Global Mesoscale Eddy Statistics Based on Integrated Kinetic Energy
Having the capability to quantify the net power deposited by wind into the entire mesoscale flow, GM parameterization for coarse-grained mesoscale eddy statistics can be used to analyze the impact of oceanic eddies on the atmosphere. This article provides an introduction to this field and provides an overview of the current status and potential applications of GM parameterization.
GM parameterization for coarse-grained mesoscale eddy statistics
Integrated kinetic energy (IKE) is the kinetic energy of eddies calculated from geostrophic velocity anomalies. IKE is usually separated into eddy kinetic energy (EKE) and geostrophic kinetic energy (GKE). In this study, IKE and GKE were calculated from eddy census data. The data were obtained from AVISO data bank. A large database of eddy census was used to calculate mean values.
The vortex database includes 32 million cyclonic MEs. Its statistics are shown in solid symbols. In this study, only dates with at least one eddy center were considered for computation of mean values. There are strong discrepancies in the bands 30-50.
AVISO fields have spatial resolution of 0.25 x 0.25 (1440 x 720 grid cells). The sea level anomaly at the center of identified eddies was used as a proxy.
The results show that the spatially integrated kinetic energy ratios can be used to estimate the effective size of single proxy vortices. After normalization, comparisons can be made between eddies and the surrounding ocean. Nevertheless, the estimates of eddy amplitudes are loaded with errors. Therefore, this method is not very reliable for gray zone areas. The sensitivity of the method was tested by shifting amplitude values up by one centimeter.
The results show that the estimated value of the mean eddy kinetic energy is similar to those obtained by the vortex tracking statistics. Averaging the statistics should be done with care, as small eddies are difficult to calculate.
Quantifying the net power deposited by wind into the entire mesoscale flow
Various studies have attempted to quantify the net power deposited by wind into the entire mesoscale flow. This can be divided into two types: advective and convective transports.
Advective transports involve advection of matter from specific sources to the system. In this case, the matter is transported from the surface to the interior, where it becomes part of the flow. The convective transport term is calculated by using a three-dimensional velocity vector, which is calculated according to Fick’s first law.
Convective/advective transports involve both advection and diffusion. The diffusion transport is calculated by using the second order diffusion tensor. This means that the diffusion transport is calculated on spatial gradients of the bulk variable concentration. It is also calculated as a net transport.
This type of transport is used in tropical cyclones to transport angular momentum. It is calculated as the flow relative to the Earth’s rotation. A negative EAMF would make the flow inside the circle more anticyclonic. A positive EAMF would make the flow more cyclonic.
In the North Sea, high GOC occurs near large river mouths. Similarly, low GOC occurs in deep northern parts of the North Sea. The latter is due to lower near-surface NPP, which reduces organic matter that would normally reach the bottom.
Effects of oceanic eddies on the atmosphere
Whether we are talking about ocean currents or oceanic mesoscale eddies, the effect of these systems on the atmosphere and climate is significant. They are key to regulating heat distribution, carbon distribution, and mixing of nutrients. They also affect the stability of the atmospheric boundary layer.
Several studies have investigated the influence of mesoscale eddies on the atmosphere. They have shown that they have a significant effect on the sea surface temperature, sea level pressure, and the atmospheric boundary layer. They also have a significant impact on the near-surface air temperature and humidity. They can also influence the ocean heat uptake and nutrient supply in coastal areas.
In the past decade, the effect of interactions between eddies and the atmosphere has been studied extensively. These studies have helped to provide useful references for numerical ocean models.
In this study, researchers used a large-eddy simulation to understand how eddies modulate the atmosphere. The simulation was run over a variety of eddie regimes. The simulation showed that the impact of eddies on the atmosphere is greater in ice-covered regions. In these areas, warmer air temperatures and higher air humidity occur above anticyclonic eddies. This results in more sensitivity of surface air to surface heat fluxes.
Researchers also investigated the impact of eddies on the carbon cycle. They found that the eddies accelerated the carbon cycle. They also found that removing eddies weakens the advection of sea ice northward. This leads to a 15% decrease in freshwater flux north of 62.5 degrees S.