Measurements made from R/P Flip using rapid profiling conductivity, temperature, and depth probes and vector-measuring current meters provide a new and detailed look at the diurnal cycle of the upper ocean. A diurnal cycle occurs when solar heating warms and stabilizes the upper ocean. This limits the downward penetration of turbulent wind mixing so that air-sea fluxes of heat and momentum are surface trapped during midday. The central problem is to learn how the trapping depth D T (mean depth value of the diurnal temperature and velocity response) is set by the competi_ng effects of wind mixing and surface heating. In this data set the diurnal range of surface temperature T s was observed to vary from 0.05 < •s < 0.4øC, with most of the day-to-day variability attributable to variations of wind stress r. Wind mixing causes a pronounced asymmetry of the T s response by limiting the warming phase to only about half of the period that the surface heat flux Q is positive. The associated wind-driven current, the diurnal jet, has an amplitude of typically •s • 0.1 m s-x, with no obvious dependence upon r. The diurnal jet accelerates downwind during the morning and midday. It is turned into the wind by the Coriolis force during early evening and is often erased by the following morning. Under the assumption that wind mixing occurs as an adjustment to shear flow stability, a scaling analysis and a numerical model study show that the daily minimum trapping depth /•T goes like •/Qx/2. It follows that •s goes like Q3/2/• and that • goes like Q•/2. These results, as well as the simulated time dependence of the diurnal cycle, are at least roughly consistent with the observations. The observed time-averaged velocity profile has a spiral shape reminiscent of the classical Ekman spiral. However, its structure is a consequence of diurnal cycling, and its parameter dependence is in some ways just opposite that of the Ekman model' e.g., increased wind stress may cause decreased vertical shear between fixed levels in the upper ocean. Paper number 6C0214 0148-0227/86/006C-0214505.00 to heating and wind mixing which can simulate the diurnal cycle (sections 4 and 7); (3) to determine the explicit parameter dependence of the diurnal cycle upon the heating rate, the wind stress, and other external variables (sections 5 and 7), and lastly (4) to show how the process of diurnal cycling acts to shape the longer term response of the upper ocean to atmospheric forcing (section 8). 2. FIELD OBSERVATIONS The field data reported here were taken in spring 1980 from R/P Flip. Measurements were begun on April 28 at 30.9øN, 123.5øW, about 400 km west of San Diego, California. Flip drifted southward with the prevailing wind, and the measurement program ended on May 24 when Flip was at 28.7øN, 124.0øW. 2.1. Data Types Precision Comments profiling CTD; T, C, P profiling VMCM; V, T, P Fixed level VMCM' V, T Wind speed U Eppley pyranometer, I 0 Air temperatures, cloud cover, pressure 128.4 < t < 145.3 days* At = 2 min T _ 0.002øC 2

The authors present inferences of diapycnal diffusivity from a compilation of over 5200 microstructure profiles. As microstructure observations are sparse, these are supplemented with indirect measurements of mixing obtained from (i) Thorpe-scale overturns from moored profilers, a finescale parameterization applied to (ii) shipboard observations of upper-ocean shear, (iii) strain as measured by profiling floats, and (iv) shear and strain from full-depth lowered acoustic Doppler current profilers (LADCP) and CTD profiles. Vertical profiles of the turbulent dissipation rate are bottom enhanced over rough topography and abrupt, isolated ridges. The geography of depth-integrated dissipation rate shows spatial variability related to internal wave generation, suggesting one direct energy pathway to turbulence. The global-averaged diapycnal diffusivity below 1000-m depth is O(10 . The compiled microstructure observations sample a wide range of internal wave power inputs and topographic roughness, providing a dataset with which to estimate a representative global-averaged dissipation rate and diffusivity. However, there is strong regional variability in the ratio between local internal wave generation and local dissipation. In some regions, the depthintegrated dissipation rate is comparable to the estimated power input into the local internal wave field. In a few cases, more internal wave power is dissipated than locally generated, suggesting remote internal wave sources. However, at most locations the total power lost through turbulent dissipation is less than the input into the local internal wave field. This suggests dissipation elsewhere, such as continental margins.

A year/long ice camp centered around a Canadian icebreaker frozen in the arctic ice pack successfully collected a wealth of atmospheric, oceanographic, and cryospheric data.

Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong Internal gravity waves are propagating disturbances of the ocean's density stratification. Their physics resembles that of surface gravity waves but with buoyancy rather than gravity providing their restoring force -making them much larger (10's to 100's of meters instead of 1 to 10 meters) and slower (hours instead of seconds). Generated primarily by tidal flow past seafloor topography and winds blowing on the sea surface, and typically having multi-kilometer-scale horizontal wavelengths, their estimated 1 TW of deep-sea dissipation is understood to play a crucial role in the ocean's global redistribution of heat and momentum 12 . A major challenge is to improve understanding of internal wave generation, propagation, steepening and dissipation, so that the role of internal waves can be more accurately incorporated in climate models.The internal waves that originate from the Luzon Strait on the eastern margin of the South China Sea (SCS) are the largest documented in the global oceans ( Figure 1).As the waves propagate west from the Luzon Strait they steepen dramatically ( Figure 1a), producing distinctive solitary wave fronts evident in sun glint and synthetic aperture radar (SAR) images from satellites ( Figure 1b). When they shoal onto the continental slope to the west, the downward displacement of the ocean's layers associated with these solitary waves can exceed 250 m in 5 minutes 8 . On such a scale, these waves pose hazards for underwater navigation and offshore drilling 4 , and supply nutrients from the deep ocean that nourish coral reefs 1 and pilot whale populations that forage in their wakes 13 .Over the past decade a number of field studies have been conducted in the region; this work has been comprehensively reviewed 10,11 . All of these studies, however, focused on the propagation of the internal waves across the SCS and their interactions with the continental shelf of China. Until the present study there had been no substantial in situ data gathered at the generation site of the Luzon Strait, in large part because of the extremely challenging operating conditions. A consequence has been persistent 5 confusion regarding the nature of the generation mechanism 11 ; an underlying cause being the sensitivity of the models employed to the system parameters, such as the chosen transect for a two-dimensional model, the linear internal wave speed or the assumed location of the waves' origin within the Luzon Strait. Furthermore, the lack of in situ data from the Luzon Strait has meant an inability to test numerical predictions of energy budgets 9 and no knowledge of the impact of the Kuroshio on the emergence of internal solitary waves 11 .The goal of IWISE is to obtain the first comprehensive in situ data set from the Luzon Strait, which in combination with high-resolution three-dimensional numerical modeling supports a cradle-to-grave picture ...