) laser and detector technologies
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