A new way to measure waves in a hurricane

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How big do hurricane waves grow? Hurricane Sandy gave us a good idea. It was the largest Atlantic Hurricane on record when it put out 32-foot waves measured at a New York buoy.

Direct measurement from buoys is one way to get accurate wave height readings in addition to altimeter measurements from satellites in space. Observations by meteorologists flying on hurricane hunters approximate the size of waves by eyeballing the foam and breakers below.

Recently a new method has been used to accurately determine wave heights with an instrument installed on the NOAA WP-3D Hurricane Hunter aircraft called the Ka-band Interferometric Altimeter (KaIA).

The instrument not only shows the height of the waves but can reveal the shape or steepness of the waves and measure the wind speed causing the waves.

Comparisons between KaIA with buoy and satellite altimeters in general, match well with other sensors and wave models.

Time-series of KaIA significant wave height retrievals (top) and SFMR retrievals (bottom) from  
Hurricane Nigel on September 19. In the top panel, the model wave forecast from the IFREMER Wavewatch3 model is shown as orange roughly matching the KaIA samples in blue.  The bottom panel shows SFMR retrievals which are windspeeds measured from the bottom of the plane. Heavy rain rates in blue colors degrade the wind measurements.

Time-series of KaIA significant wave height retrievals (top) and SFMR retrievals (bottom) from
Hurricane Nigel on September 19. In the top panel, the model wave forecast from the IFREMER Wavewatch3 model is shown as orange roughly matching the KaIA samples in blue. The bottom panel shows SFMR retrievals which are windspeeds measured from the bottom of the plane. Heavy rain rates in blue colors degrade the wind measurements.

When Hurricane Lee was passing 800 miles east of Jacksonville, the 28-foot wave heights retrieved from the Ka Altimeter were lower than the model forecasts.

Hurricane Lee east of Florida on September 13, 2023.

Hurricane Lee east of Florida on September 13, 2023.

More recently Hurricane Nigel had 34′ waves when NOAA flew into the eyewall on September 19.



Post source: News 4jax

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