METEOR-20240822

METEOR-20240822#

Summary#

RV Meteor intended to meet HALO at 7.18N, 24.44 W at 12:45 UTC, the northern entry point of their southern circle along the EarthCare orbit, for coordinated activities. Unfortunately, due to an error in our estimated departure time from our position yesterday evening and a longer than expected station during the night, Meteor was about an hour and a half late arriving at the position. We were within the northern part of HALO’s southern circle, but missed the opportunity for a direct overpass and comparison with our vertically pointing instruments. HALO was within SEA-POL’s long-range scan (245 km) during its southern circle and the southern half of its center circle; the conditions consisted of scattered, shallow convection.

After HALO left our viewing range, Meteor steamed SSW along EarthCare’s orbit. Since the sea state prohibited stopping at an optimal heading for RHI scans along EarthCare’s orbit, we continued steaming SSW during the overpass, conducting SEA-POL volume scans as well as the continuous measurements with all the vertically pointing remote sensing instruments. After the EarthCare overpass, we stopped to perform ocean microstructure measurements and our first full depth (4473 m) CTD.

The daily status briefing and science discussion was held at 10:20. Hans and Lennea presented preliminary results from the radiosondes. As of the time of the presentation, Meteor had launched 50 radiosondes during the campaign so far. The average ascent speed was 5 m/s, with the sonde taking 1 hour and 20 minutes to reach its maximum altitude (on average, 25km). The radiosondes that we are launching (Vaisala RS41P) have parachutes so that we can attempt to record the descent sounding as well. This works some of the time. The descent rate varies between 10 and 30 m/s, with the sonde taking about 30 minutes to descend. This prevents a detailed vertical profile, but provides some useful information above 2 km. We also discussed the different structures of the ITCZ observed so far during our cruise.

Remarks#

  • Radiosondes were launched on the normal 3-hourly schedule, with one extra launch before the EarthCare overpass at 14:25.

  • Near real-time (within 15 minutes) SEA-POL imagery is now available online

  • Coordination with HALO occurred today.

  • We will return to Cape Verde to retrieve parts, instruments, and personnel from Praia.

Plans#

  • 22.08 19:00 LT - 23.08 16:00 LT: Steam south towards the southern edge of the ITCZ (4N, 25W), performing MSS, CTD, SEA-POL circle every 6 hours.

  • 23.08 16:00 LT - 28.08 10:00 LT: Steam north to Praia.

  • 28.08 10:00 LT - 22:00 LT: Retrieve parts, instruments and personnel in Praia.

  • 28.08 22:00 LT - 30.08 11:00 LT: Steam to Pirata buoy at 11.5N, 23 W to retrieve drifters and gliders.

  • 30.08 17:00 LT - 31.08 14:00 LT: Steam to 9N, 23.07 W to meet EarthCare and HALO.

  • 31.08 15:00 LT - 06.09 19:00 LT: Steam to central Atlantic buoy at 8N, 38W, performing MSS, CTD, SEA-POL circle every 6 hours.

Events#

Time (Local)

Comment

23:23 - 0:44

Incubation CTD

0:50 - 1:20

SEA-POL circles

1:49 - 2:13

Incubation CTD

10:20

Meeting led by D. Klocke, Science presentation by H. Segura

13:20

Arrival at 7.18N, 24.44 W for HALO coordination

14:25

Extra radiosonde launch

14:41

EarthCare overpass

15:31 - 18:23

Full-depth CTD

19:00 -

Steam towards the southern edge of the ITCZ
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