Validation of technique to hyperspectrally characterize the lower atmosphere with limited surface observations

Abstract

This paper demonstrates the capability of AFIT/CDE's Laser Environmental Effects Definition and Reference (LEEDR) model to accurately characterize the meteorological parameters and radiative transfer effects of the atmospheric boundary layer with only surface observations of temperature, pressure, and humidity. The LEEDR model is a fastcalculating, first principles, worldwide surface to 100 km, atmospheric propagation and characterization package. This package enables the creation of profiles of temperature, pressure, water vapor content, optical turbulence, atmospheric particulates and hydrometeors as they relate to line-by-line layer transmission, path and background radiance at wavelengths from the ultraviolet to radio frequencies. Physics-based cloud and precipitation characterizations are coupled with a probability of cloud free line of sight (CFLOS) algorithm for air-to-air, air-to-surface, and surface-to-air (or space) look angles. In general, LEEDR defines the well-mixed atmospheric boundary layer with a worldwide, probabilistic surface climatology based on season and time of day, and then computes the radiative transfer and propagation effects from the vertical profile of meteorological variables. However, the LEEDR user can also directly input surface observations. This research compares the LEEDR vertical profiles created from input surface observations to actual observations from balloon launches. Results are then compared to the LEEDR ExPERT climatological sounding for the same time of day and season. RMSE are calculated and it was found that closer for those profiles made from surface observations than those made from climatological data for the same season and time. Impacts of those differences are shown with a relevant tactical scenario in AFIT/CDE HELEEOS program.

Validation of a UV-to-RF High-Spectral-Resolution Atmospheric Boundary Layer Characterization Tool

“…This input was applied on the Ground Level tab for consideration during LEEDR-performed profile (temperature and dewpoint) calculations. The second type of LEEDR atmospheric profiles (for temperature and dewpoint) that were developed considered only the WPAFB ExPERT database surface climatology (Randall et al 2011). Both winter and summer seasons were considered in this validation research.…”

“…From each time group, 25 radiosonde launches were chosen on the basis of accompanying observations indicating clear conditions. Therefore, a total of 50 winter launches from one site were used in this portion of the validation (Randall et al 2011).…”

“…LEEDR's default is to use the climatological probabilistic data that correlate with the users' input scenario (i.e., location, season, and time of day); having current surface observations creates a more realistic profile in the BL, however. The Ground Level tab provides options for identifying observed meteorological values for pressure [P, in millibars (hPa)], temperature (T, in degrees Fahrenheit), dewpoint (T d , in degrees Fahrenheit), and relative humidity (RH, in percent) at ExPERT sites (Randall et al 2011). …”

“…AFIT/CDE also incorporated into LEEDR the ability to input limited surface data in the ''Ground Level'' tab using the most easily obtainable observed data to create a more realistic data profile. This research compares the LEEDR vertical profiles created from input surface observations and surface probabilistic climatology with the radiosonde data collected for Randall et al (2011) and with numerical weather prediction (NWP) data valid at the same times. The NWP data source used for this study was the Global Forecasting System (GFS) model as obtained from the National Oceanic and Atmospheric Administration National Operational Model Archive and Distribution System (NOMADS).…”

“…One of these codes, the High Energy Laser End-to-End Operational Simulation (HELEEOS; Bartell et al 2005;Fiorino et al 2006), is perhaps the first DEW simulation package to fully incorporate a correlated, probabilistic climatological database. The infusion of such realistic atmospheric effects into the simulations allows HELEEOS to better assess variability/uncertainty in DEW system performance arising from spatial, spectral, and temporal variations in operating conditions Randall et al 2011). HELEEOS is intended as a tool for testing engineering-design performance or doing research analysis; AFIT/CDE is currently developing a missionplanning version of HELEEOS, called the High Energy Laser Tactical Decision Aid (HELTDA; Fiorino et al 2013), that would allow for high-energy-laser (HEL; generally at least 1-2 kW) mission planning with atmospheric effects determined from current or short-term forecast data rather than from climatological information (hereinafter referred to as climatology).…”