One of the objectives of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) program is to continue the long-term data set of total column ozone measurements from the Total Ozone Mapping Spectromenter (TOMS) systems while providing the increased accuracy and precision required by the NPOESS Integrated Program Office (IPO). In developing an Ozone Mapping and Profiler Suite (OMPS) sensor-algorithm system to meet the NPOESS requirements, we systematically analyzed the performance of the TOMS system and determined that it provided a strong starting point for the design of the OMPS system. In fact, our analysis showed that modern TOMS systems meet the NPOESS accuracy requirements for retrievals below 475 Dobson Units (DU). However, the NPOESS precision requirements are met only for retrievals below 225 DU. In order to meet the NPOESS accuracy and, particularly, precision requirements for all total column ozone amounts, we identified areas where improvements in the heritage design lead to the improved performance needed for the OMPS system. Simulations performed using the OMPS system design confirm that the algorithm enhancements, coupled with improvements contained in the OMPS sensor, provide performance that meets the NPOESS IPO requirements.

The Ozone Mapping and Profiler Suite (OMPS) for the United States National Polar-orbiting Operational Environmental Satellite System (NPOESS) consists of a two sensor suite and Level 1 and 2 data processing algorithms to produce calibrated radiance data and ozone total column and profile values. We describe the profiling system design that matches the limb-observing space sensor performance to measurement requirements of the retrieval algorithm and uses algorithm techniques to achieve the data quality needed for limb-scatter-based ozone profiling.

This report presents the atmospheric and surface products derived from the Advanced Microwave Sounding Unit (AMSU) and the physical bases associated with all algorithms. An example of AMSU derived temperature structure in hurricane Bonnie is used to illustrate how cloud contamination on the AMSU measurements is corrected in temperature retrieval. NOAA and other agencies are routinely utilizing the AMSU products to monitor various high-impact weather events, storm-related flooding and hurricane wind-related damages.

As more and more high-resolution FTIR instruments planned for future satellite remote sensing, robust and fast physical retrieval algorithms are needed to invert the measured radiances to geophysical parameters. One of the important components of a physical retrieval algorithm is the fast forward model. For interferometer-based sounders, the Sensor Response function (SRF) may not be localized. A fast and accurate forward model, Optimal Spectral Sampling (OSS), is used to calculate upwelling radiances in our physical retrieval algorithm. It's capable of modeling radiance spectra with either a localized or a non-localized SRF with negative side lobes. Derivatives with respect to atmospheric and surface properties can be calculated analytically and efficiently. The OSS fast RT model is idea for atmospheric sounding or atmospheric compensation applications. The inversion method is based on an optimal estimation algorithm. Empirical Orthogonal Functions (EOF) are used to transform the atmospheric profiles into more compact form for fast and stable inversions. The non-linearity of the radiative transfer function is taken into account in the algorithm so the inversion is very robust. The algorithm has been used to simulate the Environmental Data Record (EDR) retrieval performance for the Cross-track Infrared Sounder (CrIS). We extended the method to model cloud directly. The cloud parameters are retrieved simultaneously with the atmospheric and surface parameters. This algorithm has been successfully applied to the NPOESS Aircraft Sounder Testbed (NAST-I) measured radiances.

A new era in atmospheric remote sensing will begin with the launch of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) spacecraft in 2006, and the multiple operational NPOESS launches in sun-synchronous orbital planes (nominally 13:30, 17:30, or 21:30 local equatorial crossing times) starting in 2009. Cloud and atmosphere polar-orbiting environmental satellite data will be profoundly improved in radiometric quality, spectral coverage, and spatial resolution relative to current operational civilian and military polar-orbiting systems. The NPOESS Visible Infrared Imaging Radiometer Suite (VIIRS) will provide Environmental Data Records (EDRs) for day and night atmosphere and cloud operational requirements, as well as sea surface temperature (SST) and many important land EDRs by ground processing of raw data records (RDRs) from the VIIRS sensor. VIIRS will replace three currently operating sensors: the Defense Meteorological Satellite Program (DMSP) Operational Line-scanning System (OLS), the NOAA Polar-orbiting Operational Environmental Satellite (POES) Advanced Very High Resolution Radiometer (AVHRR), and the NASA Earth Observing System (EOS Terra and Aqua) MODerate-resolution Imaging Spectroradiometer (MODIS). This paper describes the VIIRS all-reflective 22-band single-sensor design, following the Critical Design Review (CDR) in Spring 2002. VIIRS provides low noise (driven by ocean color for the reflective visible and near-IR spectral bands and by SST for the emissive mid and long-wave IR spectral bands), excellent calibration and stability (driven by atmospheric aerosol and cloud EDRs, as well as SST), broad spectral coverage, and fine spatial resolution driven by the cloud imagery EDR. In addition to improved radiometric, spectral, and spatial performance, VIIRS features DMSP OLS-like near-constant resolution, global twice-daily coverage in each orbit plane, and direct heritage to proven design innovations from the successful Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Earth Observing System (Terra and Aqua) MODIS.

The Ozone Mapping and Profiler Suite (OMPS) nadir sensor and algorithms for the United States National Polar-orbiting Operational Environmental Satellite System (NPOESS) comprise a system to map ozone total column globally in 24 hours and to measure the altitude distribution of ozone in the upper stratosphere (30-50 km). The sensor consists of a wide field (110 degree) telescope and two spectrometers: an imager covering 300 to 380 nm with a 50 km nadir footprint for mapping total column ozone across a 2800 km swath, and a 250 to 310 nm spectrometer with a single 250 km footprint to provide ozone profile data with SBUV/2 heritage. Both spectrometers provide 1 nm resolution (full-width at half-maximum, FWHM) spectra. The sensitivity of the OMPS total column algorithm to sensor random and systematic errors is analyzed, and a preliminary evaluation of the potential for deriving concentrations of other trace gases from the calibrated spectral radiances is provided.

The Atmospheric Infrared Sounder (AIRS) is a space-based hyperspectral infrared instrument designed to measure the Earth’s atmospheric water vapor and temperature profiles on a global scale. AIRS has 2378 infrared channels in the spectral range of 3.7 to 15.4 microns, with a spatial resolution of 13.5 km and 4 Vis/NIR channels from 0.4 to 0.8 microns with a spatial resolution of 2.3 km. AIRS is one of several instruments onboard the Earth Observing System (EOS) Aqua spacecraft launched May 4, 2002. AIRS has completed its Activation and Evaluation (A&E) phase and is currently in its operational mode. This paper summarizes the AIRS instrument radiometric, spatial, and spectral performance as measured in orbit during the A&E phase. Instrument noise performance, spectral alignment dependence on temperature and other factors, and spatial pointing accuracy are discussed.

The Atmospheric Infrared Sounder (AIRS) was launched in early May 2002. The temperature and humidity fields retrieved from this new high-spectral resolution sounder will be used for numerical weather prediction and climate change studies. This paper presents a comparisons between observed AIRS spectra and spectra computed from profiles using the worldwide radiosonde network, as well as spectra computed from the ECMWF (European Center for Medium Range Weather Forecasts) model fields.

The MODerate Resolution Imaging Spectroradiometer (MODIS)is one of the key instruments for the NASA s Earth Observing System (EOS).The MODIS ProtoFlight Model (PFM)was launched on-board the EOS Terra spacecraft on December 18,1999 and has been providing the science community and public users global data sets for the study of the land,oceans,and atmosphere for more than two and a half years.This coverage is further enhanced by the data sets from the MODIS Flight Model (FM-1)that was launched on-board the EOS Aqua spacecraft on May 4,2002.MODIS has 36 spectral bands with wavelengths ranging from 0.41 to 14.5 μm and nadir spatial resolutions of 250m (2 bands), 500m (5 bands),and 1km (29 bands).The sensor s 20 reflective solar bands (RSB)from 0.41 to 2.1 μm are calibrated on-orbit by a solar diffuser (SD)and a solar diffuser stability monitor (SDSM)system.The other 16 thermal emissive bands (TEB)with wavelengths above 3.7 μm are calibrated by a blackbody. This paper describes the RSB on-orbit calibration approach using the SD/SDSM system,its implementation in the Level 1B algorithm,and the RSB on-orbit characterization and performance for both Terra and Aqua MODIS. The TEB calibration algorithm and performance are presented in a separate paper in these proceedings.

Aerosols are the main air pollutant in Asia. In this paper, the MODIS level 2 aerosol optical depth (AOD) products derived by NASA were validated with in situ sun-photometer observations over Hong Kong (HK). The MODIS AOD values were correlated with mass concentrations of respirable suspended particulates (RSP) measured at air quality monitoring stations over HK and Macau. Correlation between RSP and AOD were found to be statistically significant, suggesting that the satellite data is very useful for aerosol-related air pollution studies. Compared with concentrations measured from ground-based air quality monitoring networks, the AOD data cover a much larger area and have much better spatial resolution. Combining with meteorological information, the AOD data also proved to be very useful for the understanding of RSP variations at air quality monitoring stations. An example of using AOD data to help understand a pollution event over the PRD will be presented. Finally, monthly-mean distributions of AOD over Eastern China showed a distinct local maximum over the PRD, separated from high AOD areas to the north, suggesting that the aerosol problem over the PRD are mostly regional. Remote-sensing from space has provided a new and powerful way to study air pollution. To fully utilize this technique for air quality studies, the combination of a lidar and an X-band satellite receiver (for the MODIS data) is recommended. The AOD fields are vertically integrated products, together with the vertical profiles of extinction coefficients provided by a lidar, the surface distribution of aerosol could be derived.

The NASA CERES Project has developed a combined radiation and cloud property dataset using the CERES scanners and matched spectral data from high-resolution imagers, the Visible Infrared Scanner (VIRS) on the Tropical Rainfall Measuring Mission (TRMM) satellite and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. The diurnal cycle can be well-characterized over most of the globe using the combinations of TRMM, Aqua, and Terra data. The cloud properties are derived from the imagers using state-of-the-art methods and include cloud fraction, height, optical depth, phase, effective particle size, emissivity, and ice or liquid water path. These cloud products are convolved into the matching CERES fields of view to provide simultaneous cloud and radiation data at an unprecedented accuracy. Results are available for at least 3 years of VIRS data and 1 year of Terra MODIS data. The various cloud products are compared with similar quantities from climatological sources and instantaneous active remote sensors. The cloud amounts are very similar to those from surface observer climatologies and are 6-7% less than those from a satellite-based climatology. Optical depths are 2-3 times smaller than those from the satellite climatology, but are within 5% of those from the surface remote sensing. Cloud droplet sizes and liquid water paths are within 10% of the surface results on average for stratus clouds. The VIRS and MODIS retrievals are very consistent with differences that usually can be explained by sampling, calibration, or resolution differences. The results should be extremely valuable for model validation and improvement and for improving our understanding of the relationship between clouds and the radiation budget.

Infrared radiance spectra from near nadir observations have provided information about tropospheric carbon monoxide (CO). The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) aboard a high altitude aircraft with a spectral coverage of 650-2700 cm^-1 and a spectral resolution of 0.25 cm^-1 has been successfully collecting the data during many field campaigns. The spectral sensitivity of CO retrievals to uncertainties in atmospheric temperature, water vapor, and surface properties is assessed in order to understand the correlation between the IR emission and the atmospheric and surface state. The profiles are determined using a three-stage approach that combines three algorithms: (1) statistical eigenvector regression, (2) simultaneous non-linear matrix inversion, and (3) CO-physical iteration retrieval. Retrieved CO abundances are obtained in addition to temperature, moisture, ozone profiles, and surface properties. Preliminary results from several NAST-I field campaigns are presented including those from observations over the western Pacific Ocean made in conjunction with airborne truth atmospheric chemistry profiles associated with the TRACE-P campaign.

The NASA Moderate Resolution Imaging Spectrometer (MODIS) on the Terra Spacecraft has been collecting scientific data since February of 2000. MODIS is a major facility instrument for remote sensing of the atmosphere, land surfaces, and ocean color. On the MODIS instrument, there are five channels located within and around the 0.94-micron water vapor band absorption region for remote sensing of atmospheric water vapor. There is also a channel located at 1.375 micron for detecting thin cirrus clouds. In this paper, we describe the basic principles for using these near-IR channels for remote sensing of water vapor and high clouds. Based on the analysis of two years’ measurements with these channels on the Terra MODIS, we have found that reliable observations of water vapor and high clouds on regional and global scales can be made. We present results on seasonal variations of water vapor and high clouds.

The Navy Indian Ocean METOC Imaging (IOMI) mission for the Geostationary Imaging Fourier Transform Spectrometer (GIFTS) will begin in early 2006 for a period of five years. The IOMI-GIFTS will measure Earth's outgoing infrared radiation with spatial (~4 km), temporal (~half hour), and spectral (~0.625 cm^-1) resolutions and spectral coverages from longwave (LW, 685 - 1150 cm-1) for temperature profiles and short midwave (SMW, 1650 - 2250 cm^-1) for moisture profiles. Retrieval of boundary layer moisture from IOMI-GIFTS with high vertical resolution and accuracy, is a special interest of the Navy, can provide water vapor wind information over the ocean. The characteristics of boundary layer moisture retrievals from IOMI-GIFTS are demonstrated. Both theoretical analysis and a simulation study with a GIFTS forward model developed at UW-Madison show that the contrast between surface air temperature and surface skin temperature has significant impact on the accuracy of boundary layer moisture retrievals. A large contrast (> 5 K) will result in noticeable boundary layer moisture improvement over that with less contrast.

Operational MERIS (MEdium Resolution Imaging Spectrometer) level 2 processing uses auxiliary data generated by two radiative transfer tools. These two codes simulate upwelling radiances within a coupled 'Atmosphere Land' system, using different approaches based on the matrix operator method (FUB), the discrete ordinate method and the successive orders technique (LISE). Intervalidation of these two radiative transfer tools was performed in order to implement them in the MERIS level 2 processing.. An extensive exercise was conducted for cases without gaseous absorption. The scattering processes both by the molecules and the aerosols were retrieved within few tenths of a percent. Nevertheless, some substantial discrepancies occurred if the polarization is not taken into account mainly in the Rayleigh scattering computations. Errors on the aerosol optical depth reach up to 30 percent in some geometries as observed in the SeaWiFS (Sea viewing Wide Field of view Sensor) images. The parameterization of the water vapor absorption defined for each of these two codes leads to a well agreement not only for the MERIS bands with residual absorption but also in the MERIS band centred at 900nm which is used for the water vapor retrieval. As for the strong oxygen absorption at the 760.625 nm MERIS wavelength, its parameterization varies between the two codes. Nevertheless, the systematic biases in the two codes will be removed thanks to the use of a differential method between two MERIS adjacent bands. For the oxygen absorption at 760.625 nm, a more exhaustive study need to be achieved.

Based on the analyses of nonlinear time series of satellite observations, some critical issues relevant to the choice of time delay for phase space reconstruction, i.e., them utual information calculations, and the effects of the possible periodic components on the choice of the best time delay and their extraction formthe satellite signals, are studied. Some important results are obtained.

Current and future advanced atmospheric profile sounding and imaging instruments are evolving to enable global or hemispherical hyperspectral resolution measurements from space. The NASA/Navy/NOAA Geosynchronous Imaging FTS (GIFTS) for EO-3, NOAA Hyperspectral Environmental Sounder (HES) for GOES-R, and the currently operational Atmospheric Infrared Sounder (AIRS) on the NASA's Aqua Spacecraft will collect infrared high-spectral resolution/hyperspectral radiance spectra for remote sensing of the atmosphere, clouds, land, and ocean surfaces. These semi-continuous infrared high spectral- resolution/hyperspectral radiances will provide unprecedented information in the infrared region that is highly sensitive to absorption and emission of clouds. For sounding the atmospheric profiles one must perform cloud clearing or model the radiative effects of cloud explicitly if sounding is desired under cloud-contaminated conditions. We will describe the approach for modeling cloud attenuation in a fast-parameterized forward model that treats clouds as an additional absorber. Together with the usual clear forward model spectroscopic inputs, cloud altitude, effective particle size and shape and its ice or liquid water content are required input variables. Based on this efficient cloudy radiative transfer model, the simulation of the spatial and temporal coherent radiance images in three dimensions becomes possible. We will further explain how these 3-D GIFTS radiance cubes are used as test bed for a variety of trade studies.

Scattering (Mueller) matrices are calculated for typical convex ice crystal shapes: hexagonal prism, tapered hexagonal prism, bullet, and pyramid, the particles being randomly oriented in space. A pure geometric optics approach is used for the calculations. Besides. a physical optics approach to the problem is considered. Possible physical optics corrections to the geometric optics Mueller matrix are discussed.

Surface and aircraft observations show that many cloud types tend to appear simultaneously at the same location but at different altitudes. Furthermore, clouds may be continuous or broken at a given cloud level within a sensor's field of view (FOV). Therefore, it is desirable that a general radiative transfer equation (RTE) can describe all the possible cloudy atmospheres for remote sensing applications. In this paper an M-level cloudy RTE is formulated. Specific diagrams and equations for up to four-level cloud systems are illustrated.

The Tibet Plateau plays an important role in the general atmospheric circulation as a cold and heat source. In summer, the plateau is covered by active cumulus convection. So it is very important to understand the distribution of cloud over Tibet. In this paper, Meteosat image data is used to analyze the cloud cover over Tibet. The statistical method is used to perform cloud classification: first step, a two-dimensional frequency histogram is constructed from two channels images (VIS and IR); second step, dynamic clustering technique is used to automatically classify this two-dimensional histogram; third step, each pixel in original image is assigned to a cloud class. The classification results show clearly the distribution of cloud classes.

The detection of Dense Dark Vegetation (DDV) using the Atmospherically Resistant Vegetation Index (ARVI) and then the aerosol retrieval over DDV is the critical point of the atmospheric correction scheme over land for MERIS implemented in the level 2 processor. We present here what we can expect from the MERIS product by applying a MERIS-like land algorithm to SeaWiFS data over Europe. It is shown that the DDV cover is sufficient in summer but not in winter where an extension of the concept of DDV is needed in order to enable an operational aerosol characterisation. A linear relationship between ARVI and reflectance of the extended DDV in the red should allow the use of such grey targets for the retrieval of aerosol optical properties (aerosol optical thickness at 550 nm and Angström coefficient) throughout the year with a little loss of accuracy

The eruption of Miyakejima volcano started on 8 July 2000. As of September 2002, SO2 emissions measured by COSPEC average 11000 t/day. As the volcanic gas tends to behave together with the plume, we may infer the advection of the gas from the observation of the plume. Ground observations have been performed from Mikurajima using CCD cameras since September 2000. These pictures clarify the vertical structure of volcanic clouds. The horizontal dispersion of the clouds is well shown in NOAA/AVHRR, Terra/MODIS and other satellite images. Ash-rich clouds at the first stage are well detected by the difference image of NOAA/AVHRR 5 and 4, while vapor-rich clouds are insensitive to the difference. Instead, the latter are detected by the difference of AVHRR 1 and 2, and discriminated well from meteorological clouds in many cases. MODIS data is sensitive to the ash and sulfates of Miyakejima plumes in the 8.6 mm channel, and can detect the fine structure of the plumes with its high-resolution visible channels. Miyakejima plumes contain large quantities of volcanic gases, and their daily monitoring using satellites and ground observations in conjunction with upper wind data helps to understand high concentration events of sulfur dioxide downstream from the volcano.

Atmospheric aerosols play important roles in climate radiative forcing as well as environmental issues. In addition to microphysical and optical parameters, its vertical distribution is also important for both surface visibility, transport and related boundary layer stratification. Satellite-borne instruments, such as MODIS, AVHRR have monitored global aerosol distribution, but ground-based optical remote sensing is still of significance for validation and more detailed observation, such as diurnal variation and vertical distribution. In this paper, numerical simulations are conducted for clear atmosphere with various vertical structures of atmospheric aerosols. The sun direct observation is used to derive aerosol optical depth. In sun-zenith principal plane, pairs of directional scattered radiances symmetrically to solar direction (i.e. scattering angles are same but one is near zenith and the other near horizon) may be used to derive aerosol’s vertical distribution.

Two broadband radiation methods are developed to determine aerosol optical depth and the imaginary part of its refractive index. One is broadband extinction method to determine aerosol optical depth by using hourly/daily accumulated pyrheliometer data. Another is broadband solar radiation method to retrieve the aerosol imaginary part from joint pyrheliometer/paranometer data. Furthermore, aerosol optical depths over 11 meteorological observatories in China during 1980-2000, the aerosol imaginary parts and its single scattering albedoes in Beijing and Shenyang during 1993-2000 are retrieved from pyrheliometer/paranometer data by using the methods. Based on the retrieval results, the variation trends of the aerosol optical depths and its imaginary parts, the effects of Pinatubo eruption in 1991, sand-dust event and fossil fuel burning on them are empirically analyzed.

Aerosol optical depth in the urban area of Beijing has been measured by multi-wavelength sun-photometer during a one-year period from Apr. 1999 to Mar. 2000. Using the aerosol optical depth as the atmospheric correction parameter, the reflectance of the urban surface and the mean aerosol type have been retrieved by the apparent reflectance of the visible channel of the Visible and Infrared Spin Scan Radiometer (VISSR) onboard the Japanese Geostationary Meteorology Satellite.

Mineral aerosols present a particularly difficult case in climate and remote sensing studies, because their absorption and scattering of atmospheric radiation depend strongly on the dust source region, morphology (i.e. shape and size), mineralogy, and state of mixture with other species. Current aerosol retrievals rely on numerous poorly justified assumptions such as spherical shapes of dust particles and prescribed refractive indices. This study examines how the realistic particle morphology and composition affect the dust optical properties and implications for remote sensing at solar and infrared wavelengths.

In this paper, the developing of DOAS (Differential Optical Absorption Spectroscopy) in China is presented. The measurement campaigns were performed from November,2001 to February, 2002 in Shanghai and from June, 2001 to April, 2002 in AIOFM (Ahhui Institute of Optical and Fine Mechanics) Hefei respectively to determine the concentration of SO₂, NO₂ and O₃ in ambient air. For measuring the distribution of pollutants in troposphere, a new kink of DOAS system with high spatial and temporal resolution was developed under the cooperation between German and Chinese researcher. This work was described in the latest part of this paper.

One of the real challenges for the atmospheric remote sensing community in the next decade will be in the validation of data, not to the normally accepted scientific criterion and standards but to and within a new legalistic framework. As the issues created by the implementation and application of the Kyoto Protocol come into force, the attribution of sources of greenhouse gases will become critical, as will indeed the proof of compliance with Kyoto Protocol conditions. Space-borne remote sensing systems will play a key role in these measurements, and methodologies for "ground truthing" will need to be developed. This paper discusses some of the drivers of global change to set in context advances that are being made in ground based remote sensing of important atmospheric components and the potential role for these measurements in the future. Examples of the retrieval of vertical profiles of a key atmospheric species using ground based high resolution Fourier transform spectrometer system in New Zealand are also shown as an illustration of the technique.

The Measurements of Pollution In The Troposphere (MOPITT) instrument is designed to measure the spatial and temporal variation of the carbon monoxide (CO) profile and total column amount in the troposphere from the space. MOPITT channels are sensitive to both thermal emission from the surface and target gas absorption and emission. Surface temperature and emissivity are retrieved simultaneously with the CO profile. To obtain the desired 10% precision for the retrieved CO from MOPITT measurements, it is important to understand MOPITT CO channel sensitivity to surface temperature and emissivity and the impacts of the effects of any errors in retrieved skin temperature and emissivity on retrieved CO for various underlying surfaces. To demonstrate the impacts of the surface temperature and emissivity on the retrieval of the tropospheric CO profile, simulation studies are performed. The collocated Moderate Resolution Imaging Spectroradiometer (MODIS) surface products are used to assess the accuracy of the retrieved MOPITT surface temperature and emissivity.

The Improved Limb Atmospheric Spectrometer on board the Advanced Earth Observing Satellite first detected the onset of denitrification in the 1996/1997 Arctic winter stratosphere. Box model calculations along back trajectories are used to estimate the degree of denitrification caused by the formation of nitric acid trihydrate (NAT) particles followed by their growth and sedimentation. The calculated loss of reactive nitrogen explains well the observed loss, identifying the mechanism of large NAT particle formation causing Arctic denitrification.

The Solar Occultation FTS for Inclined-orbit Satellite (SOFIS) is a solar occultation Fourier transform spectrometer developed by the Ministry of the Environment (MOE) in Japan for the Global Change Observation Mission-A1 (GCOM-A1) satellite. GCOM-A1 will be placed in a 650 km non-sun-synchronous orbit, with an inclination angle of 69 degrees. ABB-Bomem is a sub-contractor of NTSpace (NEC-Toshiba Space) for the design and manufacturing of the FTS Engineering Model of SOFIS. SOFIS measures the vertical profile of the atmospheric constituents with 0.2 cm^-1 spectral resolution for the spectral range covering 3-13 μm. The atmospheric vertical resolution of SOFIS is 1 km. The target of SOFIS measurements is a global distribution of O₃, HNO₃, NO₂, N₂O, CH₄, H₂O, CO₂, CFC-11, CFC-12, ClONO₂, aerosol extinction, atmospheric pressure and temperature. NTSpace in Japan is the prime contractor of SOFIS. The spectrometer is an adapted version of the classical Michelson interferometer using an optimized optical layout and moving retro-reflectors. A solid-state laser diode operating at 1550 nm is used as metrology source of the interferometer. Its highly folded optical design results in a high performance instrument with a compact size. SOFIS FTS implements high performance control techniques to achieve outstanding speed stability of the moving mechanism. This paper describes the test activities of the SOFIS-FTS Engineering Model (EM) and preliminary results. The performances of the FTS are presented in terms of key parameters like signal-to-noise ratio, modulation efficiency and stability. Spectra acquired are shown and test methodology and analyses are presented. Lessons learned during assembly, integration and testing are described as well as improvements planned to be implemented in the Flight Model.

Under a joint agreement between the National Aeronautics and Space Agency (NASA) and the Russian Aviation and Space Agency (RASA), the Stratospheric Aerosol Gas Experiment III (SAGE III) instrument was launched in low earth orbit on December 10, 2001 aboard the Russian Meteor-3M(1) satellite from the Baikonur Cosmodrome. SAGE III is a spectrometer that measures attenuated radiation in the 282 nm to 1550 nm wavelength range to obtain the vertical profiles of ozone, aerosols, and other chemical species that are critical in studying the trends for the global climate change phenomena. This instrument version is more advanced than any of the previous versions and has more spectral bands, elaborate data gathering and storage, and intelligent terrestrial software. There are a number of Russian scientific instruments aboard the Meteor satellite in addition to the SAGE III instrument. These instruments deal with land imaging and biomass changes, hydro-meteorological monitoring, and helio-geophysical research. This mission was under development for over a period of six years and offered a number of unique technical and program management challenges for both Agencies. SAGE III has a long space heritage, and four earlier versions of this instrument have flown in space for nearly two decades now. In fact, SAGE II, the fourth instrument, is still flying in space on NASA's Earth Radiation Budget Satellite (ERBS), and has been providing important atmospheric data over the last 18 years. It has provided vital ozone and aerosol data in the mid latitudes and has contributed vastly in ozone depletion research. Ball Aerospace built the instrument under Langley Research Center's (LaRC) management. This paper presents the process and approach deployed by the SAGE III and the Meteor teams in performing the initial on-orbit checkout. It further documents a number of early science results obtained by deploying low risk, carefully coordinated procedures in resolving the serious operational issues of this satellite.

The process of relative radiometric calibration (RRC) is an important step for detecting change and monitoring environment through analyzing multi-temporal satellite images. Two key issues that focus on the RRC are how to extract invariant targets that have little or no variation in their reflectance between two images and how to acquire a linear function that expresses the relationship between the digital counts (DNs) of the two images. In this paper, an automatic method for selecting invariant targets which cover the range of bright, midrange, and dark data values is developed, and a robust estimator, which can be effective in tolerating with up to 50 percent outlier contamination, for calculating the gain and the offset of the linear function is described. The proposed methods are automatic and robust. We have applied the proposed method experimentally to synthesized images and real SPOT images, and experiment results have shown the feasibility of our algorithms.

Radiometric calibration of large aperture space-borne remote sensing instruments designed to measure atmospheric radiances in the 250 to 400 nm wavelength range is difficult. Historically the spectral radiance calibrations of these instruments have been derived from aperture radiances of integrating spheres illuminated internally by quartz-tungsten-halogen (QTH) lamps. Typical aperture radiances increase by a factor of 400 from 250 to 400 nm and by an additional factor of 10 from 400 to 900 nm. The characteristics of the aperture radiances of 51 cm diameter Spectralon sphere illuminated by an external xenon arc and by internal QTH lamps have been measured. The aperture radiance of the sphere illuminated externally by the xenon arc is 15 times larger at 250 nm than the radiance from internal QTH lamp illumination. The radiometric stability and the aperture uniformity at 290 nm from the two types of illumination are comparable. These measurements have been made with a calibration transfer standard spectroradiometer using 14 narrow ion-assisted deposition filters covering the wavelength region from 250 to 920 nm. The calibration scale of the transfer radiometer is tied to a NIST 1000 W FEL lamp spectral irradiance standard.

Aerosols three optical parameters, namely, its optical thickness ta(500) at the wavelength of 500nm, Angstrom exponent a, and real part of refractive index Nr, were retrieved from ADEOS/POLDER data by analyzing the observed directional reflectance and polarization information. In this retrieval we applied the directional R-P(Reflectance-Polarization) algorithm to the POLDERs 865nm band data. This retrieval algorithm was proposed previously in our paper and we extend it in this study. The validation on the retrieved results was made by comparing with the sky observation data. We found that the correlation coefficient between the retrieved and measured values was good (R=0.86) in the aerosol optical thickness, whereas it is poor(R=0.32) in Angstrom exponent. In addition, we presented the monthly averaged distribution maps of aerosol's three optical parameters over the oceans from the Indian Ocean to the western Pacific Ocean during April 1-31, 1997. This study indicated that there are extended aerosol regions with large values of real part of refractive index (Nr>1.5) in April in the tropical zone.

An intensive aerosol and water vapour measurement campaign, started on June 2002, is in progress at IMAA in Tito Scalo (PZ) (Southern Italy, 40°36'N, 15°44'E, 820 m above sea level) in the frame of the validation program of ENVISAT. Systematic measurements, using both active and passive ground based instruments, will be performed for a period of 12 months, in coincidence with ENVISAT overpasses. A Raman lidar system is used to perform both aerosol and water vapour measurements; aerosol backscatter and extinction coefficients are retrieved from simultaneous elastic signals at 355 nm and inelastic N2 Raman backscatter lidar signals at 386.6 nm, whereas, water vapour mixing ratio measurements are retrieved from simultaneous H2O and N2 Raman signals. A sun-photometer based on a Mechelle spectrometer is used to measure direct solar irradiance in the wavelength range 300 ÷ 1100 nm and a Fourier infrared spectrometer is used to measure vertical sky radiance in the range 500 ÷ 3000 cm^-1. All the observations are complemented with radio-sonde launches. Two measurements per week are scheduled for the first six months of the validation campaign, while one measurement per week is scheduled for the last six months. First results of the measurement campaign are presented.

This paper presents the strategy designed by the government team, IPO and NASA, for the NPOESS Preparatory Project (NPP) instrument characterization and calibration, and product validation, in preparation for the NPOESS operational system. NPP is a risk reduction mission for NPOESS, managed by the IPO and NASA. NPP will carry three (3) instruments, VIIRS, CrIS and ATMS, and an Instrument of Opportunity to be announced soon. Responsibilities will be shared between government and industry participants to ensure high performance at all system levels. This will include provision of the sensor pre-launch characterization and post-launch calibration procedures, definition of validation approaches for all NPP products, and identification of the resources and assets required to achieve these activities. This calibration and validation plan will benefit greatly from the validation efforts and infrastructure of several existing programs at the national and international scale. The synergy between the SSPR system integrator and the government team, IPO and NASA, will build the foundation for interactions that will lead to better sensors, better algorithms, and better ground data systems.

Surface emissivity is essential for many remote sensing applications including the retrieval of the surface skin temperature from satellite-based infrared measurements, determining thresholds for cloud detection and for estimating the emission of longwave radiation from the surface, an important component of the energy budget of the surface-atmosphere interface. In this paper, data from the Terra MODIS (MODerate-resolution Imaging Spectroradiometer) taken at 3.7, 8.5, 10.8, 12.0 micron are used to simultaneously derive the skin temperature and the surface emissivities at the same wavelengths. The methodology uses separate measurements of the clear-sky temperatures that are determined by the CERES (Clouds and Earth's Radiant Energy System) scene classification in each channel during the daytime and at night. The relationships between the various channels at night are used during the day when solar reflectance affects the 3.7 micron data. A set of simultaneous equations is then solved to derive the emissivities. Global results are derived from MODIS. Numerical weather analyses are used to provide soundings for correcting the observed radiances for atmospheric absorption. These results are verified and will be available for remote sensing applications.

The scattering and absorption of synthetic aerosol are the main represents of air pollution in remote sensing data. Synthetic aerosol is a referent of air pollution. In this paper, ground reflected spectrum is generalized as the composition of some basic components. Then reflectance model of every pixel is proposed with the variables of the ratios of ground surface basic components and the turbidity of synthetic aerosol. Using the model, turbidity of synthetic aerosol in the atmosphere can be calculated with multi-spectral remote sensing data. The model was applied in Shanghai district, and it was found that both of the area and extent of air pollution in the region are increasing quickly.

3~5um mid-infrared laser displaying good atmospheric transmitting properties is mostly used as laser source, in many applications such as remote sensing for air pollution determining. And it is usually obtainable in Second harmonic generation (SHG) in CO₂ laser. In the course of investigation, a homemade nonlinear optical crystal AgGaSe₂, of the size 7×8×12mm³, was used for SHG in tunable TEA CO₂ laser with different wavelengths. And, 12 coherent laser sources in 3~5μm from CO₂ spectrum region 10.6μm~9.2μm were obtained. In our results, phase-matching angles aqre in good accordance with the crystal's cutting. Theory calculating on conversion was made as well, to compare with experimental data which present changes of energy conversion under pump's rising. And in the interest of enhancing energy conversion by means of peaking pulse through cutting tail, a plasma shutter, argon charged in body under normal air pressure, was effectively arranged in experiment. As a result, about 50nS width peak pulse was generated, and up to 10% energy conversion (2mJ, 5.3μm) was achieved against 1% without shutter, both pumping in 10P(20) line.

This paper evaluates the performance of two techniques currently under development for use in the future validation of AIRS surface emissivity measurements over the Southern Great Plains Atmospheric Radiation Measurement site in Oklahoma, USA. The first technique involves a simultaneous retrieval of atmospheric temperature and water vapor, sruface skin temperature, and surface emissivity using a statistical approach; the second, a relative retrieval of the relative surface emissivity from spectral radiance observations between gaseous absorption lines. High spectral resolution upwelling radiance measurements from the aircraft-based NPOESS Atmospheric Sounder Testbed-Interferometer (NAST-I) obtained during the ARM/FIRE Water Vapor Experiment 2000 and Chesapeake Lighthouse and Aircraft Measurements for Satellites 2001 were used to compare each method. Surface truth was provided by ground-based Atmospheric Emitted Radiance Interferometer measurements.

The MODerate Resolution Imaging Spectroradiometer (MODIS)is one of the key instruments for the NASA s Earth Observing System (EOS).MODIS ProtoFlight Model (PFM)was launched on-board the EOS Terra spacecraft on December 18,1999 and the MODIS Flight Model (FM-1)was launched on-board the EOS Aqua spacecraft on May 4, 2002.MODIS has 36 spectral bands with wavelengths ranging from 0.41 to 14.5 μm and nadir spatial resolutions of 250m (2 bands),500m (5 bands),and 1km (29 bands). The sensor s 20 reflective solar bands (RSB)from 0.41 to 2.1 μm are calibrated on-orbit by a solar diffuser (SD)and a solar diffuser stability monitor (SDSM).The other 16 thermal emissive bands (TEB)with wavelengths above 3.7 μm are calibrated by a blackbody.This paper follows the discussions on the RSB calibration and instrument performance presented in a separate paper (Xiong et.al.)in these proceedings, and focuses on the 16 thermal emissive bands (TEB).

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.

Polarization measurements of the sky radiation by PSR-1000 at a ground station when the yellow sand dust (Asian dust) came flying to the Kanazawa city, Japan from the deserts in the northern part of China were made. The PSR-1000 is the multi-spectral polarimeter and has the same wavelength regions (443nm, 490nm, 565nm, 670nm, 765nm and 865nm) as the ADEOS/POLDER sensor. First of all, the wavelength dependency of degrees of polarization is examined and it is shown that the wavelength dependency for polarization will be due to the size distribution of dust particles transported from the deserts in China. Next, a new method for estimating optical properties, such as the optical thickness, the number size distribution and the refractive index, of yellow sand dust and the background reflectance from degrees of polarization measured by PSR-1000 is described. Finally, this method was applied to the polarization data acquired on March 13, 2000 and April 14, 2002.

In this paper the MODIS Level2 aerosol products over Beijing are validated by comparison with the observations from sun-photometer at Peking University (PKU) at first. The MODIS aerosol optical depths (AOD) also correlates well with the averaged mass concentration of respirable suspended particulate (RSP, PM10) calculated from released API data. The relations between the visibilities and the AOD values with distinct aerosol scale heights in different seasons are estimated. The cases described by the AOD distributions over Beijing and its surroundings show some dramatic processes. The analysis assisted by the relevant changes of meteorological variables can help us find the corresponding answer to each air pollution episodes. The seasonal AOD variations in Beijing show the mean AOD value is highest in summer, and has a decreasing trend from summer to autumn, and then to winter. It has a rapid increasing from winter to spring due to spring dust in North China. Finally we gain the seasonal mean visibility distributions of Beijing and its surroundings. The mean air quality gets worst in winter due to increased pollutant source in winter and bad dispersion conditions, and becomes the best in spring because strong wind provides fast dispersion in spite of occasional dust weathers. The results indicate the air pollution in Beijing urban area is both contributed by local urban emission and regional transport. Remote sensing from space has provided us a new view to study the air pollution.

The IR smoke is a typical sort of aerosol. The radiation is covered by the smoke aerosol, which lead attenuate further more. This covering effect is obtained from the absorption and dispersion of the aerosol. The degree of the attenuation of the aerosol is determined by two important parts: the size and the component of the aerosol particulate system. According to the equation of the signal-noise-ratio of the IR system, the covering effect can be reflected by the spectral permeation rate. The attenuation of the aersol is composed of the absorption and the dispersion when the size of the smoke particular is as that of the radiation wavelength. The key issues to calculate the radiation are three factors: the radius, the density and the refraction rate of the smoke material. Another important part which influences the attenuation is the relative humidity of the atmosphere. A lot of factors, such as the Brown motion, the temperature diffuseness, the consistency diffuseness and the climate affect the formation and the distribution of the smoke aerosol.

In order to improve the precision and enlarge the measuring range of Digital Photography Visiometer (DPV) in the daytime, a bi-blackbody algorithm is derived to eliminate the effects of dark current of CCD camera and stray light of background. Some experiments have been performed to compare DPV with one VAISALA FD12 visibility meter and one VIASALA MITRAS Runway Visual Range Assessment System at Luogang Airport, Hefei, in 2002. Plentiful results showed that these instruments work consistently within a reasonable precision when the visibility varies from 50m to 20km. The further experiments proved that DPV with the bi-blackbody algorithm is feasible and reliable at least in the range of 200 times of baseline length.

In this paper, the change of polarization property was analyzed when the partially polarized light beam from an object transmitted a CCD's optical system. A specific case is calculated, and the changes of polarization are given. Calculations show that polarization degree of partially polarized light beam presents certain distribution on the cross section of transmitted output beam changes of polarization degree not only depend on angle of incidence, but also on location of point light source.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra, with its high horizontal resolution and frequent sampling over Arctic and Antarctic regions, provides unique data sets to study clouds and the surface energy balance over snow and ice surfaces. This paper describes a polar cloud mask using MODIS data. The daytime cloud and snow identification methods were developed using theoretical snow bi-directional reflectance models for the MODIS 1.6 and 3.75 micron channels. The model-based polar cloud mask minimizes the need for empirically adjusting the thresholds for a given set of conditions and reduces the error accrued from using single-value thresholds. During night, the MODIS brightness temperature differences (BTD) for 3.75 - 11, 3.75 - 12, 8.55 - 11, and 6.7 - 11 micron are used to detect clouds while snow and ice maps are used to determine snow and ice surfaces. At twilight, the combination of the 1.6 micron reflectance and the 3.75 - 11 micron BTD are used to detect clouds. Examples of the cloud mask results from daytime, nighttime, and twilight data show good agreement with visual interpretation of the imagery. Comparisons of the modeled and observed reflectances for clear snow areas reveal good agreement at 1.6 micron, but 10 - 35% overestimates of the 3.75 micron reflectance by the model. Over the Arctic, the modeled visible reflectance is significantly greater than the observed values. Better agreement is obtained over the Antarctic where snow melt is less significant.

The Noise Cancellation is very important in the field of signal procession. In this thesis, the designation of Modified Adaptive Noise Cancellation is demonstrated in detail, the model is simulated. We have compared the performance of the new model and the old model. In the course of simulation, different signal sources and different noise sources are adopted. The result of the experiments shows that this designation improves the noise cancellation's performance greatly.

This study presents a new technique for the retrieval of Carbon Monoxide and Methane effective optical depths using upwelling infrared emission spectra from high spectral resolution Fourier Transform Spectrometer (FTS) data. Also presented is a technique for deriving mean column mixing ratios from these effective optical depths. Results are presented from aircraft flights of the Scanning-High-resolution Interferometer Sounder (S-HIS) and the National Polar-orbiting Operational Environmental Satellite System Airborne Sounder Testbed - Interferometer (NAST-I). Case study results are presented from the SAFARI 2000 experiment in Southern from the CLAMS experiment on the mid-Atlantic coast of the United States.

Spectral limb radiances measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the Envisat Environmental research satellite are characterized in terms of instrument line shape (ILS), noise equivalent spectral radiance (NESR) and possible impact of non-local thermodynamic equilibrium emission in deep space calibration spectra. Furthermore, it is assessed if the operational processing baseline to set the top of the model atmosphere to 120~km is justified. The major findings are: The ILS parametrization provided along with the measurement data is sub-optimal; spectral residuals can be reduced by application of an ILS correction function. Spectral noise as estimated in this study is systematically lower than the values provided along with the measurement data. There is no evidence for significant noise correlations in the spectral domain. There is no indication of non-local thermodynaic equilibrium induced upper atmospheric signal in the so-called 'deep-space' spectra which are used for the radiometric zero-level calibration.

The quasi-continuous measurements of direct solar and sky scattered spectrum over Beijing have been conducted since September 1998 with an automatic moderate resolution solar spectroradiometer (MORSAS) developed by the Institute of Atmospheric Physics, Chinese Academy of Sciences. The measurements of direct solar spectrum under cloud free conditions, including clear and turbid skies, were used to derive atmospheric aerosol optical thickness. During the period of Asian-Pacific Regional Aerosol Characterization Experiment (ACE-Asia) in spring 2001, a spectral radiometer CIMEL CE-318 in AERONET (owned by US NASA/GSFC) was operated at the same time and the same place with MORSAS. Comparing the observed results from the two instruments, they are consistent with each other. In this paper we present the variation of atmospheric aerosol optical thickness and Angstrom exponent which symbolizes the width of particle spectrum in Beijing during recent three years. In contrast with the middle of 1990’s, the atmospheric aerosol optical thickness in autumn and winter in recent years decreased slightly, indicating that Beijing air quality has been improved by certain local environmental management, whereas in spring in the latest 2 years the atmospheric aerosol optical thickness has evidently increased as the increase of the dust weather events, and the Angstrom exponent tends to be lower. This reveals that the ratio of larger particles especially the large dust-sand particles in the air has increased. So it is very important to enhance dust source management for those upstream and local arid and semi-arid regions.

We present the results of the first in-flight spectral calibration of the ENVISAT/MERIS instrument. An operational algorithm using the high sensitivity of absorption to the spectral location in the O₂ bands is briefly presented. We show that an accuracy of ± 0.02 nm can be reached with a careful analysis of the whole dataset. This method was successfully compared to other techniques and proved to have the lowest noise. Consequences for the MERIS Surface Pressure product are investigated and optimization of the O₂ bands setting is proposed.

The difficulties in extracting useful information from the noise-corrupted stratospheric laser echoes have elevated application of digital signal processing techniques to the atmospheric research. This paper focuses on the problem of noise elimination from the transient returns of stratospheric laser echoes, proposes a new solution approach to it. Unlike related methods which address signal modeling in time domain only, we formulate the problem in both time and frequency domain, present a new modeling environment for the joint time-frequency analysis and use a non-linear median filter for noise elimination. Experiments with various patterns of spectral clouds demonstrate that such an approach significantly increases readability and accuracy of results in terms of the back-scattering function and depolarization.

La Crau is a flat plain of 20 kilometer diameter, cover by white pebbles, and located in the south east of France. This homogeneous bright site is used by CNES since 1987 as a test site for vicarious calibration of the SPOT-HRV cameras. The former calibration activities, up to 1997, were conducted during field campaigns devoted to the characterization of the atmosphere and of the site reflectances. Since 1987, au automatic photometric station was set up on La Crau on a 10 m height pole. This station first measures at different wavelengths, the solar extinction and the sky radiances to fully characterize the optical properties of the atmosphere. Then, on a downward looking; 862 surface radiances are collected under different view directions to characterize a 20 m* 20 m site. These radiances are converted into reflectances and a bidirectional model of the site was achieved. All these data, collected at the time of overpass of SPOT, are used to predict the incoming radiance to the sensor. Spot calibration results are compared, accounting for error bars, with other vicarious calibrations provided by CNES.

Aerosol remote sensing over land requires knowing the surface reflectance in some spectral bands. Dense dark vegetation can be used in the blue and in the red based on ground based measurements of their reflectances or even space measurements from a statistical analysis for clear days. An aerosol remote sensing algorithm based on DDV is available on MERIS data (Santer et al., 1999). An other alternative is to derive the surface reflectances from space as far as you have ground based characterization of the aerosols to perform suitable atmospheric correction, at least on a representative time series (Borde and Verdebout, 2001). The two algorithms, applied on SeaWiFS images, are compared over three sites (Toulouse, Ispra, Adriatic) for which ground based measurements are available.

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.

A preliminary investigation on interferometry for space-borne atmospheric sounding is shown in this paper. It includes design, optical implementation subsystem and the testing results of the model instrument. The experiment scheme characterizes an amplitude-splitting two-beam interference, time modulation, driving reflector directly by a linear motor and reducing tilt influence using a pair of corner reflector. The reference signal is produced by He-Ne laser beam. The optical sounding wave bands with the preliminary model are 7.5-15μm. Experimental results showed that spectrum resolution is about 2 cm^-1. In addition, a further study program is also presented in the paper, which will result in a space-borne atmospheric sounding interferometer after several years. Now the program is under way. As its first step a study is made on some basic problems and on some comparisons among different designs for interferometers: translation corner reflector type, swing plane mirrors type.