Adriatic Sea surface temperature and ocean colour variability during the MFSPP

Abstract

Abstract. Two years and six months of night-time Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) and daytime Sea viewing Wide Field of view Sensor (SeaWiFS) data collected during the MF-SPP have been used to examine spatial and temporal variability of SST and chlorophyll (Chl) in the Adriatic Sea. Flows along the Albanian and the Italian coasts can be distinguished year-round in the monthly averaged Chl but only in the colder months in the monthly averaged SST's. The Chl monthly-averaged fields supply less information on circulation features away from coastal boundaries and where conditions are generally oligotrophic, except for the early spring bloom in the Southern Adriatic Gyre. To better characterise the year-to-year and seasonal variability, exploratory data analysis techniques, particularly the plotting of multiple Chl-SST histograms, are employed to make joint quantitative use of monthly-averaged fields. Modal water mass (MW), corresponding to the Chl-SST pairs in the neighbourhood of the maximum of each monthly histogram, are chosen to represent the temporal and spatial evolution of the prevalent processes and their variability in the Adriatic Sea. Over an annual cycle, the MW followed a triangular path with the most pronounced seasonal and interannual variations in both Chl-SST properties and spatial distributions of the MW in the colder part of the year. The winter of 1999 is the colder (by at least 0.5 • C) and most eutrophic (by 0.2 mg/m 3 ). The fall of the year 2000 is characterised by the lack of cooling in the month of November that was observed in the previous year. In addition to characterising the MW, the twodimensional histogram technique allows a distinction to be made between different months in terms of the spread of SST values at a given Chl concentration. During spring and summer, the spread is minimal indicating surface homothermal conditions. In fall and winter, on the other hand, a spread of points suggesting a linear negative correlation between SST and Chl is found. This behaviour is related to the high nutriCorrespondence to: E. Böhm (e.bohm@isac.cnr.it) ent content of cooler water associated with upwelling or the Po River fresh water outflow.

Temporal variation of the algae-associated molluscan assemblage of artificial substrata in Bay of Tunis (Tunisia)

“…Seawater temperatures show one of the broadest ranges known in the Mediterranean Sea (Fine et al, 2001), with near tropical seawater in summer (28ºC in July and September 2009) and a considerable decrease in winter (8ºC in February 2010), similar to that found in the northern Adriatic Sea, where the lowest temperatures during the winter months are associated with the increase in coastal flows related to the Po River outflow (Böhm et al, 2003). The low values during the winter months in the study area could also be due to the large input of fresh water through the Khéreddine Canal.…”

“…Finally, chlorophyll a showed strong fluctuations, with peaks in February, July and November 2009, and higher values during summer and autumn and minimum in spring. This data could be related to the input of nutrients through the Khéreddine Canal during the rainy seasons, as observed in the northern Adriatic Sea also (Böhm et al, 2003), and an increased volume of waste produced by the human population in summer, as found in the eastern Mediterranean Sea (Reizopoulou & Zenetos, 2005).…”

High-resolution satellite turbidity and sea surface temperature observations of river plume interactions during a significant flood event

“…6) is coherent with the overall pattern of suspended matter described in previous studies based on satellite data and conducted during autumn/winter floods, although their investigations were performed using different satellite-derived products. For instance, Barale et al (1984) presented the vertical attenuation coefficient variability, Bignami et al (2007) used both the vertical attenuation coefficient and an index for turbid (Case 2) waters' occurrence, while other studies (Barale et al, 1986(Barale et al, , 2005Böhm et al, 2003;Spillman et al, 2007) describe the basin response to freshwater discharge and wind events.…”

“…Since T higher than ∼ 3-5 FNU can be deemed as indicative of terrestrial discharge in NAS (Boldrin et al, 2005(Boldrin et al, , 2009Tesi et al, Braga et al, 2013), these values were used to delineate the surface expression of the plumes in the T field from the adjacent ocean waters (Fig. 6).…”

An observing system for the collection of fishery and oceanographic data

“…Many studies have pointed out the relationship between fish abundance and SST (Simpson, 1994;Cole, 1999;Waluda et al, 2001;Yanez et al, 2001), the latter being obtained by satellite measurements. Within the framework of MFSTEP, SST data and also surface chlorophyll are made available for the entire Adriatic Sea by the ISAC-CNR, Rome (http://www.bo.ingv.it/adricosm, Böhm et al, 2003) and temperature at depth data are also available as model outputs. Models also provide other important physical parameters in 3 dimensions such as salinity, which has been used as a further explanatory variable in the analysis.…”