Thomas H. Achtor

Global Soundings of the Atmosphere from ATOVS Measurements: The Algorithm and Validation

Abstract The International Advanced Television and Infrared Observation Satellite Operational Vertical Sounder (ATOVS) Processing Package (IAPP) has been developed to retrieve the atmospheric temperature profile, moisture profile, atmospheric total ozone, and other parameters in both clear and cloudy atmospheres from the ATOVS measurements. The algorithm that retrieves these parameters contains four steps: 1) cloud detection and removal, 2) bias adjustment for ATOVS measurements, 3) regression retrieval processes, and 4) a nonlinear iterative physical retrieval. Nine (3 × 3) adjacent High-Resolution Infrared Sounder (HIRS)/3 spot observations, together with Advanced Microwave Sounding Unit-A observations remapped to the HIRS/3 resolution, are used to retrieve the temperature profile, moisture profile, surface skin temperature, total atmospheric ozone and microwave surface emissivity, and so on. ATOVS profile retrieval results are evaluated by root-mean-square differences with respect to radiosonde observa...

Spring Season Colorado Cyclones. Part I: Use of Composites to Relate Upper and Lower Tropospheric Wind Fields

Abstract A set of 70 cases of spring season Colorado cyclone events is used to form composites which describe the upper (300 mb) and lower (850 mb) tropospheric wind fields during the early stages of cyclone formation. The 70 cases are partitioned into those which persist beyond 72 h (developing) and those which fill after 24 h (nondeveloping). The developing sample reveals a well-defined 300-mb wind maximum embedded in a short wave trough which propagates eastward during the six time periods studied. However, the nondeveloping sample composite exhibits little structure to the 300-mb wind pattern. A subsample of the developing cases, chosen on the basis of the presence of a jet streak over the New Mexico-Texas area, shows a stronger 300-mb wind maximum. The 850-mb composites show southerly flow in the southern Great Plains in the two samples and the subsample. The developing sample and jet streak subsample exhibit a marked increase in 850-mb wind speed as the exit region of the 300-mb jet maximum propagat...

McIDAS-V: a powerful data analysis and visualization tool for multi and hyperspectral environmental satellite data

The Man computer Interactive Data Access System (McIDAS) project began over 30 years ago at the University of Wisconsin-Madison to analyze and visualize data from the first generation of geostationary weather satellites. McIDAS continues to provide a strong data analysis and visualization capability for the current environmental satellites. However, the next generation of operational remote sensing instruments under development for the NPOESS and GOES-R programs require software tools with expanded capability and performance to support innovative techniques for developing algorithms, visualizing data and products, and evaluating results. A project is underway at SSEC to develop the fifth generation of McIDAS, a java-based, open-source system for multispectral and hyperspectral researchers and algorithm developers that will provide powerful new data manipulation and visualization tools to work in this data rich environment. NASA EOS MODIS and AIRS data as well as MSG SEVERI and METOP IASI data are now being used in conjunction with in situ and gridded data to develop new analysis and product validation techniques in the McIDAS-V environment. This new data analysis and visualization system will support both researchers and operational users of the advanced measurement systems on NPOESS and GOES R.

International ATOVS processing package: algorithm design and its preliminary performance

The International ATOVS Processing Package (IAPP) is under development at the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison. The IAPP will be available to world wide users for processing real time ATOVS data. The retrieval algorithm of the IAPP is described with specific reference to retrieval of atmospheric temperature profile, moisture profile, total ozone, surface skin temperature, and microwave surface emissivity. Nine adjacent HIRS/3 spot observations together with the AMSU footprint remapped to the HIRS/3 resolution, are used to retrieve one atmospheric temperature profile and the other parameters within that domain. The algorithm is tested using simulated ATOVS data for both clear and cloudy sky conditions. Results demonstrate the potential use of IAPP for processing the real time ATOVS data.

The Use of Visible Data in VAS Temperature Soundings

Abstract A method is developed that makes use of visible reflectance data to provide cloud information from the retrieval of atmospheric vertical soundings from VAS geostationary radiance observations. The technique enables estimates of fractional cloud amount for each 8–16 km VAS infrared field of view. Cloud top pressure is calculated using the CO2 slicing method or, for low-level opaque overcast cloud conditions, estimated from the VAS-observed, 11-μ,a window channel, effective brightness temperature, and the temperature profile. For semi-transparent cloud, the emissivity is obtained from the cloud level atmospheric temperature, which corresponds to the cloud top pressure derived from the CO2 slicing method, and VAS 11-μ window channel, effective brightness temperature. With the effective cloud amount and cloud top pressure, the proper clear and cloudy weighting functions of the radiative transfer equation (RTE) are specified, and a direct physical inverse solution of the RTE is used to produce vertica...

Software packages for direct broadcast data processing of ATOVS, MODIS and AIRS radiances

The Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin-Madison, USA, has a long history of software development to acquire and process radiances measurements from polar orbiting and geostationary weather satellites. Since 1983, CIMSS has worked with the International TOVS Working Group (ITWG) to create the International TOVS/ATOVS Processing Packages (ITPP/IAPP). CIMSS has also worked with NASA and the Earth Observing System (EOS) direct broadcast community to create the International MODIS/AIRS Processing Package (IMAPP). The International TOVS Processing Package (ITPP) provides Level 0 to 1B processing and software to retrieve vertical profiles of temperature and moisture from AHVRR, HIRS and MSU radiances on NOAA polar orbiting satellites through NOAA -14. For NOAA -15 through the current NOAA -17 satellites, the International ATOVS Processing Package (IAPP) works in conjunction with the AAPP (AVHRR and ATOVS Processing Package), developed by Eumetsat, to accomplish the same tasks for this new generation of NOAA polar weather satellites. Within the NASA Earth Observing System (EOS) program, a direct broadcast capability was created for MODIS and AIRS radiance measurements. The NASA Earth System Enterprise provided support to the University of Wisconsin CIMSS to develop Level 0 to 1B processing software for MODIS and AIRS radiances. The International MODIS/AIRS Processing Package (IMAPP) allows any ground station capable of receiving direct broadcast from Terra or Aqua to produce calibrated and geolocated MODIS radiances (Level 1), along with a select group of science products (Level 2). IMAPP is derived from the operational MODIS processing software developed at NASA GSFC, and is modified to be compatible with direct broadcast data. This poster will describe the functionality of the IAPP and IMAPP software, including its applications, examples from processing and how to obtain the software.