This icon derives (and returns) a Thermodynamic diagram data unit. In such diagram, temperature, humidity (represented by the dew point) and wind values are displayed with respect to pressure. There are mainly four different types of thermodynamic diagrams (Tephigram, Skew-T, Emagram and Stuve), but only the Tephigram diagram is currently implemented.
The Thermo Data icon can be plotted (using default plotting specifications) or saved as a NetCDF data file. The input data type are observations (upper air BUFR) or model field (GRIB) data.
The macro language equivalents are thermo_bufr() and thermo_grib() (depending on the specified data type).
The Thermo Data Editor
The Thermo Data editor belongs to a type of editor known as family editor which allows related sets of input specifications to be grouped in the same icon editor, each in its own tabbed pane. The available working input panes are :
Bufr Thermo - Provides input for thermodynamic diagrams based on observation (BUFR) data.
Grib Thermo - Provides input for thermodynamic diagrams based on model field (GRIB) data.
To operate with this icon first you need to select which output you want to produce by clicking the tab of the corresponding pane.
Data (Bufr Thermo)
Specifies the data to be used in the plotting of a thermodynamic diagram from observations data. The icon field assist button provides a tailor made MARS request in case you need some guidance in the data specification. The requested data is upper air sounding data (VSNS - Vertical Sounding Non-Satellite in BUFR-speak). Please note that PILOT observations (winds only) have not enough data for plotting a thermodynamic diagram.
Data (Grib Thermo)
Specifies the data to be used in the plotting of a thermodynamic diagram from model field data. The icon field assist button provides a tailor made MARS request in case you need some guidance in the data specification. The requested data are gridded model fields of Temperature, Logarithm of Surface Pressure and Specific Humidity. Fieldsets Temperature and Specific Humidity must have the same number of levels and they will be used to compute the Dew Point parameter . Fieldsets U and V wind components are optional, but if given they will be used to compute the wind vectors data unit. These two components must have the same number of levels, but not necessarily have the same number of levels of Temperature and Specific Humidity.
Point Selection
Specifies how the geographical location, for which the diagram is to be plotted, will be selected. Options are: Coordinates, Area Average and Station.
Coordinates
Specifies the latitude/longitude location for which the diagram is to be plotted.
Area Average
Specifies a geographical area (lat1/lon1/lat2/lon2) over which an area average value will be used, instead of a point value, to produce the diagram.
Station
Specifies the location for which the diagram is to be plotted. In the Bufr Thermo dialogue, this must define a meteorological station that does full upper air soundings. In the Grib Thermo dialogue, this may represent any arbitrary geographical point.
Point Extraction
Specifies the way to calculate values at the point location for GRIB thermodynamic diagrams. Options are:
• Interpolate - interpolate values from the surrounding grid points (default)
• Nearest - using the data of the nearest grid point
Dew Point Formulation
Specifies the equation to compute the Dew Point parameter. Options are: "Saturation Over Water" and "Mixed Phase 0 to -23".
Temperature Param
Specifies the parameter number of the temperature, if the data is a non-ECMWF data. ECMWF uses specific parameter numbers different from the WMO ones.
Specific Humidity Param
Specifies the parameter number of the specific humidity, if the data is a non-ECMWF data. ECMWF uses specific parameter numbers different from the WMO ones.
Lnsp Param
Specifies the parameter number of the Lnsp, if the data is a non-ECMWF data. ECMWF uses specific parameter numbers different from the WMO ones.
U Wind Param
Specifies the parameter number of the U wind component, if the data is a non-ECMWF data. ECMWF uses specific parameter numbers different from the WMO ones.
V Wind Param
Specifies the parameter number of the V wind component, if the data is a non-ECMWF data. ECMWF uses specific parameter numbers different from the WMO ones.