The climate map document uses climate normal data to provide an overview at a regional level. This data is displayed in raster format as both static layers and monthly time series. The rasters are augmented by time enabled WMO station point feature data.

Climate Research Unit (CRU) raster data

A complete set of high-resolution climate grids are available through the CRU and the Tyndall Centre at the University of East Anglia. The CRU and the Tyndall Centre proved to be the highest quality and resolution through research of the data available.

The top three files contain useful metadata about the creation of the datasets and the units in which they are stored. The datasets are gzip files and will unpack as dat files.

The files from the CRU website do not have column headers. The header information can be found on the CRU website. The easiest method of preparing these files is to:

1. Extract the dat file.
2. Import the file into Excel and insert the relevant headers.
3. Save as .txt or .csv file.
4. Open the file in ArcMap and display the XY data as a point event layer. Save this layer as a feature class.
5. Use the Point to Rasters geoprocessing tool to create monthly rasters by inputting the relevant month in the Value Field.

   The most efficient way of displaying a raster time series is to create a mosaic dataset and add start and end date fields in the attribute table. The data can then be displayed in monthly intervals.

Symbology

A comprehensive set of layer files are available for the climate datasets within the template. Because the layers render the raster climate data with classified values, you must calculate statistics for the rasters.

Importing WMO data

WMO station locations and climate variables can be downloaded as a flat text file from the WMO website. Current climate variables can be downloaded from the UN Data Explorer website. Each of the relevant variables can then be downloaded for the area you are interested in.

The WMO station location file should be saved in the (location)\MilitaryAspectsofWeather\Tools\scratch folder as WMOStations.tab.

Current climate variables should be saved within the (location)\MilitaryAspectsofWeather\ClimateData folder. File names should have no spaces, for example DryBulbTemp.txt.

To import the WMO stations, run the Import WMO Stations tool from the MAoWTools toolbox located within the (location)\MilitaryAspectsofWeather\Tools folder. This imports the delimited text file and creates a point feature class by executing the following steps:

1. The flat text file is converted to a temporary geodatabase table.
2. X and Y fields are appended to the table.
3. X and Y coordinates for each weather station are populated following conversion from Degrees, Minutes, Seconds to Decimal Degrees.
4. A new point feature layer is created based on the X and Y coordinates.
5. This feature layer is then copied into the feature class in the geodatabase.
6. X and Y fields are deleted and an attribute index is added.
7. The layer is then ready to populate with station data.

To import the WMO station data, run the Import WMO Station Data tool from the MAoWTools toolbox located within the (location)\MilitaryAspectsofWeather\Tools folder. The tool creates a subset of the point feature class and populates it with climate variables based on the downloaded WMO file. WMO stations and climate variables are joined using the WMOStationNumber attribute.

The tool executes the following steps.

1. A feature class named WMOStationData is created within the output geodatabase.
2. Relevant fields are added to the empty feature class, including WMO station number, name, month start and end, and time period.
3. These fields are then populated using text files from the WMOStationData folder. The template contains data for California as a demonstration.
4. This prepared feature class is now populated with climate variables using the supporting Iterate Weather Files and Transfer Weather Files tools.