The CERES/ARM/GEWEX Experiment (CAGEX) provides (1) INPUT, (2) OUTPUT, and (3) VALIDATION:
CAGEX is intended to foster the development of algorithms for the retrieval of vertical profiles of broadband radiative fluxes with satellite data. CAGEX has been approved by CERES, ARM, and the GEWEX Continental-scale International Project (GCIP). We invite you to check our calculated fluxes and to generate your own flux retrievals. If you can send us your calculated fluxes, we will coordinate an intercomparison with others. CAGEX should be useful for studies of the spatial and temporal variability of the surface and atmospheric radiation budget and the radiative properties of clouds.
For item (1) above, Pat Minnis and Bill Smith Jr. have supplied GOES based cloud property retrievals and interpolated NMC soundings. For (2), we include total-sky (all-sky or full-sky, i.e. with clouds if present) longwave (LW) and shortwave (SW) fluxes from the Fu and Liou (1993) Delta-4-stream code at 47-49 vertical levels. For (3), we have surface SW (pyrheliometer, pyranometer) and longwave (pyrgeometer) fluxes, and the Spinhirne micropulse lidar (MPL) cloud base heights. These surface validating measurements are provided half-hourly at one point, the ARM SGP CART central facility. For TOA validation, we have Minnis estimates of broadband LW fluxes and SW albedos, based on narrowband GOES 7 and 8 radiances, provided for the 3x3 grid.
CAGEX is a long-term project. We have a formidable task: the development and validation of radiative flux profiles for the CERES project. We're trying to do this directly (with ARM help), and we invite your participation through EOS and GEWEX. Our goal is to have our results checked and applied, and to get in touch with groups that know how to do parts of the job better.
Each Version of CAGEX spans a limited domain of several weeks. Version 2.2.0, for example, covers several September 25 to November 1, 1995. The user seeking continuous data over SGP can consult our CAVE, which has data (including CERES TRMM broadband TOA observations) from January 1, 1998 onward. CAGEX provides downloadable observations and computed fluxes; on-line documentation; on-line time series plots; and on-line tabular results with "point and click" scatter plots. CAVE is simpler and concentrates on downloadbable observations for SGP and a few other locations.
We have also included supplementary data. Most notable, sounding data from the NMC Mesoscale Analysis and Prediction System (MAPS) in version 1. Replacement of the core NMC soundings by the MAPS soundings at the central facility improves both SW and LW calculations, when compared to the validating measurements. Surface Meteorological Observation System (SMOS) 2-meter temperatures and relative humidities are used in conjunction with the MAPS soundings as input to the Fu-Liou code. Version 2 has Eta model Data Assimilation System (EDAS) outputs.
CAGEX Version 2.2 is available. V2 is somewhat similar in format to version 1, but concentrates on the October 1995 ARM IOP, coinciding with the ARESE experiment. Several additional radiometry and water vapor datasets highlight the V2 changes.
Preliminary plans are being made for CAGEX V3, which covers the August 1998 IOP. Included in V3 will be surface radiometric measurements and helicopter BRDF and spectral reflectances, both a part of Langley's CERES/ARM Radiation Experiment (CARE) .
In our acknowledgement section we note the vital contributions of several of our colleagues.
Please let us know if you have questions or comments.
Thank you,