Beschreibung: Since both German research vessels „Meteor" played a major role in G. Dietrich's work, it seemed appropriate to present his bibliography in this series. An assessment of his scientific achievements was given at an earlier date (H. U. ROLL 1973: In memoriam GüNTER DIETRICH 1911-1972. - ,,Meteor" Forsch.­ Ergebn. A, No. 12: V-X).

Beschreibung: Vertical velocity spectra can be determined by three different indirect methods: Following isopycnal surface displacements, following isothermal surface displacements, or calculating water particle displacements from temperature time series at fixed pressure levels, with the mean vertical temperature gradient used for the conversion factor. This third method is the easiest to perform. Data from GATE 1974, obtained by CTD profiling onboard R. V. "Meteor" and by temperature measurements on moorings, are used to check whether the three methods are equivalent. lt is shown that autospectra do not differ significantly within the 95 % confidence intervals, and either method can be applied. This does not infer an equivalence with respect to the actual data points since individual events were found in the low-passed time series with deviations occurring between displacement curves obtained by the different methods. These events were apparently due to the advection of another water mass.

Beschreibung: The research programmes of the German groups in JASIN 1978 are summarized, comprising projects that concern the planetary boundary layer, the radiation budget, the oceanic mixed layer and thermocline and the trace element exchange. Lists of the participating scientists and technicians are included. Brief descriptions of the field activities on board the three ships and the aircraft are given, including maps and stations lists.

Beschreibung: Oceanographic measurements by groups from the Federal Republic of Germany contributed mainly to the C-Scale Experiment (centered at 9° N, 23° W) and the Equatoria1 Experiment. In this paper the data are presented that were obtained from the moorings F 1 and F 2 in the C-area. After a short discussion of instrument problems, data processing and statistical analysis, the data are presented graphically as time series, progressive vector diagrams, frequency distributions and spectra of horizontal kinetic energy and of temperature variance.

Beschreibung: Some current meter data obtained from a mooring at 2450 m water depth near the continental slope off Portugal are presented. The mean currents at five levels with observations are northward. Mean speeds in the core of the Mediterranean Water exceed speeds at shallower levels by 2 to 3 cm/sec, indicating advection connected to this specific water mass. The current variability is dominated by semi-diurnal tidal components. Normal mode analysis reveals a predominant mode of order 2, representing 48% of the total kinetic tidal energy. Results for the barotropic tidal component are in good agreement with earlier predictions for this area. The motion at higher frequencies ω in the internal gravity wave band can be well described by a ω-2 power law for the energy density spectrum. This result is consistent with earlier observations in other parts of the ocean.

Beschreibung: The spatial distribution of the subtropical salinity maximum is identified using historical and recent data from the eastern North Atlantic. In the regions with high frequency of occurrence of the salinity maximum, the relative contributions of advection, eddy diffusion and double diffusion to the salt balance below the maximum salinity layer are determined. McDougall's (1984, Journal of Physical Oceanography, 14, 1577–1589) salt balance equation for neutral surfaces is used in this analysis. The data base consists of two meridional CTD sections along 33° and 27°W between 10° and 35°N, mean temperature-salinity profiles in 5° × 5° squares presented by Emery and Dewar (1982), and mean velocity profiles in 3° × 3° squares evaluated by Stramma (1984, Journal of Marine Research, 42, 537–558). The tropical salinity maximum tongue is found to be quite persistent in its salinity value and its geographic distribution, but less clearly in its vertical or isopycnal position. Double diffusion due to salt-fingering appears to be an important process for the salt balance below the salinity maximum layer. An approximate estimate of the double-diffusive salt flux is obtained. Near the subtropical source region, the double-diffusive salt flux is balanced primarily by isopycnal advection; further to the south it is also balanced by isopycnal eddy diffusion. Maximum double-diffusive fluxes correspond in magnitude to the mean salt flux caused by the excess in evaporation at the surface in the central subtropics. The resulting isopycnal and diapycnal eddy-mixing coefficients derived by a linear inversion technique have the reasonable values of Ki = (11 ± 5) × 102 m2 s−1 and Kd = (4 ± 2) × 10−5 m2 s−1. Considering the intermittency of the double-diffusive process, limiting values for the mean eddy-mixing coefficients are determined by neglecting the contribution of the double-diffusive salt fluxes. This leads to Ki = (5 ± 2) × 102 m2 s−1 and Kd = (5 ± 1) × 10−5 m2 s−1 for the isopycnal and diapycnal mixing coefficients, respectively.

Beschreibung: Horizontal velocity and temperature measurements observed from a two-dimensional array of moored instruments, mooring Fl, are analysed to describe the near-surface internal wave field in the GATE (GARP Atlantic Tropical Experiment) C-scale area. Spectral properties indicate strong deviations from the Garrett and Munk (1972, 1975) deep ocean internal wave models. The frequency spectrum in the upper pycnocline is dominated by three energetic bands centered at 0.0127 (inertial frequency), 0.08 (M2-tidal frequency) and 3 cph. The latter frequency band does not correspond to the local Brunt Väisälä frequency (〈 10 cph) and contains about one half of the total internal wave energy of fluctuations with periods less than 10 hours. Cross-spectral analysis of the high frequency internal waves yields corresponding wavelengths of order 1 km consistent with westward propagating first mode wave groups, if the effect of Doppler shift due to a strong mean current is taken into account