Algorithm Theoretical Basis Document (ATBD) Level 0 to Level 1

Production of Located, Calibrated MOPITT Radiances from Instrument Output Counts

Abstract:

The MOPITT Level-0 to Level-1 ATBD briefly outlines the Measurement of
Pollution in the Troposphere (MOPITT) investigation and the physics 
and mathematics of the algorithms that convert the raw instrument 
outputs in counts into calibrated radiances and geolocate them.  The inputs to
these algorithms are: 
 >	The telemetered instrument outputs, including those from the detectors,
   all temperature, pressure, time and angle sensors, and other monitors of
   instrument state and performance.

 >	Data on the spacecraft position and attitude as a function of time.


The algorithms described in this version of the ATBD are the Version 1
prototype algorithms. These are being developed by the Instrument Team at the
University of Toronto on their facilities, where they will be used to explore
different approaches to the most efficient recovery of the information from the
MOPITT output data, including taking account of the instrument effects expected
to be present in the flight data. Subsequently these algorithms will be
incorporated in formally documented production software which will be written
and tested on the NCAR Science Computing Facility (SCF).  This software will 
then be installed at the Langley DAAC, where their operation and outputs will
be verified prior to launch.  These algorithms will then be applied to the data
acquired in orbit during the flight phase of the program. 

This first version of ATBD reflects the present status of the prototype
algorithms. With time the algorithms will evolve to include the capability
to handle more complex situations, and the ATBD will be updated to reflect
these increased capabilities. The MOPITT Level 1 (L1) data are inputs to the
algorithms that retrieve vertical profiles of carbon monoxide, and total
column amounts of carbon monoxide and methane.  The algorithms to create
the Level-2 data products are discussed in a separate ATBD. The data products
are described elsewhere.