17 Sept 2010 DC-8 Platform Scientist Report (Karl) - Ed Zipser

17 Sept 2010 DC-8 Platform Scientist Report (Karl) - Ed Zipser

September 17, 2010                        DC-8 Platform Scientist Summary     Ed Zipser

This DC-8 mission completed an amazing set of missions into the disturbance that eventually became Hurricane Karl, starting with PREDICT during its early stages near Barbados, through several days of flights by the G-V, evolving into a combination of the G-V, DC-8, Global Hawk, , B-57, and NOAA 42 and 49 over nearly a week.

Takeoff 153853 Z; landing 234450 Z.

This DC-8 mission aimed at observing Karl during landfall near Veracruz Mexico.  While it was at first disappointing that the eye moved onshore just before the DC-8 arrived, we carried out the two quick legs just offshore upon arrival, dropping as many sondes as possible over water, then did the first of two planned butterfly patterns.  Then we changed our plan, eliminated the second butterfly pattern (because we were not getting over the interesting rainfall areas, or over the eye, which was hard to find), in favor of finding the eye, and doing a series of passes designed by Simone Tanelli around and through the eye, with the extra time available.  The eye was visible on the Alvarado  radar, and with assistance from the FLL team, we located it in time for the pattern there.  See attached radar image from Alvarado, one of several exciting APR-2 cross-sections, a plan view of the pattern, and a photo of the eye taken by Jason Sippel.

The dropsondes over ocean gave information that the hurricane was weakening rapidlyas the eye went inland, and in addition to the AF C-130 winds (their last pass was at 1616Zand we arrived at 1759 Z) that should provide some extra ground truth for the WB-57 which was executing their pattern at about the same time.

The most exciting moment of this mission was about halfway across the Gulf, when we levitated several passengers in a less-than-0-g moment in a strong convection encounter.  In hindsight, the mission scientist should have notified the Mission Manager about this possibility, as it was clearly visible on RTMM satellite, plus lightning data.

After leaving Karl, we still had time for a requested module through warm, non-precipitating clouds, which we did close to the west coast of Florida.  The pilot did a great job finding suitable clouds, and we made several passes through and under these clouds about 2300 UTC.  They were non-precipitating for the first several passed, but some precip formed before we exited the pattern.  See screen shot (attached) of what these clouds looked like just before the penetrations started.