Overview

CERF regionalised conceptual rainfall runoff model from Center for Ecology and Hydrology and the Environment Agency (UK).

The CERF gridded rainfall data is a simple CSV format file in which the data in each record refers to a specific day and the records increment in chronological order. The columns within the file contain the daily rainfall for each grid cell within the export. These columns increment right to left in "strips" of data for 1km cells for a common Northing but incrementing eastings. The eastings for these cells increment left to right.

Data format

The first column of the file contains the date (format: <day>/<month>/<year>). The first record contains the column headers which for a grid extract covering a box denoted by the lower left and upper right grid coordinates (nnnE, mmmN), (nnn+10E, mmm+5N) would consist of the following

Date, nnnE-mmmN,..nnn+10E-mmmN,nnnE-mmm+1N....nnn+10E-mmm+1N...etc.

Grid references are quoted in units of 1000m and rainfall data are in units of mm/day.

First element is always "Date" and can be ignored.
Next elements of header are the coordinates of grid cell centers starting at the lower left corner.
Grid cells increment first for the first row from west to east, then for the second row from west to east, etc. The rows increment from south to north. The last grid cell is the upper right corner of the grid. The grid is always rectangular with cells of 1km x 1km, without missing cells,so only coordinates of first and last column header are needed for grid definition.

A (truncated) example of a CERF Ascii Grid data file:

Date,       410E-505N , 411E-505N , 412E-505N , ... 454e-506n  
01/12/1963,	1.53  ,  1.51     ,  1.46     , ...    0
02/12/1963,     0     ,    0      ,   0       , ...    0
03/12/1963,     0     ,    0      ,   0       , ...    0
04/12/1963,     0     ,    0      ,   0       , ...    0
05/12/1963,     0     ,    0      ,   0       , ...    0
06/12/1963,    0.17   ,   0.15    ,  0.12     , ...    0
07/12/1963,    0.77   ,   0.74    ,  0.69     , ...   1.32
08/12/1963,     0     ,    0      ,   0       , ...    0
09/12/1963,     0     ,    0      ,   0       , ...    0
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Configuration

To import a CERF Grid data file, configure a module like:

<?xml version="1.0" encoding="UTF-8"?>
<timeSeriesImportRun xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fews http://fews.wldelft.nl/schemas/version1.0/timeSeriesImportRun.xsd">
	<import>
		<general>
			<importType>CERF</importType>
			<folder>$REGION_HOME$/Import/CERF</folder>
			<idMapId>idImportCERF</idMapId>
			<unitConversionsId>CERF_UnitConversions</unitConversionsId>
			<importTimeZone>
				<timeZoneOffset>+00:00</timeZoneOffset>
			</importTimeZone>
		</general>
		<timeSeriesSet>
			<moduleInstanceId>CERF_import</moduleInstanceId>
			<valueType>grid</valueType>
			<parameterId>P</parameterId>
			<locationSetId>CERF_all</locationSetId>
			<timeSeriesType>external historical</timeSeriesType>
			<timeStep unit="day" multiplier="1"/>
			<readWriteMode>add originals</readWriteMode>
			<synchLevel>1</synchLevel>
			<expiryTime unit="day"/>
		</timeSeriesSet>
	</import>
</timeSeriesImportRun>
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