These files contain a beta version of the NOAA Earth System Research
Laboratory's North American Boundary Condition for certain gases.

Version date for this release is:  2014-07-01

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Before using in a publication or public presentation, please contact:

Arlyn Andrews (Arlyn.Andrews@noaa.gov)
Colm Sweeney (Colm.Sweeney@noaa.gov)
Ken Masarie (Kenneth.Masarie@noaa.gov) 

and for CO2, N2O or CH4:  Ed Dlugokency (Ed.Dlugokencky@noaa.gov)
and for CO: Paul Novelli (Paul.C.Novelli@noaa.gov)

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A brief description of the methodology used to create this product
can be found here: Jeong, S., Y.-K. Hsu, A. E. Andrews, L. Bianco, 
P. Vaca, J. M. Wilczak, and M. L. Fischer (2013), A multitower 
measurement network estimate of California's methane emissions, 
J. Geophys. Res. Atmos., 118, 11,339–11,351, doi:10.1002/jgrd.50854.

Please note that in general there is more data available for 
the surface layer than aloft.  Thus, the 0 - 1 km altitude bin
may contain values from equator to pole, while values for higher 
altitudes may not be available for all latitudes.  We do not report
values for altitudes above 7 km.  It is up to the user decide how 
to extrapolate these fields to areas where data are unavailable,
though we can provide advice. (Note for v20121113 and subsequent 
updates, values are provided from equator to pole, but values south 
of 20N and north of 70N are filled with a constant vale for a given 
altitude.)  Although we provide separate pacific and atlantic boundary
curtains for these gases, values are identical above 3km and are derived 
to represent the pacific boundary.

We can provide information that is likely relevant for your analysis 
such as error estimates on the data or the interpolated boundary values.
We can also provide guidance about how to appropriately acknowledge 
the product.  It may be appropriate to include some or all of the above 
investigators as co-authors.  This is a new product, and feedback is welcome. 
This product relies on data from the NOAA ESRL Global Montioring Division's 
Cooperative Air Sampling Network and Aircraft Program.  We plan to 
document this product in an upcoming publication.  

The text output is organized into subdirectories by species.  In each
subdirectory, there are files containing altitude, latitude and date
vectors.  The latitude and date vectors serve as indices for the 
the [species]_bg_[altitude].txt and [species]_bgrms_[altitude].txt files. 
Each line in those files represesnts an individual date, and each column 
represents an individual latitude.  The first value in each line corresponds 
to the lowest latitude in the index vector. The "bg" files contain the 
estimated boundary values. The "bgrms" values contain root-mean-square 
errors of the residuals of the data used to construct the boundary curtains.