CAM5.5 assessment



CAM5.5 panel assessment guidelines

  • Overview

This webpage is intended to document the procedures and targets for ultimately delivering the version of the Community Atmosphere Model (CAM) for use by other CESM working groups in CMIP6 experiments. The version of CAM (to be tagged as CAM5.5) will be finalized with the inclusion of recent major physics parameterization developments. These candidate parameterizations are the Unified Convection scheme (UNICON) and the Cloud-Layers Unified By Binormals (CLUBB). Webpages providing information on the developments, including scientific background, diagnostics, output data and timings are available here: Members of the panel are:
  • Antonietta Capotondi, NOAA
  • Brian Mapes, Univ. Miami
  • Martin Miller, previously of ECMWF
  • Steve Klein, Lawrence Livermore National Laboratory
  • Paul Kushner, Univ. Toronto

  • Timelines

Developers of the candidate schemes should provide supporting material and the primary simulation (AMIP, coupled) requests as soon as possible, but by no later than December 15, 2014. At this time the panel should determine whether the candidates have provided sufficient material to move forward in the assessment process or there is insufficient material to move forward.

All requested simulations should be provided by December 30, 2015.

After a period of assessment the panel should provide a short report with their recommendation for the CAM5.5 configuration by February 1st, 2015 so that other AMWG members have chance to look over the recommendations prior to the AMWG meeting. A presentation by one or more of the panel members will then be requested for the AMWG meeting on February 18-20, 2015.

The developers shoud provide an answer to the panel recommendations by May 15, 2015.

  • Remit

Panel members will be tasked to provide a recommendation for the configuration of CAM5.5. A number of aspects should be considered when making the assessment including scientific merit and maturity, simulation fidelity and computation expense to name a few. We believe it is not for us to determine the necessity and overall value of these aspects since of course different people place a different value on the same thing. We ask only that you outline and justify your recommendation to the AMWG.

Where possible we have compared the develop simulations to both observational products and to a baseline of the CESM large ensemble. This is a set of carefully constructed simulations that represent the best coupled simulations using the current CAM5 configuration. 

The expected diagnostics to be submitted from the candidate scheme developers will be of three types (other supporting diagnostics also may be provided)

* Mean climate diagnostics (AMWG diagnostics)

This is the primary package used to assess simulations and is based on the use of climatological seasonal and monthly output data. A description of the observation datasets used in the AMWG diagnostics can be found at the climate data guide webpage.

For the coupled run, the mean climate diagnostics are arranged into atmosphere, land, ice and ocean components. Examples of the diagnostics can be found on the CESM webpage.

* Low frequency variability diagnostics(CVPD package)

These are used to assess the lower frequency modes of variability utilizing monthly mean model output e.g., ENSO, NAO, PNA etc.

* High-frequency variability diagnostics (AMWG variability)

These are used to asses the higher frequency models of variability utilizing 3hourly to daily mean model output e.g., MJO, diurnal cycle of rainfall.

If anything is incomplete or unclear on the webpages or you need more clarification please contact Rich Neale or Cecile Hannay.


Panel Recommendation and discussion


After consideration of all the available material provided by the candidates the panel has provided a summary document outlining their assessment and recommendations  for CAM5.5 and beyond. This document serves as the recommendation to the AMWG, AMWG co-chairs and the CESM Scientific Steering Committee. We encourage AMWG members to review the document and all the supporting material, particularly if they will be attending the AMWG 2015 meeting where the process of selecting CAM5.5 will be discussed in depth. To provide feedback to the panel or the AMWG co-chairs please email Rich Neale.


Responses to the panel recommendations


After carefully evaluating all of the material available and drawing on their collective expertise the panel intends to make a two-stage recommendation. First, that the CAM5.4 configuration should continue to move forward, with appropriate coupled simulations, as the choice for CAM5.5 in the short term. Second, that the two model candidate configurations continue to move forward with development activities intended to address specific areas of concern (detailed below). Whichever candidate development has addressed these areas of concern most successfully, as deemed by the panel, will be recommended to combine with CAM5.4 to form CAM5.5. If neither candidate has satisfactorily addressed the areas of concern, as deemed by the panel, then CAM5.4 will become the contingency configuration for CAM5.5.

Final Panel Recommendation


The assessment panel has now made their final recommendation to the SSC regarding the path forward for AMWG and CESM2.

The recommendation can be found below: