NASA/TMm2000-209891, Vol. 120

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jeffrey A. Newcomer, Editors

Volume 120

BOREAS ECMWF 6-Hour

Analysis and Forecast Data

Pedro _terbo, ECMWF, Shinfield Park, Reading, United Kingdom

Alan Betts, Atmospheric Research, Pittsford, Vermont

Richard Strub, Raytheon ITSS, NASA Goddard Space Flight Center,

Greenbelt, Maryland

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

September 2000

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NASA/TMm2000-209891, Vol. 120

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jeffrey A. Newcomer, Editors

Volume 120

BOREAS ECMWF 6-Hour

Analysis and Forecast Data

Pedro _terbo, ECMWF, Shinfield Park, Reading, United Kingdom

Alan Betts, Atmospheric Research, Pittsford, Vermont

Richard Strub, Raytheon ITSS, NASA Goddard Space Flight Center,

Greenbelt, Maryland

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

September 2000
NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

Price Code: A17

Available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Price Code: A10
BOREAS ECMWF 6-Hour Analysis and Forecast Data

Pedro Viterbo, Alan K. Betts, Richard Strub

Summary

In cooperation with BOREAS atmospheric research efforts, the ECMWF agreed to provide BOREAS

with a customized subset of its 6-hourly forecast data. This data set contains parameters from three

ECMWF data products in GRIB format: Surface and Diagnostic Fields, Supplemental Fields, and

Extension Data. Sample software and information are provided to assist in reading the data files.

Temporally, the atmospheric parameters are available for the four main synoptic hours of 00, 06, 12,

and 18 UTC from 1994 to 1996. Spatially, the data are stored in a 0.5- by 0.5-degree

latitude/longitude grid. To cover the entire BOREAS study area, the grid extends from 48 to 62

degrees latitude and -92 to -114 degrees longitude. The data are stored in binary data representation

known as FM 92 GRIB. Due to the complexity of the content and format of this data set, users are

advised to read Sections 6, 7, 8, and 14 before using data.

Based on agreements between BOREAS and ECMWF, users may legally obtain and use these data

only by having a set of the BOREAS CD-ROMs that contain the data. Possession or use of these data

under any other circumstance is prohibited. See Sections 11.3 and 20.4 for details.

Note that the data files on the BOREAS CD-ROMs have been compressed using the Gzip program.

See Section 8.2 for details on the compression.

Table of Contents

1) Data Set Overview

2) Investigator(s)

3) Theory of Measurements

4) Equipment

5) Data Acquisition Methods

6) Observations

7) Data Description

8) Data Organization

9) Data Manipulations

10) Errors

11) Notes

12) Application of the Data Set

13) Future Modifications and Plans

14) Software

15) Data Access

16) Output Products and Availability

17) References

18) Glossary of Terms

19) List of Acronyms

20) Document Information

Page 1
1. Data Set Overview

1.1 Data Set Identification

BOREAS ECMWF 6-Hour Analysis and Forecast Data

1.2 Data Set Introduction

In cooperation with BOReal Ecosystem-Atmosphere Study (BOREAS) atmospheric research

eflbrts, the European Centre for Medium-Range Weather Forecasts (ECMWF) agreed to provide a

customized subset of their 6-hourly forecast data. This data set contains parameters from three

ECMWF data products: Surface and Diagnostic Fields, Supplemental Fields, and Extension Data. The

data cover the four main synoptic hours of 00, 06, 12, and 18 Universal Time Code (UTC) from 1994

to 1996 and are stored in a 0.5- by 0.5-degree regular latitude/longitude grid. Before using these data,

users are advised to carefully read Sections 6.1 and 11.3, which discuss model changes, known

errors, and proper use and referencing of the data.

1.3 Objective/Purpose

The ECMWF data sets were obtained in order to compare these large-area modeled data with more

localized data sets and to provide data for large-area models.

1.4 Summary of Parameters

This data set contains parameters from three ECMWF data products: Surface and Diagnostic

Fields, Supplemental Fields, and Extension Data. The data are reported at time intervals ranging from

6 to 24 hours. See Sections 7.3.1 and 8 for details.

1.5 Discussion

These are the operational ECMWF analyses for the period 1994 to 1996, covering the entire

large-scale BOREAS area at a 6-hour time resolution and a 0.5-degree lat/long resolution. Their

advantage over point data is that they are gridded and continuous with no gaps for the whole domain

for 3 years. However, they are subject to known and unknown model errors, and the ECMWF model

had several significant changes made to the model physics during this time period.

Although the global analysis uses the upper air observations and some surface synoptic data, the

diurnal cycle of temperature and humidity and the surface fluxes over land away from the analysis

times are calculated from the model radiation, cloud, and land-surface parameterizations.

Consequently, they are subject to any errors in the model parameterizations. In particular, the

subsurface variables, for which there are no input data, can drift with time unless constrained.

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data.

1.6 Related Data Sets

BOREAS AFM-05 Level-1 Upper Air Network Data

BOREAS AFM-05 Level-2 Upper Air Network Standard Pressure Level Data

BOREAS AFM-07 SRC Surface Meteorological Data

BOREAS AES Campbell Scientific Surface Meteorological Data

BOREAS AES MARSII Surface Meteorological Data

BOREAS AES READAC Surface Meteorological Data

Page 2
2. Investigator(s)

2.1 Investigator(s) Name and Title

BOREAS Staff Science

2.2 Title of Investigation

BOREAS Staff Science Meteorological Data Acquisition Program

2.3 Contact Information

Contact 1:

Pedro Viterbo

ECMWF

Shinfield Park

Reading RG2 9AX

UK

011-44-1189-499734

011-44-1189-869450 (fax)

pedro.viterbo@ecmwf.int

Contact 2:

Keith Fielding

Data Services

ECMWF

Shinfield Park

Reading RG2 9AX

UK

(0118) 949-9453

(0118) 986-9450 (fax)

Data.Services@ecmwf.int

Contact 3:

Alan K. Betts

Atmospheric Research

58 Hendee Lane

Pittsford, VT 05763

(802) 483-2087

(802) 483-6167 (fax)

akbett s@ aol.com

Contact 4:

Jeffrey A. Newcomer

Raytheon ITSS

NASA GSFC

Code 923

Greenbelt, MD 20771

(301) 286-7858

(301) 286-0239 (fax)

Jeffrey.Newcomer@ gsfc.nasa.gov

Page 3
3. Theory of Measurements

The theory behind the acquisition of a high-resolution gridded data set with several weather parameters

is to provide data for large-area models after validation against localized data.

These model products are conveniently gridded, and extend for the 3 years of BOREAS. The

land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of the characteristics of the

surface analyses and fluxes of the ECMWF model after April 1995 are discussed in Betts et al

(1998a,b,c).

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data.

4. Equipment

4.1 Sensor/Instrument Description

The ECMWF uses surface and upper air data from numerous sources and locations around Earth to

create its 6-hour forecast product. The output data are created using multivariate optimal interpolation

analysis, followed by nonlinear normal model initialization, before 960129 and 3D-VAR from

960130, and a high-resolution spectral model that produces a first-guess forecast for the subsequent

analysis. Data were assimilated every 6 hours.

4.1.1 Collection Environment

The input data used in the ECMWF models are collected from a wide range of global stations that

are operated in ambient atmospheric conditions.

4.1.2 Source/Platform

The platforms from which the input data are collected include human observers, fixed towers of

various sorts, and tethered and free-flying balloons.

4.1.3 Source/Platform Mission Objectives

The objective is for the platforms to support the instrumentation that is being used to make the

various measurements.

4.1.4 Key Variables

This data set contains parameters from three ECMWF data products: Surface and Diagnostic

Fields, Supplemental Fields, and Extension Data. The data are reported at time intervals ranging from

6 to 24 hours. See Sections 7.3.1 and 8 for details.

4.1.5 Principles of Operation

Not applicable.

4.1.6 Sensor/Instrument Measurement Geometry

Not applicable.

4.1.7 Manufacturer of Sensor/Instrument

The ECMWF in Reading, England.

4.2 Calibration

4.2.1 Specifications

Not applicable.

Page 4
4.2.1.1 Tolerance

Not applicable.

4.2.2 Frequency of Calibration

Not applicable.

4.2.3 Other Calibration Information

The land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of the characteristics

of the surface analysis of the ECMWF model after April 1995 are discussed in Betts et al. (1998a,b,c).

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data.

5. Data Acquisition Methods

The current model resolution, introduced into operation on 17-September-1991, is T213 with 31 levels

in the vertical.

ECMWF produces routine global analyses for the four main synoptic hours 00, 06, 12, and 18

UTC and global 10-day forecasts based on 12 UTC data. As a forecasting center with the emphasis on

the medium range, ECMWF operates with long data collection times of between 18 hours for the 18

UTC analysis and 8 hours for the 12 UTC final analysis. This schedule ensures the most

comprehensive global data coverage including the Southern Hemisphere surface data and global

satellite sounding data.

6. Observations

6.1 Data Notes

Users are advised to carefully read this section, which discusses model changes and known errors,

before using these data.

This is an operational analysis, so the user needs to be aware of heterogeneity's introduced when

new model physics cycles were introduced to correct known model problems. (A reanalysis is planned

for 1999 with a current model version.)

Key changes affecting the boreal forest land surface are:

• 04-Aug-1993: 4-layer prognostic land surface scheme introduced (Viterbo and Beljaars,

1995).

• 04-Jul-1994: Soil reservoirs refilled because they had partially dried out after model had run

freely for one year. The impact of this is that the evaporation increases after 04-Jul-1994;

probably too low before that date and too high after.

• 06-Dee-1994: Nudging of soil water introduced to control long-term drifts of soil water

(Viterbo and Courtier, 1995).

• 04-Apr-1995:ERA-15 Reanalysis model introduced into operations. Including prognostic

cloud scheme of Tiedtke (1993) and new subgrid orography scheme (Lott and Miller, 1997).

The impact of this is that it improves radiative fluxes at surface, probably incoming solar is

too high before this date. The summer surface evaporation in this model appears to be too

high over the boreal forest (see Betts et al., 1998b), although in spring it is low because of an

albedo error (see below).

• 30-Jan-1996: The 3-dimensional variational data assimilation technique (3D-VAR) replaces

the optimal interpolation (OI) method. For a description see Courtier et al. (1998) and Rabier

et al. (1998); for a description of the impact on analysis and forecasts see Andersson et al.

(1998).

Page 5
19-Sep-1996: Soil freezingplusnewstableboundarylayerparameterizationandincreased

soilheatflux couplingintroduced.Theimpactof thisis thatit reducescoldbiasin winter

causedby lackof latentheatof phasechangeanduncouplingof surfacetemperaturefrom

atmosphereunderstableboundarylayer(Viterboet al., 1997).It alsoreducescold

temperaturebiasatnight,causedby stableboundarylayeruncoupling,andmayaffectdaytime

diurnalcycleof humidity(Bettset al, 1998a).

10-Dee-1996: New borealforestsnowalbedointroduced(ViterboandBetts,1997,1998),

whichreducesmaximumsnowalbedoof borealforestsfrom 0.8to 0.2.Theimpactisthat

beforethis,thewinterof 1996-97netradiationis smalluntil snowmeltsin springandspring

temperaturesaretoo coldby 10to 15K. (Bettset al., 1998b).

Primaryvalidationstudiesall dealwith themodelversionafter04-Apr-1995andareasfollows

Bettset al., 1998a,dealingwith comparisonwith theFirst InternationalSatelliteLandSurface

ClimatologyProject(ISLSCP)FieldExperiment(FIFE)data.

Bettset al., 1998b,dealingwith bothacomparisonwith theFIFEdataandtheBOREAS

TF#3blacksprucesitewestof Thompson,Manitoba.

Bettsetal., 1998c,dealingwith basinscalestudiesof theArkansas-RedRiverbasinwith the

ERA-15reanalysismodel.Thisaddressestheimpactof nudgingonthesoilhydrologyandthe

errorsin thediurnalcycleof precipitation,whichappearsto affecttheBOREASregionalso.

In brief,themodelhasa25-30%spin-upof precipitationin theanalysiscycleandthe12-24

hourforecast,whichbracketstheobservedgriddedprecipitationfrom Higginsetal. (1996)

overtheUnitedStates.Themodelhasanearlocalnoonprecipitationmaximumwhichmaybe

relatedto amorningpeakof mixingratio.

In thisdatasetthemodelspin-upcanbeassessedby comparingthethreefields:

ECHWF

Parameter

Number Description Units

142 Large Scale Precipitation (m)

143 Convective Precipitation (m)

228 Total Precipitation (m)

Fields 142 and 143 are from the analysis cycle, and field 228 is convective plus large-scale

precipitation from a 12- to 36-hour forecast after the model has spun up. Field 228 is probably a better

estimate of total precipitation, but 142+143 give a crude estimate of the diurnal cycle.

Evaporation (field 182) and latent heat flux (field 147) are inconsistent. There was a numeric

problem in the computations related to the interception reservoir, which results in the surface latent heat

flux being higher than the liquid evaporation in the subsurface hydrology, when converted to the same

units. The ratio is variable, as it depends on the variable interception. For Mississippi basin averages it

was on the order of 1.07 (see Betts et al., 1998c).

Beljaars et al., 1996, and Betts et al., 1996, deal with the improvements associated with the

introduction of the 4-layer soil water model in 1993 (Viterbo and Beljaars, 1995)

6.2 Field Notes

Not applicable.

Page 6
7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The BOREAS ECMWF data cover the area of 48 ° N to 62 ° N latitude and 114 ° to 92 ° W longitude.

The North American Datum of 1983 (NAD83) corner coordinates of the BOREAS region are:

Longitude Latitude

Northwest iii.000 W

Northeast 93.502 W

Southeast 96.970 W

Southwest iii.000 W

59.979 N

58.844 N

50.089 N

51.000 N

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The BOREAS Information System (BORIS) ECMWF data were extracted in a 0.5-degree by

0.5-degree grid. The 0.5-degree grid was interpolated from the original model resolution of Gaussian

N160 for the physics calculations. The points in the 0.5- x 0.5-degree grid are at whole degrees and

half degrees in both latitude and longitude, and they represent the center of the 0.5 x 0.5 box

surrounding them.

7.1.4 Projection

The coordinates for the BORIS ECMWF data are latitude and longitude.

7.1.5 Grid Description

The BORIS ECMWF data are stored in a systematic latitude/longitude grid.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

With the exception of parameters 236 and 237 (Soil Temperature and Soil Wetness level 4) for

1994, BORIS has all of the ECMWF parameters listed in Section 7.3.1 for every day of the years

1994 through 1996. Different parameters were modeled for different times (see Section 7.2.3).

7.2.2 Temporal Coverage Map

Not available.

7.2.3 Temporal Resolution

All the ECMWF parameters, except for Total Precipitation, are given once every 6 hours. All

fluxes are accumulated for the forecast period. The Total Precipitation values are given once every

24-hour period, calculated from the 12-36 hour forecast from 1200 UTC the preceding day.

7.3 Data Characteristics

7.3.1 Parameter/Variable

The parameters that are included in each of the three ECMWF data products and their associated

descriptions and units are:

Surface and Diagnostic Fields

Note that in 1994, data set parameters 236 and 237 (Soil Temperature and Soil Wetness level 4) are

Page 7
missing.All of theECMWFparametersareavailablefor everydayduring1995and1996.Different

parametersweremodeledfor differenttimeintervals(seeSection7.2.3).

ECHWF

Parameter

Number Description Units

129 Geopotential (as gz in m2/s 2)

134 Surface Pressure (Pa)

139 Soil Temperature level 1 (K)

140 Soil wetness level 1 (see * below)

141 Snow Depth (m)

151 Mean Sea Level Pressure (Pa)

165 U-Wind Component at 10m (m/s)

166 V-Wind Component At i0 m (m/s)

167 Temperature At 2m (K)

168 Dewpoint At 2m (K)

170 Soil Temperature level 2 (K)

171 Soil Wetness level 2 (see * below)

172 Land/Sea Mask (see ** below)

173 Surface Roughness (m)

174 Albedo (see *** below)

183 Soil Temperature level 3 (K)

184 Soil Wetness level 3 (see * below)

236 Soil Temperature level 4 (K)

237 Soil Wetness level 4 (see * below)

These are values every 6 hours at 00, 06, 12, and 18 UTC.

* The units of soil water in this archive are unusual. They are

(m s of water)/(0.07 m s of soil) for all levels 1-4. That is, if the value

in the ECMWF file is X, the value W (m s of water)/(m 3 of soil) will be W :

X/0.07. The 4 soil levels represent depths of 0 to 7 cm, 7 to 28 cm, 28 to

i00 cm and i00 to 289 cm.

** The land/sea mask contains values of 0 to indicate sea (or water) and 1 to

indicate land areas.

*** The albedo values range from 0 to 1 indicating from 0 to 100% reflectance of

the incoming radiation by the surface.

Supplemental Fields

These are 0- to 6-hour accumulated fluxes from short-term forecasts starting at 00, 06, 12, and 18

UTC. The units are peculiar in that they are accumulated in seconds of forecast time (6 hours x 3600

secs/hour). Heat and radiation fluxes are therefore in W/m2, stresses in N/m2; while precipitation,

snowfall and evaporation are in accumulated meters. Snowfall is the sum of convective and large-scale

snowfall. Evaporation and latent heat flux are numerically inconsistent (see Section 6.1).

The 1994 supplemental field data were delivered to BOREAS in two pieces. As such, two files are

required to make a complete set of supplemental variables for a given date. See Section 8 for more

information.

Page 8
ECHWF

Parameter

Number Description Units

142

143

144

146

147

164

176

177

178

179

180

181

182

Large Scale Precipitation

Convective Precipitation

Snow Fall

Surface Sensible Heat Flux

Surface Latent Heat Flux

Total Cloud Cover

Surface Solar Radiation

Surface Thermal Radiation

Top Solar Radiation

Top Thermal Radiation

East/West Surface Stress

North/South Surface Stress

Evaporation

(m)

(m)

(m)

(W * seconds) /m 2)

(W * seconds) /m 2)

(see **** below)

(W *

(W *

(W *

(W *

(N *

(N *

seconds /m 2)

seconds /m 2)

seconds /m 2)

seconds /m 2)

seconds /m 2)

seconds /m 2)

(m)

**** The Total Cloud Cover values range from 0 to 1 indicating from 0 to 100%

cloud cover.

Extension Data

These are 24-hour accumulated precipitation from the 12- to 36-hour forecast starting from 12 UTC

the previous day.

ECMWF

Parameter

Number Description Units

228 Total Precipitation

7.3.2 Variable Description/Definition

See Section 7.3.1.

(m)

7.3.3 Unit of Measurement

See Section 7.3.1.

7.3.4 Data Source

The data were provided to BOREAS by ECMWF personnel.

7.3.5 Data Range

None given.

7.4 Sample Data Record

Not applicable.

Page 9
8. Data Organization

8.1 Data Granularity

The ECMWF data are stored in multi-date GRIB files. The smallest unit of data is a multi-date

block containing several of the ECMWF parameters. Refer to section 7.3.1 for the organization of

parameters.

8.2 Data Format(s)

8.2.1 Uncompressed Data Files

The BOREAS ECMWF data set consists of multi-date blocks of three ECMWF data products

(Surface and Diagnostic Fields, Supplemental Fields, and Extension Data) and associated software

files.

The data products contain data for multiple days, with the file names containing the start date of the

multiple day period. The data in a file are stored in chronological order in a binary data representation

known as FM 92 GRIB. GRIB is a common standard used by the operational meteorological centers

for storage and exchange of gridded fields. The major advantages of the GRIB format are that files are

typically 1/2 to 1/3 of the size of normal binary files, the fields are self-describing, and GRIB is an

open, international standard.

On the BOREAS CD-ROM set, the format of the uncompressed file

YY-MM-DD REGION FILETYPE

names is:

where YY MM DD

REGION

FILETYPE

is

of

is

of

is a

(ECl,

ECl

EC2*

EC3

the starting date (YY - year, MM - month, DD - day of month

the data contained in the file,

a constant field indicating that the spatial coverage

the data is the entire BOREAS region, and

three or four character string indicating the file type

EC2, EC2a, EC2b, or EC3), where:

files contain the Surface and Diagnostic Field data,

files contain the Supplemental Fields data. In 1994 the

Supplemental Fields data were delivered in two components

EC2a and EC2b files. The EC2a files contain parameters

146, 147, 164, and 176 through 181 of the Supplemental

Fields data. EC2b files contain parameter numbers 142, 143,

144, and 182 of the Supplemental Fields data. In 1995 and

1996, all of the Supplemental Fields data are stored in a

single EC2 file.

files contain the Extension data.

Two American Standard Code for Information Interchange (ASCII) software files are provided with

the data. The first one (SOFTWARE1) contains source code that when built and run, uses the second

file (SOFTWARE2) as input and divides the SOFTWARE2 file into various components. See the

associated gribex readme.txt file for more information about these files, and section 14.1. The

specification of the GRIB code is given in the World Meteorological Organization (WMO) Publication

306, Manual on Codes.

8.2.2 Compressed CD-ROM Files

On the BOREAS CD-ROMs, the ECMWF data and software files have been compressed with the

GNU zip (Gzip) compression program (file name *.gz). These data have been compressed using gzip

version 1.2.4 and the high compression (-9) option (Copyright (C) 1992-1993 Jean-loup Gailly). Gzip

uses the Lempel-Ziv algorithm (Welch, 1994) used in the zip and PKZIP programs. The compressed

files may be uncompressed using gzip (-d option) or gunzip. Gzip is available from many Web sites

(for example, ftp site prep.ai.mit.edu/pub/gnu/gzip-*.*) for a variety of operating systems in both

Page 10
executableandsourcecodeform.Versionsof thedecompressionsoftwarefor varioussystemsare

includedontheCD-ROMs.

9. Data Manipulations

9.1 Formulae

9.1.1 Derivation Techniques and Algorithms

For a detailed description of the ECMWF/WCRP Level III-A Global Atmospheric Data Archive,

see ECMWF ECMWF/WCRP Level III-A Global Atmospheric Data Archive Technical Attachment.

9.2 Data Processing Sequence

9.2.1 Processing Steps

BORIS staff adapted the ECMWF software to extract metadata, verify the data set content, and

inventory the data in the BORIS Oracle data base. BORIS staff compressed the binary files for release

on CD-ROM.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

See Section 9.1.1.

9.3.2 Calculated Variables

See Section 9.1.1.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of

the characteristics of the surface analysis of the ECMWF model after April 1995 and its errors are

discussed in Betts et al. (1998a,b,c).

10.2 Quality Assessment

10.2.1 Data Validation by Source

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of

the characteristics of the surface analysis of the ECMWF model after April 1995 and its errors are

discussed in Betts et al. (1998a,b,c).

Page 11
10.2.2 Confidence Level/Accuracy Judgment

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The precipitation data have a known spin-up of 25 to 30% from the 6-hour

analysis cycle to the 12- to 36-hour forecast that is in the extension data set. Use the latter to assess this

and read the discussion in Betts et al. (1998c) for the Arkansas-Red River basin.

In this data set, the model spin-up can be assessed by comparing three fields.

142 Large Scale Precipitation

143 Convective Precipitation

228 Total Precipitation

Fields 142 and 143 are from the analysis cycle and field 228 accounts for convective and large-scale

precipitation from a 12- to 36-hour forecast after the model has spun up. Field 228 is probably a better

estimate of total precipitation, but 142+143 give a crude estimate of the diurnal cycle.

Model data sets will reflect model parameterizations and model problems. For example, in the

ECMWF model, the 2-m surface temperature is not itself a model variable - it is derived from the

lowest model level at - 30 m elevation above the surface and the skin temperature, using similarity

theory. The surface 'skin' temperature is sensitive to radiation errors (particularly at night), which are

themselves sensitive to model cloud amount. Thus, a variable like Train in a model must be used with

caution. Values may have absolute biases because of model cloud biases even if horizontal gradients

across the BOREAS domain are of interest. Comparison with data time series at key locations should

show these biases.

10.2.3 Measurement Error for Parameters

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of

the characteristics of the surface analysis of the ECMWF model after April 1995 and its errors are

discussed in Betts et al. (1998a,b,c).

10.2.4 Additional Quality Assessments

None.

10.2.5 Data Verification by Data Center

BORIS adapted the sample software supplied by ECMWF to extract information about the

parameters contained in each data file and the spatial and temporal extent of the data. This information

was then used to inventory the data files in the BORIS data base. The actual parameter values were not

verified or reviewed.

1 1. Notes

11.1 Limitations of the Data

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The land-surface scheme is discussed in Viterbo and Beljaars (1995). Some of

the characteristics of the surface analysis of the ECMWF model after April 1995 and its errors are

discussed in Betts et al. (1998a,b,c).

11.2 Known Problems with the Data

Users are advised to carefully read Section 6.1, which discusses model changes and known errors,

before using these data. The refilling of the soil water reservoirs on 04-Jul-1994 will increase

evaporation after that date. The winter temperatures are biased cold (by as much as 10-15 K in spring

before the winter of 1996-97, because of a stable boundary layer error (corrected on 19-Sep-1996) and

a forest snow albedo error (corrected on 10-Dec-1996) (see Viterbo et al., 1997; Viterbo and Betts,

1997).

Page 12
11.3 Usage Guidance

Before uncompressing the Gzip files on the CD-ROM, be sure that you have enough disk space to

hold the uncompressed data files. Then use the appropriate decompression program provided on the

CD-ROM for your specific system.

The ECMWF data may be used while noting the following:

• The 0.5-degree grid was interpolated from the original model resolution of Gaussian N160

• The data sets are adapted to a specific model orography; the data sets have biases that are only

partially documented

• No surface observations of T, q, precipitation, or surface wind observations over land were

used in the analysis

• Model spin-up can seriously affect the 6-hour forecast data supplied from the supplementary

fields (precipitation, fluxes, radiation, surface stress, total cloud cover, and evaporation). A

check on precipitation can be made using the data supplied from the Extension data set, which

represents a day (0000 UTC to 2400 UTC) of total precipitation. This is derived from the

36-hour forecast time step minus the 12-hour time step to reduce the effect of spin-up

• Several fields such as soil moisture and temperature (4-levels) and snow depth, although

included in the analysis data set, are not analyzed but evolve during the assimilation cycle.

The ECMWF provided data for the BOREAS CD-ROM set from the ECMWF/WCRP Level III-A

Global Atmospheric Data Archive. ECMWF data on the CD-ROM set are provided under the following

conditions:

• Based on agreements between BOREAS and ECMWF, users may legally obtain and use these

data only by having a set of the BOREAS CD-ROMs that contain the data. Possession or use

of these data under any other circumstance is prohibited.

• The proprietary rights and copyright of the software remain with ECMWF. The software

supplied is intended solely for use with ECMWF data and must not be used for any other

purpose.

• The ECMWF data and software will not be supplied in whole or in part to any third party

without the authorization of ECMWF.

• Data and software will not be used for commercial purposes.

• Articles, papers, or written scientific works of any form, based in whole or in part on data

supplied by ECMWF, will contain an acknowledgment concerning the supplied data. The data

may be cited as follows: ECMWF 1994. The Description of the ECMWF/WRCP Level III-A

Global Atmospheric Data Archive.

Although every care has been taken in preparing and testing the data and software, ECMWF cannot

guarantee that the data are correct in all circumstances, or that the software will work correctly in all

circumstances; neither does ECMWF accept any liability whatsoever for any error or omission in the

data or software, or for any loss or damage arising from its use.

11.4 Other Relevant Information

None.

12. Application of the Data Set

These are the operational ECMWF analyses for the period 1994 to 1996, covering the entire large-scale

BOREAS area at a 6-hour time resolution and a 0.5-degree latitude/longitude resolution. Their

advantage over point data is that they are gridded and continuous with no gaps for the whole domain

for 3 years. However, they are subject to known and unknown model errors, and the ECMWF model

had several significant changes made to the model physics during this time period. The ECMWF data

sets were obtained in order to compare these large-area modeled data with more localized data sets and

to provide data for large-area models.

Page 13
13. Future Modifications and Plans

A reanalysis is planned in 1999 for the period of 1979 to 1998 with a 1998/99 version of the ECMWF

model. This model will have several improvements over the operational model. In particular, the

winter surface temperatures will be improved, and the boreal forest may be better represented.

During the BOREAS follow-on research period (1998 to 1999), a gridded data set will be

produced from the various surface meteorological data sets that should be helpful in further analyzing

the ECMWF results.

14. Software

14.1 Software Description

Two ASCII software files are provided with the data. The first one (SOFTWARE1) contains

Fortran source code (data_split) that when built and run, uses the second file (SOFTWARE2 - a file of

routines) as input and divides the SOFTWARE2 file into its several subroutine components. The file

ecmwf_grib.pdf is also provided as an information source. This is a paper describing the GRIBEX

subroutine for encoding and deocoding GRIB data.

There are various sources of software on the WWW for reading GRIB format data. Two sites

provided particularly useful utilities for reading and/or inventorying the GRIB files. These sites are

mentioned below.

http://wesley.wwb.noaa.gov/reading_grib.html

This site is a great resource for users of data stored in GRIB, complete with syntax examples for

different platforms. This site has a pointer to the c-program wgrib.c that is more user-friendly than that

provided by ECMWF. The program wgrib.c processes one variable per time-step. Using the wgrib

code one can extract desired variables and put them in one image per time-step per variable. A

comment on this site states that "One's first impulse is to convert the GRIB file into some

"understandable" format. It is better to extract the desired data and leave it in GRIB. This extraction

can take as little as one command line using wgrib. Keep the data min GRIB until you need it

immediately."

http://www.nerc-bas.ac.uk/public/icd/wmc/perl.html

There isn't much documentation and information here, but this site provides a handy perl script for

decoding standard GRIB files.

14.2 Software Access

Gzip is available from many Web sites across the Internet (for example, FTP site

prep.ai.mit.edu/pub/gnu/gzip-*.*) for a variety of operating systems in both executable and source

code form. Versions of the decompression software for various systems are included on the

CD-ROMs.

The GRIB software provided on the CDROM to convert the data from GRIB Binary

Representation to ASCII is available from ECMWF. There are various additional sources on the World

Wide Web (WWW), see section 14.1.

Please note the following regarding the ECMWF-provided software: The proprietary rights and

copyright of the software remain with ECMWF. The software supplied is intended solely for use with

ECMWF data and must not be used for any other purpose. The ECMWF data and software will not be

supplied in whole or in part to any third party without the authorization of ECMWF. Data and software

will not be used for commercial purposes. Although every care has been taken in preparing and testing

the data and software, ECMWF cannot guarantee that the data are correct in all circumstances, or that

Page 14
thesoftwarewill work correctlyin all circumstances;neitherdoesECMWFacceptanyliability

whatsoeverfor anyerroror omissionin thedataor software,or for anylossor damagearisingfrom

its use.

15. Data Access

The ECMWF 6-hour analysis and forecast data are available from the Earth Observing System Data

and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active

Archive Center (DAAC).

15.1 Contact Information

For BOREAS data and documentation please contact:

ORNL DAAC User Services

Oak Ridge National Laboratory

P.O. Box 2008 MS-6407

Oak Ridge, TN 37831-6407

Phone: (423) 241-3952

Fax: (423) 574-4665

E-mail: ornldaac@ornl.gov or ornl@eos.nasa.gov

15.2 Data Center Identification

Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory

(ORNL) Distributed Active Archive Center (DAAC) for Biogeochemical Dynamics

http://www-eosdis.ornl.gov/.

15.3 Procedures for Obtaining Data

Although the BOREAS ECMWF data are being held in a public archive, agreements between

BOREAS and ECMWF limit the distribution and use of the data. The BOREAS CD-ROM series is

publicly available, and the ECMWF data on the CD-ROMs are available for use by the owner of the

CD-ROM set only. See Section 11.3 and please contact the ORNL DAAC User Services office to get

the most recent information.

Users may obtain information on these data directly through the ORNL DAAC online search and

order system [http://www-eosdis.ornl.gov/] or by contacting User Services by electronic mail,

telephone, fax, letter, or personal visit using the contact information in Section 15.1.

15.4 Data Center Status/Plans

The ORNL DAAC is the primary source for BOREAS field measurement, image, GIS, and

hardcopy data products. The BOREAS CD-ROM and data referenced or listed in inventories on the

CD-ROM are available from the ORNL DAAC.

16. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

Page 15
17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Welch, T.A. 1984. A Technique for High Performance Data Compression. IEEE Computer, Vol. 17,

No. 6, pp. 8-19.

17.2 Journal Articles and Study Reports

Newcomer, J., D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, J. Nickeson,

A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P. Sellers, eds. 2000. Collected Data of The

Boreal Ecosystem-Atmosphere Study. NASA. CD-ROM.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1994-3.0, NASA BOREAS Report (EXPLAN 94).

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1996-2.0, NASA BOREAS Report (EXPLAN 96).

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994

Operations. NASA BOREAS Report (OPS DOC 94).

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996

Operations. NASA BOREAS Report (OPS DOC 96).

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B.

Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal

ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year.

Bulletin of the American Meteorological Society. 76(9): 1549-1577.

Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M. Ryan, K.J. Ranson, P.M.

Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T.

Gower, D. Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS

in 1997: Experiment Overview, Scientific Results and Future Directions. Journal of Geophysical

Research 102(D24): 28,731-28,770.

ECMWF Physics and Its Validation (Key References):

Andersson, E., J. Haseler, P. Unden, P. Courtier, G. Kelly, D. Vasilijevic, C. Brankovic, C.

Cardinali, C. Gaffard, A. Hollingsworth, C. Jakob, P. Janssen, E. Klinker, A. Lanszinger, M.

Miller, F. Rabier, A. Simmons, B. Strauss, J.-N. Thepaut, and P. Viterbo. 1998. The ECMWF

implementation of three-dimensional variational assimilation (3D-VAR). III: Experimental results.

Quart. J. Roy. Meteor. Soc., in press.

Beljaars, A.C.M., P. Viterbo, M.J. Miller, and A.K. Betts. 1996. The anomalous rainfall over the

United States during July 1993: sensitivity to land surface parameterization and soil moisture

anomalies. Mon. Wea. Rev., 124, 362-383.

Betts, A.K., J.H. Ball, and A.C.M. Beljaars. 1993. Comparison between the Land surface response

of the ECMWF model and the FIFE-1987 data. Quart. J. Roy. Meteor. Soc., 119, 975-1001.

Betts, A.K., J.H. Ball, Beljaars, A.C.M., M.J. Miller, and P. Viterbo. 1996. The

land-surface-atmosphere interaction: a review based on observational and global modelling

perspectives. J. Geophys. Res. 101, 7209-7225.

Page 16
BettsA.K., P.Viterbo,andA.C.M. Beljaars.1998a.Comparisonof theland-surfaceinteractionin

theECMWFreanalysismodelwith the 1987FIFEdata.Mort.Wea.Rev., 126,186-198.

BettsA.K., P.Viterbo, A.C.M. Beljaars,H-L. Pan,S-Y.Hong, M.L. Goulden,andS.C.Wofsy.

1998b.Evaluationof theland-surfaceinteractionin theECMWFandNCEP/NCARreanalysesover

grassland(FIFE)andborealforest(BOREAS).J.Geophys.Res.,in press.

Betts,A.K., P.Viterbo,andE.Wood. 1998c.SurfaceEnergyandwaterbalancefor the

Arkansas-RedRiverbasinfrom theECMWFreanalysis.J.Climate,in press.

Courtier,P.,E.Andersson,W. Heckley,J.Pailleux,D. Vasilijevic, M. Hamrud,A. Hollingsworth,

F. Rabier,andM. Fisher.1998.TheECMWFimplementationof three-dimensional variational

assimilation(3D-VAR). I: Formulation.Quart.J.Roy.Meteor.Soc.,in press.

HigginsRW,K.C. Mo, S.D.Schubert.1996.Themoisturebudgetof thecentralUnitedStatesin

springasevaluatedin theNCEP/NCARandtheNASA/DAO reanalyses.Monthly WeatherReview

124:(5) 939-963.MAY 1996.

Lott, F. andM.J.Miller. 1997.A new sub-gridscaleorographicdragparameterization:Its formulation

andtesting. Quart.J.Roy.Meteor.Soc.,123,101-127.

MorcretteJ.-J.1990.Impactof changesto theradiativetransferparameterizationpluscloudoptical

propertiesin theECMWF model.Mort.Wea.Rev.,118,847-873.

MorcretteJ.-J.1991.Radiationandcloudradiativepropertiesin theEuropeanCentrefor

Medium-RangeWeatherForecastsforecastingsystem.J.Geophys.Res.,96,9121-9132.

Rabier,F.,A. McNally, E. Andersson,P.Courtier,P.Unden,J.Eyre,A. Hollingsworth,andF.

Bouttier.1998.TheECMWFimplementationof three-dimensional variationalassimilation(3D-VAR).

III: Structurefunctions.Quart.J.Roy.Meteor.Soc.,in press.

TiedtkeM. 1984.Theeffectof penetrativecumulusconvectiononthelargescaleflow in thegeneral

circulationmodel.Beitr.Phys.Atmos.57,216-239.

TiedtkeM. 1989.A comprehensivemassflux schemefor cumulusparameterizationin large-scale

models.Mon. Wea.Rev., 117,1779-1800.

Tiedtke,M. 1993.Representationof cloudsin large-scalemodels,Mon.Wea.Rev.,121,3040-3061.

Viterbo,P.,A.C.M. Beljaars,J.-F.Mahfouf, andJ.Teixeira.1997.Therole of soil waterfreezingin

theinteractionof thesurfacewith thestableboundarylayer.InternalECMWFmemo.Availablefrom

ECMWF, ShinfieldPark,ReadingRG2 9AX, UK.

Viterbo,P.andA.C.M. Beljaars.1995.An improvedland-surfaceparameterizationin theECMWF

modelandits validation.J.Clim., 8, 2716-2748.

Viterbo,P.andA.K. Betts.1997.Theforecastimpactof changesto thesnowalbedoof theboreal

forests.CAS/JSCWorking GrouponNumericalExperimentation.#25.,ResearchActivities in

AtmosphericandOceanicModelling.

Viterbo,P.andA.K. Betts.1998.Theforecastimpactof changesto thealbedoof theborealforestsin

thepresenceof snow.J.Geophys.Res.(submitted).

Page17
Viterbo,P.andP.Courtier.1995.Theimportanceof soil waterfor medium-rangeweather

forecasting.Implicationsfor dataassimilation,WorkshoponImbalanceofSlowlyVarying

Componentsof PredictableAtmosphericMotions,World Meteorol.Org.,Beijing,China.[Available

from ECMWF,ShinfieldPark,ReadingRG29AX, England].

ECMWF Initialization and Analysis System:

Bengtsson, L., M. Kanamitsu, P. Kaliberg, and S. Uppala. 1982. FGGE 4-dimensional data

assimilation at ECMWF. Bull. Amer. Meteor. Soc., 63, 29-43.

Hollingsworth, A. and P. Linnberg. 1986. The statistical structure of short-range forecast errors as

determined from radiosonde data. Part I: The wind field.

Hollingsworth, A., D.B. Shaw, P. Linnberg, L. Illari, K. Arpe, and A.J. Simmons. 1986.

Monitoring of observation and analysis quality by a data assimilation system. Mon. Wea. Rev., 114,

5,861-879.

Linnberg, P. and A. Hollingsworth. 1986. The statistical structure of short-range forecast errors as

determined from radiosonde data. Part II: The covariance of heights and wind errors, Tellus 38A,

137-161.

Lorence, A.C. 1981. A global three-dimensional multivariate statistical interpretation scheme. Mon.

Wea. Rev., 109, 701-721.

Machenhauer, B. 1977. On the dynamics of gravity oscillations in a shallow water model, with

application to normal mode initialization. Beitr. Phys. Atmos. 50, 259-271.

Shaw, D.B., P. Linnberg, A. Hollingsworth, and P. Unddn. 1987. Data assimilation: The 1984/85

revision of the ECMWF mass and wind analysis. Quart. J. Roy. Meteor. Soc., 113,533-566.

Unddn, P. 1989. Tropical data assimilation and analysis of divergence. Mon. Wea. Rev., 117,

2495-2517.

Temperton, C. 1988. Implicit normal mode initialization. Mon. Wea. Rev., 116, 1013-1031.

Temperton, C. and D.L. Williamson. 1981. Normal mode initialization for a multivariate grid-point

model: Part I linear aspects. Mon. Wea. Rev., 109, 720-743.

Wergen, W. 1988. The diabatic ECMWF normal mode initialization scheme. Beitr. Phys. Atmosph.

61,274-304.

Williamson, D.L. and C. Temperton. 1981. Normal mode initialization for a multivariate grid-point

model: Part II nonlinear aspects. Mon. Wea. Rev., 109, 744-757.

ECMWF Prediction Model:

ECMWF provides a comprehensive service from the Level II data archive, which is documented under

ECMWF. 1996. The Description of the ECMWF/WRCP Level III-A Global Atmospheric Data

Archive. ECMWF. Reading RG2 9AX, England. Interested users may write to The Director,

ECMWF, Shinfield Park, Reading RG2 9AX, U.K., for further information.

Geleyn, J.F. 1988. Interpolation of wind temperature and humidity values from model levels to the

height of measurements. Tellus, 40A, 347-351.

Page 18
Geleyn,J.F.andA. Hollingsworth.1979.An economicalanalyticalmethodfor thecomputationof the

interactionbetweenscatteringandline absorptionofradiation.Beitr.Phys.Atmos.,52, 1-16.

Geleyn,J.F.andH.J.Preuss.1983.A newdatasetof satellite-derivedsurfacealbedovaluesfor

operationaluseatECMWF.Arch. Meteor.Geophys.Bioclim., Ser.A, 32,353-359.

Hortal,M., SimmonsA., 1991.UseofreducedGaussiangrids in spectralmodels.Mort.Wea.Rev.,

119,1057-1074.

Janssen,P.,A. Beljaars,A. Simmons,andP.Viterbo.1992.On thedeterminationof thesurface

stressin anatmosphericmodel.Mort.Wea.Rev.

Jarraud,M., A. Simmons,andM. Kanamitsu.1988.Sensitivityof medium-rangeweatherforecasts

to theuseof anenvelopeorography.Quart.J.Roy.Meteor.Soc.,114,989-1025.

Miller, M., A. Beljaars,andT. Palmer.1992.The sensitivityof theECMWF modelto the

parameterizationof evaporationfrom thetropicaloceans.J.of Climate,5,418-434.

Miller, M., T. Palmer,andR. Swinbank.1989.Orographicgravity - wavedrag:its parameterization

andinfluencein generalcirculationandnumericalweatherpredictionmodel.Meteor.Atmos.Phys.,

40, 84-109.

Simmons,A. andD. Dent.1989.TheECMWF multi-taskingweatherpredictionmodel,computer

PhysicsReports,11, 165-194.

Simmons,A.J., D.M. Burridge,M. Jarraud,C. Girard,andW. Wergen.1989.TheECMWF

medium-rangepredictionmodels.Developmentof thenumericalformulationsandtheimpactof

increasedresolution.Meteor.Atmos.Phys.,40,28-60.

Slingo,J.J.1987.Thedevelopmentandverificationof acloudpredictionschemefortheECMWF

model.Quart.J.Roy. Meteor.Soc.,213,899-927.

17.3 Arehive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

Page 19
ASCII

BOREAS

BORIS

CD-ROM

DAAC

ECMWF

EOS

EOSDIS

FIFE

GIS

GSFC

HTML

ISLSCP

MARS

NAD83

NASA

NSA

OI

ORNL

PANP

PDF

SSA

URL

UTC

WMO

19. List of Acronyms

- American Standard Code for Information Interchange

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- European Centre for Medium Range Weather Forecasts

- Earth Observing System

- EOS Data and Information System

- First ISLSCP Field Experiment

- Geographic Information System

- Goddard Space Flight Center

- HyperText Markup Language

- International Satellite Land Surface

- Meteorological Archive and Retrieval

- North American Datum 1983

- National Aeronautics and Space

- Northern Study Area

- Optimal Interpolation

- Oak Ridge National Laboratory

- Prince Albert National Park

- Portable Document Format

- Southern Study Area

- Uniform Resource Locator

- Universal Time Code

- World Meteorological Organization

Climatology Project

System

Administration

20. Document Information

20.1 Document Revision Date

Written: 22-Jun- 1998

Last Updated: 20-Dec- 1999

20.2 Document Review Date(s)

BORIS Review: 04-Aug- 1998

Science Review: 04-Aug- 1998

20.3 Document ID

20.4 Citation

Articles, papers, or written scientific works of any form, based in whole or in part on the data

supplied by ECMWF, must contain an acknowledgment concerning the supplied data. The data may be

cited as follows:

ECMWF 1995. The Description of the ECMWF/WRCP Level III-A Global Atmospheric Data

Archive. ECMWF. Reading RG2 9AX, England. Please include citations of relevant papers in Section

17.2.

Page 20
If usingdatafromtheBOREASCD-ROM series,alsoreferencethedataas:

BOREASStaffScience,"BOREASStaffScienceMeteorologicalDataAcquisitionProgram."In

CollectedDataof TheBorealEcosystem-AtmosphereStudy.Eds.J.Newcomer,D. Landis,S.

Conrad,S.Curd,K. Huemmrich,D.Knapp,A. Morrell, J.Nickeson,A. Papagno,D. Rinker,R.

Strub,T. Twine,F. Hall, andP. Sellers.CD-ROM. NASA, 2000.

Also,citetheBOREASCD-ROMsetas:

Newcomer,J.,D. Landis,S.Conrad,S.Curd,K. Huemmrich,D. Knapp,A. Morrell, J.

Nickeson,A. Papagno,D. Rinker,R.Strub,T. Twine,F. Hall, andP.Sellers,eds.CollectedDataof

TheBorealEcosystem-AtmosphereStudy.NASA. CD-ROM.NASA, 2000.

20.5 Document Curator

20.6 Document URL

Page 21
REPORT DOCUMENTATION PAGE FormApproved

OMB No. 0704-0188

Public reporting burden for this collection of informationis estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

September 2000 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Technical Report Series on the Boreal Ecosystem-Atmosphere Study (BOREAS)

BOREAS ECMWF 6-Hour Analysis amd Forecast Data 923

6. AUTHOR(S) RTOP: 923-462-33-01

Pedro Viterbo, Alan Betts, and Richard Strub

Forrest G. Hall amd Jeffrey A. Newcomer, Editors

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS (ES)

Goddard Space Flight Center

Greenbelt, Maryland 20771

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS (ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

TM--2000-209891

Vol. 120

11. SUPPLEMENTARY NOTES

P.Viterbo: ECMWF, Shinfield Park, Reading, UK; A. Betts: Atmospheric Research, Pittsford, VT;

J.A. Newcomer and R. Strub: Raytheon ITSS, NASA Goddard Space Flight Center, Greenbelt, MD

12a. DISTRIBUTION / AVAILABILITY STATEMENT

Unclassifie_Unlimited

Subject Category: 43

Report available from the NASA Center for AeroSpace Information,

7121 Standard Drive, Hanover, MD 21076-1320. (301) 621-0390.

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

In cooperation with BOREAS atmospheric research efforts, the ECMWF agreed to provide BOREAS

with a customized subset of its 6-hourly forecast data. This data set contains parameters from three

ECMWF data products in GRIB format: Surface and Diagnostic Fields, Supplemental Fields, and

Extension Data. Sample software and information are provided to assist in reading the data files.

Temporally, the atmospheric parameters are available for the four main synoptic hours of 00, 06, 12,

and 18 UTC from 1994 to 1996. Spatially, the data are stored in a 0.5- by 0.5-degree latitude/longitude grid. To cover the entire BOREAS study area, the grid extends from 48 to 62 degrees latitude and

-92 to -114 degrees longitude. The data are stored in binary data representation known as FM 92

GRIB. Due to the complexity of the content and format of this data set, users are advised to read

Sections 6, 7, 8, and 14 before using data. Based on agreements between BOREAS and ECMWF,

users may legally obtain and use these data only by having a set of the BOREAS CD-ROMs that

contain the data. Possession or use of these data under any other circumstance is prohibited. See

Sections 11.3 and 20.4 for details.

14. SUBJECT TERMS

BOREAS, aircraft flux meteorology.

17. SECURITY CLASSIFICATION

OF REPORT

Unclassified

NSN 7540-01-280-5500

18. SECURITY CLASSIFICATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

21

16. PRICE CODE

20. LIMITATION OF ABSTRACT

UL

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39.18

298-102