French oceanographic cruises G. Reverdin, F. Marin

1
French oceanographic cruisesG. Reverdin, F. Marin

• French oceanographic cruises with XBTs launched
  ship steaming arond 10-12 knots between two CTDs
  typically 20-40 km apart from XBT. The launch is
  done manually from a position fairly low above
  water, typically near the aft of the ship or
  along the side (a little higher on DTX, seems to
  be)
• There seems to be generally no documentation on
  the equation used in the French archives
  (unknown). And for the recent ones, different
  choices have been done on the total depth of
  reported data (and no correlation with the
  equation used)
• Comparisons of XBT T(3m) with intake temperatures
  have not been done, but this is possible in a
  large number of cases.
• Cruises are in the tropical Oceans mostly (from
  1979, 1980, 1983, 1985, 1986, 1991, some of the
  PIRATA cruises since 1997, EGEE cruises,
  2005-2007) also mid-latitude North Atlantic
  (Semaphore, 1993 POMME 2000-2001 among others)

2
POMME winter-early spring 2001Hanawa
3
POMME late summers 2000 and 2001original
4
POMME winter-early spring 2001original
5
EGEE1 June 2005Hanawa
6
EGEE3 June 2006Hanawa
7
EGEE2 Sep 2005original
8
EGEE4 Nov 2006original
9
EGEE5 June 2007original
10
EGEE6 Oct 2007original
11

• EGEE1 numerous problems. Why?
• All EGEE (except EGEE5, 6 on the R.V. Antea) show
  positive SST anomaly (0.06C) and upper
  thermocline too warm (suggesting depth
  overestimated down to 80m). Is same software used
  (MK12 EGEE1 MK21 others, but I dont know for
  EGEE5, 6)
• Pomme winter data on Atalante dont have a
  positive SST bias. On the other hand the late
  summer Thalassa ones have a 0.12C bias (same
  software, same batch of XBTs). The DTX winter
  ones also seem to have a small bias (0.04C).
• Questions
• Do we trust the CTD SSTs during warm season?
  (mixing by the ship in station what is its
  effect?).
• Conditions on research vessels very different
  than the ones on merchant vessels (height of
  launch of XBTs also position on the ship
  somewhat different)