Using ASCAT Wind and Other Data in Marine Forecasting

1.0 Introduction » 1.4 About Ocean Wave Dynamics and Wind Conditions

Here is a brief review of ocean wave dynamics and wind conditions that are conducive to wave growth. They are important factors to keep in mind when interpreting wind and wave height observations and model output, such as from WAVEWATCH III, which we will do in the case study.

  • Wind speed: The wind blowing on the sea surface creates waves that move in its direction. The wind flow maintains wave growth. The process continues as long as the wind speed is greater than the wave speed.
  • Fetch or fetch length: This is the distance that the wind generally blows over the sea from a constant direction and at a constant speed
  • Duration: This is how long the wind affects the fetch or fetch length

Although each of these factors is important to consider, they do not all have the same impact on wave height. Wave height is most sensitive to changes in wind speed, even when fetch or duration is limited. Therefore, when you’re looking for areas of significant wave generation, consider wind speed first, followed by fetch length and wind duration. This helps explains why accurate wind forecasts are so important to wave forecasts in marine meteorology and numerical modeling.