The Atmospheric data tab is used for passing tabulated atmospheric data to PlumeRise, allowing data from observations of the atmosphere (e.g. from radiosonde ascents), numerical weather prediction models, or model atmospheres to be used.
PlumeRise requires the atmospheric pressure, temperature, relative humidity, wind speed and wind direction each as functions of height. Tabulated atmospheric data is used if the 'Use atmospheric data' radio button is selected. If 'Use atmospheric data' is selected in parameter set 1, data must be provided in the 'Atmospheric data' tab. However, parameter sets 2 through 5 inherit values from parameter set 1 unless alternative atmospheric data is added in these parameter sets, with either new atmospheric data or a model atmosphere.
The tabulated data must have each of these five quantities and the corresponding height in columns, with each row having all six quantities. Additional data can be included in the table but is not used by PlumeRise. Note, if the row is not complete (i.e. data is missing from one or more columns), none of the data in this row is read. Column headings, titles and comment lines can be included (a comment line composed of numerical data must have a character in first position in the line). In the example below, the atmospheric data is obtained from a radiosonde measurement (obtained from the Wyoming Weather Web archive of radiosonde soundings).
The tabulated data pasted into the text box must be in the correct format to allow the uploading of the data. The following formatting is required:
- columns are separated by at least one white-space character (e.g. space, tab), comma or semi-colon;
- Scientific 'e' notation for floating point numbers can be used (e.g. 10, 1.0e+01, 1.0E01 are all allowed);
- no characters (other than e or E for scientific notation) and column separators are allowed in data rows;
- the data must be sorted such that height is in ascending order;
In addition to adding the tabulated data to the text box, the number of columns in the table and the indices of the required columns must be identified using the input boxes to the right of the text box. Lines in the text file which cannot be interpreted as data are ignored, meaning that file headers, comments etc. will not usually need to be removed.
In addition to the numeric values, the units of the data must also be specified. The table below gives the available units.
| Required variable | Unit | Comment | ||||
|---|---|---|---|---|---|---|
| Height |
|
Altitude of measurement above sea level | ||||
| Wind speed |
|
The horizontal wind speed. | ||||
| Wind direction | degrees | Bearing of the wind. The angle from which the wind originates. 0° corresponds to a northerly wind; 90° to an easterly wind; 180° to an southerly wind, 270° to a westerly wind. |
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| Pressure |
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| Temperature |
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| Relative humidity | % | The ratio of vapour pressure to the saturation vapour pressure with respect to water, expressed as a percentage. |
Once the data columns and units are identified, the data is loaded using the button marked
A message will appear below the button to report the status of the data loading. If successful a message of the form "Status: Data at 43 heights loaded (h=14-11033 m)" will be reported, here indicating that 43 rows of data were successfully imported, with data points at heights between 14 m and 11033 m; these reported values should be compared with the tabulated data to ensure that the data has been loaded as expected. If the status message reports a problem loading data, the tabulated data is not properly formatted; adjusting the format of the table could allow the data to be loaded.