Top PDF Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea

Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea

Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea

In most situations, the sea ice covers only a part of the total water surface and is a mixture of ice types differing in structure and properties – level, rafted and ridged ice, possibly with cracks and leads (Lepp¨aranta and Myrberg, 2009). The numerical sea-ice models operating on the scale of tens up to thousands of kilometers reduce this informa- tion to a few parameters, typically to the concentration and mean thickness of the specified ice (and snow) classes in a given grid cell (for studies concerning the Baltic Sea see, e.g., Haapala and Lepp¨aranta, 1996; Meier et al., 1999; Haa- pala, 2000; Lehmann and Hinrichsen, 2000a; Zhang, 2000). As described below, the model used in this study belongs to that class of models. Modelling studies of the Baltic Sea ice thermodynamics and dynamics can be broadly divided into two categories. One concentrates on problems of climate and climate change, seasonal and interannual sea-ice variability, and the influence of large-scale atmospheric circulation pat- terns on the sea-ice processes in the Baltic Sea (e.g., Haapala and Lepp¨aranta, 1996; Omstedt and Nyberg, 1996; Lehmann and Hinrichsen, 2000a,b; Schrum et al., 2003). These studies are based on medium- and long-term simulations and mostly involve variables such as the maximum annual ice extent or the length of the ice season, i.e., parameters which can be understood as proxies of winter severity and which are there- fore good indicators of a climate change. The other category consists of studies which tackle smaller spatial and tempo- ral scales with the aim of analyzing effects of synoptic-scale weather patterns on the thermodynamics and dynamics of the sea ice. Good examples are provided by Uotila (2001), Br¨ummer et al. (2002), Rudolph and Lehmann (2006), Wang et al. (2006) or Bj¨ork et al. (2008). The need for more ex- tensive observational and numerical research is widely rec- ognized, particularly with respect to short- and medium-term ice dynamics in the Baltic Sea.
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N/P ratio of nutrient uptake in the Baltic Sea

N/P ratio of nutrient uptake in the Baltic Sea

field ratios are feasible in interpreting the spatial and temporal dynamics in nutrient concentration. For example, Osterroht and Thomas (2000) noticed that the N/P ratio of nutrient alteration fore and after the growing season was much different from Red- field ratios, they explained that the elemental ratios of nutrient uptake were consistent with Redfield ratios, but the nutrient mineralized from freshly produced organic material

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Sea ice biogeochemistry: a guide for modellers.

Sea ice biogeochemistry: a guide for modellers.

algae, i.e. diatoms, generally dominant in the sea ice habitat [50], detritus and gases for totally 9 state variables. A schematic diagram of the model is presented in Fig. 6, model’s variables and parameters are reported in Table S2 and Table S3 in File S1, while a mathematical description of the model is given in section S2 in File S1. The limiting nutrient is silicate, but any other nutrient can be chosen as model’s currency. Silicon was chosen because the functional group of algae is made of diatoms that require silicate uptake. If the model must have one single chemical component as currency, then silicon is likely to be the most appropriate for the sea ice system. However, many oceanic models use nitrogen as model’s currency since it often the most limiting in the oceans. In this latter case, modellers can choose if either increasing the number of state of variables of their model including both silicon and nitrogen components, either if using a N:Si conversion factor. Silicate dynamics differentiate from nitrate and phosphate dynamics as silicate does not accumulate in the cell and it is more likely to be parameterized with a simple Michaelis- Menten function (e.g [51]) and thus directly controls carbon photosynthesis. If nitrate or phosphate are instead chosen as most limiting nutrient, those are decoupled from carbon uptake because of the existence of cellular storage capabilities. The co-limitation from all nutrients can be done with a threshold method, as in [25], and it is considered in the parameterization of some processes such as chlorophyll synthesis and sinking. Multiple nutrient limitation is different for nutrients that can be stored in the cell (nitrate and
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Ecological network indicators of ecosystem status and change in the Baltic Sea.

Ecological network indicators of ecosystem status and change in the Baltic Sea.

Recent advances in network science have encouraged ecologists to study food-webs through network indices [14,67,68]. The estimations of species interactions often benefit the understanding of ecosystem response to perturbations [10,69], but it must be kept in mind that the impact of network structure on community may differ between different interaction types [70]. Consequently, the ENA analysis depends strongly on model quality and structure. As explained by Abarca-Arenas and Ulanowicz [71] and Pinnegar et al. [72] the number of functional groups and model structure have an impact on the number of flows and system properties. This has to be taken into account when comparing our results to other system outputs and other Baltic Sea models. Ecopath with Ecosim [73] is a commonly used approach that has been broadly discussed. Plaga´nyi and Butterworth [74], Aydin [75], Coll et al. [76] and Walters et al. [77] described the pros and cons of the methodology, which has been taken into account during model building, fitting and evaluation [39,78]. Niiranen et al. [78] found that data uncertainties may translate to uncertainties in modelled trophic control and hence results. However in this study the model was well fitted for several trophic levels and we have confidence in the model and data [39], which represent changes in biomasses and ecosystem dynamics well (see Fig. S1 in File S1).
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Carbon dynamics and CO<sub>2</sub> air-sea exchanges in the eutrophied coastal waters of the Southern Bight of the North Sea: a modelling study

Carbon dynamics and CO<sub>2</sub> air-sea exchanges in the eutrophied coastal waters of the Southern Bight of the North Sea: a modelling study

ure of the model to capture the observed late fall-winter min- ima (Fig. 4b). At the annual scale, Atlantic waters bring 96% of TA in BCZ and river loads and biological processes con- tribute 3.9% and 0.1%, respectively. Sensitivity tests with varying initial TA corresponding to the range of observed values in WCH (Borges and Frankignoulle, 2003) indicate that a reduction of WCH initial conditions of TA by less than 2% improves significantly model simulations of DIC (Fig. 4a) and TA (Fig. 4b) in winter while fall observations remain overestimated by the model (Fig. 4a, b). Elevated modelled TA in fall could result from an overestimation of river inputs during this period. At that time of the year (Oc- tober to January), river discharge is high and inputs of TA ac- count for 45% of annual river loads. Due to the importance of biological processes on magnitude and seasonal variability of DIC, modification of DIC initial value in the Western Chan- nel has no impact on DIC magnitude in the Belgian coastal zone.
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Scaling aspects of the sea-ice-drift dynamics and pack fracture

Scaling aspects of the sea-ice-drift dynamics and pack fracture

The ice-drift in the Arctic Ocean is driven, mainly, by the wind forcing (Lewis et al., 1994; Richter-Menge and Elder, 1998), and the variability of the weather pattern causes cy- cles of redistribution of stresses and deformations with ice breaking (Hopkins et al., 2004) followed by refreezing (Ko- rsnes et al., 2004). On 10 February 2004, a basin-wide sea- ice fragmentation occurred, and it was detected in the satel- lite images. Figure 4 shows the NOAA satellite images of the region of drift obtained on 9 February and 10 Febru- ary 2004. In Fig. 4b one can see large-scale leads (up to 400 km in length), which formed in one day between two subsequent images and a position of the research station NP 32 that drifted on the pack during that period of time. The displacements and fragmentation of the ice-cover lasted dur- ing the whole February; on 2 March 2004 the research station NP 32 was abandoned in connection with multiple breakage of the ice-field on which the observations were carried out.
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Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea

Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea

Since sea ice potentially hinders winter navigation, de- tailed forecasts of the ice conditions are in demand and reg- ularly provided by the local weather services. A typical ice forecast contains several prognostic variables, for instance ice concentration, thickness and prognosticated ice drift. Ad- ditional variables are occasionally included, e.g., ridged ice fraction, which refers to the most important deformed ice type. Ridges can form substantial obstacles to winter nav- igation and thus receive increasing attention from the re- search community (e.g., Haapala, 2000; Kankaanpää, 1988; Leppäranta and Hakala, 1992; Leppäranta et al., 1995; Löp- tien et al., 2013). The forecast of the Swedish Meteorolog- ical and Hydrological Institute (SMHI) provides additional information about convergence of the ice drift field (i.e., re- gions where the ice is compacting are marked). In regions with convergent ice motion, large ice stresses can occur, the ships might get stuck and, in the worst case, even damaged (e.g., Suominen and Kujala, 2014; Pärn et al., 2007).
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Sea ice in the Baltic Sea &ndash; revisiting BASIS ice, a historical data set covering the period 1960/1961&ndash;1978/1979

Sea ice in the Baltic Sea &ndash; revisiting BASIS ice, a historical data set covering the period 1960/1961&ndash;1978/1979

Abstract. The Baltic Sea is a seasonally ice-covered, marginal sea in central northern Europe. It is an essential waterway connecting highly industrialised countries. Because ship traffic is intermittently hindered by sea ice, the local weather services have been monitoring sea ice conditions for decades. In the present study we revisit a historical monitoring data set, covering the winters 1960/1961 to 1978/1979. This data set, dubbed Data Bank for Baltic Sea Ice and Sea Surface Temperatures (BASIS) ice, is based on hand-drawn maps that were collected and then digitised in 1981 in a joint project of the Finnish Institute of Marine Research (today the Finnish Meteorological Institute (FMI)) and the Swedish Meteorological and Hydrological Institute (SMHI). BASIS ice was designed for storage on punch cards and all ice information is encoded by five digits. This makes the data hard to access. Here we present a post-processed product based on the original five-digit code. Specifically, we convert to standard ice quantities (including information on ice types), which we distribute in the current and free Network Common Data Format (NetCDF). Our post-processed data set will help to assess numerical ice models and provide easy-to-access unique historical reference material for sea ice in the Baltic Sea. In addition we provide statistics showcasing the data quality. The website www.baltic-ocean.org hosts the post-processed data and the conversion code. The data are also archived at the Data Publisher for Earth & Environmental Science, PANGAEA (doi:10.1594/PANGAEA.832353).
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Innovative economy in the Baltic Sea region

Innovative economy in the Baltic Sea region

In Russia, the Triple Helix is still being at a very early stage of formation — not yet a system, but mostly pairwise relationships, such as: science — busi- ness, the state — science and the state — business. The specificity of the Russian Triple Helix model consists, in the first place, in the supremacy of the state over science and business. Secondly, unlike most countries of the world, Russia does not trust most of the fundamental research to universities, but delegates it to the institutes of the Russian Academy of Sciences [6]. The intensity of research and development (R & D), is measured by the ratio of R & D expenditure to GDP. In Europe, there is a direct dependence between economic growth and the size of national and regional resources allocated to research and development [7]. In 2010, total R & D expenditure in the EU-27 states was an average of 2 % of GDP, below the target of 3 % set by the 2010 recommendations of the Lisbon Strategy for the EU [8]. Among the EU countries only Finland (3.87 %), Sweden (3.42 %) and Denmark (3.06 %) exceed the 3 % of GDP [9]. In per capita terms, these states fall behind Lux- embourg. It is important to note that Finland and Denmark still are still showing growth, while Sweden has been in decline for 5 years now. Ger- many spends 2.82 % of GDP on research and development, which is lower than that of the Nordic countries, but higher than the average in the EU and the U. S.
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Uncertainties in Arctic sea ice thickness and volume: new estimates and implications for trends

Uncertainties in Arctic sea ice thickness and volume: new estimates and implications for trends

To get more robust results on long term trends, further evaluation of the radar altime- ter on board CryoSat-2 is needed, and more reliable estimates of sea ice density and snow depth on the Arctic sea ice are necessary. Our results indicate a less dramatic decline of Arctic sea ice volume than reported in previous studies, but it is not possible to draw quantitative conclusions about changes in sea ice volume between the ICESat

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Russia-EU energy efficiency cooperation in the Baltic region: the untapped potential

Russia-EU energy efficiency cooperation in the Baltic region: the untapped potential

Thus, over many years, Russia-EU cooperation in the field of energy ef- ficiency has been developing in several parallel and mutually supportive forms. However, the achieved results are still modest: technology transfer has been faced with certain problems, and the number of joint projects — especially those in the Russian regions bordering on the EU — is rather lim- ited. One of the most commonly mentioned reasons behind it [22] is an in- sufficiently favourable investment climate in Russia, which is partially a re- sult of lacking clearly defined legal conditions. Another obstacle is limited financial incentives for companies operating in the field of energy efficiency. Of course, clearly defined legal conditions and predictability of political leadership’s actions are more important in this field compared to oil and gas trade, where an alliance of giant corporations and the political leadership of countries or the EU can remove any obstacles.
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К вопросу об экономико-географической структуризации Балтийского региона

К вопросу об экономико-географической структуризации Балтийского региона

7. Mezhevich, N. M. 2000, Mezhdunarodnye organizacii Baltijskogo morja: os- novnye napravlenija i rol' v formirovanii sistemy mezhdunarodnyh otnoshenij [In- ternational organizations of the Baltic Sea: the main directions and role in the sys- tem of international relations], St. Petersburg, p. 3.

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The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The comparison of the structure and microhardness of the tool steel C90 and HS 6-5-2 remelted with the electric arc

The structure of the remelting zone of the steel C90 steel be- fore conventional tempering consitute cells, dendritic cells, sur- rounded with the cementite, inside of which there is a plate mar- tensite and retained austenite, whereas the structure HS 6-5-2 steel consititute cells, dendritic cells and dendrites surrounded with the eutectic, inside of which there is a plate martensite and retained austenite. Such a structure is characterized with the similar micro- hardness (790-800 HV0,065) and intensity of the tribilogical wear.
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Morphology and distribution of liquid inclusions in young sea ice as imaged by magnetic resonance

Morphology and distribution of liquid inclusions in young sea ice as imaged by magnetic resonance

18 cm thick young sea ice grown in an outdoor sea ice pool from experimental seawa- ter under ambient weather conditions. It is surmised that this brine drainage channel feature is a first generation one, having been formed during sea ice growth in the week previous to the sampling date, and not as result of melting processes, given the temper- ature history of the sea ice volume over the growth period of that section. The speed

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High-resolution ice nucleation spectra of sea-ice bacteria: implications for cloud formation and life in frozen environments

High-resolution ice nucleation spectra of sea-ice bacteria: implications for cloud formation and life in frozen environments

have been performed on solid surfaces (with a few exceptions, M ¨ohler et al., 2007). We find low-temperature INA for the isolates observed in this study and these isolates are therefore not likely to be important for polar atmospheric processes. Overall, knowl- edge of bacterial diversity and activity is essential to predict potential bacterial impact on cloud formation processes and air chemistry if metabolically active bacteria process

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The quality of castings obtained during lost-wax and Replicast CS processes in aspect of ecology

The quality of castings obtained during lost-wax and Replicast CS processes in aspect of ecology

Haratym, Dok ł adno ć wymiarowa odlewów wykona- nych w procesie Replicast CS, Archiwum Odlewnictwa rocznik 3, nr 9, Katowice 2003.. Arendarski, Niepewno ć pomiarów, Oficyna Wydaw- nic[r]

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Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Nowadays, magnesium alloys are used for casting into sand moulds of huge dimensional castings, high-pressure castings and precise casings. In castings of magnesium alloys defects or inconsistencies often appear (like casting misrun, porosities and cracks) particularly in the huge dimensional castings. Such defects are mended with the use of padding and welding. The welding techniques can be applied by using weld material consisting of magnesium alloy, as well as for regeneration of alloys after excessive wear. Nevertheless, the number of the repaired castings, which were permitted for use, is not satisfactory for a profitable production. The main reasons for wear are the cracks appearing during welding in brittleness high-temperature range.
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Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Zimmerman (1999) in his article titled ―Mobile Computing: Characteristics, Benefits, and the Mobile fra mework‖ defined mobile computing as ―the use of computing devices, which usually interact in some way with a centralised information system while away from the normal fixed workplace‖. He went on to say that, Mobile computing technology enables the mobile person to create, access, process, store and communicate information without being constrained to a single location. It is on the above basis that this researcher views mobile computing as embracing a host of portable technologies the can access internet using wireless fidelity (WIFI). These range from notebook computers to tablets, to smartphones and e-book readers. Such devices have brought about Mobile learning (m-Learning) in Zimbabwe Polytechnics, enabling staff and students to share academic resources, be able to research and develop applications from wherever they are. Zimmerman (1999) went on to identify mobile computing hardware, software and communications in use then. He identified hardware as palmtops, clamshells, handheld Pen Keys, pen slates, and laptops. The characteristics of such devices in terms of screen size was small, processing capability was limited and supported a few mobile applications. Over the years mobile devices have improved in such characteristics to make mobile computing easy, fast and user friendly. Great improvements also came with the associated systems software, with the modern devices now running on Android, Symbian and windows 8 mobile, as compared to then when MS DOS, Windows 3.1, Pen DOS were used. In communications Zimmerman talked of internet speeds in kilobytes per second (Kbps), while today’s communications devices have speeds of gigabytes per second (Gbps
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Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

Buying Behavior Of Organic Vegetables Product The Effects Of Perceptions Of Quality And Risk

the countries in Asia as Malaysia had more intentions of organic products from the customers in view of the importance of health on environmental issues (Saleki et al., 2012:99). This shows that attentions to organic products are already quite well received by the community. However, there needs to be studied perception of organic products in Indonesia, because Indonesia is a developing country which has a population density is quite high compared from Malaysia. And consumption of vegetable, especially organic vegetable products is still low in Indonesia (Amin, 2014:13), in particularly the province of West Java. An organic vegetable product offered by retail supermarket is assessed by consumers in both of sides, quality and risk. Price is a risk that should be accepted by consumers when buying organic vegetables. Hence, price of organic vegetables is more expensive than conventional vegetable products (Radman, 2005:263). Value of the risk products is very important for customer, which has an impact on consumer purchasing decisions (Yee et al., 2011:55). Nowadays consumers buy organic products is not as aware of the health and environmental effects but because of advised and habit of surroundings (Guido et al., 2010:99). In addition, not all consumers considered that by buying organic products, have been keeping or help conserve the environment (Arvola, 2008:449). It is alleged lack of consumer understanding of product quality organic vegetables. On last study it was discovered that the perceived quality is strong relationship with consumer purchasing decisions (Yee et al., 2011:55). Consumer’s had perception of organic products is because of quality and safety, in addition to some other benefits (Zanoli et al., 2012:70). Customer value of product influenced purchase decision of products (Shareef, 2008:105). Organic vegetable products have value in consumer where quality and satisfactions become value for consumers (Ying & Chiu, 2012:125). Higher value of consumer product quality of organic vegetables is more possibility to purchase decisions of organic vegetable products who offered in retail supermarkets. Based on previously phenomenon, this study examines the level of consumer perceptions of quality and risk in organic vegetables, as well as the impact on consumer purchasing decisions.
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Insolation and gacial meltwater influence on sea‐ice and circulation variability in the Northeastern Labrador Sea during the last glacial period

Insolation and gacial meltwater influence on sea‐ice and circulation variability in the Northeastern Labrador Sea during the last glacial period

The most pronounced IRD layers caused by the collapses of the Laurentide (H5 and H4) and Eurasian (H6 and H3) ice sheets were discovered in the Ruddiman belt (Bond et al., 1993; Grousset et al., 1993; Grousset et al., 2001; Hemming, 2004; Ruddiman, 1977). It is often assumed that the seaice cover extended to the northern edge of that belt at 55°N (Dokken et al., 2013; Vettoretti & Peltier, 2016) because the seaice edge would have blocked potential northward iceberg movement as well as northward oceanic heat transport making the Ruddiman belt the most suitable region for melting. During H‐events the over- turning circulation was reduced (e.g. Böhm et al., 2015; Henry et al., 2016; Rahmstorf, 2002) and the restart of the overturning circulation is observed in North Atlantic proxy records as a temperature over- shoot indicating the increased advection of warm water (e.g. Dokken et al., 2013; Knutz et al., 2011; Rasmussen & Thomsen, 2004; Sadatzki et al., 2019; Sessford et al., 2018; van Kreveld et al., 2000; Voelker et al., 1998). The glacial surface hydrography of the northeastern Labrador Sea was influenced by Arctic freshwater and Atlantic water and probably iceberg transport and melt from the Laurentide, Eurasian and Greenland ice sheets (Death et al., 2006; Hemming, 2004; Stoner et al., 1998). Consequently, we would expect to observe H‐related meltwater peaks associated with increased IRD fluxes and low foraminifer fluxes, followed by a signal of subsurface warming indicating an active surface and deep water circulation. Instead, the only proxy in the analyzed core sections of 22CC that shows clear evidence of all H ‐events is δ 18 O, indicating each H ‐related meltwater event. Only H6, H5 and H3 are asso- ciated with low foraminifer fluxes, H4 and H3 with pronounced IRD peaks and H5 and H4 are followed by subsurface warming (Table 3). Following the interpretations of the proxy records from this site, these differences can largely be explained by the speci
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