Buoy observations obtained in Hurricane Ian

Following the rapid-response air deployment of an array of buoys in the Gulf of Mexico ahead of Hurricane Ian, members of the Task 3A Thomson team closely monitored the data collected by the devices.

In Figure 1, the drift tracks of six Sofar Ocean Spotter buoys and two UW-APL microSWIFT buoys are shown, along with the path of Hurricane Ian over a 12-hour period on September 28th and areas of sustained winds of 34+ knots, 50+ knots, and 64+ knots.

Figure 1. Left: Path of Hurricane Ian over a 12-hour period from 09-28 06h to 18h (UTC) just before landfall on the Florida Coast, colored by intensity. Buoy drift tracks over the same period are shown as a gradient increasing from light to dark with time. The gray shaded regions surrounding the track represent the areas potentially affected by sustained winds of 34 knot tropical storm force (lightest gray), 50 knot (middle gray) and 64 knot hurricane force (darkest gray).
Right: Image in the larger context of Hurricane Ian’s path and the Florida Gulf Coast.

One buoy — Sofar Spotter SPOT-30068D or Sp1 — passed near Ian’s eye wall on the morning of September 28th. In the video in Figure 2, the arrival of the buoy near Ian's eye wall corresponds with a sharp increase in wave height and sharp decreases in sea surface temperature and barometric pressure.

Figure 2. Top: The drift track (black line) of Sofar Spotter SPOT-30068D or Sp1 (yellow pentagon) and the path of Hurricane Ian (red line). Sp1 passes near Ian’s eye wall on the morning of September 28th. Color gradient represents wave height (increasing from blue to red).
Bottom: Sp1’s significant wave height, sea surface temperature, and barometric pressure time series. The arrival of the buoy near Ian's eye wall corresponds with an increase in wave height and decreases in temperature and pressure.

In Figure 3, Sp1’s significant wave height, barometric pressure, and temperature measurements are shown for the three-day period between September 27th and September 30th. The same spikes captured by the visualization in Figure 2 are visible here.

Figure 3. Sofar Spotter Sp1’s (SPOT-30068D) significant wave height, barometric pressure, and temperature time series. The blue shaded region represents the same 12-hour period from 09-28 06h to 18h (UTC) represented in the map in Figure 1.

In Figure 4, wave spectra recorded by Sp1 show high energy, low frequency waves during the period when Sp1 passed near Hurricane Ian’s eye wall.

Figure 4. Sp1 spectrogram

As shown in Figure 1, UW-APL microSwift019, or mS1, was located northwest of Sp1, slightly further from Hurricane Ian’s eye. In Figure 5, mS1 records a spike in wave height that peaks late on September 28th. 

Figure 5. UW-APL mS1’s (microSWIFT019) significant wave height time series. The blue shaded region represents the same 12-hour period from 09-28 06h to 18h (UTC) represented in the map in Figure 1.

In Figure 6, wave spectra recorded by mS1 show high energy, low frequency waves similar to those detected by Sp1.

Figure 6. mS1 spectrogram

The observations successfully collected during this deployment will be key for improving forecast skill and are actively being used for hindcast comparisons to the models run by the Task 4 teams during Hurricane Ian.

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