Desetodnevna varijabilnost ljetne cirkulacije u sjevernom Jadranu

Current, temperature and salinity data, collected during the ASCOP experiment that was carried out in the eastern part of the North Adriatic in summer 1989, have been analyzed together with related meteorological and hydrological data. After dividing the current series into three nearly equal subintervals, residual currents have been calculated for each of them. The major feature this exercise revealed was variability at a time scale of about ten days. A similar phenomenon has been observed by Italian researchers in the northeastern part of the Adriatic during several summers. It has been shown in the paper that the wind episodes registered during the experiment, although inducing remarkable changes in temperature and salinity records, did not directly generate the observed current variability. The changes in the Po River outflow have also been ruled out as the cause of the observed current reorientation. Temperature data collected in the area have pointed to stratification as the factor controlling the observed current variations. The stratification itself was influenced by buoyancy fluxes and wind forcing. However, further theoretical and empirical work is needed to establish conclusive evidence and elaborate dynamics of the observed phenomenon

Modelling residual sea levels of the Bakar Bay

In this paper a case of extremely high sea levels, which were recorded in the Bakar Bay on 31 January/1 February 1986, has been analyzed. The comparison of residual sea levels with synoptic weather charts and time series of both atmospheric pressure and wind over the Adriatic Sea has shown that cyclones induced two disturbances which were constructively superimposed and therefore caused extremely high sea levels. After a front passed by, the wind suddenly decreased in strength causing free oscillations (seiches) which persisted for approximately ten days. It has been shown that the influence of atmospheric pressure on the sea can well be represented by the inverted barometer effect. In order to simulate the wind effect, one-dimension hydrodynamical numerical model has been developed. It was found that the model gives good results when land-based wind data are transformed into offshore data according to empirical relation published by S. A. Hsu in 1986. Moreover, it turned out that very good agreement between the observed and predicted levels can be obtained by using the value of 5×10-4 m s-1 for bottom friction coefficient, which equals the lower limit of values cited in the literature for the Adriatic area

Strong quasi-stationary wintertime atmospheric surface pressure anomalies drive a dipole pattern in the Subantarctic Mode Water formation

The deepest wintertime (Jul-Sep) mixed layers associated with Subantarctic Mode Water (SAMW) formation develop in the Indian and Pacific sectors of the Southern Ocean. In these two sectors the dominant interannual variability of both deep wintertime mixed layers and SAMW volume is a east-west dipole pattern in each basin. The variability of these dipoles are strongly correlated with the interannual variability of overlying winter quasi-stationary mean sea level pressure (MSLP) anomalies. Anomalously strong positive MSLP anomalies are found to result in the deepening of the wintertime mixed layers and an increase in the SAMW formation in the eastern parts of the dipoles in the Pacific and Indian sectors. These effects are due to enhanced cold southerly meridional winds, strengthened zonal winds and increased surface ocean heat loss. The opposite occurs in the western parts of the dipoles in these sectors. Conversely, strong negative MSLP anomalies result in shoaling (deepening) of the wintertime mixed layers and a decrease (increase) in SAMW formation in the eastern (western) regions. The MSLP variability of the Pacific and Indian basin anomalies are not always in phase, especially in years with a strong El Niño, resulting in different patterns of SAMW formation in the western vs. eastern parts of the Indian and Pacific sectors. Strong isopycnal depth and thickness anomalies develop in the SAMW density range in years with strong MSLP anomalies. When advected eastward, they act to precondition downstream SAMW formation in the subsequent winter

The effects of enhanced sea ice export from the Ross Sea on recent cooling and freshening of the Southeast Pacific

The top 2000 m of the Southern Ocean has freshened and warmed over recent decades. However, the high-latitude (south of 50°S) southeast Pacific was observed to be cooler and fresher in the years 2008-2010 compared to 2005-2007 over a wide depth range including surface, mode, and intermediate waters. The causes and impacts of this event are analyzed using the ocean—sea-ice data-assimilating Southern Ocean State Estimate (SOSE) and observationally based products. In 2008-2010, a strong positive Southern Annular Mode coincided with a negative El Niño Southern Oscillation and a deep Amundsen Sea Low. Enhanced meridional winds drove strong sea ice export from the eastern Ross Sea, bringing large amounts of ice to the Amundsen Sea ice edge. In 2008, together with increased precipitation, this introduced a strong freshwater anomaly that was advected eastward by the Antarctic Circumpolar Current (ACC), mixing along the way. This anomaly entered the ocean interior not only as Antarctic Intermediate Water, but also as lighter Southeast Pacific Subantarctic Mode Water (SEPSAMW). A numerical particle release experiment carried out in SOSE , showed that the Ross Sea sector was the dominant source of particles reaching the SEPSAMW formation region. This suggests that large-scale climate fluctuations can induce strong interannual variability of volume and properties of SEPSAMW. These fluctuations act at different time scales: instantaneously via direct forcing, and also lagged over advective time scales of several years from upstream regions

Agrotechnical measures in potatoes production for processing into chips

U ovom istraživanju analizirana je intenzivna proizvodnja krumpira koji se prerađuje u čips. U analiziranom razdoblju (2019. – 2022.) prikazane su sve agrotehničke mjere pri proizvodnji krumpira na primjeru PO „Beta“. Vidljivo je da je gnojidba svake godine provedena pri jesenskoj obradi, zatim pred samu sadnju, pri nagrtanju i prije zatvaranja redova. Zaštita krumpira je provedena pravovremeno, a kod primjene zaštitnih sredstava najviše se koriste fungicidi u zaštiti od plamenjače i koncentrične pjegavosti krumpira. Kod zaštite od krumpirove zlatice vodi se računa o korištenju pripravaka iz različitih kemijskih skupina i različitih mehanizma djelovanja. Obavezna mjera u proizvodnji je navodnjavanje koje se provodi tijekom ljetnih mjeseci (lipanj i srpanj). Vađenje krumpira obavilo se strojno, a ostvareni prinosi iznosili su prosječno 36 t/ha, što je daleko od hrvatskog prosjeka (19,1 t/ha).This study analyzed the intensive production of potatoes which are processed into chips. In the analyzed period (2019 - 2022), all agrotechnical measures in the production of potatoes are presented on the example of PO "Beta". Autumn fertilization was carried out every year during the autumn cultivation, then before planting and before closing the rows. In plant protection fungicides are mostly used to protect against potato late blight fungus and early blight of potatoes. For Colorado potato beetle used insecticides were different in active compound. Irrigation was done during the summer months (June and July). Potatoes were harvested by machine, and achieved yield was on average 36 t/ha, which is far higher than Croatian average (19.1 t/ha)

Modelling residual sea levels of the Bakar Bay

In this paper a case of extremely high sea levels, which were recorded in the Bakar Bay on 31 January/1 February 1986, has been analyzed. The comparison of residual sea levels with synoptic weather charts and time series of both atmospheric pressure and wind over the Adriatic Sea has shown that cyclones induced two disturbances which were constructively superimposed and therefore caused extremely high sea levels. After a front passed by, the wind suddenly decreased in strength causing free oscillations (seiches) which persisted for approximately ten days. It has been shown that the influence of atmospheric pressure on the sea can well be represented by the inverted barometer effect. In order to simulate the wind effect, one-dimension hydrodynamical numerical model has been developed. It was found that the model gives good results when land-based wind data are transformed into offshore data according to empirical relation published by S. A. Hsu in 1986. Moreover, it turned out that very good agreement between the observed and predicted levels can be obtained by using the value of 5×10-4 m s-1 for bottom friction coefficient, which equals the lower limit of values cited in the literature for the Adriatic area

Subantarctic Mode Water Biogeochemical Formation Properties and Interannual Variability

Subantarctic mode water (SAMW) is a key water mass for the transport of nutrients, oxygen, and anthropogenic carbon into the ocean interior. However, a lack of biogeochemical observations of SAMW properties during wintertime formation precluded their detailed characterization. Here we characterize for the first time SAMW properties across their entire wintertime formation regions based primarily on biogeochemical profiling floats. Observations show that the SAMW properties differ between the two main formation regions in the Pacific and Indian sectors of the Southern Ocean. SAMW formed in the Pacific is colder, fresher, and higher in oxygen, nitrate, and dissolved inorganic carbon (DIC) than its Indian Ocean counterpart. The relationship between potential density and biogeochemical water properties is nearly identical between the two formation regions; property differences thus predominantly reflect the difference in mean densities of SAMW formed in each region. SAMW is undersaturated in oxygen during formation, which will impact calculations of derived quantities that assume preformed oxygen saturation. SAMW is at or above atmospheric pCO2 during wintertime and therefore not a direct sink of contemporary carbon dioxide during the formation period. Results from the Biogeochemical Southern Ocean State Estimate suggest anti-correlated interannual variability of DIC, nitrate, and oxygen between the central and southeastern Pacific formation regions similar to previously established patterns in mixed layer physical properties. This indicates that the mean properties of SAMW will vary depending on which sub-region has a stronger formation rate, which is in turn linked to the Southern Annual Mode and the El-Niño Southern Oscillation. Key Points Subantarctic mode water (SAMW) biogeochemical formation properties are a function of the density of newly formed water Newly formed SAMW is undersaturated in oxygen due to opposing effects from cooling (solubility) and entrainment, and air-sea injection SAMW is near or above atmospheric pCO2 during formation and therefore not a strong direct sink of contemporary carbon dioxide Plain Language Summary In the Southern Ocean, north of the Antarctic Circumpolar Current, wintertime surface ocean heat loss cools the water, increasing its density and forming thick layers of well mixed water that enter the ocean. This water, called Subantarctic Mode Water (SAMW), represents an important pathway for anthropogenic carbon, nutrients and oxygen into the ocean interior. In this study we used new wintertime observations from profiling robots equipped with sensors that measure oxygen, nitrate, and pH in the top 2,000 m to determine important initial properties of SAMW for the first time. We find that the SAMW properties differ between the Pacific and Indian formation regions and are related to the densities of SAMW formed in each basin. These properties indicate that it is unlikely for SAMW to take up present-day carbon dioxide from the atmosphere during formation, though it may still absorb anthropogenic carbon. We investigated how these properties varied year-to-year using an ocean model linked to observations, finding connections between changes in the biogeochemical properties and physical processes as well as large-scale climate variability. These results will provide valuable constraints on interpretation of subsurface ocean measurements and model studies investigating the role of these waters in the global carbon cycle

Mooring observations of air-sea heat fluxes in two Subantarctic Mode Water formation regions

Wintertime surface ocean heat loss is the key process driving the formation of Subantarctic Mode Water (SAMW), but there are few direct observations of heat fluxes, particularly during winter. The Ocean Observatories Initiative (OOI) Southern Ocean mooring in the Southeast Pacific Ocean and the Southern Ocean Flux Station (SOFS) in the Southeast Indian Ocean provide the first concurrent, multi-year, time series of air-sea fluxes in the Southern Ocean from two key SAMW formation regions. In this work we compare drivers of wintertime heat loss and SAMW formation by comparing air-sea fluxes and mixed-layers at these two mooring locations. A gridded Argo product and the ERA5 reanalysis product provide temporal and spatial context for the mooring observations. Turbulent ocean heat loss is on average 1.5 times larger in the Southeast Indian (SOFS) than in the Southeast Pacific (OOI), with stronger extreme heat flux events in the Southeast Indian leading to larger cumulative winter ocean heat loss. Turbulent heat loss events in the Southeast Indian (SOFS) occur in two atmospheric regimes (cold air from the south or dry air circulating via the north), while heat loss events in the Southeast Pacific (OOI) occur in a single atmospheric regime (cold air from the south). On interannual timescales, wintertime anomalies in net heat flux and MLD are often correlated at the two sites, particularly when wintertime MLDs are anomalously deep. This relationship is part of a larger basin-scale zonal dipole in heat flux and MLD anomalies present in both the Indian and Pacific basins, associated with anomalous meridional atmospheric circulation