Radar maps wind over lakes
Virginia Tech geoscientists created the first large-scale high-resolution map of wind speed and direction over small bodies of water.
George Allen stand in front of a red helicoptor. A small marshy lake is in the background.
Anyone who has been sailing knows that lakes can be windy places and that wind conditions can change rapidly.
But a lake breeze does a lot more than just fill the sails. It plays a major role in dynamic processes like evaporation and emission and can affect water quality.
However, “data on wind over lakes is surprisingly limited at the global scale,” said Katie McQuillan, a Virginia Tech Presidential Postdoctoral Fellow in geosciences.
Aside from a handful of well-studied lakes that use buoys to measure wind, researchers have relied on atmospheric models to gauge wind speed and direction on smaller bodies of water. But these global models tend to be coarse and low resolution, often only making one estimate for every 30 square kilometers — which is larger than most lakes.
In its March 25 study published in Earth and Space Science, a research team led by Assistant Professor George Allen used radar measurements from NASA Surface Water and Ocean Topography satellites to precisely map the movement of wind across 19 lakes in North America and Europe.
“We found that the wind algorithms performed well on lakes of all shapes and sizes and were particularly useful for capturing detailed patterns of wind within lakes,” said McQuillan, the study’s first author. Wind speed estimates were produced at a 100-meter resolution, a large improvement over the resolution of global models.
Launched less than two years ago, the primary purpose of the radar-equipped satellite mission was to measure the height of waves on the ocean. A scientist could then work backward to calculate wind properties from the choppiness of the water.
With their new study, McQuillan and Allen proved that this method successfully transfers to much smaller bodies of water, including lakes and ponds.
“Knowledge of wind conditions is scientifically valuable for modeling evaporation, water-atmosphere greenhouse gas exchange, and water quality conditions,” Allen said. “The methods applied here could be applied globally to inform our understanding of wind and its role driving lake dynamics.”
And maybe also help people pick the best day for sailing.
Original study DOI: 10.1029/2024EA003971