Methane fluxes measured in a eutrophic peat meadow in the Netherlands dominated by vascular plants showed high spatial and temporal variability. To elucidate this variability as well as the underlying processes, various measurement techniques were used: soil gradients of methane concentrations, the chamber method, and the eddy covariance technique. Additionally, soil temperature at multiple dep...

The ocean contains many large-scale, long-lived vortices, called mesoscale eddies, that are believed to have a role in the transport and redistribution of salt, heat, and nutrients throughout the ocean. Determining this role, however, has proven to be a challenge, since the mechanics of eddies are only partly understood; a standard definition for these ocean eddies does not exist and, therefore...

The eddy-diffusion parameterization of turbulent transport is based on the assumption, often questionable for geophysical flows, of infinitesimal scales of turbulence. In this paper we quantitatively compute what are the consequences of this assumption on the estimates of dispersion for some simple flows with oceanographical scales. We compare the analytical results of two different models, one...

Deep convection energizes the entire water column. Large-eddy simulation of the oceanic boundary layer system predicts turbulence in the well-mixed layer as well as turbulence-induced internal waves propagating into the underlying stratified water column of the freely convecting wintertime Labrador Sea. Of particular interest is the downward propagation of energy from the turbulent boundary lay...

We present a physically motivated boundary-value problem for each vertical ocean column, whose solution yields a parameterized mesoscale eddy-induced transport streamfunction. The new streamfunction is a nonlocal function of the properties of the fluid column. It is constructed to have a low baroclinic mode vertical structure and to smoothly transition through regions of weak stratification suc...

This study numerically investigates the vortex-induced vibration (VIV) of an elastically mounted rigid cylinder by using Reynolds-averaged Navier-Stokes (RANS) equations with computational fluid dynamic (CFD) tools. CFD analysis is performed for a fixed-cylinder case with Reynolds number (Re) = 104 and for a cylinder that is free to oscillate in the transverse direction and possesses a low mass...

One of the most difficult processes which limit our ability to generate realistic, high-resolution simulations of the ocean state is intermittent nature of oceanic turbulence related to the presence of coherent structures at wide range of scales when simple parameterizations based on eddy diffusion concepts do not necessarily provide the correct answer. The coherent vortices have life-times in ...

Abstract For a quasi steady state condition, the water vapor flux from the ocean to atmosphere typical of the salty subtropics must be compensated by ocean processes that transfer freshwater into the evaporative regime. Observations of the North Atlantic subtropical sea surface salinity maximum region frequently reveal the presence of eddies with distinct salinity/temperature signatures of up t...

The Northern Hemisphere storm tracks have maximum intensity over the Pacific and Atlantic basins; their intensity is reduced over the continents downstream. Here, simulations with an idealized aquaplanet general circulation model are used to demonstrate that even without continents, storm tracks have a self-determined longitudinal length scale. Their length is controlled primarily by the planet...

Upper-layer circulation is investigated by using all available historical temperature profiles combined with climatological temperature–salinity relationships in the South China Sea. Two cyclonic eddies are revealed: one is located east of Vietnam (called the East Vietnam eddy) and the other is off northwest Luzon (called the West Luzon eddy). Both local Ekman pumping and remotely forced basin-...