A Technical Description of the NAVDAS Adjoint System

Abstract

This report provides a technical description of the adjoint code for the NRL Atmospheric Variational Data Assimilation System (NAVDAS). The output of the NAVDAS adjoint is an array that contains the sensitivity of a user-defined forecast cost function with respect to the complete set of observations assimilated by NAVDAS at a particular time. The input for the NAVDAS adjoint is an analysis sensitivity vector provided by the adjoint of a forecast model such as NOGAPS. Step by step guidelines for using the NAVDAS adjoint system to compute observation sensitivity are given. The basic theory of observation sensitivity is outlined, and features of the adjoint code and main subroutines are described in detail. Examples of observation sensitivity applications are provided, including the impact of innovations on short-range forecast error, and targeted observing.

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Document Details

Document Type
Technical Report
Publication Date
Mar 16, 2004
Accession Number
ADA422269

Entities

People

  • Nancy L. Baker
  • Rolf H. Langland

Organizations

  • United States Naval Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies
  • Space

DTIC Thesaurus Topics

  • Aircrafts
  • Assimilation
  • Commercial Aircraft
  • Computer Programs
  • Equations
  • Grids
  • Latitude
  • Longitude
  • Marine Meteorology
  • Meteorology
  • Military Research
  • Observation
  • Procedures (Computers)
  • Quality Control
  • Sea Level
  • Shell Scripts
  • Weather Forecasting

Readers

  • Atmospheric Science/Meteorology
  • Computer Science.
  • Ocean-Atmosphere Mesoscale Modeling, Data Assimilation, and Flux Boundary Layers