ENSO Intercomparison Project (ENSIP) - The El Nino Simulation Intercomparison Project (ENSIP) is an initiative undertaken under the auspices of the CLIVAR-GOALS Numerical Experimentation Group (NEG-1). It dovetails with the Coupled Model Intercomparison Project (CMIP) initiated by the Working Group on Coupled Modeling (WGCM) and is aimed to document the El Nino simulations in coupled ocean-atmosphere models. Outputs from about 20 rather different coupled models have been collected so far, including regional and global models, as well as coarse-resolution and high-resolution models, flux-corrected and freely running coupled models. ENSIP is a logical follow up of earlier intercomparison studies undertaken by Neelin and Latif et al. (1992) and Mechoso and Robertson et al. (1995) Sets of monthly mean fields for a minimum of 20 years of model integration have been intercompared. Sea surface temperature (SST), wind stress and upper ocean heat content (300-400m) were investigated, in order to obtain indications for the underlying ENSO dynamics in the different coupled models. Additionally, two Indian Summer Monsoon indices were requested to study the interactions of the Indian Summer Monsoon with ENSO. Since air-sea interactions play a key role for the mean state and the annual cycle in the tropical Pacific also, the performance of the coupled models with respect to these two aspects was also investigated. The following preliminary results are noted: 1.) Most models show a cold bias at the equator and have problems in simulating SSTs near the boundaries. 2.) Many models have still problems in simulating the annual cycle, which applies even to flux corrected models. 3.) The existence or absence of interannual variability do not seem to depend on the quality of the simulation of the mean state or annual cycle. There seems to be also no relationship between the application of flux correction and the quality of the simulation of the interannual variability. 4.) Only a few models show clear "delayed action oscillator"-type behavior in upper ocean heat content and SST. 5.) Most models show relatively strong correlations between the two Indian Summer Monsoon Indices requested and tropical Pacific SSTAs. References M. Latif and co-authors (2001): ENSIP: The El Nińo Simulation Intercomparison Project. Climate Dynamics, 18, 255-276. Neelin, J.D., M. Latif, M.A.F. Allaart, M.A. Cane, U. Cubasch, W.L. Gates,P.R. Gent, M. Ghil, C. Gordon, N-C. Lau, C.R. Mechoso, G.A. Meehl, J.M. Oberhuber, S.G.H. Philander, P.S. Schopf, K.R. Sperber, A. Sterl, T. Tokioka, J. Tribbia, S.E. Zebiak. (1992) : Tropical Air-sea Interaction in General Circulation Models. Climate Dynamics, 7, 73-104. Mechoso, C.R., A.W. Robertson, N. Barth, M.K. Davey, P. Delecluse, P.R. Gent, S. Ineson, B. Kritman, M. Latif, H. Le Treut, T. Nagai, J.D. Neelin, S.G.H. Philander, J. Polcher, P.S. Schopf, T. Stockdale, M.J. Suarez, L. Terray, O. Thual, J.J. Tribbia (1995) : The seasonal cycle over the tropical Pacific in coupled ocean-atmosphere General Circulation Models, Monthly Weather Review, 123, 2825-2838. Mojib Latif (latif@dkrz.de) - - Updated -