CMIP output is available for qualifying diagnostic subprojects, analogous to the AMIP diagnostic subprojects.  The CMIP Panel will review proposed subprojects with attention to (1) scientific merits, (2) probability of successful completion and (3) appropriate coordination with each other and with the modeling community.  Persons wishing to initiate subprojects should first check the available CMIP model output to be sure that it meets their needs.  They should also read the participation protocol and the collaboration protocol.  Proposals, not exceeding 1-2 pages in length, should be e-mailed to Curt Covey (

Subprojects approved to date

Participation protocol

Upon receipt of a proposal, the Chair of the CMIP Panel will distribute the proposal to the other Panel members. Once the proposals have been evaluated, prospective subproject leaders will be consulted on the establishment of a subproject. This may involve some elaboration or modification of the proposal and an agreement to adhere to the CMIP subproject collaboration protocol (Annex 2). Proposals will be limited to 1-2 pages and final subproject agreements to three pages. Note that there is no direct funding provided by CMIP to diagnostic subprojects. Participation in a CMIP1 diagnostic subproject ensures access to CMIP model output, but also entails certain obligations:

* Diagnostic subproject leaders are expected to keep modeling groups informed of results pertaining to their model. For example, before submitting a CMIP study for peer-reviewed publication, the manuscript should be sent to each modeling group whose data were used in the analysis. Modeling group representatives should be given a reasonable period (at least one month) to provide comments.

* Diagnostic subproject leaders are also expected to provide the Panel with all CMIP-related manuscript abstracts.  These will appear on the PCMDI web pages after an appropriate period.  The purpose of these summaries is to keep all CMIP participants informed of the projects' progress.

Collaboration protocol

The CMIP effort is in many ways analogous to the Atmospheric Model Intercomparison Project (AMIP). In the AMIP diagnostic subproject effort, some difficulties were encountered because it was unclear what sort of cooperation was expected among participants. Based on these experiences, the following guidelines have been developed for collaboration between diagnostic subprojects and modeling groups. These guidelines are (by necessity) compromises, but the aim is to provide an acceptable framework for all participants.

* Equal treatment of all modeling groups: Modeling groups participate in CMIP with the expectation that their simulations will be analyzed. In preparing manuscripts for journal publications, a subproject leader may choose to focus on only a few models that most clearly illustrate each point. When results for only a subset of models are shown, it is expected that the corresponding results will be sent to all modeling groups. At some level, however, results of all available models should be compared collectively (e.g., the results from all models shown on zonal mean plots or in a summary table).

* Implications of results: There are two points that should be made clear in all CMIP studies. The first is the age or model version of each simulation. For simulations more than a few years old, it should be emphasized that the results may not be indicative of the current model version. The second point that should be expressed is a warning that the results of a specific subproject do not necessarily reflect the overall performance of the coupled models. For example, attempts to rank the performance of various model simulations generally yield very different results, depending on the aspect examined.

* Participation: Modeling group representatives (not necessarily the official CMIP contact) will be given the opportunity to actively participate in diagnostic subprojects of interest. When a modeling group representative acknowledges an interest to participate in a subproject, they should expect to provide sufficient assistance to earn explicit co-authorship. The subproject leaders will exercise their professional judgment to determine what constitutes a sufficient contribution to qualify for co-authorship.

* Authorship: This issue may be a problem in large projects. Here we propose a compromise that reflects the sentiments of many subproject leaders and modelers, namely that 1) no individual should receive co-authorship in a CMIP study without directly contributing to that study, and 2) the modeling groups deserve recognition for their participation in CMIP. The suggested compromise is that if the contributing modelers do not have substantial input to a CMIP-related paper (apart from providing model output in the first place), then the acknowledgments is the proper place to thank them, rather than giving them a kind of co-authorship. 

CMIP model output:

Note: in addition to the CMIP1 and CMIP2 output listed below, a more extensive collection of data from a limited number of models is available under the extended CMIP2 phase "CMIP2+". Please refer to the Web page

I. CMIP1 atmosphere

II. CMIP1 ocean I. CMIP2 atmosphere: control and perturbed (1% per year CO2 increase) cases, 80-year runs

    a. time averaged fields

        i. geographical distributions (four 20-year means):

           --wind stress (u and v components)
           --net surface heat flux at the air-sea interface (bottom of atmosphere)
           --net surface freshwater flux at the air-sea interface (bottom of atmosphere)
           --flux adjustments (if any)
           --snow cover (average distribution of depth and please note units)
           --surface latent heat flux
           --surface sensible heat flux
           --surface net IR
           --surface net solar

        ii. zonal mean cross-sections (latitude-height) (four 20-year means):

           --u-component wind
           --v-component wind
           --moisture (i.e. specific humidity)

    b. time series of monthly means (i.e. 80x12=960 monthly mean fields):

        --surface air temperature


        --sea level pressure (trends and variability will be calculated from these data)

II. CMIP2 ocean: control and perturbed (1% per year CO2 increase) cases, 80-year runs

        i. four 20-year means, global (and by basin for zonal means, basins divided roughly at 20E and 120E or specify):

           -- meridional overturning streamfunction zonal mean cross sections (global and by basin)
           --zonal mean heat transport, single value for each latitude, not cross section (global and by basin)
           --global geographic vertically integrated mass transport streamfunction

        ii. 3-D global fields (four 20-year means):

           --temperature (includes SST)
           --salinity (includes surface salinity)

        iii. bathymetry (or bottom topography, required to compute ocean heat content, one field)

        iv. sea ice thickness and concentration

Note on data transmission:

To enable the PCMDI staff to more efficiently distribute model output, the data will be sent to investigators from approved subprojects in netCDF format.