Seasonal and Interannual Variability of Satellite-Derived Chlorophyll-a (2003-2019) in Lampung waters and surrounding area

In recent years, the phytoplankton blooming phenomenon occurred at Lampung Waters. This event harms living organisms due to its toxicity or caused oxygen depletion. Chlorophyll-a concentration (Chl-a) is the crucial biological parameter for simulating marine phytoplankton biomass. In this study, the monthly average of Chl-a ocean-color remote sensing data from 2003 to 2019 is investigated. The seasonal and interannual variability of Chl-a was analyzed in Lampung waters and its surrounding area. The study area was separated into three regions, namely the East Coast of Lampung waters, Lampung Bay and Sunda Strait area. The spatial pattern showed that the value of Chl-a on the east coast was higher than Lampung Bay and Sunda Strait, with a deal up to 7 mg/mg/m 3. The time series of spatial averages in three areas showed the seasonal and inter-annual variation. The monthly climatology of Chl-a in Lampung Bay more influenced by sea surface temperature. The maximum value occurs in October with Chl-a concentration was 0,87 mg/m 3. Meanwhile, the east coast area and Sunda Strait fit with the monthly rainfall pattern in the Lampung mainland. The maximum value occurs in February with Chl-a abundance were 2,49 mg/m 3 and 0,96 mg/m 3, respectively. The value indicated that the river runoff would be a significant impact on phytoplankton blooming. Otherwise, the interannual variability in three areas showed that the Lampung Bay was more influenced by Indian Ocean Dipole than the East Coast and Sunda Strait. The cross-correlation between Chl-a concentration and Dipole Mode Index in East Coast area, Lampung Bay, and Sunda Straits are -0.2, 0.5, and 0,1, with a significant level of 95%.

Seasonal and interannual variability in the density of the postlarvae of Litopenaeus setiferus and Farfantepenaeus duorarum in Términos Lagoon, Gulf of Mexico

White shrimps, Litopenaeus setiferus (Linnaeus, 1767) and pink shrimps, Farfantepenaeus duorarum (Burkenroad, 1939) are two pivotal species in the southern Gulf of Mexico, due to their ecological and economic importance. In this study we present observational evidence of the seasonal and interannual variability of both species in the Términos Lagoon (southern Gulf of Mexico). The results suggest that the hydrography of the water column and the surface circulation exert a strong influence on the density of both species. The results presented here contribute to a better understanding of the dynamics of both species and highlight the need to combine different methodologies to achieve a better interpretation of this system.

Biooptical characteristics and solar radiation in the surface layer of the Barents sea

The data on the calculation of bio-optical parameters in the Barents Sea are presented, for which regional algorithms have been developed. These algorithms were derived on the basis of field measurements made in the region under consideration. The seasonal and interannual variability of bio-optical characteristics was studied and coccolithophore blooms in the Barents Sea were evaluated.

Seasonal and interannual variability of global internal tides

<p>In this study, we investigate the seasonal and interannual variability of internal tides in the global ocean using a Hybrid Coordinate Ocean Model (HYCOM) and altimetry data. The variability of internal tides is caused by the time varying stratification, mesoscale activity, large-scale shifts in amphidromic points, and changes in ice cover. The variation in the background fields generates the non-phase locked internal tides which are non-stationary. Non-stationary internal tides are less predictable than stationary tides, complicating regional model forcing with remote internal tide signals and the separation of internal tides from mesoscales. We will use 6 years of steric SSH extracted from a global HYCOM simulation with a horizontal resolution of 8 km and 32 layers to study the variability of internal tides. Our objective is to analyze the spatial and temporal variability of the amplitude and phase of the diurnal and semidiurnal internal tides. The SSH time series will be divided into time segments with different durations. The least-squares harmonic analysis will be used to extract SSH amplitude and phase for M2, K1, O1, and S2 constituents for these time segments. It has been found that the stationary amplitude decreases with an increase in the duration of the time series. We will also use empirical orthogonal functions (EOF) analysis to determine the seasonal and interannual variability in the monthly-mean internal tide amplitude and phase. The global maps of the non-stationarity fraction for the internal tidal constituents will be shown for each season. These results will be compared with 25 years of satellite altimetry data to find out whether similar variance decay trends are observed in the altimetry data.</p>