CBS/OPAG-IOS/ICT-IOS-5/Doc. 4.1, p. 5
WORLD METEOROLOGICAL ORGANIZATION______
COMMISSION FOR BASIC SYSTEMS
OPEN PROGRAMME AREA GROUP ON
INTEGRATED OBSERVING SYSTEMS
IMPLEMENTATION/COORDINATION TEAM ON
THE INTEGRATED OBSERVING SYSTEM
Fifth Session
(GENEVA, SWITZERLAND, 15-18 SEPTEMBER 2008) / CBS/OPAG-IOS/ICT-IOS-5/Doc. 4.1
(11.VIII.2008)
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ITEM: 4.1
Original: ENGLISH
REVIEW OF THE STATUS OF THE SURFACE-BASED COMPONENTS OF THE GOS
RBSN / ABSN
(Submitted by the WMO Secretariat)
Summary and purpose of documentThe document provides information on the status of implementation of the RBSN / ABSN in WMO Regions and the Antarctic.
Action Proposed
The meeting is invited to note the information contained in this document when considering recommendations on the improvement of data availability from Regional networks and the Antarctic.
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Appendices: A. Status of implementation – RBSN/ABSN surface stations
B. Status of implementation – RBSN/ABSN upper-air stations
C. ECMWF List of UA stations used in WMO/CBS standard NWP verification
REGIONAL BASIC SYNOPTIC NETWORK / ANTARCTIC BASIC SYNOPTIC NETWORK (RBSN / ABSN)
1. Following standing regulations each WMO Regional Association once in four years draws up a Regional Basic Synoptic Network (RBSN) to meet the collective needs of its Members. Likewise, the Executive Council of WMO approves the Antarctic Basic Synoptic Network (ABSN) as proposed by its Panel of Experts on Antarctic Meteorology. Together, these Antarctic and Regional networks form an integrated global network that facilitates performance monitoring over the globe. Generally, surface synoptic stations are expected to report every six hours for global exchange and every three hours for regional exchange, while upper-air stations are required to report at least twice per day. The details of the observational programmes provided by these stations operated by WMO Members are given in Weather Reporting (WMO-No. 9, Volume A), and are available on the WMO website: http://www.wmo.int/pages/prog/www/ois/ois-home.html.
Surface synoptic observations
2. The status of implementation of RBSN/ABSN surface stations as of 31 July 2008, according to information provided by Members, is presented in Table I (see Appendix A). The level of implementation of the surface stations in 2008 that make 8 observations per day (complete observational programme) varied from 38% in Region IV to 97% in Region VI, with a global average of 74%. In Region I and the Antarctic there has been a significant increase in the number of stations resulting from the Regional Association and Antarctic Meteorology sessions being held during the period 2006-2008. In Regions II, III, IV and V the number of stations have decreased with a small increase in RA VI recorded during the same period. Overall there has been an increase of over 2% in the number of stations in the RBSN during the intersessional period. The percentage of non-operational stations (silent) in each Region has decreased appreciably to 3% (115 stations) globally from 5% (182 stations) during the same period.
Upper-Air observations
3. More than 90 percent of all established upper-air stations are included in the RBSNs. The status of implementation of all upper-air stations in the 2008 with comparable figures for 2006 is presented in Table II (see Appendix B). It should be noted that in this table all upper-air stations are recorded also as radiowind stations (853 stations globally), but that not all upper-air stations are radiosonde stations (798 stations globally). The differences between these two, namely 55 stations, are those upper-air stations that make only wind observations. During the intersessional period the number of fully operational stations (making 2 observations per day) has decreased, continuing the trend from the previous two-year period. Radiowind stations dropped from 571 to 554 and radiosonde stations dropped from 548 to 537. However, the implementation as a percentage of the RBSN has remained consistent at around 65% (radiowind) and 67% (radiosonde) during the same period. The geographical distribution remains a concern, with the southern hemisphere having consistently lower percentages of stations proposed for making two observations a day than the northern hemisphere. There is also a persistence of data-sparse areas over some parts of Africa and South America.
Automatic weather stations
4. The number of automatic stations in the RBSN according to information provided by Members in Weather Reporting (WMO-No. 9) Volume A, reached 871 in July 2008, compared to 858 stations in July 2006, an increase of 13% within the intersessional period. The Antarctic and Regions I and II show an increase in the number of automatic stations (Figure I), with the most significant increase recorded in Region I. Out of the current globally established stations (11000+ recorded in Volume A) a total of 3551 stations are listed as automatic stations in July 2008, compared to 3350 in 2006. Of these 25% of all surface synoptic automatic stations are in the RBSN.
Figure I
5. The establishment of National Focal Points for WMO on operational matters related to Volume A and of the Regional Basic Synoptic Network (RBSN) significantly facilitated the collection of detailed information on national specifications and also serves as an informal channel for exchange of information between the WMO Secretariat, NMHSs and the regional rapporteurs. However, it should be noted that some members are yet to nominate a relevant focal point. Additionally, prompt notifications of changes and updated information from Members are not forthcoming on a regular basis. It is envisaged that a mechanism would be established to invite members to regularly review the respective lists of focal points available on our website (see www.wmo.int/pages/prog/www/FocalPoints.html) and update the information as and when necessary. Furthermore, to potentially contribute to alleviating discrepancies specifically between Volume A and the RBSN, members will be encouraged to nominate one focal point for both related matters.
Quality of observational data
6. Following recommendation of CBS-IX (1988), three centres perform function of Lead Centres for monitoring data quality:
Centre / Data typeECMWF / Upper-air observations
RSMC Bracknell / Marine surface observations
WMC/NMC Washington / Aircraft and satellite observations
7. Following the recommendation of CBS and the concurrence of the presidents of Regional Associations, the president of CBS designated the following Lead Centres for Quality Monitoring of land surface observations in the Regions:
Centre / Data type / Area / PublicationRSMC Nairobi, from 2000 / Land surface observations / RA I / Hard copy
RSMC Tokyo, from 1990 / ““ / RA II / Website
RSMC Buenos Aires / ““ / RA III / -
RSMC Montreal, from 1993 / ““ / RA IV / Website
WMC/RSMC Melbourne, from 1990 / ““ / RA V / Website
RSMC Offenbach, from 1993 / ““ / RA VI / -
8. In implementing the procedure for monitoring the quality of data, these centres should produce monthly lists of observing stations that persistently report erroneous observations as well as six-monthly consolidated lists of suspect stations (stations reporting erroneous data). Regular reports are available form all of them but RSMCs Buenos Aires and Offenbach.
9. The WMO secretariat regularly monitors these quality monitoring reports and Members with suspect stations are advised to make an investigation and correct any possible cause of error in accordance with para 22 of Attachment II.7 of the Manual on the GDPS (WMO-No. 485).
Land surface data quality
10. The quality of land-surface reporting in each Region continues to fluctuate each year with the exception of RA V where the number of ‘suspect’ stations remained very low (see Figure II). To assist with consistency, and to allow easy comparison of results from all monitoring
centres, a revised set of monitoring rejection criteria have been adopted to overcome the
discrepancies caused by centres using disparate selection criteria (see www.wmo.int/pages/prog/www/DPS/Monitoring-home/mon-index.htm).
11. It should be noted that comparison between Regions is difficult due to the differences of NWP models and their operations. As an, example, three different RSMCs reported 6, 15 and 1 suspected stations, respectively, in June 2008 for Region V. The last figure (1) being reported by RSMC Melbourne that has responsibility for RA V. These findings suggest that, in order to have comparable figures among Regions, it may be more appropriate to present quality monitoring results provided by a single RSMC. The meeting is invited to provide advice in this respect.
12. Typical errors that have been documented are the use of a wrong station elevation or coordinates, errors in the reduction to mean sea level, use of an incorrect station pressure, and problems with consistency of barometer readings. These errors are normally fixed through remedial action of Members.
Figure II
Radiosonde data quality
ECMWF regularly performs quality monitoring of radiosonde data and the best stations are used in the WMO/CBS computation of NWP verification procedures. The stations are selected according to quality criteria for reporting frequency and wind and temperature measurements. As can be see from the statistics provided by Mr Antonio GarciaMendez (ECMWF) and the figures in Appendix C, there has been a marked improvement in the global radiosonde observing system in recent years in many parts of the world, in particular Russia, China, the tropics and also the southern hemisphere.
The number of best stations used in NWP verification procedures is in table below:
Year / North Hemisphere / Tropics / South Hemisphere / Total2004 / 308 / 71 / 64 / 443
2005 / 351 / 74 / 70 / 495
2006 / 410 / 87 / 75 / 572
2007 / 449 / 103 / 87 / 639
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CBS/OPAG-IOS/ICT-IOS-5/Doc. 4.1, p. 5
Table I
Status of implementation of RBSN/ABSN surface stations as of July 2008 compared to those in 2006. The stations report every three hours, every six hours and, less frequently, as committed to by Members in Weather Reporting (WMO-NO. 9, Volume A)
WMO Regions / 1Number of stations making observations at both the main and the intermediate standard hours per day (complete programme) / 2
Number of stations making observations at only the main standard or in addition at some intermediate hours per day (not the complete programme) / 3
Number of stations making at least one or more observations per day (incomplete programme) / 4
Number of stations not yet established or otherwise non-operational (silent) / Total number of stations in the RBSN (1+2+3+4)
Number / % / Number / % / Number / % / Number / % / Number
2006 / 2008 / 2006 / 2008 / 2006 / 2008 / 2006 / 2008 / 2006 / 2008
RA I / 370 / 480 / 65% / 61 / 43 / 6% / 170 / 210 / 28% / 10 / 11 / 1% / 611 / 744
RA II / 1153 / 1175 / 90% / 46 / 45 / 3% / 69 / 67 / 5% / 45 / 22 / 2% / 1313 / 1309
RA III / 163 / 156 / 38% / 5 / 5 / 1% / 229 / 230 / 57% / 19 / 16 / 4% / 416 / 407
RA IV / 202 / 201 / 38% / 205 / 233 / 44% / 64 / 61 / 11% / 64 / 40 / 7% / 535 / 535
RA V / 301 / 296 / 76% / 37 / 37 / 10% / 35 / 35 / 9% / 16 / 21 / 5% / 389 / 389
RA VI / 753 / 788 / 97% / 9 / 7 / 1% / 10 / 10 / 1% / 25 / 3 / 1% / 797 / 808
Antarctic / 60 / 77 / 84% / 8 / 10 / 11% / 3 / 3 / 3% / 3 / 2 / 2% / 74 / 92
Global / 3002 / 3173 / 74% / 371 / 380 / 9% / 580 / 616 / 14% / 182 / 115 / 3% / 4135 / 4284
Note: Main standard hours – 0000, 0600, 1200, 1800 UTC; Intermediate hours – 0300, 0900, 1500, 2100 UTC
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CBS/OPAG-IOS/ICT-IOS-5/Doc. 4.1, p. 5
Table II
Status of implementation of RBSN upper-air stations as of July 2008 compared to those in 2006. The number of stations expected to make observations at the 2 main standard hours and less frequently, as committed to by Members in Weather Reporting (WMO-No. 9) Volume A
(W = Radiowind, R = Radiosonde)
WMORegion / 1
Number of stations making observations at the two main standard hours per day / 2
Number of stations making at least one observation at the main standard or at intermediate hours per day / 3
Number of stations not yet established or otherwise non-operational (silent) / Total number of stations in the RBSN
(1+2+3)
Number / % / Number / % / Number / Number
2006 / 2008 / 2006 / 2008 / 2006 / 2008 / 2006 / 2008
W / R / W / R / W / R / W / R / W / R / W / R / W / R / W / R / W / R / W / R / W / R
RA I / 24 / 23 / 24 / 24 / 26% / 26% / 53 / 46 / 46 / 46 / 48% / 48% / 25 / 20 / 24 / 24 / 26% / 26% / 102 / 89 / 94 / 94
RA II / 234 / 230 / 223 / 220 / 71% / 79% / 47 / 42 / 46 / 40 / 14% / 14% / 40 / 10 / 49 / 19 / 15% / 7% / 321 / 282 / 318 / 279
RA III / 23 / 23 / 22 / 22 / 40% / 41% / 28 / 28 / 28 / 28 / 51% / 52% / 5 / 5 / 5 / 4 / 9% / 7% / 56 / 56 / 55 / 54
RA IV / 125 / 125 / 126 / 126 / 93% / 93% / 7 / 7 / 6 / 6 / 4% / 4% / 4 / 4 / 4 / 4 / 3% / 3% / 136 / 136 / 136 / 136
RA V / 51 / 33 / 47 / 33 / 44% / 36% / 54 / 48 / 58 / 57 / 54% / 61% / 9 / 2 / 3 / 3 / 2% / 3% / 114 / 93 / 108 / 93
RA VI / 111 / 111 / 106 / 106 / 84% / 84% / 15 / 15 / 18 / 18 / 14% / 14% / 3 / 3 / 3 / 3 / 2% / 2% / 129 / 129 / 127 / 127
Antarctic / 3 / 3 / 6 / 6 / 40% / 40% / 10 / 10 / 9 / 9 / 60% / 60% / 0 / 0 / 0 / 0 / 0% / 0% / 13 / 13 / 15 / 15
Global / 571 / 548 / 554 / 537 / 65% / 67% / 214 / 196 / 211 / 204 / 25% / 26% / 86 / 44 / 88 / 57 / 10% / 7% / 871 / 798 / 853 / 798
Note 1: All radiosonde (R) stations are also included in the total number of radiowind (W) stations – they are not independent. The difference provides the number of upper-air stations that make only wind observations.