Forecasting lake conditions at the World Rowing Championships
Weather is a critical factor for any rowing event. Over the eight-day World Rowing Championships at Lake Karapiro, NIWA provided web-based minute-by-minute wind and weather information, and forecasts of lake surface conditions.
Getting weather information from lake to web
A NIWA weather monitoring station, located on Karapiro dam, gave the international rowing federation (FISA, the event organisers) and competitors web-based access to local weather data. The weather station measured wind speed and direction, rain, air temperature, humidity, barometric pressure and solar radiation, and sent these data to the Neon web server every 10 minutes.
Measuring wind conditions near the lake surface
We installed a second weather station on the floating 1500-metre marker to monitor wind and other conditions near the lake surface. The station recorded weather data every eight seconds and uploaded processed data to the Neon server every minute. The data on the server was available over the Internet.
The data was input to NIWA’s EcoConnect environmental forecasting model to generate lake surface condition forecasts. A comparison between what was forecast and what actually happened, as recorded at the dam and at the floating weather station, enabled our forecaster to fine-tune the model.
How well did the model forecast the local conditions?
Feedback from the weather stations, on the dam and on the water, was essential for our wind forecasting. We significantly improved the forecasts by relating the raw model output to what was happening at the dam over two months prior to the world championships.
What did we forecast accurately?
- the one rain event of the week
- all the major wind changes
- wind speed – mostly to within two m/s of the observed wind speed
- wind direction – mostly to within twenty degrees of that observed.
At 1 pm on Sunday 31 October, officials cancelled the afternoon events when NIWA predicted the wind speed would remain above 6 metres per second that afternoon, but improve dramatically the next day.