CP-MIP studies the fidelity of model representation of convective cold pools. The goals of CP-MIP are the identification, characterization, and quantification of model biases through comparison with observed cold pool statistics, the improved representation of cold pools in simulations, and convergence of models towards a robust basis for the study of cold pools in the atmosphere. CP-MIP develops concepts, analytical approaches, and software tools, and coordinates community efforts to conduct and analyze simulations and observations. The first stage of CP-MIP focuses on shallow convective cold pools over the tropical oceans, which are primarily associated with trade cumulus clouds.
Point of Contact: Jan Kazil, University of Colorado CIRES at NOAA and Raphaela Vogel, University of Hamburg
In collaboration with the CP-MIP partners,
the project will
High temporal resolution (5 minutes or faster) 2D fields are requested to track the change in cold pool properties and their statistics in the different models. Fields at 10 m are requested as ship and buoy data are adjusted from the instrument altitude to a height of 10 m above the surface using the COARE algorithm (e.g. Quinn et al., 2021).
For models that can flexibly write high-frequency single grid-point output, CP-MIP requests vertical profiles and time series at the following locations for comparison with observations
The following quantities are requested:
CP-MIP provides code to calculate the mixed layer height using the algorithm developed by Touzé-Peiffer et al. (2022). CP-MIP requests that participants diagnose the mixed layer height in their simulations using this algorithm. This will allow comparison of the mixed layer height across models, as well as its comparison with radiosonde cold pool detections, for which the algorithm was developed.
The algorithm defines the mixed layer height Hmix as the lowest altitude Z above Zmin = 20 m where the virtual potential temperature Θν is higher than its mass-weighted average from Zmin to Z by a fixed threshold ε = 0.2 K. The original algorithm of Touzé-Peiffer et al. (2022) uses Zmin = 100 m.
Θυ is calculated assuming that the air of the lowest layers is not saturated, so that the mixing ratio of liquid water in the air can be neglected. It is hence approximated as Θυ = Θ(1 + 0.61r), r being the mixing ratio of water vapor. The calculation of Hmix thus requires only the vertical profiles of pressure, temperature and humidity.
The code provided contains a calculation of the mixed layer height
Download
For questions and bug reports, contact Jan Kazil.
Kazil, J., R. Vogel, P. Blossey, S. Boeing, L Denby, S. Ghazayel, T. Heus, R. Neggers, G. Raghunathan, and P. Siebesma, The Cold Pool Model Intercomparison Project (CP-MIP) , Americal Geophysical Union Fall Meeting, 2023.
pending