Aerosol Optical Parameters Detection from LIDARS and Applications to an Ultraviolet and Visible Radiative Transfer Model

摘要

In-situ measurements of aerosol composition as well as other atmospheric optical parameters provide valuable information for climate and atmospheric radiation processes. Remote sensing instrumentation plays a significant role in the detection of these parameters as well as atmospheric mathematical models to describe the change of properties of particulate in the atmosphere. Nowadays the use of lasers for particle detection and ranging has become obligatory in almost all atmospheric research centers in the world. These systems in conjunction with mathematical models provide us with detailed information of aerosol properties like vertical profile distribution, polarization and size characterization. In this sense, LIDARs (Light Detection and Ranging), for example, are pulsed laser transmission and receiving systems that were created for long range detection and to show their products in both spatial and temporal dimensions. The LIDARs operating in the NOAA Center for Atmospheric Sciences (NCAS) at Howard University, Beltsville Campus, Maryland are in-situ instruments that provide a variety of measurements, including, but not limited to aerosol backscattering coefficients, water vapor mixing ratios, nitrogen concentrations and cloud heights. These products are compared with Satellite information for specific days providing a full detail of the atmospheric composition of aerosols and water vapor for the region. Additionally, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite - Level 2 Clouds and Aerosol Data Products v3.01 are obtained from the Atmospheric Science Data Center for specific days and compared with ground base measurements from the LIDARs at Howard University Beltsville Campus (HUBC) site. Data from CALIPSO are organized by latitude and longitude as well as vertical and temporal resolution. On the other side, the Tropospheric Ultraviolet and Visible (TUV) radiative transfer model (Madronich, et al., 2002) calculates spectral irradiances, spectral actinic flux, photo-dissociation coefficients (J-values), and biologically effective irradiance (dose rates, doses). The model can be used for both free and cloudy specific days at specific time of the day and wavelengths. However, the outputs are at specific fixed altitude. In this work, the TUV model uses vertical profile data from the ground-based LIDARs in Beltsville and from satellite to calculate irradiances at different altitudes creating in this way vertical profiles of radiation. In conclusion, the analysis of aerosol data and the relevance of using Light Detection and Ranging (LIDAR) in Atmospheric Sciences are described. Also, calculation of aerosol backscattering profiles from Raman LIDAR data and comparison with Ceilometers and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) are also presented. Finally, these optical parameters are used as inputs in a radiative transfer model to calculate a profile of irradiances at Howard University, Beltsville Campus in Beltsville, Maryland.