Scientists use drones to study hurricanes

Hurricanes produce some of the most violent conditions on Earth. These violent conditions make it difficult to collect observations that are needed for certain applications, such as for evaluation of numerical modeling systems, and for wind-energy assessments. To obtain these much-needed observational data, an Unmanned Aircraft System (UAS) was flown into Hurricane Maria in 2017 and Hurricane Michael in 2018. These flights demonstrated the ability of a small drone to maintain altitude at low levels in hurricanes (130 m above sea level) and at hurricane-force wind speeds (up to 87 m/s). Measurements of pressure, temperature, humidity, and wind speed were made with high frequency up to 4 Hz. Using these data, researchers were able to calculate properties of turbulence at low levels in hurricanes, such as turbulent momentum flux, which can indicate the amount of drag acting on the air due to air-sea interaction. Data have also been used to document a cool and dry bias within in the operational hurricane forecast model.

Infrared satellite images of Hurricane Maria at 1927 UTC on 23 September 2017. The image on the right shows the center of the hurricane and the tracks of Coyote Flight 3 (white) and the NOAA P-3 (blue) from 1925-1927 UTC.
Figure: Infrared satellite images of Hurricane Maria at 1927 UTC on 23 September 2017. The image on the right shows the center of the hurricane and the tracks of Coyote Flight 3 (white) and the NOAA P-3 (blue) from 1925-1927 UTC.

These unique data are crucial for evaluating and calibrating new high-resolution, eddy-resolving hurricane models that are being developed at NCAR, which can be used to study the intensity and distribution of wind gusts in hurricanes.

This work was supported by the National Oceanic and Atmospheric Administration (NOAA) and was conducted in collaboration with NOAA’s Atlantic Oceanographic and Meteorological Laboratory.