Catalogue of Model Intercomparison Projects

Introduction

At a combined Working Group on Coupled Models (WGCM) and Global Analysis Interpretation and Modeling (GAIM) meeting in Victoria, B.C., Canada, it was recognized that the proliferation of various model intercomparison projects (termed "MIPs") has generated a certain degree of confusion in respective research communities. As a first step in helping everyone keep better track of activities in model intercomparisons, it was decided that it would be helpful to publish a catalogue of the MIPs  in various newsletters (e.g. CLIVAR, GEWEX, IGBP, GAIM, etc.) in addition to posting this compilation on the Coupled Model Intercomparison Project (CMIP) Web site.  Henceforth, CMIP will periodically update this information, and act as a clearing house for general MIP information and contacts.

The following catalogue represents the result of a first survey which was performed in fall 2002.

If you can provide information about other MIP's not listed here or if you have additions or corrections please supply the information in the following form:

1. The title of your MIP including the full wording (so we can accurately interpret the associated acronym)
2. Contact (incl. e-mail) and a web page address for your MIP (if any)
3. A brief one paragraph description of your MIP
4. A key publication or two (if any)

The goal is to help us all stay aware of different model intercomparison activities going on, and encourage participation and use of results from the MIPs in our respective research activities.

Table of Contents:

Arctic Ocean Model Intercomparison Project (AOMIP)

Contact: David Holland and Andrey Proshutinsky

Overview
The Arctic Ocean Model Intercomparison Project (AOMIP) is an international effort to identify systematic errors in Arctic Ocean models under realistic forcing.  The main goals of the research are to examine the ability of Arctic Ocean models to simulate variability on seasonal to interannual scales, and to qualitatively and quantitatively understand the behaviour of different Arctic Ocean models. AOMIP's major objective is to use a suite of sophisticated models to simulate the Arctic Ocean circulation for the periods 1948 2002 and 1901-2002. Forcing will use the observed climatology and the daily atmospheric pressure and air temperature fields. Model results will be contrasted and compared to understand model strengths and weaknesses.

AOMIP will bring together the international modeling community for a comprehensive evaluation and validation of current Arctic Ocean models. The project will provide valuable information on improving Arctic Ocean models and will result in a better understanding of the processes that maintain the Arctic's observed variability.

References
Proshutinsky, A., M. Steele, J. Zhang, G. Holloway, N. Steiner, S. Häkkinen, D.M. Holland, R. Gerdes, C. Koeberle, M. Karcher, M. Johnson, W. Maslowski, Y. Zhang, W. Hibler, J. Wang, 2001: The Arctic Ocean Model Intercomparison Project (AOMIP). EOS, 82 (51), 637-644.

Steele, M., W. Ermold, G. Holloway, S. Häkkinen, D.M. Holland, M. Karcher, F. Kauker, W. Maslowski, N. Steiner, and J. Zhang, 2001: Adrift in the Beaufort Gyre: A model intercomparison. Geophys. Res. Lett, 28, 2935-2838.

Arctic Regional Climate Model Intercomparison Project (ARMIP)

Amanda Lynch, Judy Curry

Overview:
A powerful method for improving regional climate simulations is the comparison of simulations produced by different models with each other as well as with available observations. Strengths and weaknesses of model structures, numerics and parameterizations can be assessed side-by-side. The utility of model intercomparisons is greatly enhanced if the models operate under the same external constraints and use a data-rich case study such as SHEBA. An international intercomparison of regional model simulations in the Arctic has been organized under the auspices of the WCRP GEWEX Cloud System Studies Working Group on Polar Clouds and the ACSYS Numerical Experimentation Group. Further queries about the ARCMIP project should be directed to Judy Curry.

References:
Curry, J.A., and A.H. Lynch, 2002: Comparing Arctic Regional Climate Models. EOS, 83, 87.

Asian-Australian Monsoon Atmospheric GCM Intercomparison Project

In-Sik Kang

The AGCM intercomparison program was initiated right after the WCRP/CLIVAR Asian-Australian Monsoon Panel meeting held in Kyong-ju, Korea in April, 1998. The main foci of this program are intercomparing intraseasonal oscillation, monsoon dynamics and hydrology, atmosphere-ocean interaction, and global heat budget at the top of atmosphere and the surface in atmospheric GCMs. 14 GCM groups from 8 countries, that is CSIRO/Australia, IAP/China., IITM/India, MRI and CCSR in Japan, SNU/Korea, DNM/Russia, NCAR, GEOS(NASA), SUNA/GSFC(NASA), GFDL, COLA in U.S., UKMO/U.K. and NTU/Taiwan gave their interests in participating this program and are doing this monsoon intercomparison experiment with their models.

References:

Kang, I.-S., K. Jin, B. Wang, K.-M. Lau, J. Shukla, V. Krishnamurthy, S.D. Schubert, D.E. Waliser W.F. Stern, A. Kitoh, G.A. Meehl, M. Kanamitsu, V.Y. Galin, V. Satyan, C.K. Park and Q. Liu, 2002: Intercomparison of atmospheric GCM simulated anomalies associated with the 1997-98 El Nino. J. Climate, 15, 2791-2805.

Kang, I.-S., K. Jin, B. Wang, K.-M. Lau, J. Shukla, V. Krishnamurthy, S.D. Schubert, D.E. Waliser W.F. Stern, A. Kitoh, G.A. Meehl, M. Kanamitsu, V.Y. Galin, V. Satyan, C.K. Park and Q. Liu, 2002: Intercomparison of the climatological variations of Asian summer monsoon precipitation simulated by 10 GCMs. Clim. Dyn., 19, 383-395.

Atmospheric Model Intercomparison Project (AMIP)

Contact: Peter Gleckler

Overview:

AMIP is a standard experimental protocol for global atmospheric general circulation models (AGCMs). It provides a community-based infrastructure in support of climate model diagnosis, validation, intercomparison, documentation and data access. This framework enables a diverse community of scientists to analyze AGCMs in a systematic fashion, a process which serves to facilitate model improvement. Virtually the entire international climate modeling community has participated in this project since its inception in 1990.

AMIP is endorsed by the Working Group on Numerical Experimentation (WGNE) of the World Climate Research Programme, and is managed by the PCMDI with the guidance of the WGNE AMIP Panel.

The AMIP experiment itself is simple by design; an AGCM is constrained by realistic sea surface temperature and sea ice from 1979 to near present, with a comprehensive set of fields saved for diagnostic research.

This model configuration enables scientists to focus on the atmospheric model without the added complexity of ocean-atmosphere feedbacks in the climate system. It is not meant to be used for climate change prediction, an endeavor that requires a coupled atmosphere-ocean model (e.g., see AMIP's sister project CMIP).

References:
Gates, W. L., J. Boyle, C. Covey, C. Dease, C. Doutriaux, R. Drach, M. Fiorino, P. Gleckler, J. Hnilo, S. Marlais, T. Phillips, G. Potter, B. Santer, K.  Sperber, K. Taylor and D. Williams, 1998:  An Overview of the Results of the Atmospheric Model Intercomparison Project (AMIP I ). Bull. Amer. Meteor. Soc., 73, 1962-1970.

Atmospheric Tracer Transport Model Intercomparison Project (TransCom)

Contact: Kevin Gurney

Overview:

TransCom is is a special project of the International Geosphere-Biosphere Programme (IGBP), Global Analysis, Interpretation, and Modeling (GAIM) Project, the objective of which is to quantify and diagnose the uncertainty in inversion calculations of the global carbon budget that result from errors in simulated atmospheric transport, the choice of measured atmospheric carbon dioxide data used, and the inversion methodology employed.

Two distinct phases of the TransCom (TransCom 1 and TransCom 2) have now been completed with a third phase currently underway (TransCom 3)

References:
Rayner, P. J. and Law, R. M., 1995. A comparison of modelled responses to prescribed CO2 sources. CSIRO Division of Atmospheric Research Technical Paper No. 36.

Denning, A. S., M. Holzer, K. R. Gurney, M. Heimann, R. M. Law, P. J. Rayner, I. Y. Fung, S.-M. Fan, S. Taguchi, P. Friedlingstein, Y. Balkanski, J. Taylor, M. Maiss, and I. Levin, 1999. Three-dimensional transport and concentration of SF6: A model intercomparison study (TransCom 2). Accepted by Tellus.

Carbon-Cycle Model Linkage Project (CCMLP)

Contact: Martin Heimann

Overview:
The Carbon-Cycle Model Linkage Project (CCMLP) has brought together several research groups to study the role of the terrestrial biosphere in the Earth system using TBMs. The focus of phase 1, recently completed, was to evaluate model responses to CO2, climate and land use for the terrestrial carbon cycle. Four models (including LPJ) were run in parallel for the period 1920-1992. Results indicated that the dominant influences on the terrestrial carbon cycle are the large and opposing effects of historical land-use changes and CO2 fertilization. In comparison, the effects of climatic changes are (still) small and the direction of the response, whether source or sink of CO2 to the atmosphere, differs among models. Nevertheless, the net fluxes over the 1980s for all four models were in agreement with inferred estimates (based on observed atmospheric CO2 concentrations, fossil-fuel emissions and ocean fluxes as computed from a state-of-the-art ocean model). The seasonal cycle of atmospheric CO2 is almost entirely due to the dynamics of the terrestrial biosphere, with a net flux to the atmosphere during the winter months associated with heterotrophic respiration and a net flux of carbon from the atmosphere to the biosphere during the summer as photosynthesis exceeds respiration. In the last decades an increase has been observed in the amplitude of the atmospheric CO2 seasonal cycle at monitoring stations, indicating an increase in terrestrial biosphere activity. LPJ captured the observed trend in amplitude of the seasonal cycle of atmospheric CO2 at the Mauna Loa monitoring station between 1960-1992.

Coupled Model Intercomparison Project (CMIP)

Contact: Gerald Meehl

Overview:

CMIP was initiatied in 1995 by the CLIVAR Working Group on Coupled Models (WGCM), and continues to compare simulations from global coupled climate models with components describing atmosphere, ocean, sea ice and land surface. There have been several phases and activities, including CMIP1 (comparing limited fields from control runs); CMIP2 (comparing limited fields from 1% per year CO2 increase simulations); CMIP2+ (same as CMIP2 except for all fields for all components from the models have been collected, monthly averaged data and some daily data); 20th Century Climate in Coupled Models (20C3M) which is a pilot study to intercompare limited fields from simulations of 20th century climate with best estimates of the time evolution of various forcings in the simulations; and CMIP Coordinated Experiments, the first of which addresses factors affecting the meridional overturning circulation in the Atlantic in global coupled models. CMIP analyses are being carried out in subprojects approved by the CMIP Panel. Access to global coupled model data collected as part of CMIP is through the CMIP Panel. Investigators should send a one paragraph summary of their proposed research to the CMIP Panel chair (Meehl) for approval by the Panel.

References:

Meehl, G.A., G.J. Boer, C. Covey, M. Latif, and R.J. Stouffer, 1997: Intercomparison makes for a better climate model. Eos, 78, 445-446, 451.

Meehl, G.A., G.J. Boer, C. Covey, M. Latif, and R.J. Stouffer, 2000: The Coupled Model Intercomparison Project (CMIP). Bull. Amer. Meteor. Soc., 81, 313--318.

Covey, C., K.M. AchutaRao, U. Cubasch, P. Jones, S.J. Lambert, M.E. Mann, T.J. Phillips, and K.E. Taylor, 2003: An overview of results from the Coupled Model Intercomparison Project (CMIP). Global and Planetary Change, in press.

Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP)

Contact: Pierre Friedlingstein

Overview:
The Coupled Carbon Cycle Climate Model Intercomparison Project (C4MIP) is designed to compare and analyze the feedbacks between the carbon cycle and climate in the presence of external climate forcing. Such feedbacks are likely to be mediated on the one hand by altered forcing of the ocean and terrestrial carbon cycles and on the other by the impact of altered CO2 concentrations in the atmosphere resulting from this forcing. The basic approach is to include models of the terrestrial and ocean carbon cycles in existing OAGCMs and run the augmented model with and without these feedbacks active.

Climate of the Twentieth Century Project (C20C)

Contact: Chris Folland , Jim Kinter

Overview:
The 20th century displayed a rich spectrum of climate variations, including El Niño and the Southern Oscillation (ENSO), monsoon floods and droughts, sub-Saharan drought, substantial variations in the character of the Arctic Oscillation, the North Atlantic Oscillation, the Pacific Decadal Oscillation, the North American Dust Bowl, changes in the Antarctic Oscillation etc. These climate variations may be the result of atmospheric (internal) modes or coupled ocean-atmosphere modes or they may be related to anthropogenic forcing functions. The International Climate of the Twentieth Century (C20C) project was conceived to address this question by imposing the observed atmospheric forcing functions of the last century or more on state-of- the-art atmospheric general circulation models (AGCMs) to determine primarily the extent to which these seasonal to interdecadal variations are reproducible and also to serve as a validation of the AGCMs themselves.

References:
Folland, C., J. Shukla, J. Kinter, and M. Rodwell, 2002: The Climate of the Twentieth Century Project. CLIVAR Exchanges, June 2002, 3 pp. (http://www.iges.org/c20c/workshop/CLIVAR_Exchanges_jun2002.pdf)

Cloud Model Feedback Intercomparison Project

Contact: Bryant McAvaney

Overview:

to be provided

References:

to be provided

Dynamics of North Atlantic Models (DYNAMO)

Contact: Claus Boening

Overview:
The goal of the DYNAMO project was an improved simulation of the circulation in the North Atlantic Ocean, including its variability on synoptic and seasonal time scales. A key activity was a systematic assessment of the ability of eddy-resolving models with different numerical formulations of the vertical coordinate to reproduce the essential features of the hydrographic structure and velocity field between 20°S and 70°N.

References:

DYNAMO Group, 1997: DYNAMO: Dynamics of North Atlantic Models: Simulation and assimilation with high resolution models. Institut für Meereskunde, Kiel, Germany. Report Nr. 294.

Ecosystem Model-Data Intercomparison (EMDI)

Contact: Kathy Hibbard

Overview:
The Ecosystem Model-Data Intercomparison (EMDI) activity will provide, for the first time ever, a formal opportunity for a wide range of global carbon cycle models to be compared with measured net primary production (NPP). The goals of the EMDI are to compare model estimates of terrestrial carbon fluxes (NPP and net ecosystem production (NEP), where available) to estimates from ground-based measurements, and improve our understanding of environmental controls of carbon allocation. The primary questions to be addressed by this activity are to test simulated controls and model formulation on the water, carbon, and nutrient budgets with the observed NPP data providing the constraint for autotrophic fluxes and the integrity of scaled biophysical driving variables.

Earth system Models of Intermediate Complexity (EMICs)

Contact: Martin Claussen

((There is no xyz-MIP acronym for this activity, because this is not only a model intercomparison excercise.

Overview:
A spectrum of models of various complexity is used in modelling the natural Earth system. Depending on the nature of questions asked and the pertinent time scales, there are, on the one extreme, conceptual, more inductive models, and, on the other extreme, three-dimensional comprehensive models operating at the highest spatial and temporal resolution currently feasible. Models of intermediate complexity bridge the gap. The EMIC network is supported by GAIM (Global Analysis Integration and Modelling), an IGBP (International Geosphere-Biosphere Program) task force and by the participating institutes (see table of EMICs).
The EMIC community meets once or twice a year at EMIC workshop to intercompare EMICs and to explore scientific problems in cooperation.

References:
Table of EMICs (report on www.pik-potsdam.de/emics with an comprehensive list of references on EMIC publications)

Claussen, M., L.A. Mysak, A.J. Weaver, M. Crucifix, T. Fichefet, M.-F. Loutre, S.L. Weber, J. Alcamo, V.A. Alexeev, A. Berger, R. Calov, A. Ganopolski, H. Goosse, G. Lohmann, F. Lunkeit, I.I. Mokhov, V. Petoukhov, P. Stone, and Z. Wang, 2002: Earth System Models of Intermediate Complexity: Closing the Gap in the Spectrum of Climate System Models. Climate Dyn., 18, 579-586.

El Niño Intercomparison Project (ENSIP)

Contact: M. Latif

Overview:
An ensemble of twenty four coupled ocean-atmosphere models has been intercompared with respect to their performance in the tropical Pacific. The coupled models span a large portion of the parameter space and differ in many respects. The intercomparison includes TOGA (Tropical Ocean Global Atmosphere)-type models consisting of high-resolution tropical ocean models and coarse-resolution global atmosphere models, coarse-resolution global coupled models, and a few global coupled models with high resolution in the equatorial region in their ocean components. The performance of the annual mean state, the seasonal cycle and the interannual variability are investigated. The primary quantity analysed is sea surface temperature (SST). Additionally, the evolution of interannual heat content variations in the tropical Pacific and the relationship between the interannual SST variations in the equatorial Pacific to fluctuations in the strength of the Indian Summer Monsoon are investigated.

The results can be summarized as follows: Almost all models (even those employing flux corrections) have still problems in simulating the SST climatology, although some improvements are found relative to earlier intercomparison studies. Only a few of the coupled models simulate the El Niño/Southern Oscillation (ENSO) in terms of gross equatorial SST anomalies rat content variations is similar to that observed in almost all models. Finally, the majority of the models show a strong connection between ENSO and the strength of the Indian Summer Monsoon.

References:
Latif, M., K. Sperber, J. Arblaster, P. Braconnot, D. Chen, A. Colman, U. Cubasch, M. Davey, P. Delecluse, D. DeWitt, L. Fairhead, G. Flato, T. Hogan, M. Ji, M. Kimoto, A. Kitoh, T. Knutson, H. Le Treut, T. Li, S. Manabe, O. Marti, C. Mechoso, G. Meehl, S. Power, E. Roeckner, J. Sirven, L. Terray, A. Vintzileos, R. Voß, B. Wang, W. Washington, I. Yoshikawa, J. Yu, and S. Zebiak, 2001: ENSIP: The El Niño Simulation Intercomparison Project. Clim. Dyn., 18, 255-276.

 

GEWEX Atmospheric Boundary Layer Study (GABLS)

Contact: Bert Holtslag

Overview:
GABLS is a new project to improve the representation of the Atmospheric Boundary Layer (ABL) in models on the basis of an advanced understanding of the relevant processes. The ABL is an important aspect of the physics in regional and global models. It is particularly important when discussing coupled atmosphere/land-surface/ocean models. GABLS an international activity under the GEWEX Modelling and Prediction Panel (GMPP) aimed at stimulating and coordinating research on boundary layer physics. GABLS like GLASS and GCSS will undertake its work in association with the other components of WCRP, especially with the Working Group on Numerical Experimentation (WGNE). This interaction will ensure that GABLS establishes the same proactive posture in engaging the NWP/GCM community that has been used in GCSS and GLASS. GABLS will include representatives of the weather and climate modelling communities in their deliberations and have them present issues of relevance to large-scale models, which GABLS will then integrate into its work plans.

GEWEX Cloud System Study (GCSS)

Contact: Steve Krueger

Overview:
There are a variety of cloud processes that affect the large-scale behavior of the climate system, but occur on scales too small to be represented explicitly in global numerical models used for climate and weather prediction. Scientists develop numerical representations or parameterizations to represent the behavior of these processes. It is generally recognized that inadequate parameterization of clouds is one of the greatest sources of uncertainty in the prediction of weather and climate. The GEWEX Cloud System Study (GCSS) will develop better parameterizations of cloud systems for climate models by an improved understanding of the physical processes at work within the following types of cloud systems:

Boundary layer Cirrus Extra tropical layer Precipitating convective

One method for testing parameterizations is called Single Column Modeling.

GCSS working groups representing each of the cloud systems under study, will perform the following activities:

Identify and develop cloud-resolving and mesoscale models appropriate for each cloud system type. Specify blueprints of minimum observational requirements for the development and validation of these models. Assemble, for particular cloud types, case-study datasets accessible to the community of (a) matched observations from satellites, surface and aircraft and (b) mode-derived synthetic data sets. Conduct workshops, including model intercomparisons using the above case study data sets. Use the datasets to derive a better understanding of the coupled processes within different types of cloud systems and to derive improved parameterization schemes for large-scale models.

GCSS Objectives

Develop the scientific basis for the parameterization of cloud processes. Highlight key issues and encourage other relevant programs to address them. Promote the evaluation and intercomparison of parameterization schemes for cloud processes.

The Second Science and Implementation Plan for the GEWEX Cloud System Study (GCSS) is available in PDF format on the web page above.

GCM-Reality Intercomparison Project for SPARC (GRIPS)

Contact: S. Pawson

Overview:
The GCM-Reality Intercomparison Project for SPARC (GRIPS) is an international activity, contributing the project "Stratospheric Processes and their Role in Climate" (SPARC), which is organized by the World Climate Research Programme (WCRP). The basic question that GRIPS is answering is: How well do current middle atmosphere-climate models perform? GRIPS has developed studies on three levels to address this question. The level-1 activities involve analyses of model runs, asking how well different features of the climate system are represented. The models include representations of all physical processes that are known to be important; the level-2 GRIPS activities are examining how well these representations (or parametrizations) perform. Finally, the level-3 activities ask how perturbations in the stratospheric climate (due to, say, ozone change, the presence of volcanic aerosols, or solar activity variations) impact the troposphere. About 13 modeling groups participate in GRIPS, along with several scientists who contribute their knowledge of and interest about different components of the middle atmosphere and climate system.

References:
T. Horinouchi, S. Pawson, K. Shibata, U. Langematz, E. Manzini, M. A. Giorgetta, F. Sassi, R.J. Wilson, K.P. Hamilton, J. de Granpre, and A. A. Scaife, 2002: Tropical cumulus convection and upward propagating waves in middle atmospheric GCMs. J. Atmos. Sci., submitted.

S. Pawson, K. Kodera, K. Hamilton, T.G. Shepherd, S.R. Beagley, B.A. Boville, J.D. Farrara, T.D.A. Fairlie, A. Kitoh, W.A. Lahoz, U. Langematz, E. Manzini, D.H. Rind, A.A. Scaife, K. Shibata, P. Simon, R. Swinbank, L. Takacs, R.J. Wilson, J.A. Al-Saadi, M. Amodei, M. Chiba, L. Coy, J. de Grandpre, R.S. Eckman, M. Fiorino, W.L. Grose, H. Koide, J.N. Koshyk, D. Li, J. Lerner, J.D. Mahlman, N.A. McFarlane, C.R. Mechoso, A. Molod, A. O'Neill, R.B. Pierce, W.J. Randel, R.B. Rood, and F. Wu, 2000: The GCM-Reality Intercomparison Project for SPARC: Scientific Issues and Initial Results. Bull. Am. Meteor. Soc., 81, 781-796.

Global Land-Atmosphere Coupling Experiment (GLACE)

Contact: Randy Koster

Overview:
In numerical atmospheric models, the degree to which the atmosphere responds to anomalies in land surface state (the "coupling strength") is a net result of complex interactions between numerous complex process parameterizations, such as those for evapotranspiration, boundary layer development, and moist convection. The great majority of AGCM land-atmosphere interaction studies appear to take a given model's implicit coupling strength on faith, not addressing either its realism or how it compares with that in other models. This is arguably a major deficiency in the current state of the science. The goal of GLACE is to quantify and document the coupling strength across a broad range of AGCMs. The project will not be able to address the realism of simulated coupling strength, since direct measurements of land-atmosphere interaction at large scales are not available. It will, however, show the extent to which coupling strength varies between models, and it will allow individual models to be characterized as having a relatively strong, intermediate, or weak coupling, for later use in interpreting various results (e.g., land use change studies, precipitation feedback studies) obtained with those models.

References:
Koster, R. D., P. A. Dirmeyer, A. N. Hahmann, R. Ijpelaar, L. Tyahla, P. Cox, and M. J. Suarez, 2002: Comparing the degree of land-atmosphere interaction in four atmospheric general circulation models. J. Hydromet., 3, 363-375.

Global Soil Wetness Project (GSWP)

Contact: Paul Dirmeyer

Overview:
The Global Soil Wetness Project (GSWP) is an ongoing environmental modeling research activity of the Global Land-Atmosphere System Study (GLASS) and the International Satellite Land-Surface Climatology Project (ISLSCP), both contributing projects of the Global Energy and Water Cycle Experiment (GEWEX). Its goals are to: 1. Produce state-of-the-art global data sets of land surface fluxes, state variables, and related hydrologic quantities. 2. Develop and test large-scale validation, calibration, and assimilation techniques over land. 3. Provide a large-scale validation and quality check of the ISLSCP data sets. 4. Compare Land Surface Schemes (LSSs), and conduct sensitivity studies of specific parameterizations and forcings, which should aid future model and data set development. GSWP-2 is closely linked to the ISLSCP Initiative II data effort, and LSS simulations in GSWP-2 will encompass the same core 10-year period as ISLSCP Initiative II (1986-1995).

References:
Dirmeyer, P. A., A. J. Dolman, and N. Sato,1999: The Global Soil Wetness Project: A pilot project for global land surface modeling and validation. Bull. Amer. Meteor. Soc., 80, 851-878.

International GEWEX Project Office, 2002: GSWP-2: The Second Global Soil Wetness Project (GSWP-2) Science and Implementation Plan. IGPO Publication Series No. 37, 65 pp.

Intercomparison of 3-Dimensional Radiation Codes

Contact: Robert F. Cahalan

Overview:
The I3RC sprung from the natural need to compare the performance of these 3D radiative transfer codes used in a variety of current scientific work in the atmospheric sciences. I3RC is jointly funded by the US Department of Energy Atmospheric Radiation Measurement Program (DoE/ARM) and by the US National Aeronautics and Space Administration Radiation Sciences Program, and is also sponsored by the GEWEX Radiation Panel and the International Radiation Commission. I3RC intends to (1) understand and document the errors and limits of 3D methods; (2) provide baseline cases for future code development for 3D radiation; (3) promote sharing and production of 3D radiation tools; (4) derive guidelines for 3D radiation tool selection; and (5) improve atmospheric science education in 3D radiative transfer. Results from I3RC are expected to guide improvements in both remote sensing and climate modeling.

References:
R. F. Cahalan and I3RC participants, 2004: The International Intercomparison of 3D Radiation Codes (I3RC): Bringing together the most advanced radiative transfer tools for cloudy atmospheres. J. Amer. Meteor. Soc.

Models and Measurements II (MMII): Stratospheric Transport

Contact: Jae H. Park

Overview:
This intercomparison has evaluated stratospheric transport and chemistry in the context of the stratospheric ozone depletion problem.

References:
Park, J. H., M.K.W. Ko, C.H. Jackman, R. Alan Plumb, J.A. Kaye, K.H. Sage, eds., 1999: Models and Measurements II: NASA Tech Note: TM-1999-209554.

Hall, T.M., D.W. Waugh, K.A. Boering, and R.Alan Plumb, 1999: Evaluation of transport in stratospheric models. J. Geophys. Res., 104, D15, 8815-18839.

Ocean Carbon-Cycle Model Intercomparison Project (OCMIP)

Overview:
The Ocean Carbon-Cycle Model Intercomparison Project (OCMIP) was initiated by IGBP/GAIM in 1995 as a means to develop international collaboration to jointly improve the predictive capacity and accelerate development of global-scale, three-dimensional, ocean carbon-cycle models through standardized model evaluation and model intercomparison. Ocean carbon-cycle models are used to simulate ocean uptake and loss of carbon and to constrain the ocean's role in the global carbon cycle. After a 3-year pilot study with 4 models (OCMIP-1), a second phase with 13 modeling groups and 2 data specialist groups took on a more detailed comparison during 1998-2001. OCMIP-2 addressed the preindustrial state of the ocean as well as its present and future perturbations. Modeling groups made common simulations for carbon, related biogeochemical tracers, and circulation tracers. Many groups also made simulations to evaluate the efficiency of purposefully injecting CO2 into the deep ocean and to evaluate the potential of mantle He-3 and He-4 to be used as tracers of deep-ocean circulation. OCMIP is now in its third phase, since 2002. Three separately funded OCMIP-3 projects focus on simulating interannual to decadal variability, inferring air-sea CO2 fluxes from related measurements in the interior ocean, and on automating standard analysis of model output.

References:
Dutay, J.-C., J. Bullister, S. C. Doney, J. C. Orr, R. G. Najjar, K. Caldeira, J.-M. Campin, H. Drange, M. Follows, Y. Gao, N. Gruber, M. W. Hecht, A. Ishida, F. Joos, K. Lindsay, G. Madec, E. Maier-Reimer, J. C. Marshall, R. Matear, P. Monfray, A. Mouchet, G. K. Plattner, J. L. Sarmiento, R. Schlitzer, R. D. Slater, I. J. Totterdell, M.-F. Weirig, Y. Yamanaka, and A. Yool, 2002: Evaluation of ocean model ventilation with CFC-11: Comparison of 13 global ocean models. Ocean Modelling, 4 (2), 89-120.

Orr, J. C., E. Maier-Reimer, U. Mikolajewicz, P. Monfray, J. L. Sarmiento, J. R. Toggweiler, N. K. Taylor, J. Palmer, N. Gruber, C. L. Sabine, C. Le Quéré, R. M. Key, and J. Boutin, 2001: Estimates of anthropogenic carbon uptake from four three-dimensional global ocean models. Global Biogeochem. Cycles, 15 (1), 43-60.

Sarmiento, J. L., P. Monfray, E. Maier-Reimer, O. Aumont, R. Murnane and J. C. Orr, 2000: Sea-air CO2 fluxes and carbon transport: a comparison of three ocean general circulation models. Global Biogeochem. Cycles, 14 (4), 1267-1281.

Ocean Model Intercomparison Project (OMIP)

Contact: Tony Hirst

Overview:
OMIP is being organised under the auspices of the WCRP/CLIVAR Working Group on Ocean Model Development, and aims to address the following goals:

  • Assess the general performance of ocean and ice model components used in coupled models to study climate and tracer uptake;
  • Assess the quality of the forcing fields: identify limitations and critical issues linked with air/sea fluxes datasets;
  • Improve understanding of the sensitivity of ocean/sea ice models to parameterisations and forcing aspects.

OMIP is currently in its pilot phase, with a limited number of participants involved in testing the proposed protocol. The main (open) phase of OMIP is expected to be launched in late 2003 or 2004.

References:
WOCE/CLIVAR Working Group on Ocean Model Development. Report of the 3rd Session. WCRP Informal Report No. 14/2002.

Paleo Modelling Intercomparison Project (PMIP)

Contact: Sylvie Joussaume

Overview

This international project involves about 18 modeling groups (USA, Canada, UK, Germany, France, Australia, Japan and Korea) (Joussaume and Taylor, 1995). This project is endorsed by both the International Geosphere Biosphere Project (under PAst Global ChangES) and the World Climate Research Program (within the Working Group on Coupled Models) and its aims are to evaluate climate models under paleoclimate conditions and improve our understanding of past climate. Following an initial phase during which boundary conditions were defined and simulations were completed, the PMIP participants have met every two years since 1995 in order to discuss the results. These workshops have fostered cooperation and forged collaborations among groups working on the two PMIP periods. Discussions at the workshops were not limited to the PMIP experiments themselves, but also to the many complementary numerical experiments performed for the mid Holocene and last glacial maximum climatic periods. This has helped to enhance our knowledge as is reflected within this report of the third PMIP workshop. Three PMIP experiments have been defined : one for the mid Holocene, 6000 years BP, and two experiments for the last glacial maximum (LGM), 21,000 years BP (18 000 radiocarbon date (Bard, et al., 1990)), either with atmosphere alone models or with atmosphere models coupled to surface ocean models.

References

Joussaume, S. and K. E. Taylor, 1995: Status of the Paleoclimate Modeling Intercomparison Project (PMIP). Proceedings of the first international AMIP scientific conference. WCRP Report, 425-430.

Braconnot, P., ed., 2000: PMIP, Paleoclimate Modeling Intercomparison Project (PMIP): Proceedings of the 3rd PMIP workshop, Canada, 4-8 October 1999, WCRP-111, WMO/TD-1007, 271pp.

Project for Intercomparison of Landsurface Parameterization Schemes (PILPS)

Contact: Ann Henderson-Sellers, Andy Pitman, Jan Polcher

Overview:
PILPS is an element of Global Land Atmosphere System Study (GLASS) under the auspices of GEWEX and the World Climate Research Programme. It has been designed to be an on-going project. Since its establishment in 1992, PILPS has been responsible for a series of complementary experiments, with focuses on identifying parameterization strengths and inadequacies. About 30 landsurface process modelling groups have been participating in PILPS.

PILPS is project designed to improve the parameterization of the continental surface, especially hydrological, energy, momentum and carbon exchanges with the atmosphere. The PILPS science plan incorporates enhanced documentation, comparison, and validation of continental surface parameterization schemes by community participation. Potential participants include code developers, code users, and those who can provide datasets for validation and who have expertise of value in this exercise. PILPS is an important exercise because existing intercomparisons, although piecemeal, demonstrate that there are significant differences in the formulation of individual processes in the available land surface schemes. These differences are comparable to other recognized differences among current global climate models such as cloud and convection parameterizations. It is also clear that too few sensitivity studies have been undertaken with the result that there is not yet enough information to indicate which simplifications or omissions are important for the near-surface continental climate, hydrology and biogeochemistry. PILPS emphasizes sensitivity studies with and intercomparisons of existing land surface codes and the development of areally extensive datasets for their testing and validation.

References:
Henderson-Sellers, A., A. J. Pitman, P. K. Love, P. Irannejad, and T. Chen, 1995: The project for Intercomparison of land surface parameterisaton schemes PILPS) Phases 2 and 3. Bull. Amer. Meteor. Soc., 76, 489-503.

Henderson-Sellers, A, K. McGuffie, and A. J. Pitman, 1996: The Project for Intercomparison of Land-surface Parameterization Schemes (PILPS): 1992 to 1995. Clim. Dyn., 12, 849-859.

Pitman, A.J. and A. Henderson-Sellers, 1998: Recent progress and results from the project for the intercomparison of land surface parameterization schemes. J. Hydrol., xx, 128-135.

Potsdam DGVM Intercomparison Project

Contact: Wolfgang Cramer

Overview
The possible responses of ecosystem processes to rising atmospheric CO2 concentration and climate change are illustrated using six dynamic global vegetation models that explicitly represent the interactions of ecosystem carbon and water exchanges with vegetation dynamics. The models are driven by the IPCC IS92a scenario of rising CO2 (Wigley et al. 1991), and by climate changes due to effective CO2 concentrations corresponding to IS92a, simulated by the coupled ocean atmosphere model HadCM2-SUL. Simulations with changing CO2 alone show a widely distributed terrestrial carbon sink of 1.4 - 3.8 Pg C yr-1 during the 1990s, rising to 3.7 - 8.6 Pg C yr-1 a century later. Simulations including climate change show a reduced sink both today (0.6 - 3.0 Pg C yr-1) and a century later (0.3 - 6.6 Pg C yr-1) due to the impacts of climate change on NEP of tropical and southern hemisphere ecosystems. In all models, the rate of increase of NEP begins to level off around 2030 due to the "diminishing return" of physiological CO2 effects at high CO2 concentrations. Four out of the six models show a further, climate-induced decline in NEP due to increased heterotrophic respiration and declining tropical NPP after 2050. Changes in vegetation structure influence the magnitude and spatial pattern of the carbon sink and, in combination with changing climate, also freshwater availability (runoff). It is shown that these changes, once set in train, would continue to evolve for at least a century even if atmospheric CO2 concentration and climate could be instantaneously stabilized. The results should be considered illustrative in the sense that the choice of CO2 concentration scenario was arbitrary and only one climate model scenario was used. However, the results serve to indicate a range of possible biospheric responses to CO2 and climate change. They reveal major uncertainties about the response of NEP to climate change due, primarily, to differences in the way modelled global NPP responds to a changing climate. The simulations illustrate, however, that the magnitude of possible biospheric influences on the carbon balance requires that this factor is taken into account for future scenarios of atmospheric CO2 and climate change.

References
Cramer, W., A. Bondeau, F.I. Woodward, I.C. Prentice, R.A. Betts, V. Brovkin, P.M. Cox, V. Fisher, J. Foley, A.D. Friend, C. Kucharik, M.R. Lomas, N. Ramankutty, S. Sitch, B. Smith, A. White, and C. Young-Molling, 2001: Global response of terrestrial ecosystem structure and function to CO2 and climate change: results from six dynamic global vegetation models. Global Change Biology, 7 (4), 357-373.

Potsdam NPP Model Intercomparison Project

Contact: Wolfgang Cramer

Overview
Seventeen global models of terrestrial biogeochemistry have been compared with respect to annual and seasonal fluxes of net primary productivity (NPP) for the land biosphere. The comparison, sponsored by IGBP-GAIM/DIS/GCTE, used standardised input variables wherever possible and was carried out through two internationa workshops and over the internet. The models differed widely in complexity an original purpose, but could be grouped in three major categories: Satellite-basedmodels that use data from the NOAA/AVHRR sensor as their major input stream (CASA, GLO-PEM, SDBM, SIB2 and TURC), models that simulate carbon fluxes using a prescribed vegetation structure (BIOME-BGC, CARAIB 2.1, CENTURY 4.0, FBM 2.2, HRBM 3.0, KGBM, PLAI 0.2, SILVAN 2.2 and TEM 4.0), and models that simulate both vegetation structure and carbon fluxes (BIOME3, DOLY and HYBRID 3.0). The simulations resulted in a range of total NPP values (44.4 - 66.3 Pg C yr-1), after two outliers (which produced extreme results as artefacts due to the comparison) had been removed. The broad global pattern of NPP and the relationship of annual NPP to the major climatic variables coincided in most areas. Differences could not be attributed to the fundamental modeling strategies, with the exception that nutrient constraints generally produced lower NPP. The regional and global sensitivity of NPP against the simulation method for the water balance was clearly illustrated. Seasonal variation among models was high, both globally and locally, providing several indications for specific deficiencies in some models. A negative correlation between total absorbed photosynthetically active radiation (APAR) and light use efficiency (LUE) across the majority of models was found after decomposition of annual NPP for those models that do not use remote sensing data into APAR and LUE, and subsequent comparison of these values against those used by the remote sensing models. This may indicate that the models are (consciously or unconsciously) calibrated to achieve 'commonly accepted values' of total NPP, despite widely differing spatial and seasonal patterns. An analysis of the resulting net ecosystem productivities (NEP), using a three-dimensional atmospheric transport model and observed seasonal CO2 observations from the flask sampling network indicates that the uncertainties are larger in water limited systems of the tropics than elsewhere.

References:
Cramer, W., D.W. Kicklighter, A. Bondeau, B. III Moore, G. Churkina, B. Nemry, A. Ruimy, A. L. Schloss, and Participants of "Potsdam'95" 1999. Comparing global models of terrestrial net primary productivity (NPP): Overview and key results. Global Change Biology, 5 (Suppl.1), 1-15.

Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects (PRUDENCE)

Contact: Jens Hesselbjerg Christensen

Overview

PRUDENCE is a European-scale investigation with the following objectives:

  1. to address and reduce the above-mentioned deficiencies in projections;
  2. to quantify our confidence and the uncertainties in predictions of future climate and its impacts, using an array of climate models and impact models and expert judgement on their performance;
  3. to interpret these results in relation to European policies for adapting to or mitigating climate change.

Climate change is expected to affect the frequency and magnitude of extreme weather events, due to higher temperatures, an intensified hydrological cycle or more vigorous atmospheric motions. A major limitation in previous studies of extremes has been the lack of: appropriate computational resolution - obscures or precludes analysis of the events; long-term climate model integrations - drastically reduces their statistical significance; co-ordination between modelling groups - limits the ability to compare different studies. These three issues are all thoroughly addressed in PRUDENCE, by using state-of-the-art high resolution climate models, by co-ordinating the project goals to address critical aspects of uncertainty, and by applying impact models and impact assessment methodologies to provide the link between the provision of climate information and its likely application to serve the needs of European society and economy.

Expected impacts:

PRUDENCE will provide a series of high-resolution climate change scenarios for 2071-2100 for Europe, characterising the variability and level of confidence in these scenarios as a function of uncertainties in model formulation, natural/internal climate variability, and alternative scenarios of future atmospheric composition. The project will provide a quantitative assessment of the risks arising from changes in regional weather and climate in different parts of Europe, by estimating future changes in extreme events such as flooding and windstorms and by providing a robust estimation of the likelihood and magnitude of such changes. The project will also examine the uncertainties in potential impacts induced by the range of climate scenarios developed from the climate modelling results. This will provide useful information for climate modellers on the levels of accuracy in climate scenarios required by impact analysts. Furthermore, a better appreciation of the uncertainty range in calculations of future impacts from climate change may offer new insights into the scope for adaptation and mitigation responses to climate change. In order to facilitate this exchange of new information, the PRUDENCE work plan places emphasis on the wide dissemination of results and preparation of a non-technical project summary aimed at policy makers and other interested parties.

Project to Intercompare Regional Climate Simulations (PIRCS)

Contact: William J. Gutowski

Overview
The Project to Intercompare Regional Climate Simulations (PIRCS) is a community-based project to intercompare regional models run in climate mode. PIRCS activities so far have consisted of a series of collaborative intercomparison experiments using mesoscale models to simulate the climate for a North American domain, focusing on the Central US. Initial experiments were for 2-month periods during the drought year of 1988 (15 May - 15 July; Exp. 1a) and the Midwest flood period of 1993 (1 June - 31 July; Exp. 1b). The periods and region coincided with GEWEX Numerical Experimentation Panel recommendations for test simulations by regional-scale models. Exp. 1a emphasized thermal and dynamical processes whereas Exp. 1b emphasized water cycle processes. We have recently released boundary conditions for Experiment 1c, which entails multi-year simulation for nearly the same North American domain as as Exps. 1a and 1b. Emphasis is on the North American Monsoon and its connection with other climatic processes across the U.S.

References
Anderson, C.J., R. W. Arritt, E. S. Takle, Z. Pan, W. J. Gutowski, R. da Silva, and PIRCS modelers, 2003:  Hydrologic processes in regional climate model simulations of the central United States flood of June-July 1993. J. Hydrometeor., in press.

Takle, E. S., W. J. Gutowski, R. A. Arritt, Z. Pan, C. J. Anderson, R. R. da Silva, D. Caya, S.-C. Chen, J. H. Christensen, S.-Y. Hong, H.-M. H. Juang, J. Katzfey, W. M. Lapenta, R. Laprise, P. Lopez, J. McGregor, and J. O. Roads, 1999:  Project to Intercompare Regional Climate Simulations (PIRCS):  Description and initial results. J. Geophys. Res., 104, 19,443-19,461.

Radiative Transfer Model Intercomparison (RAMI)

Contact: Michel Verstraete, Bernard Pinty and Jean-Luc Widlowski at JRC, Italy

Overview
The RAMI initiative is a community-driven exercise to benhchmark the models of radiation transfer used to represent the reflectance of terestrial surfaces. The overall objectives of this exercise include (1) to progressively develop a community consensus on the best ways to simulate the transfer of radiation at and near the Earth's surface (2) to inform the user community on the performance of the various models available (3) to provide a rationale for the acquisition and thus interpretation of more and better data from space remote sensing and, last but not least (4) to help developers improve their models.

Regional Climate Model Inter-comparison Project for Asia (RMIP)

Contact: Congbin Fu

Overview
The Regional Model Inter-comparison Project (RMIP) for Asia has been established since 1999 to evaluate and improve regional climate model (RCM) simulations of monsoonal climate. RMIP operates under joint support of the Asia-Pacific Network for Global Change Research (APN), Global Change System for Analysis, Research and Training (START), the Chinese Academy of Sciences and several projects of participating nations. The project currently involves 10 research groups from Australia, Chases: April 1997 - September 1998 to cover a full annual cycle and extremes in monsoon behavior; January 1989 - December 1998 to examine simulated climatology, and regional climate change scenario in 21st century by nesting with global model output.

References
a. Proceedings of Workshop of Regional Climate Model Intercomparison Project for Asia (RMIP) (Phase I)
b. A paper submitted to BAMS: Regional Climate Model Intercomparison Project for Asia (RMIP)

Rhone-AGG (Rhone Aggregation Experiment)

Contact: Aaron BOONE

Overview
The Rhone-AGGregation (Rhone-AGG) Land Surface Scheme (LSS) intercomparison project is an initiative within the Global Energy and Water Cycle Experiment (GEWEX) /Global Land-Atmosphere System Study (GLASS) panel of the World Climate Research Programme (WCRP). It is a intermediate step leading up to the next phase of the Global Soil Wetness Project (GSWP) (Phase 2), for which there will be a broader investigation of the aggregation between global scales (GSWP-1) and the river scale. This project makes use of the Rhone modeling system, which was developed in recent years by the French research community in order to study the continental water cycle on a regional scale. The main goals of this study are to investigate how 15 land surface schemes which are used in operational numerical weather prediction, global atmospheric climate, mesoscale and hydrological models, simulate the water balance for several annual cycles compared to data from a dense observation network consisting of daily discharge from over 145 gauges and daily snowdepth from 24 sites, and to examine the impact of changing the spatial scale on the simulations. Results from a series of scaling experiments are examined for which the spatial resolution of the computational grid is decreased to be consistent with large-scale atmospheric models.

References
Boone, A., F. Habets, J. Noilhan, D. Clark, P. Dirmeyer, S. Fox, Y. Gusev, I. Haddeland, R. Koster, D. Lohmann, S. Mahanama, K. Mitchell, O. Nasonova, G.-Y. Niu, A. Pitman, J. Polcher, A. B. Shmakin, K. Tanaka, B. van den Hurk, S. Vérant, D. Verseghy, P. Viterbo and Z.-L. Yang: The Rhone-Aggregation Land Surface Scheme Intercomparison Project: An Overview. 2004, J. of Climate, 17, 187-208.

Seasonal Prediction Model Intercomparison (SMIP), Seasonal Prediction Model Intercomparison Project-2 (SMIP-2) and Seasonal Prediction Model Intercomparison Project-2/Historical Forecast (SMIP-2/HFP)

Contact: Ken Sperber

Overview
The CLIVAR Working Group on Seasonal to Interannual Prediction (WGSIP) has intitiated two experimental protocols using atmospheric general circulation models to investigate: (1) potential seasonal predictability (SMIP-2) using observed SST, and (2) actual predictability using forecast SST (SMIP-2/HFP). Modelling groups may participate in either or both protocols. The basic experiment calls for ensembles of integrations, differing only by their initial conditions, for each season for 1979-2000.

References:
Results regarding the predictability of the Asian summer monsoon have been published based on a pilot SMIP project:

Sperber, K. R., C. Brankovic, M. Deque, C. S. Frederiksen, R. Graham, A. Kitoh, C. Kobayashi, T. N. Palmer, K. Puri, W. Tennent, and E. Volodin, 2001: Dynamical Seasonal Predictability of the Asian Summer Monsoon. Mon. Wea. Rev., 129, 2226-2248.

Sea-Ice Model Intercomparison Project (SIMIP) or http://www.ifm.uni-kiel.de/fb/fb1/me/research/Projekte/SIMIP/simip.html

Contact: Greg Flato

Overview:
The Sea Ice Model Intercomparison Project (SIMIP) is an international effort to develop an improved representation of sea ice in climate models. SIMIP is carried out by co-ordinated numerical experiments with contributions from several institutes in the framework of the Arctic Climate System Study (ACSYS) within the World Climate Research Programme (WCRP).

One of the main objectives of the ACSYS is to provide a valid scientific basis for the representation of the Arctic region in coupled atmosphere-ice-ocean models. The ACSYS implementation plan consists of four observational programs concerned with atmospheric, oceanic, sea ice and hydrological activities, and a modelling program which integrates these observations for improving the numerical representation of atmosphere, ocean, sea ice and hydrology.

The importance of the role of sea ice in the climate system calls for an improved representation of sea ice in global climate models. However, the interaction of atmosphere and ocean through the moving sea ice cover is one of the weak parts in current climate models. Therefore, SIMIP has been initiated within the ACSYS modelling programme to develop an improved representation of sea ice in climate simulations.

SIMIP2 is a joint initiative of the WCRP ACSYS/CliC Numerical Experimentation Group and the GEWEX Cloud System Study, Working Group on Polar Clouds. The main goal of SIMIP2 is to isolate, evaluate and improve the representation of vertical sea-ice thermodynamic processes in climate models.

At the initial planning meeting in Boulder, and subsequently at the NEG meeting in Fairbanks, a general outline of the intercomparison effort was laid out. In the following, a more concrete description of the experiment is provided, along with links to the fording, initialization and evaluation data, and a proposed list of default model parameters. At this point, only a basic experiment is described which, it is hoped, will be done by all participating modeling groups. A more comprehensive set of experiments and evaluation procedures, will arise from discussions with SIMIP2 participants. As discussed at the planning meeting, the idea would be that individual modeling groups would take the lead in focusing/coordinating efforts targeted a particular model parameterizations or numerical details.

The basic set of experiments will be strictly one-dimensional - i.e. a representation of a uniform slab of ice. Comparisons will be made to observations (by Dr. D. Perovich and colleagues) of the thermodynamic evolution of a multi-year ice floe during the SHEBA field experiment - very nearly a 1-D situation. The effects of leads and ice deformation will therefore not be included.

The basic experiment is an initial value problem, with the initial ice thickness, snow depth, temperature and salinity profiles specified from observations and corresponding to 31/October/1997. The initial conditions and a tentative list of proposed parameter values is provided in the file simip2_initialization_data.txt which can be viewed by clicking on the file name. Forcing data are also based on observations from the SHEBA experiment. Atmospheric forcing data were provided by Prof. J. Curry and colleagues, while ocean heat flux data was obtained from D. Perovich.

In addition to the basic experiment described above, the hope is that individual investigators or modeling groups will conduct a variety of experiments aimed at studying the role of individual processes, introducing more sophisticated parameterizations, evaluating the models' sensitivity to parameter values, etc. The desire is that such experiments should be coordinated in some way so as to avoid overlap and maximize the utility of this project.

References:

Kreyscher, M., M. Harder, and P. Lemke, 1997: First results of the Sea Ice Model Intercomparison Project (SIMIP). Ann. Glaciol. 25, 8-11.

Lemke, P., W.D. Hibler, G.M. Flato, M. Harder, and M. Kreyscher, 1997: On the improvement of sea ice models for climate simulations: the Sea Ice Model Intercomparison Project. Ann. Glaciol. 25, 183-187.

Kreyscher, M., M. Harder, P. Lemke, and G. M. Flato, 2000: Results of the Sea Ice Model Intercomparison Project: Evaluation of sea ice rheology schemes for use in climate simulations. J. Geophys. Res., 105(C5), 11299 - 11320.

Snow Models intercomparison project (SnowMIP)

Contact: Eric.Martin

Overview:
The project aims at comparing snow simulations at four sites (middle elevation temperate, high elevation temperate, eastern US site, arctic site) from various models. The project gathers simple models and highly sophisticated models use for research in snow physics. The aim of this intercomparison is to identify processes important for the various applications of snow models (climate runs, hydrology, snow physics, ...). The following main points will be addressed : surface energy balance, albedo, mass balance (snowmelt, SWE) and simulation of the internal state of the snow cover

References:
Etchevers, P., E. Martin, R. Brown, C. Fierz, Y. Lejeune, E. Bazile, A. Boon, Y.-J. Dai, R. Essery, A. Fernandez, Y. Gusev, R. Jordan, V. Koren, E. Kowalczyck, R. Nasonova, D. Pyles, A. Schlosser, A. Shmakin, T. G. Smirnova, U. Strasser, D. Verseghy, T. Yamazaki, and Z.-L. Yang, 2002: SnowMiP, an intercomparison of snow models : first results. In: Proceedings of the International snow science workshop, Penticton, Canada, 29 Sep.-4 Oct., 2002, 8 p.

Stretched Grid Model Intercomparison Project (SGMIP)

Contact: Michael S. Fox-Rabinovitz

Overview:
Variable-resolution GCMs using a global stretched grid (SG) with enhanced regional resolution over the area(s)s of interest represent a viable new approach to regional climate and climate change studies and applications.Using the advanced numerical technique will provide increased computational efficiency for the new SG-GCM, and will allow us to employ more flexible stretching strategies. The SGMIP (Stretched-Grid Model Intercomparison Project), with participation of NASA/GSFC, RPN/Canadian Meteorological Center, Meteo-France, and Australian CSIRO, has a potential connection to AMIP-II.

Fox-Rabinovitz, M. S., L.V. Stenchikov, M. J. Suarez, L. L.Takacs, and R.C. Govindaraju, 2000: An uniform and variable resolution stretched-grid GCM dynamical core with real orography. Mon. Wea. Rev., 128 (6), 1883-1898.

Study of Tropical Oceans In Coupled models (STOIC)

Contact: Mike Davey, Ken Sperber

(a companion project to ENSIP)

Overview:
STOIC was initiated by CLIVAR-WGSIP in 1996, with the aimed of identifying common strengths and weaknesses of coupled models in tropical ocean regions. It is complementary to another WGSIP project (ENSIP) that concentrated on ENSO and the equatorial Pacific. Fields of tropical sea surface temperature, surface wind stress and upper ocean vertically-averaged temperature were collected from 24 models (22 CGCMs, of which 14 with no tropical flux adjustments) and compared with observed behavior with regard to annual mean, seasonal cycle, and interannual variability characteristics. Reports of results have been published.

Main results:
- for annual mean equatorial SST: commonly the model central Pacific is too cool, and the zonal gradient has the wrong sign in the Atlantic.
- for SST interannual variability: equatorial Pacific variability is commonly too weak;
few models correctly simulate the observed Pacific 'horseshoe' pattern of negative correlations with Niño3 SST anomalies; few models correctly simulate observed Indian-Pacific lag correlations.
- for equatorial zonal windstress: annual mean windstress is often too weak in the central Pacific and in the Atlantic, but too strong in the west Pacific; windstress interannual variability is commonly much too weak in the central Pacific.
- for ENSO-related windstress anomalies: the models generally represent local and remote features well.
- for upper ocean vertically-averaged temperature: no models have an equatorial Pacific seasonal cycle like that observed.

References:
Davey, M., M. Huddleston, K.R. Sperber et al., 2000: STOIC: A study of coupled GCM climatology and variability in tropical ocean regions (A detailed report of results, available on ftp.)

Davey, M., M. Huddleston, K.R. Sperber et al., 2002: STOIC: a study of coupled model climatology and variability in tropical ocean regions. Clim. Dyn., 18, 403-420.

Davey, M., M. Huddleston and K. Sperber, 2000: The CLIVAR-WGSIP STOIC project. CLIVAR Exchanges, 17, 21-23.

WCRP F11 Intercomparison

Contacts: Michael Prather and Byron Boville

No further details currently available.

WCRP Radon Intercomparison

Contact: Daniel Jacob

Overview:
This intercomparison has evaluated short-lived tracer transport (especially of radon) in chemical transport models against available data.

References:
Jacob, D. and coauthors, 1997: Evaluation and intercomparison of global atmospheric transport models using 222Rn and other short-lived tracers. J. Geophys. Res., 102, D5, 5953-5970.

WCRP Scavenging Tracer Intercomparison

Contact: Phil Rasch

Overview:
This intercomparison has evaluated transport of short lived gases such as radon and and sulfur dioxide, as well as the wet deposition of lead210 and sulfate aerosols.

References:
Rasch, P.J. and coauthors, 2000: A comparison of scavenging and deposition processes in global models: Results from the WCRP Cambridge Workshop of 1995. Tellus, 52B, 1025-1056.