A critical wind speed for air-sea boundary processes

Most processes at the air-sea boundary are modified by the existing wind pattern. In general the rate of these processes varies gradually with wind speed. An exception seems to occur at a wind speed of about 7 m/sec; at that speed a number of apparently unrelated processes have been observed to undergo such abrupt changes that, in some instances, one is led to suspect the existance of discontinuities. Not only the rate, but the very nature of these processes seems to be altered at this critical wind speed...

High frequency spectrum of ocean waves

The subject Motion in the Ocean, assigned to me by President Bronk, includes fish, Aqua-lung divers and density flows. For a very good reason I must confine myself to motion of the water itself. Further, I will limit myself by considering only that part of the motion of ocean water that can be associated with surface waves. It is nearly, but not quite, the irrotational component of the motion...

A note on tidal friction

The Moon\u27s gravitational torque on the ocean tide has been computed on the basis of Dietrich\u27s cotidal charts. The result is -4.5 × 1023 dynes cm as compared to Heiskanen\u27s (1921) value of -2.9 × 1023 dynes cm based on Sterneck\u27s (1920) charts. Both values are subject to great uncertainty. The observed deceleration of the Moon implies a torque of (-3.9 ± 1.0) × 1023 dyne cm, which is consistent with both foregoing calculations. It is concluded that the deceleration of the Moon\u27s orbital motion and the associated deceleration of the Earth\u27s rotation may be due to oceanic tidal dissipation...

Statistics of the sea surface derived from sun glitter

Aerial photographs of the sun\u27s glitter on the sea surface, taken under carefully chosen conditions in the Hawaiian area, were coordinated with measurements of winds (1-27 knots) from a vessel…

Harald Ulrik Sverdrup - An appreciation

As a young man Harald Sverdrup spent seven years on Amundsen\u27s MAUD expedition in the icy wastes of the Arctic Sea. The observations he collected during this period form the basis of fifty published papers and constitute much of our factual knowledge about geophysical phenomena in the Arctic. Nevertheless, those years of voluntary exile would be of relatively small interest to his colleagues were it not for their effect on his personal and scientific qualities, and the insight which they give into his character

Some problems in optical oceanography

Problems involving the refraction and reflection of light from sun and sky by a roughened sea surface have been made accessible to numerical treatment by measurements of the probability distribution of sea surface slopes

Absorption of nutrients by aquatic plants

Formulae are derived for the rate of nutrient absorption by aquatic plants approximating the shapes of spheres, discs, cylinders, and plates. Other parameters are the size and specific gravity of the plant, the nutrient concentration of the medium, and the physical properties affecting the transfer of nutrients toward the plant surface. The formulae allow for convection, i. e., the movement of water relative to the plant. Hence absorption is aided by a current in the case of attached plants and by a rapid sinking rate in the case of plankton. The results are not materially modified by turbulence...

The optimum wiggliness of tidal admittances

Some numerical experiments with recent offshore tide measurements have examined various parameters involved in tidal prediction by the response method: the number of prediction weights, their lead (and lag) times, and the treatment of radiational tides. The optimum number of weights depends directly on the length of record and inversely on noise level in a tidal band; more weights degrade the prediction and generate an artificial wiggliness in the admittance

MODE:IGPP Measurements of Bottom Pressure and Temperature

We review the MODE deployment of IGPP bottom instruments, together with preliminary tests on the Pacific seafloor and in the laboratory. Pressure and temperature were measured with quartz-crystal transducers in different configurations. Spectra of instrument noise in the laboratory and on the seafloor were estimated from duplicate transducers. These estimates are prerequisite to the forthcoming discussions of MODE tides, the bottom experiment, and internal waves. There are two puzzling features: (i) the temperature noise continuum on the seafloor is generally 20 dB above that in the laboratory, and (ii) the pressure noise spectrum has a tidal line structure. Instrument drifts during MODE are of the order of a few millibars and a millidegree Celcius, respectively

Notes on a theory of the thermocline

The very large number of bathythermograms which have been taken during the last few years have established the essential features of the temperature structure in the upper layers of the ocean…