PMEL Programs and Plans
Accomplishments in FY 99 and Plans for FY 00
Monitoring Transport of Ocean Currents
 
Monitoring Transport of Ocean Currents
Accomplishments in FY 99
Daily mean values of the Florida Current volume transport have been
measured since 1982 from cross stream voltages using a retired
submarine telephone cable from 1982 to 1990 and an in-service cable
from 1990 to 1999 when it was retired. The data set is nearly
continuous and has been calibrated using profiling derived transports.
The decadal transport variations (excluding periods less than two years)
from 17 years of daily mean values converted to montly mean values, show
a strong correlation (0.92) with the negative value of the North
Atlantic Oscillation when the transport is lagged by 10 months. In other words,
the Florida Current transport increases when the westerlies decrease.
This high correlation reveals a strong decadal connection between the
NAO, a purely atmospheric climate indicator, and the purely
oceanographic measurement of the Florida Current. Importantly, it would not have
been possible to detect this decadal variation with shorter time
series.
Monitoring Transport of Ocean Currents
Plans in FY 00
The in-service cable has been retired and permission has been
granted by AT&T and Batelco to record voltages at the Eight Mile
Rock site, Grand Bahama Island, using the retired cable. The
voltage measurements will resume in March 2000.
The observation program will continue with a strong collaboration
between AOML and PMEL/JIASAO. AOML will maintain the cable voltage
and calibration measurements and PMEL/JIASAO will play an advisory role
until the measurement program and data reduction software is fully in
place. PMEL/JIASAO will then continue collaboration on the interpretion
of the transport measurements.
PMEL/JIASAO plans to explore ways to continue a network of existing
trans-Pacific cable measurements for montinoring ocean currents.
Measurements have been made for several years by other groups. Results
indicate a highly suggestive similarity between Hawaii-to-California
voltages and variations in the strength of large scale atmospheric
patterns related to the strength of the Aleutian Low. Climate signals
on the time scales suggested will take at least another decade of data
to begin to resolve.
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