Link to National Centers for Environmental Prediction (Formerly NMC) Home Page
Correlative gridded data from NOAA's National Center for Environmental Prediction (formerly known as the National Meteorological Center or NMC) are included as supplementary data products to the UARS Project. The main use of the correlative data from the NMC run is to provide an independent analysis for comparison with data from the UARS instruments. The correlative NMC data are intended to aid in validating the UARS instrument data. NMC data are available at the Goddard Space Flight Center (GSFC) Distributed Active Archive Center (DAAC).
NOTE: NCEP data products are still archived using NMC as part of the data set name to remain consistent with previously archived data. These acronyms refer to the same organization and may be used interchangably within this document.
NMC CORRELATIVE DAILY DATA
The Goddard DAAC keeps the most current month of correlative NMC data online for users to download via anonymous ftp.
- NMC GRIDDED DATA
The National Center for Environmental Prediction (NCEP) geopotential heights and temperatures are derived from two analysis systems:
- tropospheric fields from 1000mb to 100mb, and
- stratospheric analyses from 70 mb to 0.4 mb.
The tropospheric fields from 1000mb to 100mb are the 1200 GMT gridded fields which are part of the Global Daily Assimilation System (GDAS) described by McPherson et al. (1979), where data from radiosondes, aircraft, satellites, ships, buoys, or any other conventional means are assimilated and merged into meteorological fields (heights, temperature, winds). The stratospheric analyses developed by the National Weather Service Climate Analysis Center are 1200 GMT operational analyses at the 70-0.4mb pressure levels, produced from satellite temperature retrievals and RAOBS via a modified Cressman analysis (Gelman et al., 1987), which is a successive iteration method where the fields are iteratively adjusted by weighted data depending on distance from the grid point. Tropospheric temperature analyses use combined NOAA-10 and NOAA-11 data.
Moisture (only for Northern hemisphere) and Winds are obtained from the NCEP global data assimilation systems. Analyses from assimilation are on the same gridded fields as temperature and height analyses.
The data file structure for this file type is listed in the Standard Formatted Data Units (SFDU) documents listed in the References section below.
The goal of upper atmosphere research is to understand the chemistry, dynamics, and energy balance above the troposphere as well as the coupling between these processes and between atmospheric regions. Understanding the mechanisms that control upper atmosphere structure and variability, as well as an understanding of how the upper atmosphere responds to natural and man-made causes will help define the role of the upper atmosphere in climate variability.
There are four measured parameters for NMC correlative data: geopotential height (HEIGHT), moisture (MOISTURE), temperature (TEMP) and winds (WINDS) both meridional and zonal wind components.
Data fields will be produced at 18 standard meteorological levels from 1000 mb to 0.4 mb for heights and temperatures. For moisture only the 6 lowest altitude pressure levels are used and there is no data for the southern hemisphere. For winds there are both U and V components. U comp. and V comp. of wind are given with respect to grid in the data files. For the northern hemisphere there is wind data only for the 12 lowest altitude pressure levels (up to the 50 mb level). For the southern hemisphere there is wind data only at the 4 levels 1000, 500, 300, and 250 mb.
Other UARS data sets that measure the correlative value of the UARS instrument data include the UKMO Correlative Assimilation Data.
- Dr. Alvin Jim Miller
- Code W/NMC53 NOAA/NWS
- 5200 Auth Rd, Room 805
- Camp Springs, 20746-4304
- Telephone Numbers:
- Voice: +1 301-763-8071
- FAX: +1 301-763-8125
- Electronic Mail Address:
NMC Gridded Data Produced for UARS Project
See Principal Investigator above.
Data from radiosondes, aircraft, satellites, ships, buoys, or any other conventional means are assimilated and merged into meteorological fields (heights,temperature, winds). Stratospheric analyses are 1200 GMT operational analyses at the 70-0.4mb pressure levels, produced from satellite temperature retrievals and RAOBS. Using a successive iteration method, the fields are iteratively adjusted by weighted data depending on distance from the grid point. Tropospheric temperature analyses use combined NOAA-10 and NOAA-11 data.
The operational analyses now use satellite retrievals. The minimum variance retrieval method is not dependent on week-old regression coeficients of co-located radiosonde data with satellite radiances as was done in the past.
See Data Set Introduction above.
Upper Atmosphere Research Satellite (UARS).
UARS was launched September 12, 1991 with the mission of investigating the chemical and dynamical processes of the Earth's upper atmosphere. See the UARS Project document for more information.
Analyzed fields will be supplied to the
Central Data Handling Facility (CDHF)
for 12GMT each day, and transferred to the GSFC DAAC for distribution.
None at this time.
The gridded fields are on the standard 65x65 NMC polar stereographic grid oriented 80W (grid increment 381 km at 60N), and 100E (grid increment 381 km at 60S); Pole at (33,33).
Data coverage for NMC on 5/22/1991. (Create map of NMC data!)
Resolution is about 2.5 degrees latitude by 2.0 degrees longitude. ??The Gaussian grid of 384x190, roughly equivalent to 1x1 degree latitude/longitude.
The gridded fields are on the standard 65x65 NMC polar stereographic grid oriented 80W (grid increment 381 km at 60N), and 100E (grid increment 381 km at 60S); Pole at (33,33). The NMC uses 18 standard pressure levels for data at 1000, 850, 700, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 10, 5, 2, 1, 0.4 millibars.
Height and temperature data are produced at 18 pressure levels from 1000 mb to 0.4 mb. Moisture data are only produced in the northern hemisphere for the 6 lowest altitude pressure levels. Wind data are produced for the 12 lowest altitude levels in the northern hemisphere, and at the 4 levels 1000, 500, 300, and 250 mb in the southern hemisphere.
The Correlative NMC data are available from September 12, 1991 through September 30 2001.
The temporal resolution of NMC data granules is daily.
Analyzed fields will be produced for the following parameters listed below with the subtype name, DAAC parameter name, and units:
|Subtype ||DAAC Parameter Name ||Units |
|Temperature ||TEMP ||K |
|Geopotential Height ||HEIGHT ||m |
|Wind Components |
u comp. of wind wrt grid
v comp. of wind wrt grid
|Moisture ||MOISTURE ||% |
The granularity of NMC data are defined such that there is one granule for parameter subtype per day, for a total of 4 granules per day. Each NMC granule is a multi-file granule consisting of two files:
- The binary data file (files ending with PROD, or *PROD extension) which contains the height, moisture, temperature, or winds data.
- An ASCII metadata file (files ending with META, or *META extension) associated with the data file containing items such as the begin date, end date, altitude and record length size of the data file.
The naming convention for UARS granule file names distributed by the Goddard DAAC is as follows:
CORR_ZNMC_ Sssss_Ddddd.Vvvvv_ Ccc_xxxx
where: (dddd = UARS day, vvvv = data version #, cc = data cycle #)
- is the subtype or parameter (STEMP),
- is the UARS acquisition day (D0001 = 12 September 1991),
- is the data version number ,
- is the data version cycle number (C01), and
- is the file extension (PROD for the binary files, or META for the ASCII metadata files)
Average granule size is about 612 Kb for height and temperature granules, 115 Kb for moisture granules, and 546 Kb for wind granules. The *META files are small, only about 770 bytes each.
The data files each contain 1 header record followed by data records. Each data record contains data for both hemispheres at a constant pressure surface.
Data file structures are presented in the Standard Formatted Data Units (SFDU) documents listed in the References section.
Data used in the NMC analysis are purely from standard NMC sources, i.e., NOAA satellites, radiosondes from the worldwide network, aircraft winds, cloud vectors from satellites, and any other available data transmitted to NMC. This data are assimilated and merged into meteorological fields (heights, temperature, winds). The stratospheric analyses developed by the NMC Climate Analysis Center are 1200 GMT operational analyses at the 70-0.4mb pressure levels, produced from satellite temperature retrievals and RAOBS via a modified Cressman analysis (Gelman et al., 1987), which is a successive iteration method where the fields are iteratively adjusted by weighted data depending on distance from the grid point. Tropospheric temperature analyses use combined NOAA-10 and NOAA-11 data.
The operational analyses now use satellite retrievals based on a minimum variance simultaneous retrieval method described in Goldberg et al. (1988), Fleming et al. (1988), and Fleming et al. (1986). The minimum variance retrieval method is not dependent on week-old regression coeficients of co-located radiosonde data with satellite radiances as was done in the past.
The NMC analyses below 10mb are heavily dependent on RAOBS (parti- culary over the continents), but less dependent on the RAOBS and more dependent on the TOVS retrievals over ocean areas and ice covered regions.
Analyzed fields will be produced for temperature, geopotential height, U and V wind components, and moisture.
The data quality is given by the standard deviation of the quantity. Each data element in each file is stored along with a standard deviation which has been calculated by the analysis software. The nominal error is 10 m/s for the wind and 25 K for temperature.
All data are checked by the ????? science team and assigned quality values. These values appear as the DATA_QUALITY_UARS fields in the ASCII metadata files. The format for DATA_QUALITY_UARS is a 3 character field of the form "p.q" where:
for p 0 Machine inspected
1 Qualitative evaluation
2 Intensive analysis
for q 1 less than 50% good data
2 50% - 75% good data
3 76% - 98% good data
4 better than 98% good data
Variances are included with each data value.
Analysis quality of meteorological fields are continually evaluated and updated at NMC. Within the access codes provided to UARS, errors are attributed to profiles in a general sense, i.e., the errors are computed depending on whether the profile is given in a dense data region or in a poor data region, as over the ocean. Data files are checked to ensure that they are properly transferred. No additional data checks are performed by the DAAC.
The data files exist as UNIX stream files at the DAAC. Binary data are IEEE formatted. The binary data files should be read on 32 bit machines running UNIX operating systems. This is especially important for fields which are IEEE floating point values, such as the profile data and quality values. If you are going to use a non 32-bit and/or non-UNIX machine, then you will need to write your own conversion routines to read the data files.
File record length information is only listed in the ASCII metadata files (*META extension) which accompany the data and parameter files.
None at this time.
The main use of analyses from the NMC run is to provide an independent analysis for members of the UARS science team to compare with equivalent retrievals derived form UARS instruments.
See Usage Guidanceabove.
Future reprocessing of the data are possible.
- Simple read/dump programs are available for reading the Correlative level 4 data files. The read programs are available in C and IDL languages.
- To get the software use the links below:
- Help Desk
- NASA Goddard Space Flight Center
- Code 610.2
- Greenbelt, MD 20771
- Telephone Numbers:
- Phone: 1-301-614-5224
- FAX: 1-301-614-5268
- Electronic Mail Address:
- The UARS Correlative data are archived at the GES DISC under the UARS Project.
- The Correlative data files can be obtained from the GES DISC by several mechanisms. These include the following:
- The GES DISC currently supports Correlative level 4 data products.
The Correlative level 4 data are available to anyone free of charge. See the section above on Procedures for Obtaining Data for specific information. For more information on Correlative please refer to the ????? Home Page.
Reber, C. A., C. E. Trevathan, R. J. McNeal, and M. R. Luther, The Upper Atmosphere Research Satellite (UARS) Mission, J. Geophys. Res. 98, D6, 10643-10647, 1993.
McPherson, R., D., K. H. Bergman, R. E. Kistler, G. E. Rasch, and D. S. Gordon: "The NMC Operational Global Data Assimilation System," Mon. Wea. Rev., Vol. 107, pp 1445-61.
Fleming, H. E., M. E. Goldberg, and D. S. Crosby, 1988: "Operational Implementation of the Minimum Variance Simultaneous Retrieval Method", Proceedings, AMS Third Conference on Satellite Meteorology and Oceanography, Jan. 31 - Feb. 5, 1988, Anaheim, Calif., pp.16-19.
"Minimum Variance Simultaneous Retrieval of Temperature and Water Vapor from Satellite Radiance Measurements", Preprint Volume, Second Conference on Satellite Meteorology/Remote Sensing and Applications, May 13-16, 1986, Williamsburg, Va. Published by the American Meteorological Society, Boston, Mass., pp 20-23.
Golberg, M. D. and J. M. Daniels, 1988: "A Method for Obtaining and Improved Approximation for the Temperature/Moisture Retrieval Problem", Proceeding, AMS Third Conference on Satellite Meteorology and Oceanography, Jan. 31 - Feb. 5, 1988, Anaheim, Calif. pp. 20-23.
Documentation of NMC gridded data produced for UARS project, NURSNM01.
Horne, C., UARS Granule Level File (*META) Description, July 1994.
- DATA PRODUCT
- A collection of parameters packaged with associated ancillary and labeling data. Uniformly processed and formatted. Typically uniform temporal and spatial resolution. ????? level 3A data products include ?????_L3AL_DAILY and ?????_L3AT_DAILY. The ????? data product class is divided into data product subclasses according to measured parameters.
- DATA SET
- A logically meaningful grouping or collection of similar or related data. Data having mostly similar characteristics (source or class of source, processing level and algorithms, etc.) ????? is a subset of the UARS data set.
- A Granule is the smallest aggregation of data which is independently managed.
- A measurable or derived variable represented by the data (e.g. air temperature, snow depth, relative humidity). At the Goddard DAAC, parameters are grouped into a Parameter General category, which is broken down into Parameter Specific.
|CDHF ||Central Data Handling Facility |
|CFCl3 ||fluorocarbon 11 |
|CF2Cl2 ||fluorocarbon 12 |
|CH4 ||methane |
|ClONO2 ||chlorine nitrate |
|DAAC ||Distributed Active Archive Center |
|DCF ||Data Capture Facility |
|EOS ||Earth Observing System |
|FOV ||field of view |
|GSFC ||Goddard Space Flight Center |
|H2O ||water vapor |
|HNO3 ||nitric acid |
|HF ||hydrogen fluoride |
|IMS ||Information Management System |
|K ||Kelvin |
|km ||kilometer |
|LOS ||line of sight |
|m ||meter |
|mb ||millibar |
|CLAES ||Cryogenic Limb Array Etalon Spectrometer |
|NASA ||National Aeronautics and Space Administration |
|NO ||nitric oxide |
|NO2 ||nitrogen dioxide |
|N2O ||nitrous oxide |
|N2O5 ||dinitrogen pentoxide |
|O3 ||ozone |
|PI ||Principal Investigator |
|ppmv ||parts per million by volume |
|RAC ||Remote Analysis Computer |
|SFDU ||Standard Formatted Data Units |
|TDRSS ||Tracking and Data Relay Satellite System |
|UARS ||Upper Atmosphere Research Satellite |
|USO ||User Services Office |
- 09 February 1998
UARS UKMO Correlative Summary
Correlative assimilation data from the U.K. Meteorological Office (UKMO) are included as supplementary data products to the UARS Project. The main use of the correlative assimilation data is to provide an independent analysis for comparison with data from the UARS instruments. The analysed fields will be used as the basis for diagnostic studies of the circulation of the middle atmosphere.
The numerical model used in the assimilation system is a global primitive equation model, with a split-explicit time integration scheme. It incorporates a comprehensive range of physical parameterization schemes. It uses a hybrid vertical coordinate system, with terrain-following model levels at low levels, gradually changing to pressure levels in the stratosphere. The input to the assimilation system are from the World Weather Watch network of surface and upper air observations and satellite data.
The UKMO correlative assimilation data products consists of one data file per day containing the following parameters:
- TEMP atmospheric temperature, degrees K
- HEIGHT geopotential height, m
- ZONWIN_P westerly (zonal) wind component, m/s
- MERWIN_P southerly (meridional) wind component, m/s
- OMEGA vertical velocity, Pa/s
NOTE: Vertical velocity is available in files dated 26 August 1992 onwards.
Data coverage is global for the UKMO correlative assimilation data products. The horizontal resolution is 2.5 degrees latitude by 3.75 degrees longitude, using a staggered grid system. For parameters other than wind components, each horizontal field consists of 73 rows of 96 points, starting at 90N, 0E. The wind data are staggered by half a grid, starting at 88.75N, 1.875E (with 72 rows).
The fields have been placed at the UARS standard pressure levels, where the pressure levels are defined by P(i) = 1000*10**(-i/6), i=0,1,2,... , where i is the index into the data array. Vertical coverage for the UKMO correlative assimilation data is from 1000 mb to 0.316 mb.
- Version 2.0
- Version baselined on addition to the GES Controlled Documents List, May 5, 1998.