The evolution of ridged ice fields

Ridges are elongated ice cover features created by local deformation. In the Baltic the visible part of the ridge, the sail, is typically 1-3 m high while the bulk of the ridge volume is contained to the 5-15 m deep subsurface keel. In larger scales ridging creates ridged ice fields. The modeling of ridges and ridged ice fields is important for dynamic ice drift models, for ice navigating ships, and for the estimation of ice loads exerted against offshore structures. Ridge fields are quantified in terms of ridge heights and ridge spacings which are distances between ridge sails. The present work formulates an equation governing the evolution of ridge spacing distribution. The usual lognormal and exponential distribution models for spacing distributions are obtained as solutions. The equation also explains several statistical features found in the analysis of ice surface profile data from the Baltic and from the Kara Sea. Conservation equations for continuum fields of spacing distributions are formulated. These can be included in dynamic ice forecast models. The parameterisation links the evolution to the decrease of ice area and to the fields of concentration and strain rate. An estimate for the equivalent thickness of ridge rubble is thereby obtained and is much larger than the values estimated previously. The parameterisation requires cross-sectional modelling of the ridges. A new type of feature, a ridge cluster, is introduced to describe ridges in keel contact. Concepts to describe cluster structure and cluster occurrence are developed. The spacing equation is a specific formulation of the Kolmogorov-Feller equation which is the basic equation governing discontinuous Markov processes. Another specific formulation is the equation governing the evolution of ice thickness distribution. A general presentation of discontinuous Markov processes is given. It can be used to construct evolution equations for ice morphological quantities. In the present context it is used to formulate alternatives to the spacing equation. The most applicable of these alternatives govern the distribution of ridge sail number, or the number of sails on line segments.reviewe

Oxygen and carbon isoscapes for the Baltic Sea: Testing their applicability in fish migration studies

201

Validation of SMOS sea ice thickness retrieval in the northern Baltic Sea

The Soil Moisture and Ocean Salinity (SMOS) mission observes brightness temperatures at a low microwave frequency of 1.4 GHz (L-band) with a daily coverage of the polar regions. L-band radiometry has been shown to provide information on the thickness of thin sea ice. Here, we apply a new emission model that has previously been used to investigate the impact of snow on thick Arctic sea ice. The model has not yet been used to retrieve ice thickness. In contrast to previous SMOS ice thickness retrievals, the new model allows us to include a snow layer in the brightness temperature simulations. Using ice thickness estimations from satellite thermal imagery, we simulate brightness temperatures during the ice growth season 2011 in the northern Baltic Sea. In both the simulations and the SMOS observations, brightness temperatures increase by more than 20 K, most likely due to an increase of ice thickness. Only if we include the snow in the model, the absolute values of the simulations and the observations agree well (mean deviations below 3.5 K). In a second comparison, we use high-resolution measurements of total ice thickness (sum of ice and snow thickness) from an electromagnetic (EM) sounding system to simulate brightness temperatures for 12 circular areas. While the SMOS observations and the simulations that use the EM modal ice thickness are highly correlated (r2=0.95), the simulated brightness temperatures are on average 12 K higher than observed by SMOS. This would correspond to an 8-cm overestimation of the modal ice thickness by the SMOS retrieval. In contrast, if the simulations take into account the shape of the EM ice thickness distributions (r2=0.87), the mean deviation between simulated and observed brightness temperatures is below 0.1 K

Merenkulun kansainvälisen ilmasto- ja ympäristösääntelyn vaikutukset Suomen elinkeinoelämälle

Merenkulun ympäristösääntelyn aiheuttamien kustannusten ohella syntyy myös säästöjä muun muassa energiatehokkuuden parantumisen kautta. Tiedossa olevan ympäristösääntelyn vuosittainen kustannusvaikutus Suomen meritse tapahtuvalle ulkomaankaupalle vuosina 2020–2025 on noin 25–40 miljoonaa euroa per vuosi, mikä on noin 0,1 – 0,2 % teollisuuden ja kaupan alan kaikista logistiikkakustannuksista. Keskeisistä vientitoimialoista suurin kustannusrasitus kohdistuu metalli-, metsä- ja kemianteollisuudelle. Mikäli kasvihuonekaasupäästöjä pyrittäisiin rajoittamaan päästökaupalla, tämä nostaisi Suomen elinkeinoelämälle kohdistuvia kustannuksia vuositasolla noin 25–30 miljoonaa euroa. Sääntely luo myös liiketoiminta- ja kasvumahdollisuuksia mm. laitevalmistajille, järjestelmätoimittajille, alussuunnittelijoille sekä korjaus- ja purkutelakoille. Alusten energiatehokkuusindeksin, EEDIn tulevia vaiheita koskevissa neuvotteluissa olisi Suomen kannalta huomioitava erityisesti sääntelyn vaikutus talvimerenkulkuun ja alusten kykyyn kulkea jäissä. Sääntelymuutokset synnyttävät myös merkittävät maailmanlaajuiset markkinat alusten päästöjä ja energiankulutusta vähentäville ratkaisuille. Useat suomalaisyritykset ovat näiden teknologioiden toimittajien kärkeä, ja niillä on hyvät edellytykset hyödyntää liiketoimintapotentiaali

Satellite Observations for Detecting and Forecasting Sea-Ice Conditions: A Summary of Advances Made in the SPICES Project by the EU’s Horizon 2020 Programme

The detection, monitoring, and forecasting of sea-ice conditions, including their extremes, is very important for ship navigation and offshore activities, and for monitoring of sea-ice processes and trends. We summarize here recent advances in the monitoring of sea-ice conditions and their extremes from satellite data as well as the development of sea-ice seasonal forecasting capabilities. Our results are the outcome of the three-year (2015–2018) SPICES (Space-borne Observations for Detecting and Forecasting Sea-Ice Cover Extremes) project funded by the EU’s Horizon 2020 programme. New SPICES sea-ice products include pancake ice thickness and degree of ice ridging based on synthetic aperture radar imagery, Arctic sea-ice volume and export derived from multisensor satellite data, and melt pond fraction and sea-ice concentration using Soil Moisture and Ocean Salinity (SMOS) radiometer data. Forecasts of July sea-ice conditions from initial conditions in May showed substantial improvement in some Arctic regions after adding sea-ice thickness (SIT) data to the model initialization. The SIT initialization also improved seasonal forecasts for years with extremely low summer sea-ice extent. New SPICES sea-ice products have a demonstrable level of maturity, and with a reasonable amount of further work they can be integrated into various operational sea-ice services.</jats:p

Toxicological Profile of Ultrapure 2,2 ',3,4,4 ',5,5 '-Heptachlorbiphenyl (PCB 180) in Adult Rats

Peer reviewe

Elektrodimallien vertailu mittausvirheen ja käyttömukavuuden perusteella Firstbeat Hyvinvointianalyysi -mittauksissa

Tutkimuksen tavoitteena oli selvittää Firstbeat Technologies Oy:n Hyvinvointianalyysi -mittauksissa käytettävien kolmen eri elektrodimallin (Ambu, Arbo ja Fiab) erot mittausvirheen ja käyttömukavuuden perusteella. Tämän selvityksen jälkeen elektrodit oli määrä saada paremmuusjärjestykseen neljässä eri osa-alueessa: alhaisin mittausvirheprosentti, vähiten ihoärsytystä mittausten aikana, paras kiinnipysyvyys mittauksien aikana ja paras mittalaitteen kiinnipysyvyys elektrodeissa mittauksien aikana. Alhaisin mittausvirheprosentti elektrodimalleissa oli Ambu -elektrodilla (3,68 %). Vähiten ihoärsytystä mittauksien aikana aiheutti Fiab -elektrodit (37,81 %:ssa mittauksista). Paras elektrodien pysyvyys mittauksien aikana oli Arbo -elektrodilla (81,91 %:ssa mittauksista) ja paras mittalaitteen pysyvyys elektrodeissa oli Ambu -elektrodeissa (89,16 %:ssa mittauksista. Tutkimuksen tulosten pohjalta luotiin elektrodisuositustaulukko eri elektrodimalleille mittaustilanteen mukaan. Jos asiakkaan perustietoja ei tunneta (ikä, pituus, paino, sukupuoli, jne.) suositellaan käytettäväksi Arbo -elektrodeja. Jos asiakkaan perustiedoista ei selviä erityistarpeita, naispuolisille suositellaan Fiab -elektrodeja ja miespuolisille Ambu -elektrodeja. Herkkäihoisille asiakkaille suositellaan Fiab -elektrodeja ja jos asiakas on urheilija tai muuten aktiivisesti liikkuva, hänelle suositellaan Ambu -elektrodeja.The main goal of this thesis was to investigate the differences in measurement artifact and usability between the three types of electrodes (Ambu, Arbo and Fiab) used in Firstbeat Technologies Ltd.’s Lifestyle Assessment measurements. After this research the electrodes were put in rank order in four categories: the lowest measurement artifact percent during the measurements, the least skin irritating electrode type, the best adherence to the skin and the best in holding the measurement device in the electrodes. Ambu electrodes had the lowest measurement artifact percent during the measurements(3,68 %) while Fiab caused the least skin irritation (37,81 % of the measurements). Arbu electrodes had the best adherence (81,91 % of the measurements) and Ambu electrodes held the device best (89,16 %) during the measurements. With the help of the results of this research, an electrode type recommendation table was created to help decide which type of an electrode should be used in different measuring situations. If a customer’s personal details are unknown(age, gender, weight, height, etc.) Arbo -electrodes should be used. If the customer does not have any special needs, females should use Fiab electrodes and males should use Ambu electrodes. If a customer has sensitive skin, Fiab electrodes should be used and if the customer is an athlete or otherwise active in sports, Ambu electrode should be used. Keywords/ Customer satisfaction, electrode, Firstbeat, heart rate variability, Lifestyle Assessment, measurement artifact, usabilit

Big maritime data for the Baltic Sea with a focus on the winter navigation system

The automatic identification system (AIS) has become a key element in maritime domains of inquiry and the number of related articles has increased rapidly. The systematic integration of AIS data with other datatypes has received less attention and has mostly resulted in application-specific datasets that are small relative to the available AIS data. This work presents an accumulating multi-purpose database for the northern Baltic Sea that combines nine years of AIS data with marine environmental data. The main application is winter navigation research, for which purpose the environmental data is from ice charts and ice drift models. The AIS data is from terrestrial stations and amounts to 6 billion messages. It has a full update rate which is also required for the analysis of ice navigation as this involves close encounters, icebreaker assistance, convoy operations, and rapid speed changes. To identify and study such traffic features, distances between ships that are close to each other are included in the database. Application examples are given for spatial traffic statistics, reduction of ship speed with increasing ice thickness, and for icebreaker assistance.Peer reviewe