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(OCO-2) Level 2 Full Physics Retrieval Algorithm Theoretical Basis

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(OCO-2) Level 2 Full Physics Retrieval Algorithm Theoretical Basis OCO D-55207 Orbiting Carbon Observatory-2 (OCO-2) Level 2 Full Physics Retrieval Algorithm Theoretical Basis Version 3.0 Rev 0 December 7, 2017 Data Release 8 National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California OCO-2 Level 2 Full Physics Retrieval ATB December 7, 2017 Version 3.0, Rev 0 ORBITING CARBON OBSERVATORY (OCO) - 2 LEVEL 2 FULL PHYSICS ALGORITHM Theoretical Basis Document Hartmut Boesch University of Leicester Linda Brown Jet Propulsion Laboratory Rebecca Castano Jet Propulsion Laboratory Mathew Christi Colorado State University Brian Connor BC Consulting Limited David Crisp Jet Propulsion Laboratory Annmarie Eldering Jet Propulsion Laboratory Brendan Fisher Jet Propulsion Laboratory Christian Frankenberg Jet Propulsion Laboratory Michael Gunson Jet Propulsion Laboratory Robert Granat Jet Propulsion Laboratory James McDuffie Jet Propulsion Laboratory Charles Miller Jet Propulsion Laboratory Vijay Natraj Jet Propulsion Laboratory Denis O’Brien Colorado State University Chris O’Dell Colorado State University Gregory Osterman Jet Propulsion Laboratory Fabiano Oyafuso Jet Propulsion Laboratory Vivienne Payne Jet Propulsion Laboratory Igor Polonski Colorado State University Mike Smyth Jet Propulsion Laboratory Rob Spurr RT Solutions Inc. David Thompson Jet Propulsion Laboratory Geoff Toon Jet Propulsion Laboratory Approved by: ______________________________ Version 3.0 Jet Propulsion Laboratory December 7, 2017 California Institute of Technology Pasadena, California ii OCO-2 Level 2 Full Physics Retrieval ATB December 7, 2017 Version 3.0, Rev 0 Document History: Version Revision Date Description/Comments 1.0 1 Initial version of OCO ATBD 1.0 2 4/18/2009 Final version of OCO ATBD 1.0 3 10/15/2010 First version of OCO-2 ATBD 1.0 4 11/10/2010 Final pre-external review version, minor fixes 2.0 0 4/17/2014 Prelaunch version for OCO-2 2.0 1 2/21/2015 Draft postlaunch version for OCO-2 2.0 2 3/30/2015 Accompanying V6 and V6R public data release 3.0 0 12/7/2017 Updated for Version 8 public data release The research described in this document was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2017. All rights reserved. iii OCO-2 Level 2 Full Physics Retrieval ATB December 7, 2017 Version 3.0, Rev 0 TABLE OF CONTENTS 1 Introduction ............................................................................................................................. 1 1.1 Purpose ......................................................................................................................... 1 1.2 Scope ............................................................................................................................ 1 2 Experiment Overview .............................................................................................................. 2 2.1 Objectives ..................................................................................................................... 2 2.2 Measurement Approach ................................................................................................ 3 2.3 Instrument Characteristics ............................................................................................ 5 2.3.1 Observing Modes .................................................................................................. 7 2.3.2 Changes to Glint Mode Operations ....................................................................... 9 2.3.3 Data Product Delivery ........................................................................................... 9 3 Algorithm Description ........................................................................................................... 10 3.1 Algorithm Overview ................................................................................................... 10 3.2 Forward Model ........................................................................................................... 15 3.2.1 Optical Properties ................................................................................................ 17 3.2.2 Solar Spectrum Model ......................................................................................... 32 3.2.3 Radiative Transfer ............................................................................................... 33 3.2.4 Instrument Model ................................................................................................ 37 3.3 State Vector ................................................................................................................ 41 3.3.1 Basic Description of State Vector ....................................................................... 41 3.3.2 The a Priori State Vector and Covariance Matrix .............................................. 42 3.4 Jacobians ..................................................................................................................... 51 3.5 Inverse Method ........................................................................................................... 52 3.5.1 Formulation and Implementation ........................................................................ 52 3.5.2 Goodness of Spectral Fit ..................................................................................... 54 3.6 XCO2, Characterization, and Error Analysis ................................................................ 55 3.6.1 Pressure Weighting Function .............................................................................. 55 3.6.2 XCO2 ..................................................................................................................... 56 3.6.3 The Column Averaging Kernel aCO2 ................................................................... 56 3.6.4 Smoothing and Interference due to the State Vector ãc ...................................... 57 ~ 3.6.5 Correlation of XCO2 with non-CO2 State Vector Elements s 1 ........................... 58 3.6.6 Components of XCO2 Variance ............................................................................ 58 4 Algorithm Specification ........................................................................................................ 60 4.1 Data System Context .................................................................................................. 60 4.2 Level 2 Preprocessing ................................................................................................. 60 4.2.1 ABO2 Preprocessor ............................................................................................. 60 4.2.2 IMAP Preprocessor (and SIF Retrievals) ............................................................ 61 4.3 Level 2 Full Physics Inputs ........................................................................................ 61 4.3.1 Requirements on Inputs ....................................................................................... 62 4.3.2 Attributes of Input Products ................................................................................ 62 4.4 Level 2 Full Physics Outputs ...................................................................................... 63 iv OCO-2 Level 2 Full Physics Retrieval ATB December 7, 2017 Version 3.0, Rev 0 4.5 Description of Full Physics Major Code Sections ...................................................... 64 4.6 Lua Configuration ....................................................................................................... 65 4.7 Level 2 Processing PGEs ............................................................................................ 66 4.7.1 ECMWF Resampler ............................................................................................ 66 4.7.2 L2 A-Band Preprocessing PGE ........................................................................... 67 4.7.3 L2 IMAP-DOAS Preprocessing PGE ................................................................. 67 4.7.4 Sounding Selection PGE ..................................................................................... 67 4.7.5 L2 FP Algorithm ................................................................................................. 67 4.7.6 FP Diagnostic Product Generator ........................................................................ 68 4.7.7 FP Standard Product Generator ........................................................................... 68 4.7.8 Level 2 PGE Multiplicity Summary................................ .................................... 68 4.8 Error Handling ............................................................................................................ 69 4.9 Commercial off-the-Shelf Components ...................................................................... 69 4.10 Quality Assessment and Recording ............................................................................ 69 5 References ............................................................................................................................. 70 6 Acronyms .............................................................................................................................. 79 v OCO-2 Level 2 Full Physics Retrieval ATB December 7, 2017 Version 3.0, Rev 0 LIST OF FIGURES Figure 2-1. The OCO-2 instrument showing the major optical components and optical path (right) and images of spectra recorded by the FPA
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