Introduction

From "Atmospheric Modeling for ALMA"

ATM is a library of routines for modeling transmission of cm/mm/sub-mm wavelength radiation through the Earth's atmosphere. It is designed to simulate both the absorption/emission of radiation and the dispersion (i.e., the frequency dependent refractive index of the atmosphere).

Linuxpops uses this library to produce simple atmospheric profiles for the current observing conditions, and when use in conjunction with the recalled data scans, can show the atm conditions at the time of the observation.

Usage:

Invoke atm like this to see the help info:

Linuxpops(C) >>
Linuxpops(C) >> atm /h
                                                                                
        Plot a ATM Profile
        
        Mode: ALL
        
        Usage: atm [/g [/a | mmH2O]] [fmin fmax] [ymin ymax] [options]
        
        where: 'mmH2O' is the perceptible water vapor in mm
               'fmin & fmax' are the freq range in GHz [1.0 - 1000.0]
               'ymin & ymax' are the yplot range
        
        NOTE:  If you passed ymin & ymax, you must pass fmin & fmax first
        
        Examples: 'atm /g /a'  Generate the ATM model based on parameters from header
                  'atm /g 1.5' Generate the ATM model for 1.5 mm h2o and standard parameters
                  'atm /3 /6' (plot transmission from ALMA band 3 to 6)
                  'atm /m /3 /6' (plot transmission from ALMA band 3 to 6 including ALMA band markers)
                  'atm 200 500' (plot transmission 1.5 mm and plot from 200 to 500 GHz)
                  'atm /o 200 500' (plot O2 from 200 to 500 GHz)
        
        options are:
        
        /a Fetch parameters from header
        /b Plot Tau (O2+water) profile
        /g Generate the ATM Model
           /f Fast Generate using simple model
        /k Use Mauna Kea Default values (testing)
        /l List Info on Generated ATM Model
        /m Label with ALMA Bands
        /o Plot Tau (O2) profile
        /p Print Plot
        /s Save Plot to a PDF
        /u Place USB & LSB boxes in plot
        /v verbose
        /w Plot Tau (water) profile
        
        /1  Limit to ALMA Band-1
        /2  Limit to ALMA Band-2
        /3  Limit to ALMA Band-3
        /4  Limit to ALMA Band-4
        /5  Limit to ALMA Band-5
        /6  Limit to ALMA Band-6
        /7  Limit to ALMA Band-7
        /8  Limit to ALMA Band-8
        /9  Limit to ALMA Band-9
        /10 Limit to ALMA Band-10
        
        /h help
        
        See Also: 
        
                                                                                
Linuxpops(C) >>

Model Generation:

To generate the atmospheric model use the /g flag. You can also supply the mm of precipitable water vapour, or allow the info from the loaded scan to set the parameters of generation.

Generate the model based on parameters from scan header; NOTE: must have loaded a scan first. The site elevation will be determined from the data header.

    atm /g /a

Generate the model using standard parameters for Kitt Peak or Mt. Graham using 0.5 mm h2o. The site elevation will be determined from the data header. (Assuming one is loaded)

    atm /g 0.5

Plotting:

To generate plots just type atm followed by several options.

Plots a simple atm Zenith Opacity plot

atm

Plot zenith Opacity from ALMA Band-2 - ALMA Band-6

    atm /2 /6

Add ALMA Band labelling and shading to plot

    atm /m

Plot zenith Opacity from ALMA Band-2 - ALMA Band-6 and include ALMA Band designators.

    atm /2 /6 /m

Plot zenith Opacity from ALMA Band-2 - ALMA Band-6 and include ALMA Band designators and USB & LSB designators. (Tuned sideband in Green, other sideband in Magenta)

    atm /2 /6 /m /u