org.orekit.models.earth.weather

Class GlobalPressureTemperature2Model

java.lang.Object

org.orekit.models.earth.weather.GlobalPressureTemperature2Model

All Implemented Interfaces:

WeatherModel

public class GlobalPressureTemperature2Model
extends Object
implements WeatherModel

The Global Pressure and Temperature 2 (GPT2) model. This model is an empirical model that provides the temperature, the pressure and the water vapor pressure of a site depending its latitude and longitude. This model also provides the a_h and a_w coefficients used for the Vienna 1 model.

The requisite coefficients for the computation of the weather parameters are provided by the Department of Geodesy and Geoinformation of the Vienna University. They are based on an external grid file like "gpt2_1.grd" (1° x 1°) or "gpt2_5.grd" (5° x 5°) available at: link

A bilinear interpolation is performed in order to obtained the correct values of the weather parameters.

The format is always the same, with and example shown below for the pressure and the temperature.

Example:

 %  lat    lon   p:a0    A1   B1   A2   B2  T:a0    A1   B1   A2   B2
   87.5    2.5 101421    21  409 -217 -122 259.2 -13.2 -6.1  2.6  0.3
   87.5    7.5 101416    21  411 -213 -120 259.3 -13.1 -6.1  2.6  0.3
   87.5   12.5 101411    22  413 -209 -118 259.3 -13.1 -6.1  2.6  0.3
   87.5   17.5 101407    23  415 -205 -116 259.4 -13.0 -6.1  2.6  0.3
   ...
 

Author:

Bryan Cazabonne

See Also:

"K. Lagler, M. Schindelegger, J. Böhm, H. Krasna, T. Nilsson (2013), GPT2: empirical slant delay model for radio space geodetic techniques. Geophys Res Lett 40(6):1069–1073. doi:10.1002/grl.50288"

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_SUPPORTED_NAMES Default supported files name pattern.

Constructor Summary

Constructors

Constructor and Description
GlobalPressureTemperature2Model(double latitude, double longitude, Geoid geoid) Constructor with default supported names.
GlobalPressureTemperature2Model(String supportedNames, double latitude, double longitude, Geoid geoid) Constructor with supported names given by user.

Method Summary

Modifier and Type	Method and Description
double[]	getA() Returns the a coefficients array.
double	getPressure() Returns the pressure at the station [hPa].
double	getTemperature() Returns the temperature at the station [K].
double	getWaterVaporPressure() Returns the water vapor pressure at the station [hPa].
void	weatherParameters(double stationHeight, AbsoluteDate currentDate) Calculates the weather parameters of the model.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_SUPPORTED_NAMES

public static final String DEFAULT_SUPPORTED_NAMES

Default supported files name pattern.

See Also:

Constant Field Values

Constructor Detail

GlobalPressureTemperature2Model

public GlobalPressureTemperature2Model(String supportedNames,
                                       double latitude,
                                       double longitude,
                                       Geoid geoid)

Constructor with supported names given by user.

Parameters:

supportedNames - supported names

latitude - geodetic latitude of the station, in radians

longitude - longitude geodetic longitude of the station, in radians

geoid - level surface of the gravity potential of a body

GlobalPressureTemperature2Model

public GlobalPressureTemperature2Model(double latitude,
                                       double longitude,
                                       Geoid geoid)

Constructor with default supported names.

Parameters:

latitude - geodetic latitude of the station, in radians

longitude - geodetic latitude of the station, in radians

geoid - level surface of the gravity potential of a body

Method Detail

getA

public double[] getA()

Returns the a coefficients array.

• double[0] = a_h
• double[1] = a_w

Returns:

the a coefficients array

getTemperature

public double getTemperature()

Returns the temperature at the station [K].

Returns:

the temperature at the station [K]

getPressure

public double getPressure()

Returns the pressure at the station [hPa].

Returns:

the pressure at the station [hPa]

getWaterVaporPressure

public double getWaterVaporPressure()

Returns the water vapor pressure at the station [hPa].

Returns:

the water vapor pressure at the station [hPa]

weatherParameters

public void weatherParameters(double stationHeight,
                              AbsoluteDate currentDate)

Description copied from interface: WeatherModel

Calculates the weather parameters of the model. In order to obtain the correct values of the parameters this method has to be call just after the construction of the model.

Specified by:

weatherParameters in interface WeatherModel

Parameters:

stationHeight - the height of the station in m

currentDate - current date