Correlated-k Based Ultra-Fast Radiative Transfer (kURT) Method

摘要

A new sensor-specific correlated-k (c-k) ultra-fast radiative transfer (RT) formalism, kURT has been designed for fast broad-bandpass scene simulations from UV-visible to LWIR wavelengths. A higher resolution RT code (1 /cm MODTRAN) has been adapted to output 1 /cm correlated-k parameters for ozone water and the combined uniformly mixed species on a pressure-temperature grid which are merged to form a compact c-k set incorporating the sensor bandpass response function. The compact set is used to compute bandpass transmittance and radiance in near-real time. Scattering parameters (molecular Rayleigh clouds and aerosols) blackbody and solar functions are cast as compact k- dependent source terms and used in the radiance computations Preliminary transmittance results for 3-5 and 8-12 micron bandpasses and visible-MWIR sensors yield results within 2% of a 1 /cm MODTRAN calculation with a two- orders-of-magnitude computational savings. Applications include near-earth broadband propagation and extinction calculations for target detection and recognition mid-range tracking and search and rescue operations from ground and low altitude aircraft.