WWW.SA.I-PDF.INFO
FREE ELECTRONIC LIBRARY - Abstracts, books, theses
 
<< HOME
CONTACTS



Pages:   || 2 | 3 | 4 | 5 |   ...   | 7 |

«CONTENTS Contents 1 Introduction 3 2 BUFR format 4 2.1 Indicator section......................................... ...»

-- [ Page 1 ] --

BUFR User’s Guide

Milan Dragosavac

Operations Department

November 2007

c Copyright 2007

European Centre for Medium-Range Weather Forecasts

Shinfield Park, Reading, RG2 9AX, United Kingdom

Literary and scientific copyrights belong to ECMWF and are reserved in all countries.

The information within this publication is given in good faith and considered to be true, but ECMWF accepts

no liability for error, omission and for loss or damage arising from its use.

CONTENTS

Contents 1 Introduction 3 2 BUFR format 4

2.1 Indicator section.......................................... 4

2.2 Identification section....................................... 4

2.3 Optional section.......................................... 5

2.4 Data description section...................................... 6

2.5 Data section............................................ 7

2.6 End section............................................ 7 3 BUFR software 8

3.1 Bufr tables............................................. 8

3.2 Defaults.............................................. 8

3.3 Decoding and encoding...................................... 10 3.3.1 Subroutine BUFREX................................... 10 3.3.2 Subroutine BUFREN................................... 14

3.4 Error codes............................................ 18

3.5 Partial expansion......................................... 20 3.5.1 Subroutine BUSRQ.................................... 20 3.5.2 Example......................................... 22

3.6 Printing routines.......................................... 25 3.6.1 To print Section 0..................................... 25 3.6.2 To print Section 1..................................... 25

–  –  –

FM-94 BUFR (Binary Universal Form for data Representation) has been designed to achieve efficient exchange and storage of meteorological and oceanographic data. It is self defining, table driven and very flexible data representation system, especially for huge volumes of data.

The User’s Guide is described in six sections.

Section 2 describes Bufr format in general, and it is useful for those who are not familiar with the Bufr concept.

Section 3 explains Bufr software usage. It contains FORTRAN subroutines for expanding and packing Bufr data. A number of routines described shall be used as a tools.

A quality control representation in the Bufr is given in section 4.

Section 5 contains few example programs to decode/repack bufr data, create a new bufr message and expand data descriptors only.

Useful WMO example templates are given in the section 6.

–  –  –

A full definition of the BUFR form is given in WMO Manual on Codes, Volume I, International Codes, Part B-Binary Codes, WMO-No.306, FM 94-IX Ext. BUFR. This section offers a brief description of the basic structure and representation of the BUFR code.

The BUFR form is a binary representation of meteorological data. It is a continuous bit stream made up of a sequence of octets (one octet is eight bits). The only part of BUFR where information does not end on byte boundaries is the data section, where a length of BUFR table B elements can have any number of bits (although it must not exceed the number of bits in a computer word for non-character data).

A BUFR message consists of six sections, some of which may be completely optional (section 2) or partially optional (section 1).

The representation of data in the form of a series of bits is independent of any particular machine representation.

It is important to stress that the BUFR representation is not suitable for data visualisation without computer interpretation.

The data section consists of one or more data subsets of related meteorological data which are defined, described and represented by a single Bufr table D entry. For observational data, one subset corresponds to one observation. The data section can be in compressed or uncompressed form.

Each section included in the message always contain an even number of octets. If necessary, sections must be appended with bits set to zero to fulfil this requirement.

A BUFR message is comprised of the following sections:

–  –  –

2.1 Indicator section Indicator section or Section 0 of a Bufr message has a fixed length of eight octets. Information about the total size of the BUFR message in octets 5-7 is very useful for reading BUFR data from pure binary files. The content of Section 0 is given in the Table 1.





2.2 Identification section This section contains information relevant to data recognition without performing complete expansion of data.

Data type and observation date and time are the most important parts of it. In the case of multi-subset data the time of the earliest observation should be packed into section 1. This section also contains all information necessary do define the Bufr tables used.

–  –  –

2.3 Optional section The presence of Section 2 of the Bufr message is indicated by a flag in the 8th byte of Section 1. This section can be used locally by Automated Data Processing centres. This Section is used to keep the Report Data Base key.

The layout of Section 2 is given in table 3.

–  –  –

2.4 Data description section This section describes the data in the data section. The information which can be found in the first seven octets is the number of subsets in the message, their form and the type of data (observation/non-observation). The data descriptors start in the 8th octet of the section 3. Each descriptor is spread over two bytes and contains three parts. If F = 0, the descriptor is an element descriptor and values of X and Y define entries in Bufr Table

–  –  –

B. For F = 1, the descriptor is a replication descriptor. If F = 2, the descriptor is one of the operators from bufr Table C. F = 3 means that the descriptor represents the sequence descriptor from Bufr Table D. The table D entries contain a list of element descriptors, operators, and/or other sequence descriptors.

In an ideal situation, data in Section 4 should be described by one Bufr Table D entry only.

X stands for class of elements in the range from 0-63 and Y is an entry within class 0-255. Classes 48-63 are reserved for local use and entries from 192-255 within all classes are also reserved for local usage.

Layout of Data description section is given in the Table 5.

–  –  –

2.5 Data section The Data section, like all sections, starts with the length of Section 4 followed by a continuous stream of bits from byte 5 onward.

Layout of Data section is given in the Table 6.

–  –  –

2.6 End section The End section is comprised of four ”7” characters in CCITT International Alphabet No.5 and this marks the end of the Bufr message. The layout of the End section is given in the Table 7.

–  –  –

The first version of ECMWF Bufr software was designed and implemented in 1987. A great deal of experience has been gathered in handling binary coded observations since. Bufr software is written in FORTRAN 77.

Versions for C90, VAX, IBM, SGi, SUN, HP and for all UNIX and LINUX based platforms are available. It has been installed on Mac OSX as well.

–  –  –

BUFR is a table driven system. It uses three main tables.

• Bufr Table B - classification elements

• Bufr Table C - text and meaning of all code/flag tables

• Bufr Table D - list of common sequences Bufr Tables B and D are used to collect all necessary information to pack/unpack Bufr data. Which table is to be loaded is decided at runtime using information from Section 1 of the Bufr message. The naming convention

for Bufr binary tables is as follows:

Bssswwwwwxxxxxyyyzzz.TXT Cssswwwwwxxxxxyyyzzz.TXT Dssswwwwwxxxxxyyyzzz.TXT where

• sss - Master table number (zero for WMO meteorological tables)

• wwwww - Originating sub-centre

• xxxxx - Originating centre

• yyy - Version number of master table used

• zzz - Version number of local table used ECMWF is currently using B0000000000098013001.TXT, C0000000000098013001.TXT and D0000000000098013001.TXT tables. Keep in mind that Bufr Table C in this software is a code table. Bufr has Table C in its definition, where Bufr Operators are defined. If standard WMO tables are used, the Originating centre xxxxx will be set to 00000.

Current version of the software will keep in memory up to JTMAX=10 versions of tables in the round robin fashion.

–  –  –

NVIND = 2147483647

Real missing value indicator:

RVIND = 1.7E38 Default path for Bufr Tables is hard coded in the software. To change the path set environmental variable

BUFR TABLES :

export BUFR TABLES=/.../ The path must end with ”/” During decoding Bufr table path and the names are printed. If user doeas not want that, set: VARIABLE PRINT TABLE NAMES=false export PRINT TABLE NAMES=false

–  –  –

3.3 Decoding and encoding 3.3.1 Subroutine BUFREX Purpose Decodes Bufr message into fully expanded form, returning information relevant to all Bufr Sections, expanded values, Bufr Table B element names and units.

Interface CALL BUFREX(KBUFL,KBUFF,KSUP,KSEC0,KSEC1,KSEC2,KSEC3,KSEC4, KELEM,CNAMES,CUNITS,KVALS,VALUES,CVALS,KERR)

where:

• Integer variables are denoted by first letter K.

• Real variables are denoted by first letter V.

• Character variables are denoted by first letter C.

Input arguments

• KBUFL - An INTEGER variable containing length of Bufr message in words.

• KBUFF - An INTEGER array containing Bufr message.

• KELEM - An INTEGER variable containing expected number of expanded elements

• KVALS - An INTEGER variable containing expected number of data values.

Output arguments

• KSEC0 - An INTEGER array (size 3) containing Bufr Section 0 information.

• KSEC1 - An INTEGER array of at least 40 words containing Bufr Section 1 information. When Section 1 contains data for local use, KSEC1 should be sized accordingly.

• KSEC2 - An INTEGER array of 4096 words containing Bufr Section 2 information. ECMWF uses this section to store Report Data Base key.

• KSEC3 - An INTEGER array of 4 words containing Bufr Section 3 information.

• KSEC4 - An INTEGER array of 2 words containing Section 4 information.

• KSUP - An INTEGER array (size 9) containing supplementary information.

–  –  –

• CNAMES - CHARACTER*64 array of KELEM words containing element names.

• CUNITS - CHARACTER*24 array of KELEM words containing element units.

• VALUES - REAL*8 array of KVALS words containing element values.

• CVALS - CHARACTER*80 array of KVALS containing CCITT IA No.5 element entries.

• KERR - An INTEGER containing an error code.

KSEC0 - An INTEGER array (size 3) containing Bufr Section 0 information

–  –  –

Method A Bufr message passed as an argument to this routine is decoded section by section. Before Section 3 expansion Bufr tables are loaded using KSEC1 information to create table names. The loaded Bufr tables are kept in memory and swapped only if the next message is requesting different tables.

Section 3 Data descriptors are unpacked and expanded applying all necessary operators in force and creating a list of Bufr Table B elements which correspond one to one to the data in the Data section of the Bufr message.

Word and bit pointers are calculated for each element in the message.

Having all this information, unpacking of the data is performed applying reference value and scaling to get the final value for one element in the Bufr message. Unpacked data are stored in VALUES array. The corresponding element names and units are stored in the CNAMES and CUNITS arrays respectively.

To achieve efficiency, original Data descriptors are saved for the following comparison. If the Data descriptors for the next observation are not different from the previous, the former word and bit pointers to the elements are used saving time for data descriptors expansion.

–  –  –

If a Bufr Table B element is type character, the corresponding VALUES element contains a real number which, when truncated to an integer represents index * 1000 + length

where:

• index - subscript of the element in CVALS where character string is stored.

• length - number of characters represented.

In the case of multi subset data, the one dimensional array VALUES contains all subsets of data. The formula

to find the index to the VALUES array of the i-th element of observation is:

index=i + (nsub-1)*KELEM so start of next subset is KELEM apart.

Current version of the Bufr software can handle KELEM up to 160000 and KVALS up to 4096000.

Reference

WMO -No. 306 Manual on Codes Volume I, Part B - Binary Codes: J.K. Gibson and M. Dragosavac 1988:

Decoding Data Represented in FM 94-IX Ext. BUFR

–  –  –

where

• Integer variables are denoted by first letter K.

• Real variables are denoted by first letter V.

• Character variables are denoted by first letter C Input arguments

• KSEC0 - An INTEGER array (size 3) containing Bufr Section 0 information

• KSEC1 - An INTEGER array of at least 40 words containing Bufr Section 1 information. When Section 1 contains data for local use, KSEC1 should be sized accordingly.

• KSEC2 - An INTEGER array of 4096 words containing Bufr Section 2 information. ECMWF uses this section to store Report Data Base key.

• KSEC3 - An INTEGER array of 4 words containing Bufr Section 3

• KSEC4 - An INTEGER array of 2 words containing Section 4 information.

• KTDLEN - An INTEGER variable containing the number of data descriptors to be packed in Section 3 of Bufr message

• KTDLST - An INTEGER array containing the list of KTDLEN data descriptors

• KDLEN - An INTEGER variable containing the dimension of KDATA array

• KDATA - An INTEGER array containing the delayed replication factors which which appear in the Data section of Bufr message

• KELEM - An INTEGER variable containing the expected number of expanded elements

• KVALS - An INTEGER variable containing the expected number of data values

• VALUES - REAL*8 array of KVALS words containing element values.

• CVALS - CHARACTER*80 array of KVALS containing CCITT IA No.5 element entries.

–  –  –

Output arguments

• KBUFL - An INTEGER variable containing the length of the Bufr message in words.

• KBUFF - An INTEGER array containing the Bufr message.

• KERR - An INTEGER containing an error code.



Pages:   || 2 | 3 | 4 | 5 |   ...   | 7 |


Similar works:

«INTRODUCTION Working capital management is the life blood for every small scale industry, therefore management of working capital considered as one of the most important area in the field of financial management. Working capital management is the most important area in the field of financial management. Every small scale industry as well as large scale industry requires some amount of fixed capital to get fixed assets like plant and machinery, land and building, furniture, vehicles, loose tools...»

«Lyra lay, unmoving. The bright sun, bathing Metropony City in Celestia’s warmth, could barely penetrate the thick blinds that had been snapped shut days ago. The heavy plastic slats cast lines of shadow like prison bars across the unicorn’s lithe yet immobile frame. The room was sweltering, summer heat and faulty air-conditioning to blame. Lyra’s bed was soaked in sweat, but she didn’t care. All was still. Even the insects had been battered into submission by the heatwave. The only...»

«Lung Cancer (Small Cell) Overview The information that follows is an overview of this type of cancer. It is based on the more detailed information in our document Lung Cancer (Small Cell). This document and other information can be obtained by calling 1-800-227-2345 or visiting our website at www.cancer.org. What is small cell lung cancer? Note: This document covers only the small-cell type of lung cancer. The treatment for small cell lung cancer is very different from the treatment for...»

«Experiences Building Security Applications on DHTs Roxana Geambasu∗ Jarret Falkner∗ Paul Gardner† Tadayoshi Kohno∗ Arvind Krishnamurthy∗ Henry M. Levy∗ ∗ University of Washington and † Vuze, Inc. Abstract In the recent past we introduced two new security applications built on peer-to-peer systems and distributed hashtables (DHTs). First, we designed Adeona [18], which leverages DHTs to provide a privacy-preserving laptop tracking solution. Second, we designed the Vanish [10]...»

«The Preface(s) to the Critique of Pure Reason It doesn’t take long in reading the Critique before we are faced with interpretive challenges. Consider the very first sentence in the A edition: Human reason has the peculiar fate in one species of its cognitions that it is burdened with questions it cannot dismiss, since they are given to it as problems by the very nature of reason itself, but which it also cannot answer, since they transcend every capacity of human reason. Where to begin? We...»

«Embedded Value: Practice and Theory Robert Frasca1 and Ken LaSorella2 Published in the March 2009 issue of the Actuarial Practice Forum Copyright 2009 by the Society of Actuaries. All rights reserved by the Society of Actuaries. Permission is granted to make brief excerpts for a published review. Permission is also granted to make limited numbers of copies of items in this publication for personal, internal, classroom or other instructional use, on condition that the foregoing copyright notice...»

«Muerte perinatal: Las actuaciones ante el duelo utilizadas por Enfermeras y Matronas estadounidenses y españolas Int. J. Palliat Nur.s 21(2) http://www.magonlinelibrary.com/doi/10.12968/ijpn.2015.21.2.79 Sue Steen RN MS Perinatal Nurse Navigator, Maple Grove Hospital, MN. Asst. Prof. of Nursing, Bethel University, Minnesota, US Correspondencia:s-steen@bethel.edu Resumen Antecedentes: Se han publicado pocos estudios sobre una perspectiva global respecto a las necesidades de las Enfermeras y...»

«No. 16-_ IN THE Supreme Court of the United States JOHN T. CHISHOLM, ET AL., Petitioners, v. TWO UNNAMED PETITIONERS, Respondents. JOHN T. CHISHOLM, ET AL., Petitioners v. THE HONORABLE GREGORY PETERSON, AND EIGHT UNNAMED MOVANTS, Respondents. On Petition for a Writ of Certiorari to the Supreme Court of the State of Wisconsin PETITION FOR A WRIT OF CERTIORARI (REDACTED ORIGINAL) JOHN T. CHISHOLM LARRY E. NELSON District Attorney District Attorney BRUCE J. LANDGRAF Counsel of Record DAVID ROBLES...»

«CHAPTER ELEVEN LEARNING MORALITY Heidi Fung and Benjamin Smith Excerpt 1 While adults are engaging in conversation, Didi (at age 3) approaches the researcher’s unattended camcorder. As soon as his mother finds out, she yells at him, “Eh, eh, Didi! What has Mama told you? You’ve never [listened to me].... You cannot [approach Auntie’s camcorder]! I’m gonna spank you. You’re a child who doesn’t obey rules (bu shou guiju de xiaohaizi).” By this time, although Didi has left the...»

«RNA NGS Data Analysis Report Project: Differential expression analysis of hoxa1 Customer: Test Company/Institute: Test Date: Monday, January 18, 2016 Performed by: XploreRNA Exiqon A/S Company Reg. No. (CVR) 18 98 44 31 Skelstedet 16 DK-2950 Vedbæk Denmark Contact information: exiqon.com/contact EXIQON | mRNA NGS Data Analysis Report | Ref code: 00059-00108 The files listed below can be found in My Projects at XploreRNA Content Description file_descriptions.html Overview of all result files....»

«the at's Wh ZZ? BU Welcome from. WVASFAA President, Kathy Bialk Dear WVASFAA Colleagues: On behalf of the 2016 WVASFAA Executive Committee and the Conference Committee, I welcome you to the 2016 WVASFAA Spring Conference at The Oglebay Resort & Conference Center in Wheeling, West Virginia. WVASFAA is a volunteer organization devoted to enhancing professional competency, assisting in the development of effective programs, facilitating communication, and providing training opportunities for those...»

«TTJ 17.2 (2014): 214-228 ISSN 1598-7140 Christ-Centered Preaching in the Postmodern World: Problems, Challenges, and Suggestions Dick O. Eugenio Asia-Pacific Nazarene Theological Seminary, Philippines The apostle Paul’s admonition to the early Christians to “understand the present times” in which they lived (Rom 13:11) is sensible advise for us today. In one way or another, either as observers or participants, every Christian relates with the Zeitgeist. Consciously or unconsciously,...»





 
<<  HOME   |    CONTACTS
2017 www.sa.i-pdf.info - Abstracts, books, theses

Materials of this site are available for review, all rights belong to their respective owners.
If you do not agree with the fact that your material is placed on this site, please, email us, we will within 1-2 business days delete him.