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The common information model for climate modelling digital repositories: The metafor project
No full textA poster highlighting the common information model for climate modelling digital repositorie
The BADC Text File Guide for users, and producers.
No full textThis document is aimed at people developing or producing data files in the BADC-csv file format. It describes the structure of the format and the rules for its content
AN EXAMINATION OF ATMOSPHERIC LIDS DURING COPS
No full textThe understanding of the nature, origin and prevalence of atmospheric lids is low. There is, therefore, an opportunity to contribute significantly to this area of meteorology - this is the goal of this work. The context for this paper is the Convective and Orographically-induced Precipitation Study (COPS). The COPS observational campaign, which was undertaken in 2007, was based around the Black Forest region with the aim of improving precipitation forecasts in low mountainous regions. However, the project also represents a great data archive with which to analyse isolated features, such as atmospheric lids. In short, lids play a vital role in the development of convective storms. For example, evidence from the Convective Storm Initiation Project (CSIP), which was run in the UK in 2005, has shown that lids are important not only in determining whether a storm occurs but also when and where they develop and how intense they are – sometimes, counterintuitively, they appear to increase the intensity. This extended abstract is intended as a brief overview of the previous literature on lids in order to place the work presented at ICAM-2009 in the wider scientific context
Air Quality forecasts using a numerical weather prediction model: Potential sources of error
No full textThe meteorological processes responsible for transporting tracer during the second ETEX (European Tracer Experiment) release are determined using the UK Met Office Unified Model (UM). The UM predicted distribution of tracer is compared with observations from the ETEX campaign and predictions from the UK Met Office operational air quality forecast model (NAME). The dominant meteorological process is a warm conveyor belt which transports large amounts of tracer away from the surface up to a height of 4km over a 36 hour period. Convection is also an important process, transporting tracer to heights of up to 8km
Potential sources of error when using an operational numerical weather prediction model to forecast air quality are also investigated. These potential sources of error include model dynamics, model resolution and model physics. In the UM a semi-Lagrangian advection scheme is used with polynomial interpolation. This can result in unrealistic negative values of tracer which, when combined with a positive definite scheme in which negative values of tracer are set to zero, results in a failure of the model to conserve tracer mass. This problem occurs where sharp gradients of tracer concentration exist, such as are found close to source locations and leads to an overprediction of tracer concentrations. Model resolution can also affect the accuracy of predicted tracer distributions. Low resolution simulations (50km grid length) were unable to resolve a change in wind direction associated with the cold front, this led to an error in the transport direction and hence an error in tracer distribution. High resolution simulations (12km grid length) captured the change in wind direction and hence produced a tracer distribution that compared better with the observations. The representation of convective mixing was found to have a large affect on the vertical transport of tracer. Turning off the convective mixing parameterisation in the UM significantly reduced the vertical transport of tracer. Finally, air quality forecasts were found to be sensitive to the timing of synoptic scale features. Errors in the position of the cold front relative to the tracer release location of only 1 hour resulted in changes in the predicted tracer concentrations that were of the same order of magnitude as the absolute tracer concentrations