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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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