Lori Borg

Cross-track infrared sounder (CrIS) spectral radiance calibration and evaluations

The Cross-track Infrared Sounder (CrIS) is a high spectral resolution infrared sounder on the Suomi-NPP satellite. CrIS will compliment and extend similar data records begun by the Atmospheric Infrared Sounder (AIRS) on EOS-Aqua and by the Infrared Atmospheric Sounding Interferometer (IASI) on METOP. Primary uses of CrIS include assimilation of the radiance data into NWP models for medium range weather forecasting, retrievals of vertical profiles and temperature and water vapor, and various climate studies. Following Suomi-NPP launch on 28 October 2011, the CrIS was powered on on 20 January 2012. As part of NOAA and NASA efforts, over the past several months CIMSS/SSEC researchers have played a key role in the early checkout of the sensor including fine tuning of various calibration coefficients and characterization of the sensor’s performance.

High Spectral Resolution Infrared and Raman Lidar Observations for the ARM Program: Clear and Cloudy Sky Applications

This grant began with the development of the Atmospheric Emitted Radiance Interferometer (AERI) for ARM. The AERI has provided highly accurate and reliable observations of downwelling spectral radiance (Knuteson et al. 2004a, 2004b) for application to radiative transfer, remote sensing of boundary layer temperature and water vapor, and cloud characterization. One of the major contributions of the ARM program has been its success in improving radiation calculation capabilities for models and remote sensing that evolved from the multi-year, clear-sky spectral radiance comparisons between AERI radiances and line-by-line calculations (Turner et al. 2004). This effort also spurred us to play a central role in improving the accuracy of water vapor measurements, again helping ARM lead the way in the community (Turner et al. 2003a, Revercomb et al. 2003). In order to add high-altitude downlooking AERI-like observations over the ARM sites, we began the development of an airborne AERI instrument that has become known as the Scanning High-resolution Interferometer Sounder (Scanning-HIS). This instrument has become an integral part of the ARM Unmanned Aerospace Vehicle (ARM-UAV) program. It provides both a cross-track mapping view of the earth and an uplooking view from the 12-15 km altitude of the Scaled Composites Proteus aircraft when flown over the ARM sites for IOPs. It has successfully participated in the first two legs of the “grand tour” of the ARM sites (SGP and NSA), resulting in a very good comparison with AIRS observations in 2002 and in an especially interesting data set from the arctic during the Mixed-Phase Cloud Experiment (M-PACE) in 2004. More specifically, our major achievements for ARM include 1. Development of the Atmospheric Emitted Radiance Interferometer (AERI) to function like a satellite on the ground for ARM, providing a steady stream of accurately calibrated spectral radiances for Science Team clear sky and cloud applications (Knuteson et al. 2004a), 2. Detailed radiometric calibration and characterization of AERI radiances, with uncertainty estimates established from complete error analyses and proven by inter-comparison tests (Knuteson et al. 2004b), 3. AERI data quality assessment and maintenance over the extended time frames needed to support ARM (Dedecker et al., 2005) 4. Key role in the radiative transfer model improvements from the AERI/LBLRTM QME (Turner et al. 2004) and AERI-ER especially from the SHEBA experiment (Tobin et al. 1999), 5. Contributed scientific and programmatic leadership leading to significant water vapor accuracy improvements and uncertainty assessments for the low to mid troposphere (Turner et al. 2003a, Revercomb et al. 2003), 6. Leadership of the ARM assessment of the accuracy of water vapor observations from radiosondes, Raman Lidar and in situ aircraft observations in the upper troposphere and lower stratosphere (Tobin et al. 2002, Ferrare et al. 2004), 7. New techniques for characterizing clouds from AERI (DeSlover et al. 1999, Turner 2003b, Turner et al. 2003b), 8. Initial design and development of the Scanning-HIS aircraft instrument and application to ARM UAV Program missions (Revercomb et al. 2005), and 9. Coordinated efforts leading to the use of ARM observations as a key validation tool for the high resolution Atmospheric IR Sounder on the NASA Aqua platform (Tobin et al. 2005a) 10. Performed ARM site and global clear sky radiative closure studies that shows closure of top-of-atmosphere flux at the level of ~1 W/m2 (Moy et al 2008 and Section 3 of this appendix) 11. Performed studies to characterize SGP site cirrus cloud property retrievals and assess impacts on computed fluxes and heating rate profiles (Borg et al. 2008 and Section 2 of this appendix).

Clear and All Sky Radiative Closure Studies for OLR Assessment with CERES and AIRS

The earth’s radiant energy budget is a balance between absorbed solar radiation and emitted outgoing longwave radiation (OLR). For almost 50 years now, accurate, long term records of solar insolation, planetary albedo, and OLR have been collected to monitor climate change. This paper describes results of two closure studies: one tests how well a state of the art radiative model using satellite retrievals from Atmospheric Infrared Sounder (AIRS) reproduces clear sky observations of OLR obtained by the Clouds and the Earth’s Radiant Energy System (CERES) broadband radiometer, and the other tests how well the AIRS retrievals input into the radiative model reproduces AIRS radiances. In both studies the methodologies were tested at the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program site in the US Southern Great Plains (SGP) then applied globally. The clear sky OLR comparisons were impressive; RRTM calculations agree with CERES observations to ∼1 W/m2 with an uncertainty of ∼1 W/m2 a...

Analysis of the CrIS Flight Model 1 Radiometric Linearity

The CrIS Flight Model 1 has recently completed thermal vacuum testing. Here we present the independent UW-SSEC analyses of various test data to assess the radiometric linearity of the sensor.