METEOR-20240904

METEOR-20240904#

Summary#

RV Meteor continues its trek westward towards the Pirata buoy at 8N, 38W.

We held our regular daily briefing and science discussion at 10:20 LT. Michael Bell shared the most recent tropical cyclone (TC) outlook from his group at Colorado State University and a newly released assessment led by his colleague Phil Klotzbach on why the season has been unexpectedly quiet so far. This week is the climatological peak of Atlantic TC activity, yet there are no active TCs. While there is still a lot of the season left to go, so far things have been quieter than expected. As described in the report, this is primarily due to the monsoon trough and ITCZ being located further North than normal, causing stronger shear in the eastern Atlantic than expected due to low-level southwesterly winds and upper-level easterly winds, as well as advection of dry air from the north into the main development region. We have experienced these brisk southwesterly winds throughout much of of our cruise, which have sometimes been perpendicular to the swell leading to rough seas at times. The tropical waves have also been further north when they move off the African coast, putting them in a less hospitable environment for TC development. As we move later into September, we expect that the monsoon trough and ITCZ will shift southward following the typical seasonal migration, so Meteor will need to continue closely monitoring the potential for TC develompent through the rest of the cruise.

As for today, after two days of rain we found ourselves in the doldrums this morning with sunny skies, light winds, and calm seas. The tropical wave axis has nearly caught up to us and the main convectively active region is to our northwest, leaving just some scattered afternoon pop-up convection in our vicinity. We continued with our usual program of oceanographic measurements, with regular CTD profiles and microstructure soundings. These regular measurements help us build a comprehensive picture of the distribution of ocean temperature, salinity, and density and structure of ocean turbulence. Preparations are also underway to re-deploy our gliders, drift buoys, and WireWalker once we reach the Pirata buoy the day after tomorrow. For the second time on this cruise, these instruments will measure the physical properties of the ocean on their own for days at a time, until we return to retrieve them before heading even further west.

Remarks#

  • Meteor is in the UTC-2 time zone.

  • Radiosondes were launched on the normal 3-hourly schedule.

  • We will meet HALO within the eastern circle of their transfer flight tomorrow (05.09), near 8N, 35W.

Plans#

  • 04.09 - 05.09 07:00 LT: Steam to meet HALO in the eastern circle of their transfer flight on 05.09, near 8N, 35 W, performing MSS, CTD, drone flight, and SEA-POL circles every 6 hours.

  • 05.09 07:00 LT - 06.09 10:00 LT: Steam to central Atlantic buoy at 8N, 38W, performing MSS, CTD, drone flight, and SEA-POL circles every 6 hours.

  • 06.09 - 11.09: Deploy oceanographic gliders and drift buoys near the Pirata mooring at 8N, 38 W. Perform ITCZ transect (details TBD) and recover the instruments.

Events#

Time (Local)

Comment

07:57 - 08:24

MSS

08:30 - 09:51

CTD

10:20

Meeting led by D. Klocke, brief TC discussion by M. Bell.

17:03 - 18:22

CTD

18:29 - 19:10

MSS
Contents