Continuous single-column model evaluation at permanent meteorological supersites
Authors
Roel Neggers — University of Cologne
A. Pier Siebesma — Royal Netherlands Delft University of Technology
Category
Modeling
Description
The 213m tower at the Cabauw meteorological site in The Netherlands. More information can be found online at http://www.cesar-observatory.nl.
Uncertainties in numerical predictions of weather and climate are often linked to the representation of unresolved processes that act relatively fast compared to the resolved general circulation. These processes include turbulence, convection, clouds, and radiation. Single-column model (SCM) simulation of idealized cases has become an often-used and relied-upon method to obtain insight at process-level into the behavior of such parameterization schemes; benefits are the enhanced model transparency and computational efficiency. Although having achieved demonstrable success, some shortcomings of this approach have been identified; (1) the statistical significance and relevance of single idealized case studies might be questioned, and (2) the use of observational data sets has typically been relatively limited.
The recently initiated project described in this presentation, named the KNMI Parameterization Testbed (KPT), is part of a general move towards more statistically significant process-level evaluation. With the emphasis on the representation of atmospheric boundary-layer processes, KPT has two main goals that are designed to address the shortcomings of single idealized case-studies as mentioned above:
To reproduce with the SCM the same statistical level at which a GCM climate is typically evaluated, by means of generating continuous series of SCM simulations that cover long (i.e. multiyear) periods of time
To evaluate the complete parameterized system at multiple time-scales against as many independent observational data sets as possible: for example, as available at permanent meteorological sites.
This presentation is dedicated to motivating this strategy and illustrating its potential. Example model evaluation studies are discussed that make use of observational data products from, among others, the ARM SGP site and the Cabauw Meteorological site in the Netherlands. The KPT project takes part in the ongoing European Union Cloud Intercomparison, Process Study and Evaluation (EUCLIPSE) project, as well as the Fast-physics System Testbed and Research (FASTER) project funded by the Department of Energy's Earth System Modeling (ESM) program.
