This directory contains receptor lists for ch4.

The version of obspack used for continuous receptors was 
obspack_ch4_1_GLOBALVIEWplus_v1.0_2019-01-08.

NOTE: Please read and follow the Fair Use Statement for obspack data
explained at

https://www.esrl.noaa.gov/gmd/ccgg/obspack/index.html

Flask receptors came directly from the NOAA/GMD flask database, but also are
included in the obspack.

The background values are from the 20171105 version of the empirical background by 
Arlyn Andrews.

Files:

Note: {year} represents the 4 digit number for the year.  Years available are
2007 to 2015.

Note: The actual footprints for each receptor are available at 
ftp://aftp.cmdl.noaa.gov/products/carbontracker/lagrange/footprints/ctl-na-v1.1/

Note: Each line in the receptor files includes the path and file name used by NOAA/GMD.
The path should be replaced by the user with the actual path being used.  The file name
should remain the same.

flask_receptors_{year}_ch4.txt 
	- List of receptors that have a NOAA flask ch4 measurement.  

continuous_receptors_{year}_ch4.txt 
	- List of receptors that have a ch4 measurement from obspack.
	- This is a subset of the full ct-lagrange footprint library,
	- containing only those footprints that have a ch4 observation
	- from the given obspack package.

flask_receptors_info_{year}_ch4.txt 
	- Additional information about each flask receptor. Contains an additionl
	- 18 header lines explaining the fields in each line of data.

continuous_receptors_info_{year}_ch4.txt 
	- Additional information about each continuous receptor. Contains an additionl
	- 18 header lines explaining the fields in each line of data.

flask_obs_{year}_ch4.txt 
	- The ch4 value for flask receptors. Order in the file is the same as
	- in the receptor file.

continuous_obs_{year}_ch4.txt 
	- The ch4 value and standard deviation for continuous receptors. Order in the 
	- file is the same as in the receptor file.

flask_bg_{year}_ch4.txt 
	- The background ch4 valuase for flask receptors. Order in the file is the same as
	- in the receptor file.

continuous_bg_{year}_ch4.txt 
	- The background ch4 values for continuous receptors. Order in the file is the same as
	- in the receptor file.