4.1.1.0 atmosphere.initAtmProfile

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atmosphere.initAtmProfile - Function

4.1.1 Set initial atmospheric profile for atmosphere tool

Description

An atmospheric profile is composed of 4 quantities as a function of altitude z:

* the layer thickness * the pressure P * the temperature T and * the gas densities for H2O, O3, CO and N2O.

This method is needed for computing the absorption and phase coefficients, as well as for performing radiative transfer calculations (only layer thickness/T are needed).

This method builds an atmospheric profile that can be used to calculate absorption and phase coefficients, as well as to perform forward and/or retrieval radiative transfer calculations. It is composed of a set of parameters needed to build a layer thickness/P/T/gas densities densities profile from simple parameters currently available at observatories (from weather stations for example) using functions from the ATM library. The set of input parameters consists of the pressure P, the temperature T and the relative humidity at the ground, the altitude of the site, the tropospheric temperature lapse rate,... The profile is built as: thickness of the considered atmospheric layers above the site, and mean P,T,H2O,O3,CO,N2O in them. The total number of atmospheric layers in the particular profile is also available (a negative value indicates an error). The zenith column of water vapor can be calculated by simply integrating the H2O profile.

Arguments


Inputs
altitude	m	Site altitude - Quantity with units of altitude, meter
		allowed:	doublem
		Default:	5000.
temperature	K	Ambient Temperature - Quantity with units of temperature, K
		allowed:	doubleK
		Default:	270.0
pressure	mbar	Ambient pressure - Quantity with units of pressure, mbar
		allowed:	doublembar
		Default:	560.0
maxAltitude	km	altitude of the top pf the modelled atmosphere - Quantity with dimension of length, and units of kilometer
		allowed:	doublekm
		Default:	48.0
humidity		used to guess water (0-100)
		allowed:	double
		Default:	20.0
dTem_dh	K/km	the derivative of temperature with respect to height - Quantity with units of K/km
		allowed:	doubleK/km
		Default:	-5.6
dP	mbar	initial pressure step - Quantity with the units of pressure, mb
		allowed:	doublembar
		Default:	10.0
dPm		pressure multiplicative factor for steps
		allowed:	double
		Default:	1.2
h0	km	scale height for water( exp distribution ) - Quantity with the dimension of length, and units of kilometer
		allowed:	doublekm
		Default:	2.0
atmType		atmospheric type 1(tropical),2(mid latitude summer),3(mid latitude winter), 4(subarctic summer),5(subarctic winter), dimensionless
		allowed:	int
		Default:	1

Returns
string

Example

tmp = qa.quantity(270.0, ’K’)
pre = qa.quantity(560.0, ’mbar’)
hum = 20.0
alt = qa.quantity(5000, ’m’)
h0  = qa.quantity(2.0, ’km’)
wvl = qa.quantity(-5.6, ’K/km’)
mxA = qa.quantity(48, ’km’)
dpr = qa.quantity(10.0, ’mbar’)
dpm = 1.2
att = 1
myatm = at.initAtmProfile(alt, tmp, pre, mxA, hum, wvl, dpr, dpm, h0, att)
print myatm
# BASIC ATMOSPHERIC PARAMETERS TO GENERATE REFERENCE ATMOSPHERIC PROFILE
#
# Ground temperature T:         270 K
# Ground pressure P:            560 mb
# Relative humidity rh:         20 %
# Scale height h0:              2 km
# Pressure step dp:             10 mb
# Altitude alti:                5000 m
# Attitude top atm profile:     48 km
# Pressure step factor:         1.2
# Tropospheric lapse rate:      -5.6 K/km
# Atmospheric type:             TROPICAL
#
# Built atmospheric profile with 20 layers.

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