Summer upwelling at the Boknis Eck time-series station (1982 to 2012) – a combined glider and wind data analysis

Karstensen, Johannes; Liblik, Taavi; Fischer, Jürgen; Bumke, Karl; Krahmann, Gerd

doi:10.5194/bg-11-3603-2014

Cited by 24 publications

(19 citation statements)

References 29 publications

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“…In general, wind conditions in the Baltic Sea region are dominated by westerlies [42] with south-westerly (SW), northerly (N), and north-easterly (NE) winds occurring most frequently over the entire Baltic Sea basin [43]. However, upwelling events are rather episodic here [44], varying in accordance with the local winds and coastline configuration. The N and NE winds are known to trigger coastal upwelling in the SE Baltic Sea, and in only in the northernmost part of Latvia and along the Polish coast it is favored by winds from other directions.…”

Section: Meteorological Conditions Prior To Upwelling Developmentmentioning

confidence: 99%

Remote Sensing of Coastal Upwelling in the South-Eastern Baltic Sea: Statistical Properties and Implications for the Coastal Environment

et al. 2018

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A detailed study of wind-induced coastal upwelling (CU) in the south-eastern Baltic Sea is presented based on an analysis of multi-mission satellite data. Analysis of moderate resolution imaging spectroradiometer (MODIS) sea surface temperature (SST) maps acquired between April and September of 2000-2015 allowed for the identification of 69 CU events. The Ekman-based upwelling index (UI) was applied to evaluate the effectiveness of the satellite measurements for upwelling detection. It was found that satellite data enable the identification of 87% of UI-based upwelling events during May-August, hence, serving as an effective tool for CU detection in the Baltic Sea under relatively cloud-free summer conditions. It was also shown that upwelling-induced SST drops, and its spatial properties are larger than previously registered. During extreme upwelling events, an SST drop might reach 14 • C, covering a total area of nearly 16,000 km 2 . The evolution of an upwelling front during such intensive events is accompanied by the generation of transverse filaments extending up to 70 km offshore. An analysis of the satellite optical data shows a clear decline in the chlorophyll-a concentration in the coastal zone and in the shallow Curonian Lagoon, where it drops down by an order of magnitude. It was also shown that a cold upwelling front alters the stratification in the atmospheric boundary layer, leading to a sudden drop of air temperature and near-surface winds.upwelling fronts also importantly modifies the vertical stratification and turbulent regime in the marine-atmosphere boundary layer (MABL), resulting in a change in the surface wind stress and direction in the coastal zone [3,9].Nutrient-rich waters brought up from deeper layers to the surface, particularly in the summer time, and the exposure of upwelled phytoplankton to surface radiation enhances the primary production and phytoplankton biomass during upwelling events [10,11], hence influencing the coastal pelagic communities and higher trophic levels [12]. Moreover, upwelling-related coastal ocean dynamics may eventually modify the spatial patterns of background algae blooms in the coastal zone by transporting them farther offshore.During the summer-time holiday season, CU might also have a negative impact on particular tourist areas as a result of a rapid drop in water and air temperatures near the shore [2]. Furthermore, bathing tourism depends on good water quality, while post-upwelling phytoplankton blooms might significantly reduce it, making coastal waters unattractive for recreation [13].The need to study coastal upwelling in the Baltic Sea is also essential in order to assess the regional variability of water and energy exchange, salinity dynamics, and the response of marine ecosystems to extreme events-some of the "Grand Challenges" of the Baltic Earth Science Plan [14], established in 2016. Thus, the upwelling phenomenon is indeed of certain interest to researchers, fishermen, and coastal managers [15]. The availability of wide spatial and temporal co...

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Section: Meteorological Conditions Prior To Upwelling Developmentmentioning

confidence: 99%

Remote Sensing of Coastal Upwelling in the South-Eastern Baltic Sea: Statistical Properties and Implications for the Coastal Environment

et al. 2018

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“…As can be deduced from the pressure fields constructed for each circulation pattern, mostly alongshore winds trigger upwelling, which is in line with the Ekman rule. However, upwelling can also be induced by the stress of normal to coastal seaward winds, as mentioned in several previous studies (Myberg and Andrejev 2003;Karstensen et al 2014;Krężel et al 2005).…”

Section: Conclusion and Discussionmentioning

confidence: 72%

Regional circulation patterns inducing coastal upwelling in the Baltic Sea

Bednorz

Półrolniczak

Tomczyk

2021

Theor Appl Climatol

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Atmospheric feedback involved in the occurrence of coastal upwelling in a small semi-enclosed sea basin, i.e., the Baltic Sea, was analysed, and the regional circulation conditions triggering upwelling in different coastal sections were identified. Upwelling in the summer season (June–August, years 1982–2017) was recognized on the basis of sea surface temperature patterns. Circulation conditions were defined using (1) the established daily indices of zonal and meridional airflow and (2) the synoptic situation at sea level distinguished by applying rotated principal component analysis to sea level pressure data. The 12 daily synoptic patterns differed substantially in the intensity and location of their pressure centres. The mean seasonal frequency of upwelling was generally higher along the western Baltic shores than along the meridionally oriented eastern shores and varied from less than 10 to over 30% along the more predestined coastal sections, i.e., the northwestern coast of the Gulf of Bothnia, the northern Gulf of Finland and the southern Swedish coast. Due to the variable orientations of coastlines, upwelling could occur under almost any prevailing wind direction, and thus, each of the classified synoptic patterns could induce upwelling in some coastal sections. As deduced from the pressure fields for each circulation pattern, mostly alongshore winds triggered upwelling, which is in line with the Ekman rule. With time, upwelling could also be induced by the stress of normal to the coastline seaward winds.

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“…As more ocean data and finer scale models become available there is a need of a more systemic view on short term underwater exchange processes in the Baltic Sea [1,4]. There is an increasing effort put into understanding of main ocean and atmospheric drivers that play role in generation of ocean parameters anomalies at different timescales [3].…”

Section: Discussionmentioning

confidence: 99%

“…On a shorter timescales coastal upwelling can contribute to the changing conditions, especially in shallow coastal areas of Baltic. It is demonstrated that such episodic processes drive reventilation of the bottom layers [4]. Apart from upwelling and inflow events there are other processes contributing to large changes of physicochemical parameters at multiple time scales.…”

Section: Introductionmentioning

confidence: 99%

Image Classification by Deep Neural Network of Event-Type Anomalies in The Southwestern Baltic Sea

Shchekinova

2020

OFOAJ

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In the paper we propose a binary classification method to identify episodes of anomalies in physicochemical parameters related to mixing and exchange of water masses. For training and validation of classifier we use high resolution time series from the Boknis Eck monitoring station in the southwestern Baltic Sea. To study the role of air ocean coupling, in addition to ocean parameters, we use high resolution wind speed observations from the Kiel lighthouse weather station. The detection accuracy of anomalies relies upon training of deep neural network on image data generated from historical data interval of ocean parameters. Our data driven analysis suggests strong causality between variations in atmospheric wind and ocean physiochemistry that underlies short term ocean exchange processes in the study area.

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Summer upwelling at the Boknis Eck time-series station (1982 to 2012) – a combined glider and wind data analysis

Cited by 24 publications

References 29 publications

Remote Sensing of Coastal Upwelling in the South-Eastern Baltic Sea: Statistical Properties and Implications for the Coastal Environment

Remote Sensing of Coastal Upwelling in the South-Eastern Baltic Sea: Statistical Properties and Implications for the Coastal Environment

Regional circulation patterns inducing coastal upwelling in the Baltic Sea

Image Classification by Deep Neural Network of Event-Type Anomalies in The Southwestern Baltic Sea

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