Multiple long-term cloud retrievals are now available for five ARM sites in the ACRED data set.
Multiple long-term cloud retrievals are now available for five ARM sites in the ACRED data set.
A new ARM evaluation product, the ARM Cloud Retrieval Ensemble Data Set (ACRED), is now available for testing by the science community. ACRED was developed with the motivation to provide a rough estimate of the uncertainties in current retrieved cloud microphysical properties for climate model evaluation and development. It was created by assembling numerous existing ground-based cloud retrievals together for the ARM Facility’s permanent research sites at the Southern Great Plains (SGP), North Slope of Alaska (NSA), and Tropical Western Pacific (TWP).

The current ACRED data set contains measurements of:

  • Cloud liquid effective radius, liquid water content, and liquid water path
  • Cloud ice effective radius, ice water content, and ice water path
  • Cloud liquid optical depth and ice optical depth at solar wavelength
  • Cloud fraction

To facilitate use by climate modelers, the quantities in ACRED are averaged hourly with a vertical resolution of 45 meters, consistent with the temporal and vertical resolutions in the ARM Climate Modeling Best Estimate (CMBE) value-added product. ACRED contains three to six retrieval products for the following ARM sites and dates:

  • SGP.C1 (Lamont, OK) 1999–2008
  • NSA.C1 (Barrow, AK) 1997–2008
  • TWP.C1 (Manus Island) 1999–2007
  • TWP.C2 (Nauru) 1998–2006
  • TWP.C3 (Darwin, AU) 2003 and 2005–2009.

To access the ensemble data set, log into the ARM Data Archive (go here to request an account). Supporting details about the data set, including the various cloud retrieval algorithms used as the basis for the ensemble, are contained in the README file and technical report.

Please contact relevant PIs for more information or for assistance in interpreting their data, and provide feedback on the data set to Shaocheng Xie. Feedback obtained during this 6-month evaluation period will be used to improve ACRED and guide development of future cloud data products.