After a lengthy waiting period, we have successfully deployed our instrumentation to make aerosol measurements inside a tropical storm/hurricane.
As of our last post, instrumentation was mounted aboard the NOAA hurricane hunter aircraft but we were awaiting installation of an inlet. This is not a trivial task, as any structure mounted to the exterior of an airplane requires a fair amount of hardware fabrication and engineering review in order to ensure flight safety. After a doubler plate was manufactured (at the interface between the aircraft and the inlet), we were cleared to make measurements. Below is a picture of our inlet on the plane (directly forward of the american flag).
NOAA WP-3D Kermit, with aerosol inlet
With the inlet installed, we were able to fly a brief test-flight near Tampa, FL, and three flights into CRISTOBAL last week. These flights were back-to-back-to-back (1 every 24-hours) with 2am takeoffs, sampling the storm at 3km altitude during its transition from depression to tropical storm (8/24), as a tropical storm (8/25), and as a weak category-1 hurricane (8/26). GOES-IR images below show the storm’s minimal organization as it slowly moved North from Hispaniola.
Tropical-Depression (3) – 8/24
Tropical Storm Cristobal – 8/25
Hurricane Cristobal – 8/26
Below are a few pictures from the flights. Since there was only moderate convection, turbulence on the aircraft generally wasn’t too uncomfortable. Our 2-am take-off time allowed a very pleasant sunrise about halfway through each flight. We could even see a rainbow in the storm vicinity, an unexpected sight while inside a hurricane!
In the NE quadrant of Hurricane Cristobal. Low level clouds with lots of cirrus outflow
Rainbow during Hurricane Cristobal Flight
Typical view from the Hurricane Hunter aircraft, rain.
Sunrise flying into Tropical Storm Cristobal
If able to sample more organized storms, we hope to observe new particle formation inside the hurricane eye, a potential mechanism for intensifying the storm. Additionally, we aim to assess how hurricanes can redistribute biological particles that could act as efficient seeds for ice clouds at higher altitudes.
No storms are on the immediate horizon, but it is looking like a deployment to St. Croix is going to happen in the last half of September.
Thanks for reading. Luke