56
Russ E. Davis
with the mean, the inherent nonlinearity of the propeller leads to errors up to 10%
associated with the sensor measuring water that has already been changed in the propeller’s wake. The lesson I take from this is that in the presence of noise, linearity
is a prerequisite to accuracy. The VMCM was first used on a surface mooring in the
1977 Mixed Layer Experiment (MILE) where comparison with VACMs showed the
VMCM to be less susceptible to mooring motion (Davis et al., 1981). For several
years it was the mainstay of our mooring work.
Between a growing interest in equatorial currents and the development of the
VMCM, SIO began to develop a small mooring group. Halpern’s PMEL group was
of great assistance in this, sharing with us the basics, clever new tricks developed
by Milburn, and general procedures. This made our group a third-generation in
the Buoy Group line. At the same time Bob Weller finished his Ph.D. and went to
WHOI to work with Mel Briscoe, eventually heading the surface-mooring part of the
Buoy Group. One of Weller’s early successes was elaborating the VMCM into a
three-axis current meter with which he produced a remarkable observational
description of Langmuir circulation (Weller and Price, 1988). It was with dismay
that we observed the Buoy Group search for continuing leadership and eventually
dissolve into three loosely related enterprises. In two ways the Buoy Group was a
victim of its own success. First, as performance improved and the lifetimes of subsurface moorings made long current records feasible, there was less reason to devote
resources to improving moored measurements. Second, the effort that was required
to make the multiuser group successful was tremendous and those asked to shoulder
the leadership role began to feel the effort was not worthwhile.
A PRODUCTIVE MEETING
Ever since MODE, oceanographers can hardly escape organizational meetings, a great
many of which are inefficient uses of time. For me, two exceptional meetings were the
MODE summer planning session and a 1982 meeting called at NCAR by Bill Large
and Pearn (Peter) Niiler to improve ocean observations. At the 1982 meeting a group
of oceanographers interested in observing technology surveyed the status of the field
and, in an unusual collaboration, devised a plan by which each development would
get the attention it deserved. Surface-drifter improvements, including survivability,
reduced cost, wind and other meteorological sensors, current-following accuracy,
and thermistor chains, were assigned to various teams coordinated by Niiler and
Large. This effort led to the CASID air–sea interaction buoys used in experiments
like STREX (Large, McWilliams, and Niiler, 1986) and Ocean Storms (Large and
Crawford, 1995) and to drifters optimized to accurately measure near-surface velocity
and temperature (Niiler et al., 1987) that played a central role in TOGA and WOCE.
Doug Webb (co-developer of the SOFAR float) and I agreed on a plan of action
for two projects: self-contained ADCPs and autonomous subsurface floats. I was
then working with RD Instruments to develop a self-contained ADCP suitable for use
Russ E. Davis
with the mean, the inherent nonlinearity of the propeller leads to errors up to 10%
associated with the sensor measuring water that has already been changed in the propeller’s wake. The lesson I take from this is that in the presence of noise, linearity
is a prerequisite to accuracy. The VMCM was first used on a surface mooring in the
1977 Mixed Layer Experiment (MILE) where comparison with VACMs showed the
VMCM to be less susceptible to mooring motion (Davis et al., 1981). For several
years it was the mainstay of our mooring work.
Between a growing interest in equatorial currents and the development of the
VMCM, SIO began to develop a small mooring group. Halpern’s PMEL group was
of great assistance in this, sharing with us the basics, clever new tricks developed
by Milburn, and general procedures. This made our group a third-generation in
the Buoy Group line. At the same time Bob Weller finished his Ph.D. and went to
WHOI to work with Mel Briscoe, eventually heading the surface-mooring part of the
Buoy Group. One of Weller’s early successes was elaborating the VMCM into a
three-axis current meter with which he produced a remarkable observational
description of Langmuir circulation (Weller and Price, 1988). It was with dismay
that we observed the Buoy Group search for continuing leadership and eventually
dissolve into three loosely related enterprises. In two ways the Buoy Group was a
victim of its own success. First, as performance improved and the lifetimes of subsurface moorings made long current records feasible, there was less reason to devote
resources to improving moored measurements. Second, the effort that was required
to make the multiuser group successful was tremendous and those asked to shoulder
the leadership role began to feel the effort was not worthwhile.
A PRODUCTIVE MEETING
Ever since MODE, oceanographers can hardly escape organizational meetings, a great
many of which are inefficient uses of time. For me, two exceptional meetings were the
MODE summer planning session and a 1982 meeting called at NCAR by Bill Large
and Pearn (Peter) Niiler to improve ocean observations. At the 1982 meeting a group
of oceanographers interested in observing technology surveyed the status of the field
and, in an unusual collaboration, devised a plan by which each development would
get the attention it deserved. Surface-drifter improvements, including survivability,
reduced cost, wind and other meteorological sensors, current-following accuracy,
and thermistor chains, were assigned to various teams coordinated by Niiler and
Large. This effort led to the CASID air–sea interaction buoys used in experiments
like STREX (Large, McWilliams, and Niiler, 1986) and Ocean Storms (Large and
Crawford, 1995) and to drifters optimized to accurately measure near-surface velocity
and temperature (Niiler et al., 1987) that played a central role in TOGA and WOCE.
Doug Webb (co-developer of the SOFAR float) and I agreed on a plan of action
for two projects: self-contained ADCPs and autonomous subsurface floats. I was
then working with RD Instruments to develop a self-contained ADCP suitable for use