An “Uneventful” Leg During MAGIC

Published: 24 July 2013

Editor’s note: Ernie Lewis, principal investigator for the Marine ARM GPCI Investigations of Clouds (MAGIC) field campaign, sent this update on July 11, 2013.

Thursday, July 11, evening

We are just pulling into port in Honolulu (about 8pm local time on Thursday), a day later than normal, but we had left Los Angeles a day later than normal also. The trip was mostly uneventful (only one power outage), which is a good thing; typically anything that would make a trip “eventful” is not desirable. The instruments worked well, the techs-Pat and Mark-and, Trevor -a grad student-have been fun to work with, and the food was excellent. It was overcast nearly the entire way. It was bright a few times the last two days near Hawaii, but there was almost no blue sky, only for about an hour this afternoon. One night there were a few stars visible for one of the balloon launches, but not for the other ones.

The winds were strong when we left L.A. (relative winds ~17 m/s, which is equivalent to 33 knots, or 38 mph), and we lost the first two balloon launches. On the first the radiosonde dipped into the water, and the second didn’t archive. The remaining 32 launches-one every three hours-were all successful, with more than half attaining altitudes greater than 27 km, and one getting higher than 30 km (with pressure less than 12 mbar). The winds had died down until the relative winds were near zero for the last day out, and the balloons went straight up after being released. I saw one illuminated by the lidar at night-that was a neat sight! Of course, if the relative winds are near zero that means that the true winds are equal to the ship’s speed, which in turn means that on the way back we’ll have headwinds at roughly twice the ship’s speed (which is near 20 knots). That’ll be interesting.

The first two days out we were under a stratocumulus deck, and the inversions were rather abrupt: I saw one instance in which the temperature above cloud top rose 10 degrees Celsius in 10 meters! The clouds showed more structure as we approached Hawaii but never cleared up for long. We had some rain and several instances of drizzle. There wasn’t much to see on the way over; Trevor saw a few flying fish, and the mates said they saw a few whales one day, but we didn’t see any. One night a Brown Booby perched on the optical rain gauge on our meteorological mast, but it was gone by the next morning. We saw a Masked Booby then, but it didn’t stick around long either. The plankton could be seen fluorescing at night near the bow when the ship churned up the water. As Trevor said, it was like fireflies in the water. Today, just after we saw land (at about 4 in the afternoon), we saw several birds and some flying fish, and as we were coming in there were a lot of birds around.

We’ll be in port for just over a day, then turn around and head back early Saturday morning. We’ll all go out to dinner and then back to the ship.


Ernie Lewis