Ronald J Maddalena

September 9, 2014

September 9, 2014

The script underlies the calibration for the GBT data pipeline

getForecastValues -- Returns either Opacities, Tsys_atm, Tatm, or Rest for a

list of frequencies and MJD's or a list of polynomial

coefficients that can then be used to generate values. Uses

polynomial fits which are archived once per hour by the CLEO

forecast utilities. The results are generated much faster

than when using the full-blown cleo forecasts programs,

though there is a small loss of accuracy over that provided

by cleo forecasts. The archive goes back to 5 May 2004 and

extends to up to 7 days into the future.

SYNOPSIS

getForecastValues [-h | -help]

[-type
Opacity|Tatm|AtmTsys|Tsys|TotalTsys|Est|Rest|Trcvr|Tau0|Tatm0]

[-timeList listMJDs] [startTime mjd] [stopTime mjd] [incrTime mjd]

[-freqList listGHz] [startFreq GHz] [stopFreq GHz] [incrFreq GHz]

[-elev elevation] [-dir path] [-coeff] [-debug]

DESCRIPTION

If -coeff is NOT specified:

Returns a list of time and frequency-stamped values using the polynomial

coefficients found as subdirectories of ~rmaddale/Weather. The values

in these files are calculated hourly by the CLEO forecasting package

from the average of the three local town forecasts.

The returned values will be interpolated between the nearest time stamps

in the archived coefficient data. The output will be multiple lines,

each line will give the quantities 'type' (Opacity, Tsys, Tatm, or

Rest, ...), followed by the frequency and MJD of the calculated value

within parentheses, an equal sign, and then the calculated value.

For example:

Opacity(115.45,54553.8158912) = -9999

Opacity(22.2,54553.8158912) = 0.185762649207

Opacity(30.0,54553.8158912) = 0.113792336834

Opacity(45.0,54553.8158912) = 0.270589812026

If a value cannot be calculated (either the users supplied a frequency or

time stamp that is not covered by the archive, or there is a hole > 4 hrs

in the archive for the desired time stamp), -9999 will be returned.

If -coeff is specified:

Returns a list of coefficients so that the user can then calculate their

own values at any frequency. The returned values will be interpolated

between the nearest time stamps in the archived coefficient data. The

output will be multiple lines, each line will give the quantities 'type'

(Opacity, Tsys, Tatm, or Rest), followed by the MJD of the calculated

value within parentheses, an equal sign, and then a TCL list. The list

will have three sublists, one for each of three frequency bands. Each

sublist will itself contain a list of polynomial coefficients that are to

be used in that lists band, followed by thechi square of the fit.

For example:

# Frequency Bands: 6 - 22.2, 22.2 - 50, 67 - 116, in GHz

Opacity(55088.6778935) = {{0.1253202697 -0.04723900904 0.006761806394

-0.0004079950568 9.012215005e-06} 6.053071176e-06

{3.519785243 -0.3868765402 0.01625918622 -0.0003067177559

2.209766347e-06} 0.000106007689 {2109.17448 -141.386304

3.940260533 -0.05841611896 0.0004858081949 -2.14846586e-06

3.947017435e-09} 7.022269956e-05}

If coefficients cannot be found (probably because time stamp is not

covered by the archive or there is a hole > 4 hrs in the archive),

coefficients and chi squares of -9999 will be returned.

UNITS

Output units for the generated quantities are:

Kelvin
: System Temperature, Atmosphere Temperature, Rest,

Receiver Temperature

Nepers/Air Mass : Opacity

OPTIONS

The user can use default options by not specifying any command-line

arguments or supply values to the following arguments:

-h or -help

Brings up this help page and all other options are ignored

-coeff

Whether
coefficients, and not values, are to be returned. The default

is to supply values. Only available for -types of Opacity or Tatm

-typeList list

A list of the types of the values to be returned (Default: Opacity).

Opacity: the total zenith opacity

Tatm: the opacity-weighted (i.e., representative) temperature of

the atmosphere and is the value that should be used when

fitting traditional tipping curves.

AtmTsys: the part of the system temperature due to just the

atmosphere, doesn't include CMB, spillover, and electronics,

and is calculated for the specified elevation.

Tsys: Deprecated -- the same as AtmTsys

TotalTsys: the above-described Tsys value, augmented by an

estimate of the contributions from the receiver, spillover,

and the CMB.

Est: the Effective System Temperature for the specified elevation.

Rest: the Relative Effective System Temperature, which includes

the contributions from the CMB, spillover, and electronics,

and is calculated for the specified elevation.

Trcvr: An estimate of the receiver temperature for the given

frequency and MJD

Tau0: The best possible opacity for the given frequency and MJD

Tau10, Tau25, Tau50, Tau75, Tau90: The opacity for various

percentile weather conditions for the given frequency and MJD,

based on multi-year statistical studies.

Tatm0: The Tatm for the given frequency and MJD at the time of the

best possible opacity.

Tatm10, Tatm25, Tatm50, Tatm75, Tatm90: The Tatm for various

percentile weather conditions for the given frequency and MJD,

based on multi-year statistical studies.

-elev deg

The elevation, in degrees, to use for Tsys, TotalTsys, Est and REST

calculations. Ignored for all other calculations. Default
is 30 deg.

-freqList list

List of frequencies in GHz that can range from 6 to 116 GHz.

Ignored if -coeff is specified

-startFreq, -stopFreq, incrFreq

Alternatively, one can enter a start, stop frequency and a frequency

increment, all in GHz. These are ignored if freqList or -coef is

specified. Defaults are 6, 116, and 1 GHz

-timeList list

List of MJD's. Default is the current time. Must be between

5 May 2004 and within two hours of the last entry in the archive,

which is usually the current hour.

-startMJD, -stopMJD, incrMJD

Alternatively, one can enter a start, stop time and a time increment,

all specified as MJD's These are ignored if timeList is specified.

Default is the current time and 0.04166666 (i.e., 1 hr).

-dir path

Optional path to the database files. Normally, this is not needed

since the default path usually points to the best dataset.

-debug

Turns on debugging