Wyniki wyszukiwania - BazTech

1

A study on loops and eddies identified from the trajectories of drifters in the North Indian Ocean

Dora Shrikant, Aparna Sreekumar G.

Oceanologia

|

2021

|

No. 63 (4)

516--530

EN

We identify loops and eddies from the trajectories of the drifters in the North Indian Ocean (NIO) from October 1985 to March 2019. We use the geometric identification method to identify loops and eddies and compare them with the loops identified from loopers provided by Lumpkin (2016). In NIO, the number of loops estimated from loopers is less than the number of loops and eddies identified by the geometric identification method. A total of 761 loops are identified, of which 346 are eddies, whereas the loops identified from loopers are only 149. Larger radii loops and eddies are observed in the western and central Bay of Bengal (BoB) and the southwestern part of the Arabian Sea (AS). Temporal variation of loops and eddies shows a peak during April–May in the AS and September–October in the BoB. In the BoB, the temporal variation of cyclonic eddies matches with the variation in chlorophyll.

2

“Noise” in climatologically driven ocean models with different grid resolution

Tang Shengquan, von Storch Hans, Chen Xueen, Zhang Meng

Oceanologia

|

2019

|

No. 61 (3)

300--307

EN

The internally generated variability in the climate system, which is unrelated to any external factors, can be conceptualized as “noise”. This noise is a constitutive element of high-dimensional nonlinear models of such systems. In a three-layer nested simulation, which is forced by climatological (periodic) atmospheric forcing and includes an (almost) global model, a West-Pacific model, and South China Sea (SCS) model, we demonstrate that such “noise” builds also ocean models. They generate variability by themselves without an external forcing. The “noise” generation intensifies with higher resolution, which favors macroturbulence.

3

Scales of Turbulent Eddies in a Compound Channel

Kozioł A.

Acta Geophysica

|

2015

|

Vol. 63, no. 2

514--532

EN

Experimental research was undertaken to investigate the changes in scales of turbulent eddies (macro- and microeddies) in a compound channel and the influence of rigid, emergent floodplain vegetation on scales of turbulent eddies. The results of eight tests for different roughness conditions (smooth bed, rough bed) and with a tree system on the floodplains from two earlier studies are presented. The increase of the channel roughness resulted in a decrease of longitudinal sizes of macroeddies in the whole channel. Trees on the floodplains resulted in disintegration of the sizes of macroeddies, making values of sizes more uniform. A more significant decreasing influence on sizes of macroeddies in the whole channel was exerted by an increase of the main channel sloping bank roughness, having a higher effect than a twofold decrease in the floodplain trees density. The microeddies’ sizes are larger in the main channel centreline than on the floodplains and the smallest ones were present in the main channel/floodplain interface.

4

Method of convective velocity determination from dissipative range of energy spectrum

Kurasiński T., Kuncewicz C., Stelmach J.

Chemical and Process Engineering

|

2012

|

Vol. 33, nr 1

19-29

EN

In the study a new proposal of convective velocity determination necessary for eddy size determination from the dissipative range in a turbulent flow in a mixer was made. The proposed quantity depends on all the mean and fluctuating velocity components. By applying convective velocity one may determine the distribution of time and linear Taylor microscale in a stirred vessel.

5

Circulation and winter deep-water formation in the northern Red Sea

Manasrah R., Badran M., Lass H. L., Fennel W.

Oceanologia

|

2004

|

No. 46 (1)

5-23

EN

Water mass characteristics and circulation patterns in the Gulf of Aqaba and northern Red Sea were studied for the first time during the r/v "Meteor" cruise leg 44/2 from February 21st to March 7th 1999 using temperature-salinity profiles and current observations. The deep water in the northern Red Sea had similar characteristics to the well-mixed upper 450 m of water in the Gulf of Aqaba. This indicates that the winter mixed waters of the Gulf of Aqaba contribute significantly to deep-water in the northern Red Sea. Mixing in the Gulf of Aqaba is an annually repeated event that starts with the cooling of the surface water during November-December and reaches a maximum, which in most years extends down the entire water column in March-April. Waters deeper than the mixed layer in the Gulf seems to be rather passive and play no specific role in water mass formation in the northern Red Sea. In contrast to the Gulf of Aqaba, the upper 200 m of the northern Red Sea were stratified (21.5-23.5oC, and 40.0-40.3 PSU). Stratification at the Strait of Tiran was weak (21.6-22.0oC, and 40.3-40.5 PSU) and disappeared abruptly in the Gulf of Aqaba (21.4-21.6oC, and 40.6-40.7 PSU). A well-developed cyclonic gyre with a diameter of about 50-60 km and maximum velocity of about 0.4 m s-1 was observed in the stratified upper 200 m of the northern Red Sea waters. The gyre may contribute to the preconditioning for intermediate water formation in the northern Red Sea.