Please wait...Met Office - Rain radar products (NIMROD)
General Info
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Rain radar data from the Met Office's Nimrod system. Nimrod is a fully automated system for weather analysis and nowcasting based around a network of C-band rainfall radars. This dataset has the fine-resolution analyses of rain rate for the UK and Europe.
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Introduction
The UK has a network of 15 C-band rainfall radars and data form these are processed by the Met Office NIMROD system. Four or five radar scans at different elevations at each site are processed to give the best possible estimate of rainfall at the ground. The main quality checking method is routine evaluation using rain gauges as ground truth. The BADC holds the analyses of rainfall rate at a time resolution of 5 or 15 minutes. Data are available from late 2002. Images are available for the UK as well as a further image including neighbouring European countries from 1999. Data files are available on a 1 km and 5 km Cartesian grid. Single radar site data are available for 2 and 5 km Cartesian grids for 7 UK radar sites. Finally data that has only been minimally processed and is in the original polar data coordinates is available for two radar sites. The value of radar-based data from the Nimrod system has been highlighted repeatedly. For example, in two severe flooding events during 1998 (at Easter over the Midlands and in late October over Wales), estimates of surface rainfall derived from radar data provided evidence of the extent and severity of the rainfall events. The following composite products are available:
The 1 km resolution data files are the best estimate of the precipitation at any one point but single radar site data are also available on 2 and 5 km Cartesian grids for the Jersey radar (49°12'34"N, 2°11'56"W), the Predannack radar (50°00'12"N,5°13'21"W) in Cornwall, the Cobbacombe Cross radar 50°57'48"N,3°27'10"W) in Devon, the Chenies radar (51°41'21"N, 0°31'50"W) near Amersham, the Clee Hill radar (52°23'53"N,2°35'49"W) in Shropshire, the Hameldon Hill radar (53°45'17"N,2°17'19"W) in Lancashire, and the no longer operating Wardon Hill radar in Dorset. The 2 km data files reach to 100 km from the radar, the 5km files to 250 km. Detailed radar site location are given in the Met Office Weather Radar Factsheet. Data that has only been minimally processed and is in the original polar data coordinates is available for two and sometimes more radar sites. Time resolution is 5 or 15 minutes depending on the product.
Restricted Data Access
The Met Office wish to monitor the use of these analyses and require an acknowledgement of the data source if they are used in any publication. The online application for access to the Met Office Nimrod data includes acceptance of the Met Office Conditions of Use. Please note that the Met Office data sets are available for bona fide academic research only, on a per person per project basis (i.e. all members on a same project who will be using the data must individually apply for access to the data). If you wish to access the Met Office data for commercial or personal purposes, please contact the Met Office directly. Once your application has been processed you can access the data via the web
Data availability and file format
A calendar of available data is available from here The current situation is that we are not able to fulfil requests for data that are missing from this archive. The data may be available at a cost by contacting the Met Office directly with required dates. It is worth contacting the BADC first to check if the reason for the gap is already identified as being due to the data not existing at all. Data formatNIMROD product data are in a non-standard binary format described in the NIMROD format document. However, the documentation does not indicate there are three 4 byte elements in each record. These are located before each block of data within the record, the first and second should be equal to 512 to confirm the size of the next data block; the third should be equal to twice the size of the data grid (e.g. if the data are in a grid 200 by 500 boxes, then this third entry should be 200,000)The BADC does not support reading software but programs written by the community to do this task in IDL, Matlab, FORTRAN and Python are available in the dataset software directory. Those interested in importing to ArcGIS should see the Lancaster ArcGIS page. The data files contain integer precipitation rates in unit of (mm/hr)*32. Each value is between 0 and 32767. In practice it is rare to see a value in excess of 4096 i.e. 128 mm/hr. At 10:00 on 14 June 2005, the 1 km composite data files became larger with 2175 rows by 1725 columns compared to the previous 775 rows by 640 columns. From 14:55 on 30 August 2006, the 1 km composite data files are gzipped files. From 13 Nov 2007, the 1 km composite is derived directly from processed polar (600m x 1 degree) rain rate estimates and there is more detail in the rain structure. The raw polar data format is different and described in the polar data header format document. The actual elevations of individual scans are recorded in the polar data files. The file names for the polar data follow the BADC file name convention but those for the normal data products do not.
Documentation and Links to further information and references
Links
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Who to contact
If you have queries on this page or about obtaining the data then you should contact BADC Support. Your query should be answered within one working day. When follow-up work is required, the BADC support will carry out the work as quickly and efficiently as possible, and in any case, the user will be kept informed of progress. | |||
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Data are acquired from rain radar network in the UK and Europe by the Met Office's NIMROD system. Composite products (images and data) and single site data are then sent to the BADC by the Met Office's DART operational dissemination system. Raw polar data from single sites are sent through from the RADARNET team at the Met Office. On arrival at the BADC the data are ingested after a one day quarantine.
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Data are from the Met Office's operational NIMROD system
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