3.3                                   Meteorological services

Meteorological services in the Antarctic generally have components that include a basic monitoring or climate focus; forecasting facilities such as the reception of satellite data; and then the forecasting services themselves. This section provides a brief overview of aspects of each of these.

3.3.1                                Environmental conditions and climatological study

An important component of planning operations to Antarctica is a climatological study of the area in question. For example, as the economics of operating flights to Antarctica are often heavily dependent on the ability to predict the best operating windows for landings and take‑offs, a climatological study of the airstrip conditions is essential to maximize mission success.

These types of studies can include a statistical analysis, based on historical meteorological data, of the amount and height of low cloud, surface horizontal visibility, and surface wind direction and speed. With these data, comparisons can be made between potential sites as to their suitability for aircraft operations. Estimates can be made of the percentage of time that meteorological conditions would be safe for landing or take–off. An example of such an approach applied to conditions at a station is given, for example, for Casey Station, in Section 7.10.1.4.

3.3.2                                Forecasting facilities

The following equipment is considered important in providing meteorological information for forecasting purposes:

3.3.2.1                          Satellite data

The availability and use of satellite data are discussed in Section 4.3. A very brief overview is given here

High Resolution Picture Transmission (HRPT)

Images of nominally 1.1 km horizontal resolution, obtained from the AVHRR instruments on board the NOAA series of polar–orbiting satellites (see Section 4.3.1.2) are available to provide meteorological information. The HRPT station at McMurdo, for example, provides coverage of much of Antarctica. A similar facility at Rothera provides coverage of the Antarctic Peninsula while the HRPT station at Casey provides data for all of East Antarctica. Even the HRPT facility at Melbourne provides data as far south as the Antarctic coast near Dumont d'Urville.

Increasingly re–supply and research vessels: for example, the Chinese Antarctic Research Expedition (CHINARE) and the BAS vessels are equipped with HRPT facilities.

3.3.2.2                          Automatic Picture Transmission (APT) data

NOAA satellite imagery at four– km horizontal resolution may be available at some stations, on some ships, and at some remote locations using APT equipment, which is a simpler system than HRPT, for example, needing only an omni–directional antenna. The Meteor series of satellites also provide a similar type of data (see Section 4.3.1.2).

3.3.2.3                          Geostationary Meteorological Satellite (GMS) data

Hourly satellite imagery from the geostationary meteorological satellites is available to provide useful information between low latitudes and the Antarctic coastal regions (see Section 4.3.1.1).

3.3.2.4                          DMSP

The USA Defense Meteorological Satellite Program series of satellites (see Section 4.3.1.2) are, for example, monitored in real time by McMurdo and Palmer Stations. In the case of McMurdo the NOAA, DMSP, and Meteor satellite data are received and processed providing McMurdo Station and the Ross Ice Shelf area with nearly continuous coverage. The “TeraScan” processor enables overlay, and still animation for the DMSP and NOAA images.

3.3.2.5                          Numerical weather prediction

As will be seen in Chapter 7 output from NWP models is widely used in many aspects of weather forecasting and provides the main means of producing forecasts for the next few days ahead. See also Section 4.2.

3.3.2.6                          Global Telecommunications System (GTS), High Frequency (HF) radio–facsimile, File Transfer Protocol (FTP) and the World Wide Web

The GTS is the prime source of weather observations in real-time. However, in a personal communication, Ian Hunter, Deputy Director, Marine Meteorological Services for the South African Weather Bureau cautions, "Forecasters must realise that the data on the GTS have to be requested. For example, we missed very valuable data from the vessel Polarstern because the data were going via Meteosat to Darmstadt and were never routed to Pretoria. We have had similar problems with the Marion Dufresne's VOS data. In other words, forecasters must find out what data they should be getting on the GTS."

Increasingly the above data, plus many other data types, can be provided point–to–point using facilities such as FTP and can be made available on the World Wide Web. Conventional fax may also be used where appropriate. HF radio–facsimile is another valuable source of data, particularly chart-based information. A comprehensive list of global radio–facsimile (and other information) may be found at: http://www.nws.noaa.gov/om/marine/rfax.pdf .

3.3.2.7                          Automatic Weather Stations 

Table 7.1.1 (in Appendix 1) includes many of the AWSs that are in operation in the Antarctic and notes which of these are available on the GTS. Local readout of AWSs for the entire Antarctic continent is usually available at stations with HRPT facilities.

3.3.2.8                          Forecast dissemination

There are several methods by which forecasts are disseminated to the user:

·                         E-mail and the Word Wide Web;

·                         Point to point via satellite transmission;

·                         Broadcast by satellite, for example, all the South African Weather Bureau forecasts are broadcast via Inmarsat's Atlantic Ocean Region–East or Indian Ocean Region satellites;

·                         High Frequency (HF) broadcasts.

3.3.3                                Forecast services

Typically, Antarctic weather forecasting services and meteorological advices are provided by the various nations/agencies to support/provide:

·                         national re–supply and research vessels en–route to and from Antarctica;

·                         ship–shore–ship helicopter operations;

·                         helicopter operations within the local area (about 400 km range) from stations or field base as well as the so called "long range" helicopter operations between stations;

·                         weather forecast and sea ice analysis assistance to other nations/agencies, if requested;

·                         public style weather forecasts and warnings for the various stations and their immediate environs, especially the issuing of prior advice of impending blizzards;

·                         weather sensitive activities during summer field (mostly scientific) programmes;

·                         fixed–winged aircraft operations within the Antarctic, or to and from the continent;

·                         tourist activities (mostly inter and intra–continental flights and ship voyages).

3.3.3.1                          Aviation specific services

Area or Forecasts of Route Conditions (ROFOR)

Route forecasts of wind velocities and temperatures at standard flight levels over a specific flight path for a specified period of validity are provided by many forecasting services.

Significant Weather Prognosis (SiG WHR PROG)

Significant weather prognoses are a useful pictorial means of portraying the forecast weather elements.

Terminal Aerodrome Forecasts (TAFs)

Terminal aerodrome forecasts for the destination, alternate landing strips and the place of departure are prepared by relevant forecasting offices.

Weather watch

Most forecast services would maintain a close watch on the forecasts that they have issued and provide an amendment service if specified error criteria are met or exceeded.