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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 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:

• Areal distribution of cloudiness;

• Precipitation location, occurrence, amount and type;

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

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

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

• Numerical products providing sea-state or storm-surge forecasts;

(c) Prognoses four to ten days in advance, including:

(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 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:

• Areal distribution of cloudiness;

• Precipitation location/occurrence/amounts;

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

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

• Jet stream and layer of maximum wind locations;

• 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:

• Tropical storm positions and tracks;

• Tropical depression and easterly wave positions and movement;

(c) Prognoses four to five days in advance, including:

(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 NWP prognoses using statistical or statistical/dynamical methods to produce maps or specific location forecasts of cloudiness, temperature range, precipitation probability, 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;

(c) Intercomparison of products, verification and diagnostic studies, as well as NWP model development;

(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, 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.

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

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

Each WMC applying sophisticated high-resolution global NWP models 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 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;

(c) Climate-related diagnostic products, particularly for tropical regions;

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

1.3.1.1 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;

(c) Providing opportunities for training personnel in data processing;

(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.

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 extra-tropical 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, humidity, etc.), subject to agreement between Members, where appropriate;

(c) Guidance on storm-position and track forecasts for the areas affected by tropical storms;

(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

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) Extended- and long-range weather forecasts and related mean analysed values and anomalies;

(c) Tropical cyclone warnings and advisories, storm position, intensity and track forecasts for their areas;

(d) Three-dimensional environmental emergency response transport model trajectories, integrated pollutant concentration, and total deposition;

(e) Drought monitoring products such as drought indices.

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 Binary/character conversion capabilities for transmission

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 responsiblity;

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

(c) Carrying out comparative verifications of RSMC products and making results available to all Members concerned;

(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;

(c) Research concerning operations to meet national requirements.

 
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