Ocean basin properties Flashcards
Density (continued)
not measured directly but based on temp, salinity, and pressure measurements
density anomaly
Vertical structure
mixed layer - upper layer in which temp and salinity ate relatively constant with depth
pycnocline - middle zone in which density increases rapidly with depth
deep zone - little additional change of density with increasing depth = 80% of world’s water
thermocline
zone in which temp decreases rapidly with depth
halocline
zone in which salinity increases rapidly with depth
vertical profiles by region
tropical - strong thermo and halo = strong strat
temperate - weak to strong thermo based on season = mod strat
polar - thermo almost absent, moderate halo = weak strat
water mass
a water body identifiable by its salinity and temp (therefore density), gas content, another indicator
volume of water sharing same history
formed at surface, then sink to depth based on density
Ocean comparisons
see google doc
CTD probe
conductivity, temp, depth
rosette - metal frame holding water sampling bottles, ctd often attached
niskin bottles - opened at both ends to sample, closed at a given depth, water trapped and analyzed
In situ observation methods
argo floats - autonomous profiling floats drifting with currents and measuring temp, salinity, pressure between surface and 2km
can have other sensors (O2, fluorescence)
gliders - telecommanded underwater robotic vehicles, uses wings and Archimides’ Principle for buoyancy-based propulsion
vertical and horizontal motions in top 1500 m
has GPS
measures salinity, temp, O2, chlorophyll, etc
animal-borne instruments - CDT sensors glued to animals’ foreheads, data transmitted by satellite-relay data loggers
Remote observations
remote sensing - from aircraft or satellites, surface temp from infrared sensors, broad spatial and high temporal coverage, but only gives surface info
