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AVIRIS-C Methane Quicklook Distribution Document 
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David R. Thompson, David.R.Thompson@jpl.nasa.gov 
Andrew K. Thorpe, Andrew.k.thorpe@jpl.nasa.gov 
Robert O. Green, Robert.O.Green@jpl.nasa.gov
Sarah R. Lundeen, Sarah.R.Lundeen@jpl.nasa.gov
Riley M. Duren, riley.m.duren@jpl.nasa.gov 

This document describes the "Classic" Airborne Visible Infrared Imaging 
Spectrometer (AVIRIS-C)  CH4 Quicklook data products.  AVIRIS-C is an imaging 
spectrometer that measures reflected radiance at 5nm intervals in the 
Visible/Short-Wave Infrared (VSWIR) spectral range from 380-2500nm.  

The process for generating CH4 data products is described at detail in the 
following publication:

Thompson, et al., "Real-time remote detection and measurement for airborne 
  imaging spectroscopy: a case study with methane", Atmos. Meas. Tech., 8, 
  pages 4383-4397, 2015. URL http://www.atmos-meas-tech.net/8/4383/2015/

The background statistics are estimated using a clustered Matched Filter 
method described in the following publication:

Funk, Christopher C., et al. "Clustering to improve matched filter detection 
  of weak gas plumes in hyperspectral thermal imagery." IEEE Transactions on 
  Geoscience and Remote Sensing, 39:7, pages 1410-1420, 2001. 

Additional information may be found at http://aviris.jpl.nasa.gov

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OVERVIEW
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Each flightline uses a specific base filename prefix: fyyymmddt01p00rnn

yy:    The year of the airborne flight run.
mm:    The month of the airborne flight run (i.e. 05 represents May).
dd:    The day of the airborne flight run (22 is the 22nd day of the month).
nn:    The run number of the flight run.

The AVIRIS-CL methane products have the suffix _cmfv (CH4 methane matched filter).  Each flightline is associated with two files:

fyymmddt01p00rnnrdn_b_sc01_ort_img_cmfv
fyymmddt01p00rnnrdn_b_sc01_ort_img_cmfv.hdr

These align with the standard orthocorrected, spectral radiance files available in the 
AVIRIS-CL archive at http://aviris.jpl.nasa.gov: 

fyymmddt01p00rnnrdn_b_sc01_ort_img
fyymmddt01p00rnnrdn_b_sc01_ort_img.hdr

The .hdr files contain ASCII header data, in an ENVI-compatible format 
described at https://www.harrisgeospatial.com/docs/enviheaderfiles.html.
They describe the format of each AVIRIS-C methane scene. The number of lines, samples, channels, etc. are captured in the header file.

The *_cmfv files contain  retrieved CH4 mixing ratio lengths
in ppm m units estimated from a matched filter detection of the 2300 nm 
absorption feature.  They are binary files in 32-bit little-endian floating 
point IEEE format in Band Interleaved by Line (BIL) layout. The bands 
contain:
   Band 1: CH4 estimated mixing ratio length (ppm m)
   Band 2: Mean radiance (uW/sr/cm2/sr) of all channels

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ACKNOWLEDGEMENTS
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This research was performed at the Jet Propulsion Laboratory, California 
Institute of Technology, under contract with the National Aeronautics and 
Space Administration (NASA).  We are thankful for the support of the NASA Earth
Science Directorate.  This research was possible with the help and assistance of 
colleagues including Bo-Cai Gao (NRL), Ian McCubbin (JPL), Dar Roberts (UCSB),
Mark Helmlinger (JPL), Scott Nolte (JPL), Ernie Diaz (JPL), Daniel Nunes (JPL),
Yasha Mouradi (JPL), and the rest of the AVIRIS-NG team. Copyright 2016 
California Institute of Technology.  All Rights Reserved.  U.S. Government 
Support Acknowledged.


