GCMD

+ Visit NASA.gov


	Links FAQ Contact Us Site Map




	Data Analysis And Visualization

	Data Management/Data Handling

	Education/Outreach

	Environmental Advisories

	Hazards Management

	Metadata Handling

	Models

	Reference And Information Services

	Web Services





	Earth Science Links


	Portal Collaborations



	Questions?

Are you using a browser that doesn't support JavaScript or have you disabled JavaScript?

If you have disabled JavaScript, you must re-enable JavaScript to use this page.
Or you can view this record using the Text Only Format .

Record Search Query:

MERRA HIRS2 NOAA08 : Gridded Monthly Time-Mean Observation minus Analysis (oma) Values V001 at GES DISC
Entry ID: GES_DISC_MA_HIRS2_NOAA08_OMA_V001

[ Update this Record ]

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: VIEW PROJECT HOME PAGE

Description: The GES DISC Data Modelling and Assimilation web site.

Link: VIEW RELATED INFORMATION

Description: The GMAO home page

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

TB
EOSDIS

Distribution Media

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

Publications/References

(),

Creation and Review Dates

SERF Creation Date:
SERF Last Revision Date:

View Text Only Format

			+ Privacy Policy and Important Notices			Webmaster: Monica Holland Responsible NASA Official: Lola Olsen Last Updated: June 2013