AOML’s Hurricane Research Division (HRD) ran its 2017 Hurricane Field Program from July 27th through October 27th and accomplished many of the objectives set for this busy hurricane season. In addition to carrying out Tail Doppler Radar (TDR) missions in coordination with NOAA’s Environmental Modeling Center (EMC), HRD flew the Analysis of Intensification Processes Experiments (AIPEX) (a new collaborative effort between AOML/HRD and the National Hurricane Center (NHC) to investigate the processes that lead up to periods of rapid intensification) into Tropical Storm Franklin and Hurricanes Harvey and Nate. Another highlight of the Field Program was the use of the COYOTE (Unmmaned Aerial Vehicles) UAVs in Hurricane Maria and the Doppler Wind LIDAR (DWL) instrument in Hurricanes Jose, Maria, and Nate. HRD cooperated with NASA’s East Pacific Origins and Characteristics of Hurricanes (EPOCH) project, processing dropsondes from the Global Hawk around Franklin, Harvey, and Hurricane Lidia in the east Pacific. We also worked to transition a new tail radar system with a three-fold increase in along-flight-track data resolution into operations, and coordinated NOAA missions with overflights by the Cyclone Global Navigation Satellite System (CYGNSS) satellite.
The Field Program began on August 8th with a TDR mission flown by NOAA42 (P3) into Tropical Storm Franklin in the southern Gulf of Mexico. A follow-on flight the next morning was carried out in conjunction with the Global Hawk, which provided a wide-scale portrait of the environment surrounding the storm.
A week later, when Harvey formed in the Atlantic, HRD teams deployed to St. Croix. However aircraft problems and Harvey’s weakening delayed the first Harvey TDR mission until August 24th, when it reformed in the southern Gulf of Mexico. This mission coincided with another Global Hawk overflight. It also began a series of four such TDR flights into the hurricane as it intensified before its devastating landfall on the Texas coast. This sequence of missions covered Harvey’s rapid intensification from tropical depression to a Category-4 hurricane.
Another Global Hawk mission was carried out into East Pacific hurricane Lidia on August 30th through 31st, with HRD personnel processing the dropsonde data in real-time.
On September 2nd, HRD teams deployed to Barbados, and this time were able to fly missions from a forward base into Hurricane Irma as it moved toward the Leeward islands. A series of five TDR flights were carried out until the hurricane was over the Lesser Antilles. Two more TDR missions were accomplished as Irma moved between the Greater Antilles and the Bahamas. The early experiments caught Irma at its peak as a Category-5 storm, and even during the subsequent series Irma remained a major hurricane.
As the Irma flights came to an end, AOML had to close down as the Laboratory is in a flood zone on Virginia Key. This complicated operations as support for aircraft missions had to be conducted off site, and the aircraft’s new home base in Lakeland would come under hurricane warnings. The Laboratory itself experienced tropical storm-force winds and hurricane-force gusts. The building experienced some minor flooding which affected AOML’s computers, further exasperating operations. The Lab did not re-open until Sept. 18th.
Despite this, two TDR flights were carried out into Hurricane Jose on Sept. 17th and 18th, as it moved between the Carolinas and Bermuda and began to transition into a hybrid cyclone. The Jose missions also allowed the DWL system to be run for the first time this year in a hurricane.
Immediately after the Jose flights, HRD began several missions into Hurricane Maria just east of the Bahamas after it had devastated Puerto Rico. The flights were able to gather more DWL data, which supplemented the Doppler radar data, especially in regions without rainfall.
These research missions also carried out the first successful launch of the COYOTE UAV into a hurricane since 2014. The COYOTEs were able to accomplish a variety of different flight patterns and gather data from the eye, eyewall, and outer rainband regions of Maria.
When Nate formed off the coast of Nicaragua and was forecast to move northward into the Gulf of Mexico, an Ocean Survey mission was flown over the eastern Gulf, dropping ocean probes to measure the sea temperatures and currents. This was followed by NOAA42 flying three AIPEX missions into the storm as it moved quickly northward and became a hurricane in the Gulf. When NOAA42 was unavailable for the final flight, the NOAA49 (G-IV) jet modified its tasking and accomplished an AIPEX mission of its own as Hurricane Nate approached landfall in Louisiana and Mississippi. This series of missions was then capped by a follow-on Ocean Survey mission that measured the changes in sea temperature in the Gulf due to the passing storm.
After Nate, the tropical Atlantic quieted down and the Field Program came to an end on Oct. 27th. During the campaign, 29 missions were flown by NOAA42, one research and 20 operational flights were accomplished by NOAA49, and three Global Hawk missions were supported. HRD personnel flew 430 man-hours and provided approximately 230 man-hours of ground support. 311 dropsondes and 209 ocean probes were deployed during HRD-associated missions. An additional 638 dropsondes were deployed in operational Synoptic Surveillance missions by NOAA49.