scholarly journals Multi-sensor in situ observations to resolve the sub-mesoscale in the stratified Gulf of Finland, Baltic Sea

2016 ◽  
Author(s):  
U. Lips ◽  
V. Kikas ◽  
T. Liblik ◽  
I. Lips
Keyword(s):  
High Resolution ◽  
Coastal Upwelling ◽  
Spatiotemporal Variability ◽  
Gulf Of Finland ◽  
High Resolution Data ◽  
Temperature Variance ◽  
Ocean Upper Layer ◽  
Mesoscale Processes ◽  
The Gulf Of Finland

Abstract. High-resolution numerical modelling, remote sensing and in situ data have revealed significant role of submesoscale features in shaping the distribution pattern of tracers in the ocean upper layer. However, in situ measurements are difficult to conduct with the required resolution and coverage in time and space to resolve the sub-mesoscale, especially in such relatively shallow basins as the Gulf of Finland where the typical baroclinic Rossby radius is 2–5 km. In order to map the multi-scale spatiotemporal variability in the gulf, we initiated continuous measurements with autonomous devices, including a moored profiler and ferrybox system, which were complemented by dedicated research vessel based surveys. The analysis of collected high-resolution data in summers 2009–2012 revealed pronounced variability at the sub-mesoscale in the presence of mesoscale upwelling/downwelling, fronts and eddies. The horizontal wavenumber spectra of temperature variance in the surface layer had slopes close to −2 between the lateral scales from 10 to 0.5 km. Similar tendency towards the −2 slopes of horizontal wavenumber spectra of temperature variance was found in the seasonal thermocline between the lateral scales from 10 to 1 km. It suggests that the ageostrophic sub-mesoscale processes could contribute considerably to the energy cascade in such stratified sea basin. We showed that the intrusions of waters with different salinity, which indicate the occurrence of layered flow structure, could appear in the process of upwelling/downwelling development and relaxation in response to variable wind forcing. We suggest that the sub-mesoscale processes play a major role in feeding surface blooms in the conditions of coupled coastal upwelling and downwelling events in the Gulf of Finland.

scholarly journals Multi-sensor in situ observations to resolve the sub-mesoscale features in the stratified Gulf of Finland, Baltic Sea

Ocean Science ◽  
2016 ◽  
Vol 12 (3) ◽  
pp. 715-732 ◽  
Author(s):  
Urmas Lips ◽  
Villu Kikas ◽  
Taavi Liblik ◽  
Inga Lips
Keyword(s):  
High Resolution ◽  
Coastal Upwelling ◽  
Spatiotemporal Variability ◽  
Gulf Of Finland ◽  
High Resolution Data ◽  
Temperature Variance ◽  
Seasonal Thermocline ◽  
Mesoscale Processes ◽  
The Gulf Of Finland

Abstract. High-resolution numerical modeling, remote sensing, and in situ data have revealed significant role of sub-mesoscale features in shaping the distribution pattern of tracers in the ocean's upper layer. However, in situ measurements are difficult to conduct with the required resolution and coverage in time and space to resolve the sub-mesoscale, especially in such relatively shallow basins as the Gulf of Finland, where the typical baroclinic Rossby radius is 2–5 km. To map the multi-scale spatiotemporal variability in the gulf, we initiated continuous measurements with autonomous devices, including a moored profiler and Ferrybox system, which were complemented by dedicated research-vessel-based surveys. The analysis of collected high-resolution data in the summers of 2009–2012 revealed pronounced variability at the sub-mesoscale in the presence of mesoscale upwelling/downwelling, fronts, and eddies. The horizontal wavenumber spectra of temperature variance in the surface layer had slopes close to −2 between the lateral scales from 10 to 0.5 km. Similar tendency towards the −2 slopes of horizontal wavenumber spectra of temperature variance was found in the seasonal thermocline between the lateral scales from 10 to 1 km. It suggests that the ageostrophic sub-mesoscale processes could contribute considerably to the energy cascade in such a stratified sea basin. We showed that the intrusions of water with different salinity, which indicate the occurrence of a layered flow structure, could appear in the process of upwelling/downwelling development and relaxation in response to variable wind forcing. We suggest that the sub-mesoscale processes play a major role in feeding surface blooms in the conditions of coupled coastal upwelling and downwelling events in the Gulf of Finland.

High-resolution dynamics of the spring bloom in the Gulf of Finland of the Baltic Sea

2014 ◽  
Vol 129 ◽  
pp. 135-149 ◽  
Author(s):  
Inga Lips ◽  
Nelli Rünk ◽  
Villu Kikas ◽  
Aet Meerits ◽  
Urmas Lips
Keyword(s):  
High Resolution ◽  
Baltic Sea ◽  
Spring Bloom ◽  
Gulf Of Finland ◽  
The Baltic Sea ◽  
The Baltic ◽  
The Gulf Of Finland

scholarly journals Primary production calculations for sea ice from bio-optical observations in the Baltic Sea

Elem Sci Anth ◽  
2016 ◽  
Vol 4 ◽  
Author(s):  
Susann Müller ◽  
Anssi V. Vähätalo ◽  
Jari Uusikivi ◽  
Markus Majaneva ◽  
Sanna Majaneva ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Sea Ice ◽  
Primary Production ◽  
Baltic Sea ◽  
Gulf Of Finland ◽  
Radiative Transfer Model ◽  
Quantum Yields ◽  
Transfer Model ◽  
The Gulf Of Finland

Abstract Bio-optics is a powerful approach for estimating photosynthesis rates, but has seldom been applied to sea ice, where measuring photosynthesis is a challenge. We measured absorption coefficients of chromophoric dissolved organic matter (CDOM), algae, and non-algal particles along with solar radiation, albedo and transmittance at four sea-ice stations in the Gulf of Finland, Baltic Sea. This unique compilation of optical and biological data for Baltic Sea ice was used to build a radiative transfer model describing the light field and the light absorption by algae in 1-cm increments. The maximum quantum yields and photoadaptation of photosynthesis were determined from 14C-incorporation in photosynthetic-irradiance experiments using melted ice. The quantum yields were applied to the radiative transfer model estimating the rate of photosynthesis based on incident solar irradiance measured at 1-min intervals. The calculated depth-integrated mean primary production was 5 mg C m–2 d–1 for the surface layer (0–20 cm ice depth) at Station 3 (fast ice) and 0.5 mg C m–2 d–1 for the bottom layer (20–57 cm ice depth). Additional calculations were performed for typical sea ice in the area in March using all ice types and a typical light spectrum, resulting in depth-integrated mean primary production rates of 34 and 5.6 mg C m–2 d–1 in surface ice and bottom ice, respectively. These calculated rates were compared to rates determined from 14C incorporation experiments with melted ice incubated in situ. The rate of the calculated photosynthesis and the rates measured in situ at Station 3 were lower than those calculated by the bio-optical algorithm for typical conditions in March in the Gulf of Finland by the bio-optical algorithm. Nevertheless, our study shows the applicability of bio-optics for estimating the photosynthesis of sea-ice algae.

scholarly journals Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007–2013

2015 ◽  
Vol 12 (6) ◽  
pp. 2863-2898 ◽  
Author(s):  
V. Kikas ◽  
U. Lips
Keyword(s):  
Baltic Sea ◽  
Coastal Area ◽  
Coastal Upwelling ◽  
Gulf Of Finland ◽  
Maximum Temperature ◽  
Time Interval ◽  
Temperature Deviation ◽  
Average Temperature ◽  
Average Wind ◽  
The Gulf Of Finland

Abstract. Ferrybox measurements are carried out between Tallinn and Helsinki in the Gulf of Finland (Baltic Sea) in a regular basis since 1997. The system measures autonomously water temperature, salinity, chlorophyll a fluorescence and turbidity and takes water samples for further analyses at a pre-defined time interval. We aimed to show how the Ferrybox technology could be used to study the coastal upwelling events in the Gulf of Finland. Based on the introduced upwelling index and related criterion, 33 coastal upwelling events were identified in May–September 2007–2013. The number of events as well as frequency of their occurrence and intensity, expressed as a sum of daily average temperature deviations in the 20 km wide coastal area, were almost equal near the northern and southern coast. It is shown that the wind impulse needed to generate upwelling events of similar intensity differ between the two coastal areas whereas this difference is related to the average wind forcing in the area. Two types of upwelling events were identified – one characterized by a strong temperature front and the other revealing gradual decrease of temperature from the open to coastal area with maximum temperature deviation close to the shore.

The link between the drop scale, high resolution measurements and precipitation estimates at the catchment scale

2021 ◽  
Author(s):  
Luca G. Lanza ◽  
Arianna Cauteruccio
Keyword(s):  
High Resolution ◽  
Spatiotemporal Variability ◽  
Precipitation Process ◽  
Monitoring Networks ◽  
Catchment Scale ◽  
Rainfall Process ◽  
Precipitation Measurement ◽  
Precipitation Estimates ◽  
Source Of Information

<p>In-situ liquid precipitation measurements are the essential source of information about the rainfall process, its spatiotemporal variability, and the expected frequency of intense events. Other sources are remote sensors or the measurement of hydrologically connected variables, such as the water flow in rivers or evaporation, but all these only provide indirect estimates of precipitation. Notwithstanding the advantage of allowing areal estimates, they still require accompanying in-situ measurements for calibration or validation purposes.</p><p>The accuracy of in-situ precipitation measurements, though understated in most research studies and hydrological applications, is imperative to substantiate both scientific achievements and decision making. Unfortunately, due to budgetary shortages and other priorities, the managers of monitoring networks rarely address accuracy and traceability issues to a significant extent, and measurements are performed at a much lower level of accuracy than the current scientific knowledge and technological development would actually permit.</p><p>The neglected precipitation measurement biases propagate through the applications or the modelling chain and their awareness is often rapidly lost, together with the reliability of the obtained results. The comparability and homogeneity of precipitation estimates and their hydrological consequences between different studies is also questionable.</p><p>High-resolution measurements, even down to the scale of the single drop, are the way to achieve better knowledge of the precipitation process and to raise the confidence of users in the accuracy of their basic source of information. In this work, based on the most recent results in precipitation measurement studies, we aim at demonstrating that the accuracy of catchment scale rainfall and snowfall estimates rely on the interpretation of high-resolution raw data from traditional sensors and on the knowledge of the drop size distribution and other microphysical parameters of the rainfall process. Drop scale measurements must be accurate as well, and this is still an open issue for the currently available disdrometers.</p>

The use of high-resolution bathymetry for circulation modelling in the Gulf of Finland

2010 ◽  
Vol 16 (3) ◽  
pp. 187 ◽  
Author(s):  
O Andrejev ◽  
A Sokolov ◽  
T Soomere ◽  
R Värv ◽  
B Viikmäe
Keyword(s):  
High Resolution ◽  
Gulf Of Finland ◽  
High Resolution Bathymetry ◽  
The Gulf Of Finland

scholarly journals Comparison of analytical methods used for measuring major ions in the EPICA Dome C (Antarctica) ice core

2002 ◽  
Vol 35 ◽  
pp. 299-305 ◽  
Author(s):  
Geneviève C. Littot ◽  
Robert Mulvaney ◽  
Regine Röthlisberger ◽  
Roberto Udisti ◽  
Eric W. Wolff ◽  
...  
Keyword(s):  
High Resolution ◽  
Ion Chromatography ◽  
Major Ions ◽  
Full Range ◽  
Ice Core ◽  
Flow Analysis ◽  
Ice Cores ◽  
High Resolution Data ◽  
Wide Range

AbstractIn the past, ionic analyses of deep ice cores tended to consist of a few widely spaced measurements that indicated general trends in concentration. the ion-chromatographic methods widely used provide well-validated individual data, but are time-consuming. the development of continuous flow analysis (CFA) methods has allowed very rapid, high-resolution data to be collected in the field for a wide range of ions. In the European Project for Ice Coring in Antarctica (EPICA) deep ice-core drilling at Dome C, many ions have been measured at high resolution, and several have been analyzed by more than one method. the full range of ions has been measured in five different laboratories by ion chromatography (IC), at resolutions of 2.5–10 cm. In the field, CFA was used to measure the ions Na+, Ca2+, nitrate and ammonium. Additionally, a new semi-continuous in situ IC method, fast ion chromatography (FIC), was used to analyze sulphate, nitrate and chloride. Some data are now available to 788 m depth. In this paper we compare the data obtained by the three methods, and show that the rapid methods (CFA and FIC) give an excellent indication of trends in ionic data. Differences between the data from the different methods do occur, and in some cases these are genuine, being due to differences in speciation in the methods. We conclude that the best system for most deep ice-core analysis is a rapid system of CFA and FIC, along with in situ meltwater collection for analysis of other ions by IC, but that material should be kept aside for a regular check on analytical quality and for more detailed analysis of some sections.

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