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Wåhlstrom, Irene
Alternative names
Publications (6 of 6) Show all publications
Edman, M., Eilola, K., Almroth-Rosell, E., Meier, M., Wåhlstrom, I. & Arneborg, L. (2018). Nutrient Retention in the Swedish Coastal Zone. Frontiers in Marine Science, 5, Article ID UNSP 415.
Open this publication in new window or tab >>Nutrient Retention in the Swedish Coastal Zone
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2018 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 5, article id UNSP 415Article in journal (Refereed) Published
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-5164 (URN)10.3389/fmars.2018.00415 (DOI)000457228900002 ()
Available from: 2019-02-12 Created: 2019-02-12 Last updated: 2019-02-12Bibliographically approved
Karlson, B., Eilola, K., Johansson, J., Linders, J., Mohlin, M., Willstrand Wranne, A. & Wåhlstrom, I. (2017). Distribution of cyanobacteria blooms in the Baltic Sea. In: Proenca, L. A. O. and Hallegraeff, G. (Ed.), Proenca, L. A. O. and Hallegraeff, G. (Ed.), Marine and Fresh-Water Harmful Algae.: . Paper presented at Proceedings of the 17th International Conference on Harmful Algae. (pp. 100-103). International Society for the Study of Harmful Algae Intergovernmental Oceanographic Commission of UNESCO
Open this publication in new window or tab >>Distribution of cyanobacteria blooms in the Baltic Sea
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2017 (English)In: Marine and Fresh-Water Harmful Algae. / [ed] Proenca, L. A. O. and Hallegraeff, G., International Society for the Study of Harmful Algae Intergovernmental Oceanographic Commission of UNESCO , 2017, p. 100-103Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
International Society for the Study of Harmful Algae Intergovernmental Oceanographic Commission of UNESCO, 2017
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-4477 (URN)978-87-990827-6-6 (ISBN)
Conference
Proceedings of the 17th International Conference on Harmful Algae.
Available from: 2018-01-24 Created: 2018-01-24 Last updated: 2018-01-24Bibliographically approved
Wåhlström, I., Eilola, K., Edman, M. & Almroth-Rosell, E. (2017). Evaluation of open sea boundary conditions for the coastal zone. A model study in the northern part of the Baltic Proper..
Open this publication in new window or tab >>Evaluation of open sea boundary conditions for the coastal zone. A model study in the northern part of the Baltic Proper.
2017 (English)Report (Other academic)
Abstract [en]

The environmental conditions in the coastal zone are strongly connected with the conditions in the open sea as the transports across the boundaries are extensive. Therefore, it is of critical importance that coastal zone models have lateral boundary forcing of high quality and required parameters with good coverage in space and time.

The Swedish Coastal zone Model (SCM) is developed at SMHI to calculate water quality in the coastal zone. This model is currently forced by the outcome from a one-dimensional model, assimilated to observations along the coast. However, these observations are scarce both in space, time and do usually not include all required parameters. In addition, the variability closer to the coast may be underestimated by the open sea monitoring stations used for the data assimilation. These problems are partly overcome by utilize the one-dimensional model that resolves all the variables used in the SCM. However, the method is not applicable for examine either the past period or future scenario where the latter analyze how climate change might affect the coastal zone. In the present study, we therefore evaluate the possibility to use results from a three-dimensional coupled physical and biogeochemical model of the Baltic Sea as open sea boundary conditions for the coastal zone, primarily to investigate the two periods mentioned above.

Seven sensitivity experiments have been carried out in a pilot area of the coastal zone, the northern part of the Baltic proper, including the Stockholm Archipelago. The sensitivity tests were performed in order to explore methods to extract the outcome from the three-dimensional model, RCO-SCOBI, and apply as lateral boundary forcing for the SCM. RCO-SCOBI is a model for the open Baltic Sea with high horizontal and vertical resolution of the required variables. The results from the different tests were examined and evaluated against observations in the coastal zone. This was executed for both the physical and the biogeochemical variables utilizing a statistical method.

The results from this study concluded that the outcome from the RCO-SCOBI is applicable as forcing files for the SCM. The best results in the tests was obtained with a method extracting depth profiles for the required variables from the RCO-SCOBI at a position 10 nautical miles to the east and 10 nautical miles to the south in the Baltic proper or north in the Gulf of Bothnia outside each of the outer basins.

Abstract [sv]

Miljötillståndet i Sveriges kustvatten är starkt kopplat till tillståndet i det öppna havet på grund av det stora vattenutbytet mellan dessa. Det är därför viktigt att modeller utvecklade för kustzonens vatten har drivning från utsjön av god kvalitet med bra täckning i tid och rum samt med information om de variabler som krävs.

För att beräkna vattenkvalitén i kustnära vatten har SMHI utvecklat en modell kallad kustzonsmodellen (SCM). Den drivs för närvarande från öppna havet av resultatfiler från en en-dimensionell modell som med hjälp av observationer har korrigerat och förbättrat modellresultaten. Tyvärr är dessa observationer undermåliga i tid och rum, och saknar nödvändiga variabler för att få bra drivning av SCM modellen. Dessa mätstationer ligger också längre ut i öppna havet och kan därför underskatta variabiliteten närmare kusten för de olika parametrarna. Dessa problem löses delvis med den en-dimensionella modellen som beräknar alla de variabler som är nödvändiga i SCM. Dock är dessa resultat inte användbara om man vill undersöka en historisk period eller framtida klimatförändringar i kustzonen. På grund av dessa tillkortakommanden undersöker vi i denna studie om det är möjligt att istället ersätta dagens drivning från öppna havet med resultat från en tre-dimensionell, kopplad fysisk och biogeokemisk modell för Östersjön som drivning för SCM, framförallt för att undersöka de två ovan nämnda perioder.

I denna studie har sju känslighetsexperiment utförts i en pilotstudie för Norra Östersjön, inklusive Stockholms skärgård. De sju känslighetsexperimenten utfördes för att utvärdera olika metoder att extrahera resultat-filer från den tre-dimensionella modellen RCO-SCOBI med avsikt att användas som drivning för SCM. RCO-SCOBI är en modell för Östersjön med hög horisontell och vertikal upplösning av de variabler som krävs. Resultaten för både de fysiska och biogeokemiska processerna från de olika testen undersöktes och utvärderades mot observationer i kustzonen med hjälp av en statistisk metod.

Slutsaten från dessa test är att resultatfiler från RCO-SCOBI är tillämpbara som utsjödrivning för SCM. Den bästa metoden är att extrahera en djupprofil per variabel för varje ytterbassäng i SCM i en punkt 10 nautiska mil österut och 10 nautiska mil söderut i egentliga Östersjön eller norrut i Bottenhavet för varje ytterbassäng i SCM.

Publisher
p. 23
Series
RO, Report Oceanography, ISSN 0283-1112 ; 55
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-3914 (URN)
Available from: 2017-01-25 Created: 2017-01-25 Last updated: 2018-01-13Bibliographically approved
Eilola, K., Lindqvist, S., Almroth-Rosell, E., Edman, M., Wåhlstrom, I., Bartoli, M., . . . Zilius, M. (2017). Linking process rates with modellingdata and ecosystem characteristics.
Open this publication in new window or tab >>Linking process rates with modellingdata and ecosystem characteristics
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2017 (English)Report (Refereed)
Abstract [en]

This report is related to the BONUS project “Nutrient Cocktails in COAstal zones of the Baltic Sea” alias COCOA. The aim of BONUS COCOA is to investigate physical, biogeochemical and biological processes in a combined and coordinated fashion to improve the understanding of the interaction of these processes on the removal of nutrients along the land-sea interface. The report is especially related to BONUS COCOA WP 6 in which the main objective is extrapolation of results from the BONUS COCOA learning sites to coastal sites around the Baltic Sea in general. Specific objectives of this deliverable (D6.4) were to connect observed process rates with modelling data and ecosystem characteristics.

In the report we made statistical analyses of observations from BONUS COCOA study sites together with results from the Swedish Coastal zone Model (SCM). Eight structural variables (water depth, temperature, salinity, bottom water concentrations of oxygen, ammonium, nitrate and phosphate, as well as nitrogen content in sediment) were found common to both the experimentally determined and the model data sets. The observed process rate evaluated in this report was denitrification. In addition regressions were tested between observed denitrification rates and several structural variables (latitude, longitude, depth, light, temperature, salinity, grain class, porosity, loss of ignition, sediment organic carbon, total nitrogen content in the sediment,  sediment carbon/nitrogen-ratio, sediment chlorphyll-a as well as bottom water concentrations of oxygen, ammonium, nitrate, and dissolved inorganic  phosphorus and silicate) for pooled data from all learning sites.

The statistical results showed that experimentally determined multivariate data set from the shallow, illuminated stations was mainly found to be similar to the multivariate data set produced by the SCM model. Generally, no strong correlations of simple relations between observed denitrification and available structural variables were found for data collected from all the learning sites. We found some non-significant correlation between denitrification rates and bottom water dissolved inorganic phosphorous and dissolved silica but the reason behind the correlations is not clear.

We also developed and evaluated a theory to relate process rates to monitoring data and nutrient retention. The theoretical analysis included nutrient retention due to denitrification as well as burial of phosphorus and nitrogen. The theory of nutrient retention showed good correlations with model results. It was found that area-specific nitrogen and phosphorus retention capacity in a sub-basin depend much on mean water depth, water residence time, basin area and the mean nutrient concentrations in the active sediment layer and in the water column.

Publisher
p. 56
Series
RO, Report Oceanography, ISSN 0283-1112 ; 61
Keywords
Coastal zone, Eutrophication, Biogeochemistry, Nutrient retention
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-4437 (URN)
Available from: 2017-12-04 Created: 2017-12-04 Last updated: 2018-01-13Bibliographically approved
Wåhlström, I., Dieterich, C., Pemberton, P. & Meier, M. (2016). Impact of increasing inflow of warm Atlantic water on the sea-air exchange of carbon dioxide and methane in the Laptev Sea. Journal of Geophysical Research - Biogeosciences, 121(7), 1867-1883
Open this publication in new window or tab >>Impact of increasing inflow of warm Atlantic water on the sea-air exchange of carbon dioxide and methane in the Laptev Sea
2016 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 121, no 7, p. 1867-1883Article in journal (Refereed) Published
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-3258 (URN)10.1002/2015JG003307 (DOI)000382581900011 ()
Available from: 2016-10-04 Created: 2016-10-04 Last updated: 2018-01-14Bibliographically approved
Wåhlstrom, I. & Meier, M. (2014). A model sensitivity study for the sea-air exchange of methane in the Laptev Sea, Arctic Ocean. Tellus. Series B, Chemical and physical meteorology, 66, Article ID 24174.
Open this publication in new window or tab >>A model sensitivity study for the sea-air exchange of methane in the Laptev Sea, Arctic Ocean
2014 (English)In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 66, article id 24174Article in journal (Refereed) Published
Abstract [en]

The ocean's sinks and sources determine the concentration of methane in the water column and by that regulating the emission of methane to the atmosphere. In this study, we investigate how sensitive the sea-air exchange of methane is to increasing/decreasing sinks and sources as well as changes of different drivers with a time-dependent biogeochemical budget model for one of the shallow shelf sea in the Siberian Arctic, the Laptev Sea. The applied changes are: increased air temperature, river discharge, wind, atmospheric methane, concentration of nutrients in the river runoff or flux of methane from the sediment. Furthermore, simulations are performed to examine how the large range in observations for methane concentration in the Lena River as well as the rate of oxidation affects the net sea-air exchange. In addition, a simulation with five of these changes applied together was carried out to simulate expected climate change at the end of this century. The result indicates that none of the simulations changed the seawater to becoming a net sink for atmospheric methane and all simulations except three increased the outgassing to the atmosphere. The three exceptions were: doubling the atmospheric methane, decreasing the rivers' concentration of methane and increasing the oxidation rate where the latter is one of the key mechanisms controlling emission of methane to the atmosphere.

Keywords
Arctic Ocean, Laptev Sea, methane, carbon, sea-air exchange, modelling
National Category
Oceanography, Hydrology and Water Resources
Research subject
Oceanography
Identifiers
urn:nbn:se:smhi:diva-140 (URN)10.3402/tellusb.v66.24174 (DOI)000343869400001 ()
Available from: 2015-04-09 Created: 2015-03-26 Last updated: 2018-01-11Bibliographically approved
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