Description

The Commission for Hydrology (CHy),through Resolution 7 (CHy-15), requested that the President andthe Advisory Working Group(AWG):

  • Ensure that all hydrological aspects and specifics and in particular the needs andconcerns of National Hydrological Services are properly reflected in the development of the new seamless Global Data-processing and Forecasting System (GDPFS);
  • Develop a proposal of a comprehensive structure for hydrology within the new

seamless Global Data-processing and Forecasting System that would encompass hydrological data, analysis and forecasting and could include new entities such as world, regional and national hydrological centres, with clearly defined roles and responsibilities; and

  • Develop documentation describing the procedures for the designation, mandatoryfunctions and activities of new centres, taking into account the principle that world and regional centres shall respect the primary roles and responsibilities of National Meteorological and Hydrological Services in the delivery of flood forecasting and warning services;

In response to these requests,the following initial proposal has been developed.

Based on review of the new GDPFS Manual ( and its definition of various types of centers and their responsibilities, and considering the hydrological practices and requirements, CHy proposesthe inclusion oftwo types of hydrological centres in the manual:

  1. National Hydrological Centres (NHCs); and
  2. Hydrological Analysis and Forecasting Centres (HAFCs) with presumed global or regional coverage.

Currently the definition of World Meteorological Centres and Regional Specialized Meteorological Centres is made jointly as follows:

Considering thatother non-meteorological specialized centres have already been included in the Manual (such as Numeric ocean wave prediction centres, or Regional Climate Centres) and are understood to be a specific type of RSMC, it would be highly unlikely to reach an agreement for including World Hydrological Centres as a special category equivalent to WMCs. In addition, the differences between hydrological centres operating at global and regional levels are insignificant[1]. Therefore the proposal is to include HAFCs as one type of RSMCs, by simply adding its designation criteria into chapter 2.2 of part II of the Manual (see a proposal below).

It is, however, also proposed to include a definition for National Hydrological Centres in the Manual (part I, chapter 2). The reason, is to highlight the differences typically found in institutional arrangements between nationalmeteorological and hydrological services with respect to legal responsibilities associated with flood forecasting and warnings that are issued by National Hydrological Services; which is the case in a significant number of countries around the World. In addition, it is obvious that two or more institutions could hardly be considered NMCs under the following definition of the Manual:

Therefore, a new definition of National Hydrological Centres is proposed (see below).

Proposed definition of National Hydrological Centres to be included in the GDPFS Manual, part I, chapter 2

2.1.XNHCs

National Hydrological Centres (NHCs) of WMO Members carry out functions that meet the national, subnational and, in some instances,international requirements of the Member in the field of hydrology and water resources assessment. Each Member shall ensure that it has a National Hydrological Centre adequately staffed and equipped to enable it to fulfill its responsibilities, particularly with respect to transboundary river basins.

The functions of a National Hydrological Centre shall include the preparation of hydrological analyses, forecasts and warnings at all time scalesnecessary to meet the requirements of the Member and also, depending on the context, other activities such as the production of:

(a)Special productsand services for real-time water resources management including operation of facilities; and

(b)Non-real-time products and services, such as hydrological statistics, design flows, water resources assessments and maps, water quality assessments, groundwater assessments,etc.

Proposed definition of National Hydrological Centres to be included in theGDPFS Manual, part II, chapter 2.2

HYDROLOGICAL ANALYSIS AND FORECASTING CENTRES (HAFC)

Designation criteria for HAFC

Centres conducting Hydrological Analysis and Forecasting Centre functionsat the transboundary basin, regional or global scale shall:

Operate a system that providesin near real-time hydrological data, analyses of the current state of the surface water conditions (e.g. soil moisture, river levels and flows, lake levels, snow water equivalence), and forecasts of water conditions with lead-times of hours to seasonal within their geographical area of responsibility. The list of desired products is defined in Appendix A.II.2.2.X-a;

Provide access to this service to NHCs whose operational forecasting and warning services may benefit from it;

Respect the primary roles and responsibilities of NMHSs in the delivery of flood forecasting and warning services when developing its products and allowing access to them by users other than the relevant NHCs;

Make verification statistics available according to the standard defined in Appendix A.II.2.2.X-b;

Make up-to-date information on the characteristics of its production systemavailable on a website. The minimum information to be provided is given in Appendix A.II.2.2.X-c.

RESPONSIBILITY
CHANGES TO ACTIVITY SPECIFICATION
To be proposed by: / CHy/AWG
To be approved by: / CHy
To be decided by: / EC/Congress
CENTRES DESIGNATION
To be approved by: / CHy
To be decided by: / EC/Congress
COMPLIANCE
To be monitored by: / CHy/AWG
To be reported to: / CHy

Appendix A.II.2.2.X-a

LIST OF DESIRED HYDROLOGICAL FORECASTING PRODUCTS

Analysis products

-Soil moisture, soil moisture anomaly

-Snow cover extent, snow cover depth, snow water equivalence

-Groundwater recharge/ground water anomaly (indexes)

-Flow/ flow anomaly (at water gauges, river reach)

-Runoff/runoff anomaly (basin, grid, indexes)

-Evapotranspiration (potential, actual)

-Precipitation/precipitation anomaly, including specific indexes (e.g. SPI)

-Lakes and reservoir status/ anomaly

Forecasting products

-Flash flood threat

-Snow cover extent, snow cover depth, snow water equivalence

-Groundwater recharge/ground water anomaly (indexes)

-Flow/ flow anomaly (at stream gauges, damage centres or points of interest on rivers)

-Runoff/runoff anomaly (basin, grid, indexes)

-Lakes and reservoir status/ anomaly

-Water resources assessment – water availability and anomaly

-Impacted flooded areas

Appendix II.2.1.X-b

STANDARDIZED VERIFICATION OF HYDROLOGICAL FORECASTING PRODUCTS

Deterministic forecast (for all lead time ranges):

  • Hit Rate (POD - Probability Of Detection)
  • False Alarm Rate (FAR)
  • Frequency Bias (Bias)
  • Critical Success Index (CSI)

Ensemble forecast (for short, medium, sub-seasonal to seasonal forecasting ranges), at the minimum:

  • Category (tercile) hit rate
  • Cumulative rate probability score or Brier score
  • Cumulative rate probability skill score or Brier skill score
  • Root mean square error (RMSE)
  • Relative operational characteristic

Alarms (peak over the threshold information – e.g FFGS (special case of short term))

  • Hit Rate (POD - Probability Of Detection)
  • False Alarm Rate (FAR)
  • Frequency Bias (Bias)
  • Critical Success Index (CSI)

Analysis (calibration)

  • Nash-Suttcliffe criteria
  • Root mean square error
  • ???

Appendix II.2.1.X-c

CHARACTERISTICS OF HYDROLOGICAL ANALYSIS AND FORECASTING SYSTEMS

1. System
System name
Date of implementation
Operator
2. Configuration
Domain
Horizontal resolution of the model
Forecast length and forecast step interval
Runs per day (Times in UTC)
Temporal resolution
Calibration period
Source and characteristics of soil characteristics data
Source and characteristics of geology data
Source and characteristics of river network characteristics
Source and characteristics of land-use data
Source and characteristics of DMT
Source and characteristics of hydrological data used for calibration
Source and characteristics of meteorological data for calibration
Additional comments
3. Methods and models
Method of snow accumulation and ablation
Method of glacier accumulation and ablation modelling
Method of rainfall-runoff (soil) modelling
Method of Groundwater modelling
Method of channel routing procedure
Methods of lake modelling
Methods of inundation modelling
Method of reservoir description
Method of evapotranspiration modelling
Methods of estuary (river-see interaction modelling)
Additional comments
4. Data for real-time operation of the system
Sources of observations of hydrological and meteorological variables (elements)
Methods of analysis (e.g. spatial interpolation)
Source and characteristics of inputting meteorological forecast
Other input variables (e.g. reservoir operation schemes)
Additional comments
5. Further Information
Operational contact point
URLs for system documentation
URL for list of products

[1] While in the case of meteorology, the modelling of the atmosphere on the global scale and with growing demand for nested limited area models and the interaction between these for initial boundary conditions, is different than hydrological methods of modelling. The lattertend to be the same approaches only applied over different (but always hydrological closed) special scales or territory like a basin, from small to larger sizes.