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MERRA HIRS2 AM : Gridded Monthly Time-Mean Observation minus Analysis (oma) Values V001 at GES DISC

Entry ID: GES_DISC_MA_HIRS2_AM_OMA_V001

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Summary

Abstract: The differences between the observations and the forecast background used for the analysis (the innovations or O-F for short) and those between the observations and the final analysis (O-A) are by-products of any assimilation system and provide information about the quality of the analysis and the impact of the observations. Innovations have been traditionally used to diagnose observation, ... background and analysis errors at observation locations (Hollingsworth and Lonnberg 1989; Dee and da Silva 1999). At the most simplistic level, innovation variances can be used as an upper bound on background errors, which are, in turn, an upper bound on the analysis errors. With more processing (and the assumption of optimality), the O-F and O-A statistics can be used to estimate observation, background and analysis errors (Desroziers et al. 2005). They can also be used to estimate the systematic and random errors in the analysis fields. Unfortunately, such data are usually not readily available with reanalysis products. With MERRA, however, a gridded version of the observations and innovations used in the assimilation process is being made available. The dataset allows the user to conveniently perform investigations related to the observing system and to calculate error estimates. Da Silva (2011) provides an overview and analysis of these datasets for MERRA.

The innovations may be thought of as the correction to the background required by a given instrument, while the analysis increment (A-F) is the consolidated correction once all instruments, observation errors, and background errors have been taken into consideration. The extent to which the O-F statistics for the various instruments are similar to the A-F statistics reflects the degree of homogeneity of the observing system as a whole. Using the joint probability density function (PDF) of innovations and analysis increments, da Silva (2011) introduces the concepts of the effective gain (by analogy with the Kalman gain) and the contextual bias. In brief, the effective gain for an observation is a measure of how much the assimilation system has drawn to that type of observation, while the contextual bias is a measure of the degree of agreement between a given observation type and all other observations assimilated.

With MERRAs gridded observation and innovation data sets, a wealth of information is available for examination of the quality of the analyses and how the different observations impact the analyses and interact with each other. Such examinations can be conducted regionally or globally and should provide useful information for the next generation of reanalyses.

Related URL

Link: GET DATA > ECHO

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Geographic Coverage

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Spatial coordinates

N: 90.0

S: -90.0

E: 180.0

W: -180.0

Data Set Citation

Dataset Originator/Creator: GMAO

Dataset Title: MERRA HIRS2 AM : Gridded Monthly Time-Mean Observation minus Analysis (oma) Values

Dataset Release Date: June 1, 2011

Dataset Release Place: NASA Goddard Space Flight Center

Version: 001

Data Presentation Form: Digital Science Data

Online Resource: http://disc.sci.gsfc.nasa.gov/MDISC/

Temporal Coverage

Start Date: 2005-01-01

Location Keywords

GEOGRAPHIC REGION > GLOBAL

Data Resolution

Latitude Resolution: 2/3 degrees
Longitude Resolution: 1/2 degrees
Vertical Resolution: 19 levels
Temporal Resolution: Monthly

Science Keywords

ATMOSPHERE > ALTITUDE > BAROMETRIC ALTITUDE

LAND SURFACE > LAND USE/LAND COVER > LAND COVER

LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

Project

EOSDIS > Earth Observing System Data Information System

ESIP > Earth Science Information Partners Program

MERRA TIME-MEAN OBSERVATION DATA > MERRA for Research and Applications Gridded Monthly Time-Mean Obs Dataset

CWIC > CEOS WGISS Integrated Catalog

Ancillary Keywords

EOSDIS

Data Set Progress

COMPLETE

Data Center

Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA

Data Center URL: http://disc.gsfc.nasa.gov/

Data Center Personnel
Name: GES DISC HELP DESK SUPPORT GROUP Phone: 301-614-5224 Fax: 301-614-5268 Email: gsfc-help-disc at lists.nasa.gov Contact Address: Goddard Earth Sciences Data and Information Services Center Code 610.2 NASA Goddard Space Flight Center City: Greenbelt Province or State: MD Postal Code: 20771 Country: USA

Distribution

Distribution Media: Online (FTP)

Distribution Format: HDF (Grid)

Fees: Free

Personnel

GLOBAL MODELING AND ASSIMILATION OFFICE

Role: TECHNICAL CONTACT

Phone: 301-614-6142

Email: data at gmao.gsfc.nasa.gov

Contact Address:

NASA Goddard Space Flight Center

Code 610.1

City: Greenbelt

Province or State: MD

Postal Code: 20771

Country: USA

DANA OSTRENGA

Role: DIF AUTHOR

Phone: 301-614-5475

Email: dana.m.ostrenga at nasa.gov

Contact Address:

NASA Goddard Space Flight Center

Code 610.2

City: Greenbelt

Province or State: MD

Postal Code: 20771

Country: USA

ARLINDO DASILVA

Role: INVESTIGATOR

Email: Arlindo.Dasilva at nasa.gov

Contact Address:

NASA/Goddard Space Flight Center

Data Assimilation Office

City: Greenbelt

Province or State: MD

Postal Code: 20771

Country: USA

Creation and Review Dates

DIF Creation Date: 2006-06-27

Last DIF Revision Date: 2009-04-20

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