DIAMET (Diabatic influences on mesoscale structures in extratropical storms) project
The project is aimed at a better understanding and prediction of mesoscale structures in synoptic-scale storms. Such structures include fronts, rain bands, secondary cyclones, sting jets etc, and are important because much of the extreme weather we experience (e.g. strong winds, heavy rain) comes from such regions. Weather forecasting models are able to capture some of this activity correctly, but there is much still to learn. By a combination of measurements and modelling, mainly using the Met Office Unified Model (UM), we will work to better understand how mesoscale processes in cyclones give rise to severe weather and how they can be better represented in models and better forecast. The project is organised into three broad work packages. The first of these aims to look at real mesoscale structures in the atmosphere, using high-resolution in situ and radar measurements to derive their morphology and dynamics. The key to the latter is to calculate the production of potential vorticity by diabatic processes - especially phase changes of water (vapour/liquid/ice) and air-sea fluxes of sensible and latent heat. The associated high-resolution modelling programme will use the UM to simulate a representative number of events, diagnosing the PV tendency in the model and comparing with the measurements. Sensitivity studies and further diagnostics with the model will reveal the sensitivity of the forecasts to the correct representation of these processes and the dynamical consequences of diabatically-generated PV, both on the mesoscale and larger scales. Two student projects will investigate the role of boundary-layer processes in storm behaviour and conduct a statistical investigation of mesoscale precipitation features, based on archived radar and wind profiler data. The second WP examines particular physical processes and the way these are represented in forecast models. Convection cannot be explicitly represented in current large-scale models (it is just beginning to be resolvable by high-resolution local-area models) so it needs to be parameterised. The schemes that are used are not optimised for mid-latitude storms, where convection often initiates at altitude rather than at the Earth's surface. A combination of novel diagnostics and new (or modified) schemes aimed at improving the representation of convection will be developed in this WP. Also addressed here will be the derivation of air-sea fluxes of heat and momentum from aircraft flights, and their use (as part of a larger, ongoing international project) to derive a better parameterisation for these quantities in high wind conditions. Lastly, microphysical measurements made with the FAAM aircraft will be used to derive latent heating/cooling rates as a function of the microphysical environment and used to improve the model simulations in the first WP and to improve microphysical parameterisations in the UM The final WP addresses the problem of predictability, using a combination of ensemble and data assimilation techniques. A unique archive of forecast ensembles produced at the Met Office will be exploited to determine how well the forecast ensemble actually generates realistic mesoscale features, and the skill with which this is done (using standard measures of skill). Model errors in representing convection, air-sea fluxes and microphysics will be investigated to determine their impact on the forecasts for different flow conditions. The relationship between different model variables on the mesoscale is poorly known at present and this will be investigated using ensembles and the results of the measurement programme. Finally, novel approaches to data assimilation will be investigated through a student project.
|Keywords:||Storms Risk, DIAMET|
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More Information (under review)
Storms have had an increasing social and economic cost over recent years and are likely to be a main cause of loss of life or assets in the UK over the next few decades.
The Storm Risk Mitigation through Improved Prediction and Impact Modelling programme aims to improve short and longer term forecasting of storms and their impacts on catchments and coasts.
Storms Risk Mitigation is a NERC research programme 2009-2014. It has 3 sub projects :
Data providersProject participants needing to submit data to the BADC for archiving will need to apply for access to the depositor group in order to upload data. As a data depositor you will be asked to abide by the depositor conditions.
FTP Project space for participants
A secure project workspace, accessible by FTP, has been set up for use by Storms Risk Mitigation programme participants to facilitate the exchange of documents and preliminary data files. Please note this is separate from the data archive and validated, formatted data files should be subsequently be submitted to the ARCHIVE in the normal way.
To gain access the FTP-project-space you will need be a BADC registered user and:
- apply to the Storms Risk Mitigation FTP project space and be authorised by the programme management team.
The workspace can then be accessed by FTP to proj-ftp.ceda.ac.uk directory project_spaces/stormsrisk_ps. For help with FTP see the BADC FTP guide. Access to view and download files may be obtained via your web browser using the URL ftp://firstname.lastname@example.org (you will be prompted for your password) however to upload files you will need an FTP client.
Accessing project data
A dedicated dataset collection has been prepared for the DIAMET project. This includes the data archived at the BADC produced during the project by participants and submitted for long term archiving and also third party data relevant to the project. For access to these data visit the DIAMET data collection and use the relevant "apply for access" links.
As stated in the Storms Risk Mitigation Data Management Plan: NERC funded data will be made publically available 2 years after the date of collection in line with the NERC Data Policy..
Instructions for data providers
To upload data to the ARCHIVE you will need to have access to the depositor group - see 3) above.
You can then either FTP files to ftp.badc.rl.ac.uk directory incoming/stormsrisk or use the Stroms Risk file uploader to submit your files over the web.
In general, model data should be formatted in CF compliant NetCDF files, although there will be exceptions (e.g. PP and HDF will also be accepted). Documentation on formats and conventions is available from the BADC, which also provides links to downloadable free software packages to support NetCDF access.
Detailed metadata is normally incorporated fully into the header section of data files, although can be submitted separately if this is not practical. With the aim of providing a consistent way of describing atmospheric data sets, the BADC promotes the use of the NetCDF Climate and Forecast (CF) Metadata Convention. This is a standard dealing mainly with vocabulary rules for parameter names and units. Although this standard was developed with the NetCDF format in mind, it can be applied to any set of geophysical data, and probably extended to cover a much broader range of disciplines as well. The BADC requests that all metadata (especially those contained in file headers) be as close to CF compliance as practicable.
In addition to the standard metadata, investigators are encouraged to archive all relevant information electronically, including references, photographs, reports, etc.
General queries about these pages or browsing the data should be directed to the BADC Support Line.