Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: sea surface

Sortuj według:

Ogranicz wyniki do:

Long term variation of sardine Sardina pilchardus spawning along the Atlantic coast of northwest Africa (21-26°N) : characterization and spatiotemporal variability in spawning habitat

Abdelouahab Hinde, Berraho Amina, Baibai Tarik, Larissi Jamila, Charib Said, Agouzouk Aziz, Makaoui Ahmed, Ettahiri Omar, Errhif Ahmed

Oceanologia

2021

No. 63 (1)

1--11

Small pelagic fish such as sardine show strong recruitment variability often associated with environmental changes influencing the spawning process and ultimately, affecting population dynamics. Sardine (Sardina pilchardus, Walbaum 1792) is one of the most exploited pelagic species along the northwest African coast. The main spawning occurs during the cold season (autumn-winter). A time-series autumn-winter surveys extending from 1994 to 2015 sampled sardine eggs, along the southern area of the Moroccan Atlantic coast (26°N-21°N) were analyzed. The present work focuses on examining the inter-annual variability of the spawning habitat by analyzing the spatial-temporal variability of sardine egg distribution and density extracted from the data collected over the period 1994-2015. Generalized additive models (GAM) were used to detect the relationships between the sardine distribution, expressed as egg density and the presence or absence data and relevant hydrobiological environmental variables, such as salinity, temperature and zooplankton biomass. The generalized additive models showed significant relationships between the environment variables (SST, SSS and Zooplankton biomass) and sardine density, but not with sardine presence. Given that the study area is characterized by high mesoscale features and significant upwelling activities, the variability of upwelling processes could explain the changes of spawning ground position and thermal window.

Problem efektu stykowego w kompresji danych opisujących kształt powierzchni dna morskiego

Maleika W.

Zeszyty Naukowe / Akademia Morska w Szczecinie

2006

nr 11 (83)

203-210

W artykule omówiono występowanie problemu efektu stykowego w kompresji danych opisujących kształt powierzchni dna morskiego. Wyjaśniono przyczynę jego występowania, a następnie zaproponowano rozwiązanie problemu. Przedstawiono kompletny algorytm kompresji uwzględniający przyjęte rozwiązanie.

In the article the problem of artefacts in the block compression of sea-floor surface data is presented. The cause of such artefacts as well as an appropiate solution are included. In the end the complete compression algorithm dealing with the boundary effect is proposed.

The modification of light flux leaving a wind-roughened, oil covered sea surface: example of computations for hallow seas

Otremba Z., Piskozub J.

Oceanological Studies

2000

Vol. 29, No. 1

117-133

This paper presents chosen results of modelling of upward light flux over a rough sea surface covered with an oil film. In upward irradiance computations (by means of Monte Carlo method), the optical parameters of two types of water were taken into consideration: water typical for bays of the Baltic Sea (Case 2 water) and ocean (Case 1) waters, both covered with an oil layer 5 mum thick (Romashkino). Coefficients of reflectance and transmission for the oil film were used for the calculations. These coefficients were obtained through the mathematical simulation of the route of light rays, both upward and downward, through the oil film. The obtained results show that oil films influence upward light fluxes over the sea surface, and that this influence depends on the depth and roughness of the sea. The analyses of oil film visibility on sea surfaces revealed also the influence of the direction of observation.