DPFS_Manual_Part_II

DATA-PROCESSING AND FORECASTING ASPECTS

1. FUNCTIONS OF WMCs, RSMCs AND NMCs

1.1 GDPFS products and services

Each Member or group of Members(s) responsible for a GDPFS Centre should ensure that its centre performs the relevant category of the following functions:

1.1.1 Real-time products and services for middle latitudes and subtropical areas

For middle latitudes and subtropical areas, the GDPFS should provide the following products derived from deterministic and ensemble NWP systems and services in real time:

(a) Surface and upper-air analyses;

(b) Prognoses one to three days in advance, including:

(i) Surface and upper-air prognoses of pressure (geopotential), temperature, humidity and wind in map or other form;

(ii) Diagnostic interpretation of numerical weather prediction (NWP) products to give:

a. Areal distribution of cloudiness;

b. Precipitation location, occurrence, amount and type;

c. Sequences at specific locations (time diagrams), at the surface and aloft, of temperature, pressure, wind, humidity, etc., subject to agreement between Members where appropriate;

d. Vorticity advection, temperature/thickness advection, vertical motion, stability indices, moisture distribution, and other derived parameters as agreed by Members;

e. Jet-stream location and tropopause/layer of maximum wind;

f. Numerical products providing sea-state or storm-surge forecasts;

(i) Surface and upper-air prognoses of pressure (geopotential), temperature, humidity and wind;

(ii) Outlooks of temperature, precipitation, humidity and wind in map or other form;

(d) Extended- and long-range forecasts of averaged weather parameters as appropriate, including sea-surface temperature, temperature extremes and precipitation;

(e) Interpretation of numerical products using relations derived by statistical or statistical/dynamical methods to produce maps or spot forecasts of probability of precipitation or precipitation type, maximum and minimum temperature, probability of thunderstorm occurrence, etc.;

(f) Sea-state and storm-surge forecasts using models driven by winds from global NWP models;

(g) Environmental quality monitoring and prediction products;

(h) Independent real-time quality control of the Level II and Level III data defined in Note (3) to paragraph 1.5.2.

1.1.2 Real-time products and services for tropical areas

For tropical areas, the GDPFS should provide the following products from deterministic and ensemble NWP systems and services in real time:

(a) Surface and upper-air analyses;

(b) Prognoses one to three days in advance, including:

(i) Surface and upper-air prognoses, particularly of wind and humidity in map or other form;

(ii) Diagnostic interpretation of NWP products to give:

a. Areal distribution of cloudiness;

b. Precipitation location/occurrence/amounts;

c. Time sequence of weather parameters at specific locations, subject to agreement between Members, where appropriate;

d. Vorticity, divergence, velocity potential, vertical motion, stability indices, moisture distribution and other derived parameters as agreed by Members;

e. Jet stream and layer of maximum wind locations;

f. Numerical products providing sea-state or storm-surge forecasts;

(iii) The use of special NWP-nested models or diagnostic interpretation of fine-mesh global models to give:

a. Tropical storm positions and tracks;

b. Tropical depression and easterly wave positions and movement;

(i) Surface and upper-air prognoses, particularly of wind and humidity;

(ii) Outlooks of precipitation, wind, cloudiness and wet and dry periods;

(iii) Life cycle of tropical storms;

(d) Extended- and long-range forecasts of averaged weather parameters, as appropriate, including sea-surface temperature, temperature range and precipitation;

(e) Interpretation of numerical products, using relations derived by statistical/dynamical methods to produce maps or at specific location of forecast probability of cloudiness, temperature range, precipitation, thunderstorm occurrence, tropical cyclone tracks and intensities, etc.;

(f) Environmental quality monitoring and prediction products;

(g) Sea-state and storm-surge forecasts using models driven by winds from global NWP models;

(h) Independent real-time quality control of the Level II and Level III data defined in Note (3) to paragraph 1.5.2.

1.1.3 Non-real-time products and services

The GDPFS should also provide the following products and services in non-real time:

(a) Long-range weather and climate monitoring products when operationally useful;

(b) Climate-related diagnoses (10- or 30-day mean charts, summaries, anomalies, etc.) particularly for the tropical/subtropical belt;

(d) Access to data, products and intercomparison results using internationally-accepted formats and media;

(e) Provision of continuously updated catalogues of data and products;

(f) Regional and global analyses (circulated by Members or research institutions) of the atmosphere and oceans, including means and anomalies of surface and upper-air pressure, temperature, wind and humidity, ocean currents, sea-surface temperature, and ocean surface layer temperature; derived indices, including blocking and teleconnection indices;

(g) Satellite remote sensing products distributed by Members; including outgoing long-wave radiation, sea-surface elevation, and normalized vegetation indices;

(h) Monthly and annual means or totals for each year of a decade (e.g. 1971–1980, etc.) and the corresponding decadal (10-year) averages of pressure (station level and mean sea level), temperature and precipitation, principally from CLIMAT reporting stations;

(i) Climatological standard normals (for the periods 1931–1960, 1961–1990, etc.) of selected elements, principally from CLIMAT reporting stations;

(j) Guidelines on the operational use of GDPFS centre products; and

(k) Carrying out periodic monitoring of the operation of the WWW.

1.2 Functions of Members responsible for GDPFS centres

1.2.1 Interpretation at NMCs

National Meteorological Centres (NMCs) should be able to use, interpret and interact fully with GDPFS products in order to reap the benefits of the WWW system. Appropriate guidance on the methods for the interpretation of the GDPFS output to end-user products should be made available to Members, as well as methods for the verification and intercomparison of forecasts.

1.2.2 Accessibility of products

GDPFS products should be accessible through a system of World Meteorological Centres (WMCs) and Regional Specialized Meteorological Centres (RSMCs)* with functions and responsibilities as defined in the Manual and according to agreements among Members when appropriate.

1.2.3 Data management

The WWW data management function shall be used to coordinate the real-time storage, quality control, monitoring and handling of GDPFS data and products.

1.3 WMC responsibilities

1.3.1 Output products

1.3.1.1 Each WMC applying sophisticated high-resolution global NWP models including ensemble prediction systems should prepare for distribution to Members and other GDPFS centres the following products, based on the list in paragraphs 1.1 to

1.1.3 above:

(a) Global (hemispheric) analysis products;

(b) Short-, medium-, extended- and long-range weather forecasts based on deterministic and ensemble NWP system with global coverage presented separately, if required, for:

(i) The tropical belt;

(ii) The middle and high latitudes or any other geographical area according to Members’ requirements;

(d) Environmental quality monitoring, analyses, forecasts and prediction products.

1.3.1.2 Global model products required to meet the needs of all WMO Programmes should be made available to national and regional centres at the highest possible resolution given technological and other constraints.

1.3.2 Use of products

WMCs should also carry out verification and intercomparison of products and make results available to all Members concerned, support the inclusion of research results into operational models and their supporting systems and provide training courses on the use of WMC products.

1.3.3 The functions of a WMC should also include the following non-real-time activities:

(a) Carrying out the development of research in support of large- and planetary-scale analyses and forecasting;

(b) Exchanging technical information with other centres;

(d) Managing non-real-time data involving:

(i) Collection and quality control of data not available from the GOS in real-time, via mail or other means;

(ii) Storage and retrieval of all basic observational data and processed information needed for large- and planetary-scale research and applications;

(iii) Making non-real-time data available to Members or research institutes upon request;

(e) Continuously updating and providing, on request, catalogues of available products.

(*) The present structure of the GDPFS is given in Appendix I-1.

1.4 RSMC responsibilities

1.4.1 Output products

1.4.1.1 Regional Specialized Meteorological Centres (RSMCs) with geographical specialization

Regional Specialized Meteorological Centres (RSMCs) with geographical specialization shall be designated in each Region, capable of preparing with the support of WMCs, and where applicable RSMCs outside the Region, analyses and short-, medium-, extended- and long-range weather forecasts with the highest possible quality and with meteorological content, geographical coverage and frequency required by Members and agreed for the system. Output products from RSMCs should comprise:

(a) Analyses and prognoses at the surface and/or in the free atmosphere for short, medium, extended and long ranges, for the tropical, subtropical and extratropical areas, according to the obligations of each RSMC and as agreed by the regional association;

(b) Interpreted forecasts of specific weather parameters in map form or at specific locations (e.g. precipitation amounts, temperature, wind and humidity), subject to agreement between Members, where appropriate;

(d) Climate analyses, long-range forecasts, onset, intensity and cessation of the rainy season(s);

(e) Environmental quality monitoring and predictions, such as UV-B;

(f) Results of forecast verifications and intercomparison studies.

1.4.1.2 Regional Specialized Meteorological Centres (RSMCs) with activity specialization

A Regional Specialized Meteorological Centre (RSMC) with activity specialization shall be designated, subject to the formal commitment by a Member or group of cooperating Members, to fulfil the required functions of the centre and meet the requirements for the provision of WWW products and services initiated and endorsed by the relevant WMO constituent body or bodies concerned. The centre should be capable of preparing independently or with the support of WMCs, and where appropriate, other GDPFS centres and disseminating to Members concerned:

(a) Global medium-range forecasts and related analyses;

(b) Global extended- and long-range forecasts and related mean analysed values and anomalies;

NOTE: Centres producing global long-range forecasts, and recognized as such by CBS, are called Global Producing Centres for Long-range Forecasts (GPCs). The criteria to be recognized as a GPC and the list of designated GPCs is given in Appendix II-8.

(d) Three-dimensional atmospheric modelling products including trajectories, integrated pollutant concentration, and total deposition for environmental emergency response, atmospheric backtracking modelling procedures;

(e) Regional LRF products, climate monitoring products, climate watches, drought monitoring products, climate data services, and tailored climate products.

NOTE: Centres producing regional long-range forecasts and other regional climate services or groups of centres that collectively provide these forecasts and services in a distributed network, and are recognized as such by CBS and CCl at the request of regional associations, are called Regional Climate Centres (RCCs) or RCC-Networks, respectively. Definitions of RCCs and RCC-Networks, the list of designated RCCs and RCC-Networks, and mandatory functions of RCCs and RCC-Networks can be found in Appendix II-10. The criteria to be recognized as an RCC or RCC-Network are given in Appendix II-11.

1.4.1.3 Regional model output products required to meet the needs of all WMO Programmes should be made available to national centres at the highest possible resolution given technological and other constraints.

1.4.1.4 The overall list of output products required for international exchange from GDPFS centres is given in Appendix II-6.

1.4.2 Conversion capabilities for transmission of products

In order to meet the requirements of NMCs for output products in character representation and/or graphical form, all RSMCs should have facilities for conversion of products from binary to character and/or graphical form for regional transmission.

1.4.3 Constraints for adjacent centres

To the maximum extent feasible, adjacent RSMCs with geographical specialization should be prepared to assume each other’s functions. This does not necessarily mean that each RSMC should be prepared to use the analytical models employed by RSMCs adjacent to it. Each RSMC should, however, be able to issue products covering equivalent geographical areas and to give information generally similar to that contained in the products of adjacent RSMCs.

1.4.4 The functions of an RSMC should also include the following non-real-time activities:

(a) Assistance in the management of non-real-time data involving:

(i) Assistance to the WMC in management and maintenance of non-real-time data, in particular by obtaining late and delayed observational data for its area of responsibility;

(ii) Storage and retrieval of basic observational data and processed information needed to discharge the non-real-time responsibilities of the RSMC;

(iii) Making non-real-time data available to Members or research institutes upon request;

(b) Development and refinement of new techniques and applications;

(d) Regular exchange with other centres of information on techniques and procedures used and results achieved;

(e) Providing opportunities for training of personnel in manual and automated techniques;

(f) Continuously updating and providing, on request, a catalogue of available products.

1.5 Members’ responsibilities

Each Member shall ensure that it has a National Meteorological Centre adequately staffed and equipped to enable it to play its part in the World Weather Watch.

1.5.1 NMC functions

Each Member should ensure that its National Meteorological Centre performs the functions defined in Part I, paragraph 4.1.3 and as elaborated in Part II, paragraphs 1.1 to 1.2.3.

1.5.2 Checking of collected information

Each Member shall designate a National Meteorological Centre, or other appropriate centre, to be responsible for meteorological checking of information collected before transmission on the Global Telecommunication System.

NOTES:

(1) It is for each Member to decide, in the light of its own capabilities and needs, the extent to which it wishes to receive and use products of WMCs and RSMCs.

(2) The telecommunication functions of World Meteorological Centres and National Meteorological Centres are specified in the Manual on the GTS.

(3) Definition of data levels. In discussing the operation of the GDPFS it is convenient to use the following classification of data levels, which was introduced in connection with the data-processing system for the Global Atmospheric Research Programme (GARP):

Level I: Primary data. In general these are instrument readings expressed in appropriate physical units and referred to Earth coordinates. Examples are: radiances or positions of constant-level balloons, etc. but not raw telemetry signals. Level I data still require conversion to the meteorological parameters specified in the data requirements.

Level II: Meteorological parameters. These are obtained directly from many kinds of simple instruments, or derived from the Level I data (e.g. average winds from subsequent positions of constant-level balloons).

Level III: Initial state parameters. These are internally consistent data sets, in grid-point form obtained from Level II data by applying established initialization procedures. At those centres where manual techniques are employed, Level III data sets will consist of a set of manually-produced initial analyses.

1.5.3 The functions of an NMC should also include the following non-real-time activities:

(a) Support, as required, of the appropriate RSMC in managing non-real-time data, including management of its national database;

(b) Storage and retrieval (including quality control) of observational data and processed information to meet national and certain international requirements;

2. QUALITY CONTROL OF OBSERVATIONAL DATA AND THEIR RECEPTION AT GDPFS CENTRES IN REAL- AND NON-REAL TIME

2.1 Quality control of observational data

2.1.1 Definitions

2.1.1.1 Quality assurance should be taken to mean the procedures that ensure the best possible quality of the data which are used for purposes of the GDPFS.

2.1.1.2 Quality control (QC) requires that an operational entity, be it a WMC, RSMC, NMC or observing site, has the ability to select, edit, or otherwise manipulate observations according to its own set of physical or dynamical principles. Furthermore, real-time QC should carry the connotation that such a centre has the ability to feedback, or query, an observation-originating point of a responsible staff, where appropriate, on erroneous or questionable data, or on the lack of an expected report within a time sufficient to retain the synoptic usefulness of the report.

2.1.1.3 Quality monitoring, on the other hand, is the act of aggregating information on the quality of a sample of observations from the point of view of a particular application, e.g. numerical weather prediction. It is important to make a distinction between quality monitoring and delayed-time quality control. The latter needs to be clarified in terms of the actual practices of the centres producing delayed-time products.

2.1.1.4 Quantity monitoring is the act of aggregating information on the numbers of observations available, transmitted and used by a centre.

2.1.2 Responsibility for real-time quality control

2.1.2.1 The primary responsibility for quality control of all observational (Level II) data should rest with the national Meteorological Service from which the observation originated ensuring that when these observations enter the GTS they are as free from error as possible.

2.1.2.2 Quality control of observational data needed for real-time uses shall not introduce any significant delay in the onward transmission of the data over the GTS.

2.1.2.3 To detect errors which may escape the national quality-control system and errors introduced subsequently, RSMCs, WMCs and other GDPFS centres should also carry out appropriate quality monitoring of the observational data they receive.

2.1.3 Minimum standards

2.1.3.1 Members should implement minimum standards of real-time quality control at all NMCs, RSMCs and WMCs. These standards of quality control for real-time data are given in Appendix II-1.

2.1.3.2 For the NMCs not capable of implementing these standards, Members concerned should establish agreements with an appropriate RSMC or NMC to perform the necessary quality control on an interim basis.

2.2 Requirements for observational data

2.2.1 In determining observational data requirements for their data-processing functions, Members shall keep in mind the needs of all WMO Programmes and WMO supported programmes.

2.2.2 To determine the minimum overall area of data coverage required, Members shall consider the area for which they are preparing analyses and forecasts, the scale of phenomena being dealt with, and the needs of the actual analysis/forecast process in use.

NOTES:

(1) Requirements of GDPFS centres for national, regional and global exchange of observational data needed, including in particular those of large-scale advanced NWP, are given in Appendix II-2.

(2) Intra- and inter-regional exchange programmes of observational data for large-scale and mesoscale analysis are set up by the regional associations concerned.

2.3 Times of receipt of observational data

2.3.1 The observational data required for real-time purposes shall reach the national Meteorological Services sufficiently quickly to be used effectively.

2.3.2 The observational data shall therefore be handled rapidly during pre-processing by the GDPFS and during transmission by the GTS.

NOTE: Target times for the receipt of observational data are given in Appendix II-3.

3. ANALYSIS AND FORECASTING PRACTICES

NOTE: In addition to the regulations contained in this chapter, detailed guidance is given in the Guide on the Global Data-processing System (WMO-No. 305) and in the International Meteorological Tables (WMO-No. 188).

3.1 Reference surfaces for upper-air analysis

3.1.1 The principal type of reference surface for representing and analysing the conditions in the free atmosphere over large areas shall be isobaric.

3.1.2 The standard isobaric surfaces for representing and analysing the conditions in the lower atmosphere shall be the 1 000 hPa, 850 hPa, 700 hPa, 500 hPa, 400 hPa, 300 hPa, 250 hPa, 200 hPa, 150 hPa and 100 hPa surfaces.

3.1.3 The standard isobaric surfaces for representing and analysing the conditions in the atmosphere above 100 hPa should be the 70 hPa, 50 hPa, 30 hPa, 20 hPa and 10 hPa surfaces.

3.2 Preparation of upper-air charts

3.2.1 Members should either prepare or have available upper-air charts for at least four of the six following standard isobaric surfaces: 850 hPa, 700 hPa, 500 hPa, 300 hPa, 250 hPa and 200 hPa.

3.3 Short-range weather forecasting

In the short-range weather forecasting process, Members should:

- Evaluate the present meteorological situation;

- Examine the quality and relevance of the analysis;

- Indentify the key elements of the meteorological situation, according to the accepted conceptual models and/or guidance or tools;

- Examine the various guidance products and choose the most likely scenario;

- Describe the evolution of the atmosphere corresponding to the chosen scenario;

- Deduce the consequences for smaller scale and specific areas;

- Describe the expected weather in terms of weather elements, including automated production techniques when applicable;

- Decide on the opportunity or necessity to issue or end warnings;

- Distribute the various products to users;

- Evaluate according to performance measurements or verify forecasts.

4. PRACTICES FOR PICTORIAL REPRESENTATION OF INFORMATION ON METEOROLOGICAL CHARTS AND DIAGRAMS

4.1 Scales and projections of meteorological charts

4.1.1 The following projections, as appropriate, should be used for weather charts:

(a) The stereographic projection on a plane cutting the sphere at the standard parallel of latitude 60°;

(b) Lambert’s conformal conic projection, the cone cutting the sphere at the standard parallels of latitude 10° and 40° or 30° and 60°;

4.1.2 The scales along the standard parallels should be as follows for weather charts:

(a) Covering the world: 1 : 40 000 000

Alternative: 1 : 60 000 000

(b)        Covering a hemisphere:               1 : 40 000 000

                                           Alternatives: 1 : 30 000 000

                                                                1 : 60 000 000

(c)        Covering a large part of a hemisphere or hemispheres: 1 : 20 000 000

                                           Alternatives: 1 : 25 000 000

                                                               1 : 30 000 000

                                                               1 : 40 000 000

(d) Covering a portion of a continent or an ocean or both 1 : 10 000 000

                                           Alternatives: 1 : 25 000 000

                                                               1 : 20 000 000

                                                               1 : 15 000 000

                                                               1: 7500 000

4.1.3 The name of the projection, the scale at the standard parallels and the scales for other latitudes should be indicated on every weather chart.

4.2 Symbols used on meteorological charts

4.2.1 A standard set of symbols and models should be used for plotting data on meteorological charts.

4.2.2 A standard set of symbols should be used for representing analyses and forecasts on meteorological charts.

NOTE: The symbols used for the pictorial representation of observational data, analyses and forecasts on meteorological charts are those given in Appendix II-4.

4.3 Construction of aerological diagrams

4.3.1 Diagrams used for representation and analysis of upper-air observations of pressure, temperature and humidity should:

(a) Be constructed on the basis of:

(i) The values of the physical constants and parameters given in the Technical Regulations (WMO-No. 49), Volume I, Appendix A;

(ii) The assumption of ideal gas properties, except for the values of both saturation vapour pressure and heats of transformation of phases of water, at specific temperatures;

(b) Bear a legend stating the principles used in their construction.

4.3.2 Diagrams used for the accurate computation of geopotential from upper-air observations of pressure, temperature and humidity should possess the following features:

(a) Equal-area transformation of pressure-volume diagram;

(b) Straight and parallel isobars;

(c) A scale such that the errors involved in computation are significantly smaller than those arising from instrumental errors.

4.4 Preparation of charts and diagrams for facsimile transmission

4.4.1 Preparation of charts

4.4.1.1 When preparing charts for facsimile transmission, the following basic considerations in the preparation of the original copy should be followed:

(a) The minimum line thickness should be sufficiently large to ensure clear reproduction;

(b) Lines which are required to be reproduced uniformly should be of uniform width and intensity;

(c) The minimum separations of detail in letters, figures, symbols, etc. should be sufficient to avoid filling-in of the spaces in the reproduction;

(d) Letters, figures, symbols, etc. should be drawn as simply as possible;

(e) Models employed in plotting should be as simple as possible.

4.4.2 Standardization of maps for facsimile transmission

4.4.2.1 The standard projections and scales in paragraphs 4.1.1 and 4.1.2 should also apply to documents prepared for facsimile transmission.

4.4.3 Colours and features

4.4.3.1 Since the reproduced chart or diagram may show little, if any, colour differentiation between the different elements plotted on the original copy, the original should be prepared either using a monochromatic system or, if a polychromatic system is employed, in such a way that the reproduction conforms to a monochromatic system. For example, on the original copy, fronts should be entered in their appropriate colours, providing the symbols used to draw the fronts conform to the frontal symbols of the monochromatic system given in Appendix II-4.

4.4.3.2 Synoptic weather maps and charts prepared for transmission by facsimile should include the following features:

(a) Geographical outlines of minimum detail necessary for orientation purposes with coastlines interrupted where station data are to be plotted;

(b) Selected meridians and parallels printed in double thickness (bold-face) for orientation purposes;

(c) Map references required only for convenience in the entering of data, e.g. index numbers, 1° intersections of latitude and longitude, station circles, etc., to be printed in non-photo blue;

(d) Letter and figures of a size compatible with resolution characteristics of the transmission system(s) over which the charts are to be transmitted.

4.4.4 Legend

4.4.4.1 All charts and diagrams transmitted by facsimile should bear a bold legend including:

(a) The type of chart or diagram;

(b) The date and time to which the data refer or, in the case of forecast charts, the time to which the forecast applies;

NOTE: Minimum requirements for identification of charts transmitted in pictorial form are also given in the Manual on the Global Telecommunication System (WMO-No. 386) (see Volume I, Part II, paragraph 3.1).

4.4.5 Plotted data

4.4.5.1 Entries on the original copy should conform to the basic principles outlined in Appendix II-4.

4.4.6 Analysed data

4.4.6.1 Isopleths, frontal symbols, areas of precipitation, etc. should be entered, as appropriate, in the manner laid down in Appendix II-4. Care should be taken not to obliterate one set of plotted data by another.

5. EXCHANGE OF PRODUCTS BETWEEN CENTRES

5.1 Times of availability of products

5.1.1 Processed data (products) required for real-time and non-real time purposes shall reach the national Meteorological Service sufficiently quickly to be of effective use in its associated timescale. Both observational and processed data shall therefore be handled rapidly by both the GDPFS and the WIS/GTS. On the WIS/GTS, transmission of observational data shall have priority over the transmission of processed data.

NOTE: Target times for the availability of processed information are given in Appendix II-5.

5.2 Programmes of output products

5.2.1 Members shall establish programmes of output products for general distribution by their WMCs and/or RSMCs, taking into account requirements of other Members and the capability of the GTS to handle these products.

NOTE: Overall lists of products, to be used as general guidance by Members in establishing output programmes for their WMCs and RSMCs, are found in Appendix II-6.

5.2.2 Members shall establish programmes of output products for general distribution by their WMCs and/or RSMCs, taking into account requirements of other Members and the WIS/GTS operational arrangements required to handle and distribute these products.

5.2.3 In order to avoid overloading the WIS/GTS, Members should limit requests by their NMCs for products, taking into account the following considerations:

(a) Members should require output products from RSMCs with geographic specialization normally from one RSMC located in the same WMO Region (exceptions should be restricted to cases where the area, for which a Member needs to receive RSMC output products, is not covered by the products from one RSMC in the same Region);

(b) If there is an urgent need for a Member to receive the same product from more than one geographically specialized RSMC or WMC for special operational purposes, these requirements should be limited to a selection of two levels of analyses and prognoses;

NOTE: The lists of global and regional model products, to which the highest priority should be given by WMCs and RSMCs for preparation, are given in Attachments II.1 and II.2.

5.3 Transmission priorities for GDPFS products

5.3.1 Transmission priorities for GDPFS products described in this section are intended as guidance to GDPFS centres on providing observational data and output products to the WIS/GTS in the proper sequence. As regards the relay and distribution of information by WIS centres, the provisions of the Manual on the Global Telecommunication System and the Manual on WIS apply.

5.3.2 Transmission priorities for global and regional model products

5.3.2.1 Priorities for the transmission of global model output products should be used when several such WMC and RSMC products are available at the same time. Priorities for transmission of regional model products should be based on the requirements for interregional exchange of RSMC products.

5.3.3 Transmission priorities after transmission outages on the MTN and its branches

5.3.3.1 In case of WIS centre or communication link failure, WIS/GTS provisions for backup apply. After transmission outages that have disrupted the normal information exchange, normal transmission schedules of observational data should be resumed no later than the first main standard time of observation following the cessation of the outage. Procedures for the transmission of accumulated meteorological data should not interfere with the resumption of normal transmission schedules. If these data are redundant, they should not be transmitted.

5.3.4 Transmission priorities for global and regional model products after outages

5.3.4.1 Global and regional model products from RSMCs accumulated due to communication link disruption should be transmitted with the least possible delay. The regional model products should have a higher priority than global model products for transmission after outages.

5.3.5 Priority of observational data over processed data

5.3.5.1 Until such time as all centres are in a position to convert output products in GRIB, GRID and/or BUFR code form into pictorial form, Members should transmit certain of their WMC and RSMC products also in pictorial form in addition to alphanumeric and/or binary form.

NOTES:

(1) Members are encouraged to transmit processed information in the GRID, GRIB and/or BUFR code forms.

(2) As Members develop the capability at their centres for transforming these products from GRID, GRIB and/or BUFR to pictorial form, the pictorial transmission will be discontinued, where appropriate.

5.3.6 Procedures and formats for the exchange of monitoring results

5.3.6.1 GDPFS centres participating in the exchange of monitoring results should implement standard procedures and use the agreed formats.

NOTE: Procedures and formats for the exchange of monitoring results are given in Attachment II.9.

5.3.7 Standards in the provision of international services by Regional Specialized Meteorological Centres (RSMCs) for atmospheric modelling in radiological environmental emergency response

5.3.7.1 The designated RSMCs with activity specialization in the provision of international services for atmospheric transport modelling in radiological environmental emergency response shall implement agreed standard procedures and products, given in Appendix II-7.

5.3.8 Standards in the provision of international services by Regional Specialized Meteorological Centres (RSMCs) for atmospheric transport modelling in backtracking

5.3.8 .1 The designated RSMCs with activity specialization in the provision of international services for atmospheric transport modelling in backtracking shall implement agreed standard procedures and products. Standards in the provision of international services by RSMCs for CTBT Verification support are given in Manual on GDPFS, Appendix II-9.

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DPFS_Manual_Part_II