1. CTD AND XBT TEMPERATURE MEASUREMENT COMPARISON
LT Scott Boedeker

4. CTD 10/XBT 4

5. REPRESENTATIVE PAIRS

7. For the 27 comparisons from this cruise, the XBT temperature has a warm bias of degrees C over the depth range
This is similar to results obtained from previous OC3570 cruises
The greatest bias was in the upper levels

8. CTD-XBT Temp Difference
R/V Point Sur
08/ / /2000
Roth (2001) Schmeiser (2000)
Depth
(m)
Mean
(C)
Std
25-125
0.5135
0.1779
0.3598
0.2131
0.0951
0.1975
0.2157
0.0960
0.1981
0.2372
0.0903
0.2194
Sfc-750
0.2147
0.1047
0.2151

9. Why the Bias? Manufacturing Defects Method of deployment
-CTD casts are made nearly vertical with the
vessel stopped.
-XBT casts are made with the vessel in motion and
are therefore not as vertical. This results in
the XBT being shallower than it is recorded.

10. Questions?