scholarly journals 100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

Ocean Science ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 617-632 ◽  
Author(s):  
Lauri Laakso ◽  
Santtu Mikkonen ◽  
Achim Drebs ◽  
Anu Karjalainen ◽  
Pentti Pirinen ◽  
...  
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Saline Water ◽  
Seawater Temperature ◽  
Ice Cover ◽  
Atmospheric Temperature ◽  
Research Station ◽  
The Baltic Sea ◽  
Marine Research ◽  
The Baltic

Abstract. The Utö Atmospheric and Marine Research Station introduced in this paper is located on Utö Island (59∘46.84′ N, 21∘22.13′ E) at the outer edge of the Archipelago Sea, by the Baltic Sea towards the Baltic Proper. Meteorological observations at the island started in 1881 and vertical profiling of seawater temperature and salinity in 1900. Since 1980, the number of observations at Utö has rapidly increased, with a large number of new meteorological, air quality, aerosol, optical and greenhouse gas parameters, and recently, a variety of marine observations. In this study, we analyze long-term changes of atmospheric temperature, cloudiness, sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality-assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO), major Baltic inflow (MBI) and Baltic Sea river runoff data from the literature as reference variables to our data. Our analysis is based on a statistical method utilizing a dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and has taken place only since the early 1980s, with a rate of 0.4 ∘C decade−1 during the last 35 years. We also see an increase in seawater temperatures, especially on the surface, with an increase of 0.3 ∘C decade−1 for the last 100 years. In deeper water layers, the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and freshwater inflow from rivers and by wind-driven processes influenced by the local bathymetry. The date when air temperature in the spring exceeds +5 ∘C became 5 days earlier from the period 1951–1980 to the period 1981–2010 and the date when sea surface water temperature exceeds +4 ∘C changed to 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö has changed into a new phase, in which the sea ice no longer reduces the local temperature increase caused by the global warming.

scholarly journals One hundred years of atmospheric and marine observations at Utö Island, the Baltic Sea

2018 ◽  
Author(s):  
Lauri Laakso ◽  
Santtu Mikkonen ◽  
Achim Drebs ◽  
Anu Karjalainen ◽  
Pentti Pirinen ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Water Temperature ◽  
Sea Water ◽  
Seawater Temperature ◽  
Ice Cover ◽  
Atmospheric Temperature ◽  
Research Station ◽  
The Baltic Sea ◽  
Marine Research ◽  
The Baltic

Abstract. Utö Atmospheric and Marine Research Station is located on Utö Island (59°46’50 N, 21°22’23 E) at the outer edge of the Archipelago Sea, Baltic Sea towards the Baltic Sea Proper. Meteorological observations at the island started in 1881 and vertical profiling of sea water temperature and salinity in 1900. In this study, we analyze long-term changes of atmospheric temperature, cloudiness and sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO) and Major Baltic Inflow (MBI) data from the literature as reference variables to our data. Our analysis is based on statistical method utilizing dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and takes place only since early 1980's, with a rate of 0.4 °C/decade during the last 35 years. We also see an increase on sea water temperatures, especially on the surface, with an increase of 0.3 °C/decade for the last 100 years. In deeper water layers the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and fresh water inflow. Date when air temperature in the spring exceeds +5 °C has become 5 days earlier from the period 1951–1980 to period 1981–2010 and date when sea surface water temperature exceed +4 °C has changed 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö may have changed into a new phase, in which ice do not reduce the local effects of global temperature increase.

scholarly journals Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea

Ocean Science ◽  
2011 ◽  
Vol 7 (2) ◽  
pp. 257-276 ◽  
Author(s):  
A. Herman ◽  
J. Jedrasik ◽  
M. Kowalewski
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Air Temperature ◽  
Ice Cover ◽  
Surface Fluxes ◽  
Rate Of Change ◽  
The Baltic Sea ◽  
Ice Dynamics ◽  
Ice Concentration ◽  
The Baltic

Abstract. In this paper, a numerical dynamic-thermo-dynamic sea-ice model for the Baltic Sea is used to analyze the variability of ice conditions in three winter seasons. The modelling results are validated with station (water temperature) and satellite data (ice concentration) as well as by qualitative comparisons with the Swedish Meteorological and Hydrological Institute ice charts. Analysis of the results addresses two major questions. One concerns effects of meteorological forcing on the spatio-temporal distribution of ice concentration in the Baltic. Patterns of correlations between air temperature, wind speed, and ice-covered area are demonstrated to be different in larger, more open sub-basins (e.g., the Bothnian Sea) than in the smaller ones (e.g., the Bothnian Bay). Whereas the correlations with the air temperature are positive in both cases, the influence of wind is pronounced only in large basins, leading to increase/decrease of areas with small/large ice concentrations, respectively. The other question concerns the role of ice dynamics in the evolution of the ice cover. By means of simulations with the dynamic model turned on and off, the ice dynamics is shown to play a crucial role in interactions between the ice and the upper layers of the water column, especially during periods with highly varying wind speeds and directions. In particular, due to the fragmentation of the ice cover and the modified surface fluxes, the ice dynamics influences the rate of change of the total ice volume, in some cases by as much as 1 km3 per day. As opposed to most other numerical studies on the sea-ice in the Baltic Sea, this work concentrates on the short-term variability of the ice cover and its response to the synoptic-scale forcing.

Modeling the impact of reduced sea ice cover in future climate on the Baltic Sea biogeochemistry

2013 ◽  
Vol 40 (1) ◽  
pp. 149-154 ◽  
Author(s):  
K. Eilola ◽  
S. Mårtensson ◽  
H. E. M. Meier
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Ice Cover ◽  
Future Climate ◽  
The Baltic Sea ◽  
The Baltic ◽  
The Impact

scholarly journals Multimodel estimates of the changes in the Baltic Sea ice cover during the present century

2014 ◽  
Vol 66 (1) ◽  
pp. 22617 ◽  
Author(s):  
Anna Luomaranta ◽  
Kimmo Ruosteenoja ◽  
Kirsti Jylhä ◽  
Hilppa Gregow ◽  
Jari Haapala ◽  
...  
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Ice Cover ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Sea ice in the Baltic Sea – revisiting BASIS ice, a historical data set covering the period 1960/1961–1978/1979

2014 ◽  
Vol 6 (2) ◽  
pp. 367-374 ◽  
Author(s):  
U. Löptien ◽  
H. Dietze
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Environmental Science ◽  
Set Covering ◽  
The Baltic Sea ◽  
Data Set ◽  
Marine Research ◽  
Joint Project ◽  
Finnish Meteorological Institute ◽  
The Baltic

Abstract. The Baltic Sea is a seasonally ice-covered, marginal sea in central northern Europe. It is an essential waterway connecting highly industrialised countries. Because ship traffic is intermittently hindered by sea ice, the local weather services have been monitoring sea ice conditions for decades. In the present study we revisit a historical monitoring data set, covering the winters 1960/1961 to 1978/1979. This data set, dubbed Data Bank for Baltic Sea Ice and Sea Surface Temperatures (BASIS) ice, is based on hand-drawn maps that were collected and then digitised in 1981 in a joint project of the Finnish Institute of Marine Research (today the Finnish Meteorological Institute (FMI)) and the Swedish Meteorological and Hydrological Institute (SMHI). BASIS ice was designed for storage on punch cards and all ice information is encoded by five digits. This makes the data hard to access. Here we present a post-processed product based on the original five-digit code. Specifically, we convert to standard ice quantities (including information on ice types), which we distribute in the current and free Network Common Data Format (NetCDF). Our post-processed data set will help to assess numerical ice models and provide easy-to-access unique historical reference material for sea ice in the Baltic Sea. In addition we provide statistics showcasing the data quality. The website http://www.baltic-ocean.org hosts the post-processed data and the conversion code. The data are also archived at the Data Publisher for Earth & Environmental Science, PANGAEA (doi:10.1594/PANGAEA.832353).

scholarly journals Sea ice in the Baltic Sea – revisiting BASIS ice, a~historical data set covering the period 1960/1961–1978/1979

2014 ◽  
Vol 7 (1) ◽  
pp. 419-440
Author(s):  
U. Löptien ◽  
H. Dietze
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Environmental Science ◽  
Data Bank ◽  
Set Covering ◽  
The Baltic Sea ◽  
Data Set ◽  
Marine Research ◽  
Joint Project ◽  
The Baltic

Abstract. The Baltic Sea is a seasonally ice-covered, marginal sea, situated in central northern Europe. It is an essential waterway connecting highly industrialised countries. Because ship traffic is intermittently hindered by sea ice, the local weather services have been monitoring sea ice conditions for decades. In the present study we revisit a historical monitoring data set, covering the winters 1960/1961. This data set, dubbed Data Bank for Baltic Sea Ice and Sea Surface Temperatures (BASIS) ice, is based on hand-drawn maps that were collected and then digitised 1981 in a joint project of the Finnish Institute of Marine Research (today Finish Meteorological Institute (FMI)) and the Swedish Meteorological and Hydrological Institute (SMHI). BASIS ice was designed for storage on punch cards and all ice information is encoded by five digits. This makes the data hard to access. Here we present a post-processed product based on the original five-digit code. Specifically, we convert to standard ice quantities (including information on ice types), which we distribute in the current and free Network Common Data Format (NetCDF). Our post-processed data set will help to assess numerical ice models and provide easy-to-access unique historical reference material for sea ice in the Baltic Sea. In addition we provide statistics showcasing the data quality. The website www.baltic-ocean.org hosts the post-prossed data and the conversion code. The data are also archived at the Data Publisher for Earth & Environmental Science PANGEA (doi:10.1594/PANGEA.832353).

scholarly journals Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea

2011 ◽  
Vol 8 (1) ◽  
pp. 113-157
Author(s):  
A. Herman ◽  
J. Jedrasik ◽  
M. Kowalewski
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Air Temperature ◽  
Ice Cover ◽  
Surface Fluxes ◽  
Rate Of Change ◽  
The Baltic Sea ◽  
Ice Dynamics ◽  
Ice Concentration ◽  
The Baltic

Abstract. In this paper, a numerical dynamic-thermodynamic sea-ice model for the Baltic Sea is used to analyze the variability of ice conditions in three winter seasons. The modelling results are validated with station (water temperature) and satellite data (ice concentration) as well as by qualitative comparisons with the Swedish Meteorological and Hydrological Institute ice charts. Analysis of the results addresses two major questions. One concerns effects of meteorological forcing on the spatio-temporal distribution of ice concentration in the Baltic. Patterns of correlations between air temperature, wind speed, and ice-covered area are demonstrated to be different in larger, more open sub-basins (e.g., the Bothnian Sea) than in the smaller ones (e.g., the Bothnian Bay). Whereas the correlations with the air temperature are positive in both cases, the influence of wind is pronounced only in large basins, leading to increase/decrease of areas with small/large ice concentrations, respectively. The other question concerns the role of ice dynamics in the evolution of the ice cover. By means of simulations with the dynamic model turned on and off, the ice dynamics is shown to play a crucial role in interactions between the ice and the upper layers of the water column, especially during periods with highly varying wind speeds and directions. In particular, due to the fragmentation of the ice cover and the modified surface fluxes, the ice dynamics influences the rate of change of the total ice volume, in some cases by as much as 1 km3 per day. As opposed to most other numerical studies on the sea-ice in the Baltic Sea, this work concentrates on the short-term variability of the ice cover and its response to the synoptic-scale forcing.

scholarly journals Operational SAR-based sea ice drift monitoring over the Baltic Sea

Ocean Science ◽  
2012 ◽  
Vol 8 (4) ◽  
pp. 473-483 ◽  
Author(s):  
J. Karvonen
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Vector Fields ◽  
Phase Correlation ◽  
The Baltic Sea ◽  
Sar Images ◽  
Envisat Asar ◽  
Ice Drift ◽  
Sea Ice Drift ◽  
The Baltic

Abstract. An algorithm for computing ice drift from pairs of synthetic aperture radar (SAR) images covering a common area has been developed at FMI. The algorithm has been developed based on the C-band SAR data over the Baltic Sea. It is based on phase correlation in two scales (coarse and fine) with some additional constraints. The algorithm has been running operationally in the Baltic Sea from the beginning of 2011, using Radarsat-1 ScanSAR wide mode and Envisat ASAR wide swath mode data. The resulting ice drift fields are publicly available as part of the MyOcean EC project. The SAR-based ice drift vectors have been compared to the drift vectors from drifter buoys in the Baltic Sea during the first operational season, and also these validation results are shown in this paper. Also some navigationally useful sea ice quantities, which can be derived from ice drift vector fields, are presented.

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