Weather Radar Observations

Introduction
Weather Radar Observations
The WMO Weather Radar Database
Weather Radar Focal Points
— Responsibilities

1. Introduction

The Global Observing System (GOS) is made up of many component observing systems which contribute observations of meteorological parameters in support of the World Weather Watch (WWW) Programme and fall under the two major categories, namely Surface-based Observations and Space-based Observations.

In addition to the better known and more traditional systems that provide in situ observations at both the earth's surface and through the troposphere and lower stratosphere (Synoptic, Marine and Aircraft-based Observations), there is a relatively new suite of observing systems that can be utilised to derive observations through remote sensing technologies and techniques.

Within the category of surface-based remote sensing systems is the weather radar observing system, from which Weather Radar Observations are provided to the WWW Programme.

2. Weather Radar Observations

Weather radars have been used in the detection of precipitating water droplets and the derivation of rainfall rates within clouds (Cumulonimbus and Nimbostratus) since the 1950s.

Most modern weather radars utilise a pulse-Doppler technique that, in addition to providing estimates of precipitation rate, also enable the detection of droplet motion with respect to the radar and, as a result, can be used to determine radial wind speeds.

More recently, dual polarized weather radars have been developed that enable more accurate determination of precipitation types and sizes.

3. The WMO Weather Radar Database

In September 2009, the Commission for Instruments and Methods of Observation (CIMO) Expert Team on Operational Remote Sensing (ET-ORS) undertook a questionnaire of WMO Members in order to determine the global status and future plans for the utilisation of weather radars and also to obtain data towards the establishment of a global database of weather radars operated by WMO Members and their partner organizations.

The report on the results and analysis of the survey is available in the report Evaluation of CIMO Weather Radars Survey and Web-based Weather Radar Database (PDF, 8MB).

The Turkish Meteorological Service (TMS), in consultation with CBS and CIMO has taken the lead in developing and establishing an online database of world weather radars based on the data gathered in the 2009 questionnaire on weather radars. In 2012, the TMS undertook to maintain the WMO Radar Database (WRD) on behalf of WMO Members in an operational capacity.

4. Weather Radar Focal Points

In September 2011, the Secretariat wrote a letter to WMO Members requesting that all Members either operating or intending to operate weather radar systems in support of the WWW Programme, should nominate a Weather Radar Focal Point who would have responsibility for seeding and maintaining the weather radar metadata within the WMO Radar Database (WRD). The list of Focal Points for Weather Radar Metadata is available from the WMO Country Profile Database here.

Members should please advise of additions or changes to the list of Focal Points by contacting the Secretariat.

Responsibilities of Focal Points for Maintenance of Weather Radar Metadata

The Focal Points for Weather Radar Metadata are responsible for:

Obtaining a login to the WRD by sending an email request to the WMO Weather Radar Metadata Focal Points email list or directly to the Secretariat.
Ensuring that metadata contained within the WMO Radar Database and for which the Focal Point (FP) is responsible, is current and accurate; and
Entering and maintaining the WRD with weather radar metadata by following the procedures available from the WRD once FPs have logged in.

The WRD should be routinely checked by the FP for completeness and accuracy and updated accordingly on at least a quarterly (3-monthly) basis. It is therefore suggested that FPs carry out their routine maintenance on weather radar metadata in the last week of March, June, September and December of each year.

Inaccurate metadata can and should be corrected as and when it is discovered.

World Meteorological Organization