First results of operational retrieval of atmospheric ozone profile from the Moderate Resolution Imaging
Spectroradiometer (MODIS) infrared radiances over Siberian Region are presented. Nearly identical copies of
MODIS are operating onboard the Earth Observing System (EOS) Tena and Aqua satellites. MODIS images have
been collected using EOScan receiving station located in Barnaul. The modified Product Generation Executable
(PGE) 03 code, including synthetic regression retrieval algorithm, PGE 02 and the International MODIS/AIRS
Processing Package (IMAPP) have been used to retrieve the vertical ozone distributions under clear-sky conditions.
Evaluation of retrieved ozone profiles is performed by a comparison with retrievals from lidar observations, the
Stratospheric Aerosol and Gas Experiment III (SAGE 111)/Meteor-3M and the Atmospheric Infrared Sounder
(AIRS)/Aqua sensors. We demonstrate, that the MODIS mixing ozone ratio (in ppmv) and additionally measured
temperature information will be useful tools in regional stratospheric ozone studies. The main role of MODIS will
be the monitoring of the ozone trends in the stratosphere at the scale with 5 km x 5 km resolutions.
The International MODIS (Moderate Resolution Imaging Spectroradiometer) and AIRS (Atmospheric Infrared Sounder) Processing Package (IMAPP) is supported by NASA with the goals of developing a software package which is freely available for processing MODIS and AIRS/AMSU/HSB Data and promoting and supporting the worldwide use of EOS data, and involving the international community in EOS validation efforts. Both NASA's TERRA and AQUA spacecrafts have direct broadcast (DB) X-band downlinks that allow MODIS (on board both TERRA and AQUA) and AIRS/AMSU/HSB and AMSR-E (on board AQUA only) data to be received in real time by sites having the proper reception hardware. In addition to the current released IMAPP, which allows ground stations capable of receiving EOS direct broadcast data to generate products derived from MODIS and AIRS/AMSU/HSB, products from AMSR-E are under developed. Comparison of one month direct broadcast AMSR-E level 1 data with standard AMSR-E level 2A (level 1 data embedded) data archived by MSFC, NASA, have been carried out and the results have shown that the DB level 1 implementation successfully matches the standard products of brightness temperatures in terms of bias, RMS errors and correlation coefficients, i.e., the DB level 1 data are well calibrated and geo-located and are ready for retrieval for geophysical products. The AMSR-E level 2 products for precipitation and soil moisture are currently under evaluation. Those products will be compared with and validated against the official products.
The 36 channel Moderate Resolution Imaging Spectroradiometer (MODIS) offers the opportunity for multispectral approaches to cloud detection. The MODIS cloud mask developed at the Cooperative Institute for Meteorological Satellite Studies (CIMSS) uses several cloud detection tests to indicate a level of confidence that the MODIS is observing clear skies. The MODIS cloud mask algorithm identifies several conceptual domains according to surface type and solar illumination, including land, water, snow/ice, desert, and coast for both day and night. The updated cloud mask has many improvements, such as improved cloud/surface discrimination over desert regions, sun glint processing and thin cirrus detection. For non-snow-covered land areas, a clear sky confidence of 0.96 (probably clear) will be assigned if thresholds are met for three tests: 3.9-11 μm and 3.75-3.9 μm brightness temperature differences and a 1.24/0.55 μm reflectance ratio test. Values of these must be <15K, <11K and >2.0, respectively. A change has been made to the NIR (band 2) reflectance test for sun glint processing. The updated method is to calculate a cloud threshold as a linear function of sun-glint angle in three separate ranges. A new clear-sky restoral test was added where the ratio of band 17/18 reflectance is utilized to discriminate between low clouds and water surfaces. The thin cirrus thresholds using corrected band 26 (1.38 μm) reflectances were also modified.
The algorithm for retrieving atmospheric temperature, moisture, and total column ozone using the Moderate Resolution Imaging Spectroradiometer (MODIS) longwave infrared radiances is presented. The operational MODIS algorithm performs clear sky retrievals globally over land and ocean for both day and night. The algorithm is based on a regression and has an option to follow the statistical retrieval with a nonlinear physical retrieval. The regression coefficients are determined from an extension of the NOAA-88 data set containing more than 8400 global radiosonde measurements of atmospheric temperature, moisture and ozone profiles. Evaluation of atmospheric products is performed by a comparison with data from
ground-based instrumentation, geostationary infrared sounders, and polar orbiting microwave sounders. MODIS moisture products are in general agreement with the gradients and distributions from the other satellites, while MODIS depicts more detailed structure with its improved spatial resolution.
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.
The MODerate resolution Imaging Spectroradiometer (MODIS) instrument provides high spatial and spectral resolution views of each point on the earth four times per day. Both Terra and Aqua platforms have a direct broadcast X-band downlink that allows MODIS (Terra) and MODIS/AIRS (Aqua) data to be received in real time by sites having the proper reception hardware. In order to facilitate use of the data, science production software is being freely distributed through the International MODIS/AIRS processing package (IMAPP). The current suite of IMAPP MODIS products includes navigation and calibration (L1B), cloud mask and cloud top properties, including thermodynamic phase, and atmospheric profiles and water vapor retrievals. The applications have been modified from the operational versions running at the Goddard Distributed Active Archive Center (DAAC) such that the only required external toolkit is NCSA HDF4. Distribution of this software provides scientists around the world with the capability to produce local real-time high spatial resolution science products. MODIS data produced from the University of Wisconsin direct broadcast automated processing is used for a variety of science applications, including calibration and product validation. The data is also being used by other institutions for a range of purposes including assisting USA National Weather Service forecasters and the monitoring of Hudson Bay shipping routes by the Canadian Ice Service. The science software is being implemented globally from Australia to South America. IMAPP has been successful in providing a portable, relatively easy to install and user friendly software package for converting direct broadcast MODIS data into valuable science products.
The impact of non-unit calibration blackbody emissivity on MODIS airborne simulator (MAS) absolute thermal calibration accuracy is investigated. Estimates of blackbody effective emissivity were produced for MAS infrared channels using laboratory observations of a thermally controlled external source in a stable ambient environment. Results are consistent for spectrally close atmospheric window channels. SWIR channels show an effective emissivity of about 0.98; LWIR channels show an effective emissivity of about 0.94. Using non-unit blackbody effective emissivity reduces MAS warm scene brightness temperatures by about 1 degree Celsius and increases cold scene brightness temperatures by more than 5 degrees Celsius as compared to those inferred from assuming a unit emissivity blackbody. To test the MAS non- unit effective emissivity calibration, MAS and high- resolution interferometer sounder (HIS) LWIR data from a January 1995 ER-2 flight over the Gulf of Mexico were compared. Results show that including MAS blackbody effective emissivity decreases LWIR absolute calibration biases between the instruments to less than 0.5 degrees Celsius for all scene temperatures, and removes scene temperature dependence from the bias.
The MODIS airborne simulator (MAS), a scanning spectrometer built by Daedalus Enterprises for NASA Goddard Space Flight Center and Ames Research Center, is used for measuring reflected solar and emitted thermal radiation in 50 narrowband channels between 0.55 and 14.3 micrometers . The instrument provides multispectral images of outgoing radiation for purposes of developing and validating algorithms for the remote sensing of cloud, aerosol, water vapor, and surface properties from space. Nineteen of the channels on MAS have corresponding spectral channels on the moderate resolution imaging spectroradiometer (MODIS), an instrument being developed for the Earth Observing system (EOS) to be launched in the late 1990s. Flown aboard NASA's ER-2 aircraft, the MAS has a 2.5 mrad instantaneous field of view and scans perpendicular to the aircraft flight track with an angle of +/- 43 degree(s) about nadir. From a nominal ER-2 altitude of 20 km, images have a spatial resolution of 50 m at nadir and a 37 km swath width. We report on the status of the instrument, discuss recent design changes, and provide comparisons with MODIS. We also summarize MAS calibration work, especially efforts to calibrate those channels with strong water vapor absorption.