With the complexity and cost of weather forecasting technology expanding at an accelerating rate, South Africa is under pressure to ensure it has the technology infrastructure and resources needed to keep pace – and to save lives in the event of severe weather conditions.
The South African Weather Service (Saws), a government agency, gives daily guidance on potentially catastrophic weather systems in Southern African countries. For short-range forecasts (up to six hours), meteorological services like Saws rely on weather radars and satellite information. For just about everything else, high-performance computing (HPC) is crucial.
Observations (data) from weather stations and the upper atmosphere are used as input for models (codes). The ageing Cray XC30 supercomputer in use by Saws is decrepit and lacks the capacity to store weather radar data.
According to a recent forensic investigation, Saws has the budget (R100-million) for a new high-performance computer, but procurement has been delayed, allegedly because of manipulation of specifications to favour a particular service provider.
Currently two Eclipse Holdings employees are permanently on site, evidently to manage the Cray system, since Saws lacks the necessary IT skills. A criticism levelled at Saws is that it employs too many managers and too few scientists. The agency did not respond to a request for comment.
Saws meteorologists are highly sought-after globally. Most are graduates of the University of Pretoria, the only South African university that offers a BSc degree in meteorology. According to UP professor of meteorology Liesl Dyson, graduates are often poached to go abroad. At least 15 now work in New Zealand; others are in the US, Canada and the Middle East.
New HPC needed
Training incorporates the physics and calculus needed for solving complex problems. “The Saws Cray computer is not only needed for seasonal forecasting but for data crunching, climate applications, archiving of data and many other processes,” said Dyson. The need for a new HPC cannot be understated.”
Francois Engelbrecht, director of the Global Change Institute and professor of climatology at the University of the Witwatersrand, said South Africa must make deals with international forecasting services to get products as cheaply as possible so that Saws can do its own probabilistic forecasts of extreme weather events.
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In the next 10 years, Engelbrecht expects up to 64 large samples of 3km-resolution forecasts will be issued by big international weather forecasting centres daily. So-called exascale computers, which can use a million CPUs or more will be employed to generate these forecasts. “South Africa simply can’t afford it,” he said.
Saws has a contractual relationship with the UK Met Office, which executes numerical weather prediction, seasonal forecasting and climate modelling spanning a few days to hundreds of years. With information from this global model, Saws runs a “limited area model” in Southern Africa. New developments in the UK get added to this model.
“It goes to such a small resolution that you can resolve a cloud, not just the environment in which the cloud forms, but the actual cloud – you can actually see where the clouds are forming and where precipitation will occur,” Dyson said.
There are only two HPCs in the public sector in South Africa that have advanced computing capabilities. One is owned and operated by the CSIR and the other one by Saws. The CSIR is currently installing a new HPC and updating its current system to improve its computational facilities.
“We are lagging behind,” said Happy Sithole, centre manager for the National Integrated Cyber Infrastructure System. “The new system has four times the capacity we have now, but we still don’t compare with the rest of the world, which [has supercomputers that are] a thousand times faster.”
Saws uses the CSIR supercomputer, located in Cape Town, as a failover service, providing limited forecasting services should the Saws system be unavailable. “Lack of capacity is problematic. We should be doing better for a country of our size with the level of investment. I am hoping Saws is moving very fast to correct the situation,” Sithole said.
The introduction of advanced satellite data in recent years has increased Saws’s capacity to forecast big weather systems, including cut-off lows (which often bring heavy rain to South Africa), tropical cyclones, cold fronts and high-pressure systems, said Mary Jane Bopape, director of the South African National Research Foundation’s South African Environmental Observation Network.
“It has narrowed the modelling skills gap between the southern and northern hemispheres, but there are still not enough ground observations in South Africa and the rest of the African continent to calibrate and verify satellite products and model simulations,” she said.
Magnitude
The European Centre for Medium-Range Weather Forecasts (ECMWF), which is among the most advanced that exists, gives a sense of the magnitude of systems in other parts of the world.
An Integrated Forecasting System is central to operations. Head of the evaluation section in the forecasts and services department Matthieu Chevallier explained to TechCentral that 50 million quality-controlled (primarily satellite) observations are used to produce its forecasts.
Expertise required includes numerical modelling, meteorology, atmospheric science and physics or related fields (hydrology, oceanography), and applied mathematics and statistics.
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Deputy director of ECMWF’s computing department Christine Kitchen described the advanced HPC facility that supports ECMWF’s operations and research activities. Specifically designed for the complex, data-intensive requirements of numerical weather prediction, with stringent commitments to deliver time-critical forecasts, it is upgraded via a tender process on a four- to five-year cycle. – © 2024 NewsCentral Media
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