Wetenschap - 24 augustus 2011

New weather radar gives better forecast

Four people died due to a sudden rainstorm during Pukkelpop. A new weather radar with a very high resolution would be useful, says hydrology professor Remko Uijlenhoet. But it wouldn't prevent every calamity,


Foto: .

The climate seems to get more and more quirky. During the rock music festival Pukkelpop, for example, as much rain fell within twenty minutes as it normally does in one month. Forecasting such regional phenomena is an impossible task for our weathermen and weatherwomen, says Remko Uijlenhoet. The technical weather data are just not specific enough for doing that. 'There are currently two big weather radar stations in the Netherlands, located in De Bilt and in Den Helder', explains this hydrologist. 'Together with a station in the Belgian Ardennes, they have to cover the entire Benelux. The problem lies in having to work with a big wave length, resulting in a relatively coarse image.'
Uijlenhoet has been working with KNMI and the Delft University of Technology for several years to find a solution: a finely meshed network of regional radar stations with a much higher resolution. With this, it would be possible to show where downpours will occur at street level. The prototype is ready. It is situated at the top of the mast in De Bilt. High resolution radar does have a disadvantage, says Uijlenhoet: its range is only several tens of kilometres. However, it is cheaper. 'That makes it possible to create a network in which data from all the stations are linked up.'
For this reason, it is important to have enough buyers. The first one has shown up: the Port of Rotterdam. Shipping and harbour-based companies will also be interested in being kept informed of sudden downpours and other catastrophes. Uijlenhoet expects that there are more parties with commercial dealings interested  in the relatively cheap system, especially in the west of the country. Even water boards can benefit from having their own weather radar, he says. If there are sufficient customers, data from the various equipment can be viewed as a network and combined into a weather chart covering a bigger area.
In any case, this new network of radar stations (should it materialize) would not be able to solve all weather problems immediately. More detailed data would also mean that a more complex weather model is required for making forecasts. But it's a start.