Argo Floats as a Novel Part of the Monitoring the Hydrography of the Bothnian Sea

We made an assessment of the hydrography in the Bothnian Sea based on data collected by the Argo floats during the first 6 years of operation in the Bothnian Sea (2012-2017). We evaluated the added value of Argo data related to the pre-existing monitoring data. The optimal usage and profiling frequency of Argo floats was also evaluated and the horizontal and vertical coverage of the profiles were assessed. For now we lose 4 m of data from the surface due to sensor design and some meters from the bottom because of the low resolution of available bathymetry data that is used to avoid bottom collisions. Mean monthly temperature and salinity close to surface and below halocline from the float data were within the boundaries given in literature, although some variation was lost due to scarcity of winter profiles. The temporal coverage of the Argo data is much better than that of ship monitoring, but some spatial variability is lost since the floats are confined in the over 100 m deep area of the Bothnian Sea. The possibility to adjust the float profiling frequency according to weather forecasts was successfully demonstrated and found a feasible way to get measurements from storms and other short term phenomena unreachable with research vessels. First 6 years of operation have shown that Argo floats can be successfully operated in the challenging conditions of the Bothnian Sea and they are shown to be an excellent addition to the monitoring network there. With multiple floats spread in the basin we can increase our general knowledge of the hydrographic conditions and occasionally get interesting data related to intrusions and mixing during high wind events and other synoptic scale events.Peer reviewe

Sea ice and related data sets from the Baltic Sea AICSEX : Metadata report

Julkaisu sisältää myös kolme muuta artikkelia: Kimmo K. Kahma, Heidi Pettersson & Laura Tuomi: Scatter diagram wave statistics from the northern Baltic Sea Matti Perttilä (Editor): Assessment — State of the Gulf of Finland in 2002 Tapani Stipa, Morten Skogen, Ian Sehested Hansen, Anders Eriksen, Inga Hense, Anniina Kiiltomäki, Henrik Soiland & Antti Westerlund: Short-term effects of nutrient reductions in the North Sea and the Baltic Sea as seen by an ensemble of numerical model

Estimating Currents From Argo Trajectories in the Bothnian Sea, Baltic Sea

Argo floats have been used in the environmental monitoring of the very shallow Bothnian Sea, a sub-basin of the Baltic Sea, for 5 years as part of the Finnish Euro-Argo programme. The Bothnian Sea is so far considered to be an environmentally healthy part of the Baltic Sea because the deep waters of the basin are well-ventilated by inflowing oxygen-rich saltier and heavier surface layer waters of the Baltic Sea proper. Thus the deep water flow is of interest in the Bothnian Sea. In this study, we used Argo float data from six different long-term missions, from 111 to 512 days, to analyze the deep-water flow in the Bothnian Sea where no continuous monitoring of currents exist. We estimated mainly the flow below the expected halocline from the paths of the floats. We analyzed the movements statistically and estimated the error caused by the surface drift of the floats during their stay at the surface by using 3D hydrodynamic model results as reference data. Our results show a northward flowing resultant current in the deep trench of the Bothnian Sea. There seemed to be very little exchange between coastal zone and open-sea waters in deeper layers. The drifting speed of the floats in the deep layers of Bothnian Sea generally was around 2 cm/s but instantaneous speeds of up to 30 cm/s in the middle-layer (50 dbars) were observed. In the Bothnian Sea deep, the deep trench on the Finnish side of the Bothnian Sea, the vast majority of the observations showed deep currents from south to north, with the same average speed of around 2 cm/s but the instantaneous maximum was smaller at 13 cm/s. Our study indicates that the routine Argo float observations can be used to get information on the deep currents in the basin in addition to hydrographic observations.Peer reviewe

Circulation patterns in the Gulf of Finland from daily to seasonal timescales

We studied circulation patterns in the Gulf of Finland (GoF), an estuary-like sub-basin of the Baltic Sea. Circulation patterns in the GoF are complex and vary from season to season and year to year. Estuarine circulation in the gulf is heavily modified by many factors, such as wind forcing, topography and geostrophic effects. Based on a 7-year run of the NEMO 3D hydrodynamic model with a 500 m horizontal resolution, we analysed seasonal changes of mean circulation patterns. We found that there were clear seasonal differences in the circulation patterns in the GoF. Features that moved or changed direction from season to season were damped or hidden in the averages. To further study these differences, we also carried out a self-organising map (SOM) analysis of currents for several latitudinal sections. The results of the SOM analysis emphasised the estuary-like nature of the GoF. Circulation changed rapidly from normal estuarine circulation to reverse estuarine circulation. The dominant southwesterly winds supported the reversal of the estuarine circulation. Both normal and reversed estuarine circulation were roughly as common in our data. The SOM analysis also demonstrated how the long-term cyclonic mean circulation field and the average salinity field emerged from the interaction of normal and reversed estuarine circulation

First SMOS Sea Surface Salinity dedicated products over the Baltic Sea

1st ESA Ocean Science Cluster Collocation Meeting, 29 November - 2 December 202

Suomen merentutkimuksen ydinkysymykset - Merentutkimuslaitos suomalaisessa yhteiskunnassa

Julkaisu sisältää myös toisen artikkelin: Kimmo K. Kahma: Scientific impact of the Finnish Institute of Marine Research: a citation analysi

Immune-microbiota interaction in Finnish and Russian Karelia young people with high and low allergy prevalence

Background After the Second World War, the population living in the Karelian region was strictly divided by the "iron curtain" between Finland and Russia. This resulted in different lifestyle, standard of living, and exposure to the environment. Allergic manifestations and sensitization to common allergens have been much more common on the Finnish compared to the Russian side. Objective The remarkable allergy disparity in the Finnish and Russian Karelia calls for immunological explanations. Methods Young people, aged 15-20 years, in the Finnish (n = 69) and Russian (n = 75) Karelia were studied. The impact of genetic variation on the phenotype was studied by a genome-wide association analysis. Differences in gene expression (transcriptome) were explored from the blood mononuclear cells (PBMC) and related to skin and nasal epithelium microbiota and sensitization. Results The genotype differences between the Finnish and Russian populations did not explain the allergy gap. The network of gene expression and skin and nasal microbiota was richer and more diverse in the Russian subjects. When the function of 261 differentially expressed genes was explored, innate immunity pathways were suppressed among Russians compared to Finns. Differences in the gene expression paralleled the microbiota disparity. High Acinetobacter abundance in Russians correlated with suppression of innate immune response. High-total IgE was associated with enhanced anti-viral response in the Finnish but not in the Russian subjects. Conclusions and clinical relevance Young populations living in the Finnish and Russian Karelia show marked differences in genome-wide gene expression and host contrasting skin and nasal epithelium microbiota. The rich gene-microbe network in Russians seems to result in a better-balanced innate immunity and associates with low allergy prevalence.Peer reviewe

First regional SMOS Sea Surface Salinity products over the Baltic Sea: quality assessment and oceanographic added-value

European Geosciences Union (EGU) General Assembly, 19-30 Apr 2021.-- 2 pagesThe Baltic Sea is a strongly stratified semi-enclosed sea with a large freshwater supply from rivers, net precipitation and water exchange and high-saline water from the North Sea through the Kattegat Strait. In the Danish Straits the water exchange is hampered by bathymetric constraints , such as narrow and shallow sills, and by hydrodynamic restrictions, such as fronts and mixing. The shallow depth of the Baltic Sea (i.e. 54 m in average) yields to highly variable ocean dynamics controlled mainly by local atmospheric forcing. The water exchange between the Baltic Sea and the North Atlantic Ocean is restricted by the narrows and sills of the Danish Straits (i.e. via Kattergat Strait at the East of the Baltic Sea) and by different river outflows distributed across the Baltic Sea. The bottom water in the deep sub-basins is ventilated mainly by large perturbations, so-called major Baltic saltwater inflows. The occurrence of these events needs still further investigation. The description of the complex oceanographic conditions within the Baltic Sea in current model simulations could also be developed. Furthermore, model simulations of the Baltic Sea are constrained to the initialization of the model (i.e. parametrization of the initial surface atmospheric and ocean conditions). For this, the Earth Observation salinity measurements have a great potential to help in the understanding of the dynamics in the basin and to improve the regional models there. However, the Baltic Sea is one of the most challenging regions for the sea surface salinity (SSS) retrieval from satellite measurements. The available EO-based SSS products are quite limited over this region both in terms of spatio-temporal coverage and quality. This is mainly due to several technical limitations that strongly affect the satellite brightness temperatures (TB) measurements, particularly over semi-enclosed seas, such as the high contamination by Radio-Frequency Interferences (RFI) and the contamination close to land and ice edges. Besides, the sensitivity of TB to SSS changes is very low in cold waters and much larger errors are expected compared to temperate oceans. As a main result of the ESA Baltic+ Salinity Dynamics project (), a new regional SSS product derived from the measurements provided by the European Soil Moisture and Ocean Salinity (SMOS) mission has been developed. In this work, first, we describe briefly the enhanced algorithms used in the generation of SMOS SSS fields. Second, we show a complete quality assessment by comparing the satellite and the in situ salinity measurements. For this, we use in situ measurements provided by SeaDataNet and Helcom and Ferry box lines. Finally, we compare the satellite salinity measurements with the salinity fields provided by a model. We focus our analysis in two aspects: i) the description of the freswater fluxes coming from continental discharge and sea-ice melting; and ii) the capability of describing the dynamics of the saltier Atlantic water that enters into the basin through the Kattegat straitPeer reviewe

First SMOS Sea Surface Salinity dedicated products over the Baltic Sea

26 pages, 24 figures, 4 tables.-- Data availability: Access to the data is provided by the Barcelona Expert Center, through its FTP service. The DOI of the L3 product is https://doi.org/10.20350/digitalCSIC/13859 (González-Gambau et al., 2021a). The DOI of the L4 product is https://doi.org/10.20350/digitalCSIC/13860 (González-Gambau et al., 2021b). Seasonal averaged L4 SSS products are also available in the HELCOM catalogue (https://metadata.helcom.fi/geonetwork/srv/eng/catalog.search#/metadata/9d979033-1136-4dd1-a09b-7ee9e512ad14, BEC team, 2021b), and they can be visualized in the HELCOM Map and Data service (https://maps.helcom.fi/website/mapservice/?datasetID=9d979033-1136-4dd1-a09b-7ee9e512ad14, last access: 9 November 2021).-- This work is a contribution to the CSIC Thematic Interdisciplinary Platform TeledetectThis paper presents the first Soil Moisture and Ocean Salinity (SMOS) Sea Surface Salinity (SSS) dedicated products over the Baltic Sea. The SSS retrieval from L-band brightness temperature (TB) measurements over this basin is really challenging due to important technical issues, such as the land–sea and ice–sea contamination, the high contamination by radio-frequency interference (RFI) sources, the low sensitivity of L-band TB at SSS changes in cold waters, and the poor characterization of dielectric constant models for the low SSS range in the basin. For these reasons, exploratory research in the algorithms used from the level 0 up to level 4 has been required to develop these dedicated products. This work has been performed in the framework of the European Space Agency regional initiative Baltic+ Salinity Dynamics. Two Baltic+ SSS products have been generated for the period 2011–2019 and are freely distributed: the Level 3 (L3) product (daily generated 9 d maps in a 0.25∘ grid; https://doi.org/10.20350/digitalCSIC/13859, González-Gambau et al., 2021a) and the Level 4 (L4) product (daily maps in a 0.05∘ grid; https://doi.org/10.20350/digitalCSIC/13860, González-Gambau et al., 2021b)​​​​​​​, which are computed by applying multifractal fusion to L3 SSS with SST maps. The accuracy of L3 SSS products is typically around 0.7–0.8 psu. The L4 product has an improved spatiotemporal resolution with respect to the L3 and the accuracy is typically around 0.4 psu. Regions with the highest errors and limited coverage are located in Arkona and Bornholm basins and Gulfs of Finland and Riga. The impact assessment of Baltic+ SSS products has shown that they can help in the understanding of salinity dynamics in the basin. They complement the temporally and spatially very sparse in situ measurements, covering data gaps in the region, and they can also be useful for the validation of numerical models, particularly in areas where in situ data are very sparseThis work has been carried out as part of the Baltic+ Salinity Dynamics project (4000126102/18/I-BG), funded by the European Space Agency. It has been also supported in part by the Spanish R&D project INTERACT (PID2020-114623RB-C31), which is funded by MCIN/AEI/10.13039/501100011033. We also received funding from the Spanish government through the “Severo Ochoa Centre of Excellence” accreditation (CEX2019-000928-S)Peer reviewe