The infrared Absolute Radiance Interferometer (ARI) instrument - developed at University of Wisconsin-Madison, Space Science and Engineering Center (SSEC) - measures absolute spectrally resolved infrared radiance (200-2000 cm-1 or 5-50 μm at 0.5 cm-1 resolution) with ultra-high accuracy (< 0.1 K 3-sigma brightness temperature at scene temperature). The ARI prototype instrument was deployed for field measurements of clear-sky far infrared (FIR) surface emissivity and radiances on the SSEC rooftop. Currently there are very few measurements available in the FIR spectral region. Our targeted samples include snow and ice surfaces which are important for radiative cooling in the polar regions. We will demonstrate the ARI instrument configuration, capability for ground-based measurements in the FIR region, and the retrieval of infrared emissivity spectra. The ARI ground-based FIR measurements would support scientific applications that involve FIR studies, such as the PREFIRE (Polar Radiant Energy in the Far InfraRed Experiment) and the European FORUM (Far-infrared-outgoing Radiation Understating and Monitoring) missions.
Observations in the Terra MODIS PVLWIR bands 27 – 30 are known to be influenced by electronic crosstalk from those bands as senders and into those same bands as receivers. The magnitude of this crosstalk affecting L1B radiances has been steadily increasing throughout the mission lifetime, and has resulted in several detectors within these bands to be unusable for making L2 and L3 science products. In recent years, the crosstalk contamination has been recognized as compromising the climate quality status of several MODIS L2 and L3 science products that depend on the PVLWIR bands. In response, the MODIS Characterization Support Team (MCST) has undertaken an effort to generate a crosstalk correction algorithm in the operational L1B radiance algorithm. The correction algorithm has been tested and established and crosstalk corrected L1B radiances have been tested in several Terra MODIS L2 science product algorithms, including MOD35 (Cloud Mask), MOD06 (Cloud Fraction, Cloud Particle Phase, Cloud Top Properties), and MOD07 (Water Vapor Profiles). Comparisons of Terra MODIS to Aqua MODIS and Terra MODIS to MetOp-A IASI show that long-term trends in Collection 6 L1B radiances and the associated L2 and L3 science products are greatly improved by the crosstalk correction. The crosstalk correction is slated for implementation into Collect 6.1 of MODIS processing.
Monitoring of IR Clear-Sky Radiances over Oceans for SST nearreal
time web-based system has been established in July 2008. It analyzes Model (Community Radiative Transfer Model,
CRTM) minus Observation (M-O) biases in clear-sky ocean brightness temperatures (BT) in AVHRR bands 3.7 (IR37),
11 (IR11), and 12μm (IR12) onboard NOAA-16, -17, -18, -19 and Metop-A. In January 2012, AVHRR-like bands of
VIIRS onboard the Suomi National Polar Partnership (S-NPP; launched in October 2012), and two MODIS instruments
onboard Terra and Aqua, were included in MICROS. Double-differences are employed to check various sensors for
radiometric consistency. The VIIRS and AVHRR have been in-family, and the consistency further improved after the
VIIRS IR calibration was fine-tuned on 7 March 2012. However, MODIS M-O biases have been out of family (by -0.6K
in IR 11, and -0.3K in IR12). Analyses have shown that these anomalies in MODIS M-O biases are caused by the "M"
term, i.e., incorrect MODIS transmittance coefficients in CRTM v2.02. Based on feedback from NESDIS SST and U.
Wisconsin Teams, CRTM Team updated transmittance coefficients in CRTM v2.10. As a result, MODIS M-O biases are
now in agreement with AVHRR/VIIRS. However, cross-platform Terra/Aqua bias of ~0.3 K in Ch20 (3.9μm) remains,
likely due to calibration uncertainties in MODIS L1b product. This paper documents the joint effort by the SST, MODIS
Characterization Support and CRTM Teams towards identifying and resolving observed cross-platform inconsistencies.
The high-spectral-resolution AIRS (Atmospheric InfraRed Sounder) instrument onboard the NASA (National Aeronautics and Space Administration) Earth Observing System (EOS)-Aqua satellite represents the most advanced sounding system in space and provides unprecedented wealth of highly accurate radiance measurements. This paper describes a standalone and fast single field-of-view (FOV) algorithm to retrieve atmospheric sounding profiles (temperature, humidity, ozone) and surface parameters (surface skin temperature, surface emissivity) from AIRS Level 1B (L1B) clear only infrared radiance measurements. The retrieval algorithm is part of the International MODIS (Moderate Resolution Imaging Spectroradiometer)/AIRS Processing Package (IMAPP) software package, which provides international users with the capability of receiving and processing direct broadcast data in real-time. The IMAPP AIRS retrieval algorithm is based on principal component regression to obtain fast and accurate estimates of the atmospheric state at single FOV. This algorithm is designed specifically for real-time direct broadcast applications where sounding products can be processed efficiently at highest possible spatial resolution. Simulated radiance data is trained on a global set of profiles, representative of a wide variety of atmospheric scenes, which makes the algorithm globally applicable. The results presented and discussed in this paper demonstrate that the IMAPP AIRS retrieval product is rigorously evaluated by various product sources such as numerical weather prediction model analysis fields, retrieved parameters from the operational AIRS L2 product and data from other instruments.
Radiances from current polar orbiting infrared (IR) and microwave (MW) sounders are used to infer temperature and moisture profiles in the troposphere in a physical retrieval algorithm. Specification of the tropopause and the surface are necessary boundary conditions in the profile retrieval. Good definition of the tropopause has been elusive via radiometric approaches. The Global Positioning System (GPS) provides an opportunity to derive very accurate upper atmospheric temperature profiles by using radio occultation (RO) techniques. In this paper we show that the combination of radiometric (IR and MW) and geometric (RO) information yields improved tropospheric temperature and moisture profiles when compared to those inferred from either system alone. RO and IR/MW measurements are simulated from the National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service (NOAA/NESDIS) NOAA88 global radiosonde data set. Retrievals are performed using a statistical regression approach. Surface data are set as the lowest level of a radiosonde profile. A variety of simulation tests will be presented to illustrate the impact of surface and tropopause information on the temperature and humidity retrievals.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.