80
The platform can be fitted with a variety of atmospheric and oceanographic
instrumentation. In July 2017, the Alaska Ocean Acidification Network, coordinated by the Alaska Ocean Observing System, launched a pair of these vehicles
equipped with an advanced version of the MAPCO2 instrument (ASVCO2) with
the mission of characterizing ocean acidification in remote Bering Sea and Arctic
waters.
3.2.4 Underwater Gliders
The technology of underwater gliders, developed initially by Douglas Webb, building upon the successful developments of profiling floats, was first proposed and
popularized in a visionary publication by Henry Stommel (1989) describing a new
profiling float with wings that allowed horizontal displacement during dive and
ascent, a vehicle that he named the Slocum float in honor of Joshua Slocum, the first
single-handed world circumnavigator. Stommel envisioned a worldwide fleet of
these profilers operated by mission control of a World Ocean Observing System.
Stommel saw the grand opportunity to garner a harvest of data on a global deepocean basis far in excess of that available with, by then traditional, CTD casts from
ocean-going vessels. Webb went on to build and commercialize the first operational
gliders.
Today the operational fleet of gliders exceeds 1000 units used for multiple applications including defense. Widely available commercial vehicles are sufficiently
small to be deployed and recovered from small vessels (even rubber dinghies) by
two people. Hulls, usually less than 2.5 m length overall, are roughly torpedo or
tear-drop shaped with cylindrical hulls, bow bulbs, and faired sterns, or may exhibit
more hydrodynamic spindle-formed external fairing covering the pressure
hull. Most models feature wings to achieve hydrodynamic lift with spans typically
under about 120 cm (Fig. 3.9). A European product dispenses with the wings
achieving lift through hull design alone.
In contrast to the profile achieved by the ARGOS float dependent on current
drift, the wings allow the glider to achieve a slanted glide path resulting in a sawtooth pattern of descents to depths to 1500 m or shallower as required, and subsequent ascent. Profiling gliders have most certainly transformed the field of ocean
observing increasing the spatial and temporal data coverage from the world ocean
and coastal seas (Rudnick et al. 2004).
Vehicle pitch and thus the descent angle are controlled in most gliders by shifting
the battery pack internally fore or aft. Steering on the horizontal plane is achieved
either by using a stern mounted rudder much like an airplane or by an ingenious
system that moves the battery package laterally along a semicircular rack and pinion
arrangement inside the pressure hull thus shifting the center of mass laterally.
Redundant stern- or wing-mounted antennae provide satellite communication by
various means for positioning data relay and vehicle control. Upon surfacing,
the antennae pierce the surface allowing radio communications. Payload bays
3 Platforms for Coastal Ocean Observing
The platform can be fitted with a variety of atmospheric and oceanographic
instrumentation. In July 2017, the Alaska Ocean Acidification Network, coordinated by the Alaska Ocean Observing System, launched a pair of these vehicles
equipped with an advanced version of the MAPCO2 instrument (ASVCO2) with
the mission of characterizing ocean acidification in remote Bering Sea and Arctic
waters.
3.2.4 Underwater Gliders
The technology of underwater gliders, developed initially by Douglas Webb, building upon the successful developments of profiling floats, was first proposed and
popularized in a visionary publication by Henry Stommel (1989) describing a new
profiling float with wings that allowed horizontal displacement during dive and
ascent, a vehicle that he named the Slocum float in honor of Joshua Slocum, the first
single-handed world circumnavigator. Stommel envisioned a worldwide fleet of
these profilers operated by mission control of a World Ocean Observing System.
Stommel saw the grand opportunity to garner a harvest of data on a global deepocean basis far in excess of that available with, by then traditional, CTD casts from
ocean-going vessels. Webb went on to build and commercialize the first operational
gliders.
Today the operational fleet of gliders exceeds 1000 units used for multiple applications including defense. Widely available commercial vehicles are sufficiently
small to be deployed and recovered from small vessels (even rubber dinghies) by
two people. Hulls, usually less than 2.5 m length overall, are roughly torpedo or
tear-drop shaped with cylindrical hulls, bow bulbs, and faired sterns, or may exhibit
more hydrodynamic spindle-formed external fairing covering the pressure
hull. Most models feature wings to achieve hydrodynamic lift with spans typically
under about 120 cm (Fig. 3.9). A European product dispenses with the wings
achieving lift through hull design alone.
In contrast to the profile achieved by the ARGOS float dependent on current
drift, the wings allow the glider to achieve a slanted glide path resulting in a sawtooth pattern of descents to depths to 1500 m or shallower as required, and subsequent ascent. Profiling gliders have most certainly transformed the field of ocean
observing increasing the spatial and temporal data coverage from the world ocean
and coastal seas (Rudnick et al. 2004).
Vehicle pitch and thus the descent angle are controlled in most gliders by shifting
the battery pack internally fore or aft. Steering on the horizontal plane is achieved
either by using a stern mounted rudder much like an airplane or by an ingenious
system that moves the battery package laterally along a semicircular rack and pinion
arrangement inside the pressure hull thus shifting the center of mass laterally.
Redundant stern- or wing-mounted antennae provide satellite communication by
various means for positioning data relay and vehicle control. Upon surfacing,
the antennae pierce the surface allowing radio communications. Payload bays
3 Platforms for Coastal Ocean Observing