Stanislav Kireev

Dual-Regression Retrieval Algorithm for Real-Time Processing of Satellite Ultraspectral Radiances

AbstractA fast physically based dual-regression (DR) method is developed to produce, in real time, accurate profile and surface- and cloud-property retrievals from satellite ultraspectral radiances observed for both clear- and cloudy-sky conditions. The DR relies on using empirical orthogonal function (EOF) regression “clear trained” and “cloud trained” retrievals of surface skin temperature, surface-emissivity EOF coefficients, carbon dioxide concentration, cloud-top altitude, effective cloud optical depth, and atmospheric temperature, moisture, and ozone profiles above the cloud and below thin or broken cloud. The cloud-trained retrieval is obtained using cloud-height-classified statistical datasets. The result is a retrieval with an accuracy that is much higher than that associated with the retrieval produced by the unclassified regression method currently used in the International Moderate Resolution Imaging Spectroradiometer/Atmospheric Infrared Sounder (MODIS/AIRS) Processing Package (IMAPP) retriev...

Hazard Detection Analysis for a Forward-Looking Interferometer

The Forward-Looking Interferometer (FLI) is a new instrument concept for obtaining the measurements required to alert flight crews to potential weather hazards to safe flight. To meet the needs of the commercial fleet, such a sensor should address multiple hazards to warrant the costs of development, certification, installation, training, and maintenance. The FLI concept is based on high-resolution Infrared Fourier Transform Spectrometry (FTS) technologies that have been developed for satellite remote sensing. These technologies have also been applied to the detection of aerosols and gases for other purposes. The FLI concept is being evaluated for its potential to address multiple hazards including clear air turbulence (CAT), volcanic ash, wake vortices, low slant range visibility, dry wind shear, and icing during all phases of flight (takeoff, cruise, and landing). The research accomplished in this second phase of the FLI project was in three major areas: further sensitivity studies to better understand the potential capabilities and requirements for an airborne FLI instrument, field measurements that were conducted in an effort to provide empirical demonstrations of radiometric hazard detection, and theoretical work to support the development of algorithms to determine the severity of detected hazards

Simulation of Airborne Radiometric Detection of Wake Vortices

This paper describes an analysis of the potential of using an airborne Fourier transform spectrometer (FTS) or radiometer to detect wake vortices. The goal was to determine the requirements for an infrared (IR) FTS to effectively detect wake vortices. Initially, a theoretical analysis of wake vortex detection by thermal radiation was realized in a series of simulations. The first stage used the Terminal Area Simulation System (TASS) dynamic model to simulate wake vortex temperature, moisture, and velocity fields. The second stage used these fields as input to the line-by-line radiative transfer model (LBLRTM) to simulate responses from both an imaging IR hyperspectral FTS and an IR imaging radiometer. These numerical simulations generated FTS and radiometer imagery that was compared with the original temperature data. This research supported an effort, using ground-based imaging FTS instruments, to make measurements of wake vortices of various landing aircraft. Results from two different field campaigns have been previously reported. Instrument specifications for wake vortex thermal detection are recommended for an imaging radiometer sensitive within the following two narrow spectral bands: 670-750 cm-1 and 2200-2350 cm-1 . The instrument must have at the very minimum a noise equivalent differential temperature <; 2 mK and a spectral resolution of at least 32 cm-1.

Validation assessment model for atmospheric retrievals

A linear mathematical error model for the assessment of validation activity of atmospheric retrievals is presented. The purpose of the validation activity is to assess the actual performance of the remote sensing validated system while in orbit by comparing its measurements to some relevant-validating-data sets. The validating system samples volumes of the atmosphere at times and locations that are different from the ones when and where the validated system makes its own observations. The location of the validating system can be either stationary, e.g. a ground ARM site, or movable, e.g. an aircraft or some other satellites. The true states may be correlated or not. The sampled volumes differ from each other by their location, timing, and size. The validated and validating systems have different vertical resolution and grid, absolute accuracy, and noise level. All the above factors cause apparent differences between the data to be compared. The validation assessment model makes the comparison accurate by allowing for the differences. The model can be used for assessment and interpretation of the validation results when the above mentioned sources of discrepancies are significant, as well as for evaluation of a particular validating data source.

Hyperspectral image turbulence measurements of the atmosphere

A Forward Looking Interferometer (FLI) sensor has the potential to be used as a means of detecting aviation hazards in flight. One of these hazards is mountain wave turbulence. The results from a data acquisition activity at the University of Colorados Mountain Research Station will be presented here. Hyperspectral datacubes from a Telops Hyper-Cam are being studied to determine if evidence of a turbulent event can be identified in the data. These data are then being compared with D&P TurboFT data, which are collected at a much higher time resolution and broader spectrum.

Interferometric radiometer for in-flight detection of aviation hazards

The Forward-Looking Interferometer (FLI) is a new instrument concept for obtaining the measurements required to alert flight crews to potential weather hazards to safe flight. To meet the needs of the commercial fleet, such a sensor should address multiple hazards to warrant the costs of development, certification, installation, training, and maintenance. The FLI concept is based on high-resolution Infrared Fourier Transform Spectrometry (FTS) technologies that have been developed for ground based, airborne, and satellite remote sensing. The FLI concept is being evaluated for its potential to address multiple hazards including clear air turbulence (CAT), volcanic ash, wake vortices, low slant range visibility, dry wind shear, and icing, during all phases of flight. This project has three major elements: further sensitivity studies and applications of EOF (Empirical Orthogonal Function) Regression; development of algorithms to estimate the hazard severity; and field measurements to provide an empirical demonstration of the FLI aviation hazard detection and display capability. These theoretical and experimental studies will lead to a specification for a prototype airborne FLI instrument for use in future in-flight validation. The research team includes the Georgia Tech Research Institute, Hampton University, the University Corporation for Atmospheric Research, the Air Force Institute of Technology, and the University of Wisconsin.

Imaging Geostationary Fourier Transform Spectrometer-revolutionary tool for tropospheric chemistry

The Geostationary Imaging Fourier Transform Spectrometer (GIFTS) has been selected by the National Aeronautics and Space Administration (NASA) for its 2004 New Millennium Program mission. The GIFTS geophysical data products are derived from measurements of atmospheric thermal emission in 2 spectral bands: 685-1130 cm/sup -1/ and 1650-2250 cm/sup -1/, at high spectral resolution (up to 0.3 cm/sup -1/) on a 4-km spatial grid. Among key data products are vertically-resolved distributions of ozone and carbon monoxide. Vertical resolution attainable is in the range of 3- to 11-km, depending on a target gas and altitude. To evaluate the GIFTS capability for atmospheric chemistry studies, e.g., sources, sinks, transport and transformation of trace gas, simulations of the GIFTS observations have been performed. Real aircraft in situ profiles and results of the Harvard 3-D model were used as inputs for the simulations.