Introduction

CAVE is an informal record containing radiation and meteorological data for a number of specific sites having:

• (1) top-of-the-atmosphere (TOA) broadband observations from CERES,
• (2) retrievals of the Surface and Atmospheric Radiation Budget (SARB) - the CERES vertical profiles of fluxes,

collocated with,

• (3) surface broadband flux measurements from ARM, SURFRAD, CMDL, and BSRN and
• (4)ancillary meteorological data, such as vertical profiles of temperature and humidity,column integrated aerosol optical depth, and cloud properties.

CAVE aims to build and provide access to a long-term record of (1) thru (4) beginning on January 1, 1998.

CAVE is maintained by the Clouds and the Earth's Radiant Energy System (CERES) through the CERES Surface and Atmospheric Radiation Budget (SARB)Working Group.(local group only) The SARB group uses radiative transfer calculations to determine the vertical profiles of fluxes and the forcing by aerosols and clouds. The long-term CAVE record provides surface and TOA closure for SARB validation. CERES operated on the low latitude TRMM (mostly for January to August 1998 and March 2000) and now observes from the global, sun-synchronous Terra (from February 2000) and Aqua (from July 2002).

The continuous and geographically dispersed CAVE record is a coarser version of its more intensive (but now dated) cousin, the CERES ARM GEWEX Experiment (CAGEX). CAGEX focused on smaller domains of a few weeks.

What about the surface boundary conditions for radiative transfer? CERES includes two field deployments (COVE and C-FAR) to determine spectral and directional boundary conditions at the surface. The CERES Ocean Validation Experiment (COVE), makes long-term, detailed measurements of the sea surface from a rigid platform. A main goal of COVE is the development of an ever sharper ocean spectral BRDF. For land BRDF, measurements are needed at many points. This was done during the earlier CERES ARM Radiation Experiment (CARE) provides helicopter based spectral fluxes and BRDF over ARM SGP (Oklahoma) from August 1998. Global reference maps of surface optical properties for CERES SARB calculations are maintained at (surface properties homepage).

Much of the data on CAVE is preliminary. For example, note the Formal Disclaimer in the section on CERES ES8 TOA data; the archived ES8 fluxes will eventually be superseded by more accurate SSF fluxes for the same space and time domains. Comments on CAVE data are sincerely requested. As CAVE develops, we plan to acknowledge more thoroughly the assistance of researchers associated with ARM, CERES, SUNY Albany, CMDL, INDOEX and other institutions, who are providing this wealth of scientific information.

Temporal Domain

CAVE is a continuous data stream beginning on 1/1/98. Most surface data is placed into 15 minute bins. Some is averaged (SIRS is comprised of 30 minute averages of one minute data) and some is binned (water temperature at the COVE site which is 1 hour data). The satellite data are instantaneous snapshots.

Spatial Domain

CAVE uses a score of broadband sites from the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) located in Oklahoma and Kansas. Individual sites worldwide are supplied by CMDL, ARM, SURFRAD, and BSRN. Satellite and gridded data are used on a nearest neighbor basis. Each data set has an information page which alludes to its spatial characteristics.

TOP Menu Bar

• Surface Observations: Description of contents of CAVE files containing surface flux and meteorological observations. Includes on-line plots and ftp access to data base and Fortran programs to read data files.
• Satellite Data: Files of SARB (vertical profiles of flux) CRS. Here they are neatly subset at CAVE ground sites for workstations running FORTRAN 90 (V6.2 or higher). This is an (relatively) easy alternative to the official, huge, HDF files on NASA Langley ASDC (Useful Links). A Quality Summary Report (in English) tells how CERES gets the SARB. They can serve as a good introduction to the CRS data before downloading the larger official files from the ASDC.
• Atmospheric Profiles: Data files (with fortran programs) of temperature and humidity for some CAVE sites. For profiles of radiative flux, see CERES CRS Data.
• Useful Links: A sincere attempt to help you to navigate to other useful sites.

Side Bar (Left)

• Overview: You are now reading the Overview section of CAVE.
• Plot CAVE Data Online: This page has a list of all of the CAVE site's on-line plotting programs. It includes the important ground-based records of surface radiation and related parameters and validation plots. The record of SARB vertical profiles of fluxes are not available as point and click plots.
• Validation Plots & Statistics: Since the primary purpose of CAVE is to validate the CERES CRS data product this link takes you directly to a tool that shows SARB radiation transfer results in terms of tables and plots for each site (and a number of groups of sites) for each month of CERES operation. You can toggle between GIF (PC friendly) and POSTSCRIPT plots.
• Publications and Posters: Our electronic library.
• Cloud Fraction in CAVE: Point and click plots of cloud cover derived from time series of ground-based radiometers. Not currently available.
• Aerosols in CAVE: Special information on the record from ground-based photometers. If you use the CAVE aerosol record, read this brief section with care. Not currently available.
• Access to CAVE data: HTTP tool for accessing collected surface and satellite data.
• The Group: The core characters involved in this project.

Side Bar (Right)

• COART - Coupled Ocean-Atmosphere Radiation Transfer Model: On line computations of spectral SW fluxes and radiances with a sophisticated coupled ocean-atmosphere radiative transfer code. Point and click your aerosol, wind speed, and chlorophyll concentration. To squeeze sensitive quantities like aerosol forcing out of satellite data, a first class description of that most ubiquitious of boundary conditions - the ocean surface - is needed.
• Ocean Albedo Look-Up-Table: Parameterization of COART model. This code is used in CERES processing for SARB for determining ocean albedo under all atmospheric conditions.
• Langley Fu & Liou On-Line Radiation Transfer model: Broadband SW and LW calculations on line. Point and click for plots of heating rate profiles.
• CRS Advice: Retrievals of SARB (vertical profiles of flux) contain the lable CRS. We will put any informal advice on official SARB/CRS products here.
• COVE: Link to Chesapeake Lighthouse data source, CERES/Ocean Validation Experiment (COVE).
• CLAMS: A link to the huge Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign (summer 2001) around the COVE sea platform, our most important validation site.
• ULDB - Balloon Observations: A unique program to observe broadband fluxes directly at 35km.

Any questions, comments or information about these data or this homepage are greatly appreciated. Please contact CAVE manager David Rutan at David.A.Rutan@nasa.gov or CERES liaison Tom Charlock Thomas.P.Charlock@nasa.gov