scholarly journals Evaluation of the heat balance components over the Baltic Sea using four gridded meteorological databases and direct observations

2005 ◽  
Vol 36 (4-5) ◽  
pp. 381-396 ◽  
Author(s):  
A. Rutgersson ◽  
A. Omstedt ◽  
Y. Chen

In this paper, which reports on part of the BALTEX project, various components of the heat balance over the Baltic Sea are calculated using a number of gridded meteorological databases. It is the heat exchange between the Baltic Sea surface and the atmosphere that is of interest. The databases have different origins, comprising synoptic data, data re-analysed with a 3D assimilation system, an ocean model forced with gridded synoptic data, ship data and satellite data. We compared the databases and found that the greatest variation between them is in the long- and short-wave radiation values. However, considerable upward long-wave radiation is followed by considerable downward short-wave radiation, so the total radiation component is partly compensated for in the total budget. The variation in the total heat transport in the databases therefore appears smaller (1.5±3 W m−2) as the average and one standard deviation. The turbulent heat fluxes estimated from satellite data have very low values; this can largely be explained by the method of calculating air temperature, which also produces an unrealistic stratification over the Baltic Sea. The ERA40 data was compared with measured values: there, we found a certain land influence even in the centre of the Baltic proper. The indicated turbulent heat fluxes were too large, mainly in the fall and winter, and the sensible heat flux was too large in a downward direction in spring and summer.

1966 ◽  
Vol 6 (44) ◽  
pp. 267-287 ◽  
Author(s):  
C. M. Platt

AbstractMeteorological observations were made on Lewis Glacier, Mount Kenya, during the “long rains” in April 1960. General meteorological observations indicated rather similar conditions to those found in other months. Ablation occurred on each day but amounts were generally small. Rather more accumulation occurred than is expected during the dry season, but again amounts were small. The net accumulation over a to day period was only 0.38 cm. water-equivalent, although about 30 cm. new snow (about 10 cm. water-equivalent) was lying when the expedition arrived. Detailed observations of short-wave radiation, temperature, wind and humidity with estimates of long-wave radiation were used to calculate the heat balance at the surface of the upper ablation region. Agreement between calculated and measured ablation was reasonably good. Over the periods considered, radiation accounted for 89.5 per cent of ablation, turbulent exchange from the air for 8.0 per cent and evaporation for 2.5 per cent. Subsurface melting was taken into account and the formation of ice bands in terms of such melting is discussed.


2001 ◽  
Vol 99 (1) ◽  
pp. 53-84 ◽  
Author(s):  
Anna Rutgersson ◽  
Ann-Sofi Smedman ◽  
Anders Omstedt

2015 ◽  
Vol 22 (3) ◽  
pp. 43-49 ◽  
Author(s):  
Mirosława Ostrowska ◽  
Mirosław Darecki ◽  
Adam Krężel ◽  
Dariusz Ficek ◽  
Kazimierz Furmańczyk

Abstract The SatBałtyk (Satellite Monitoring of the Baltic Sea Environment) project is being realized in Poland by the SatBałtyk Scientific Consortium, specifically appointed for this purpose, which associates four scientific institutions: the Institute of Oceanology PAN in Sopot - coordinator of the project, the University of Gdańsk (Institute of Oceanography), the Pomeranian Academy in Słupsk (Institute of Physics) and the University of Szczecin (Institute of Marine Sciences). The project is aiming to prepare a technical infrastructure and set in motion operational procedures for the satellite monitoring of the Baltic Sea ecosystem. The main sources of input data for this system will be the results of systematic observations by metrological and environmental satellites such as TIROS N/NOAA, MSG (currently Meteosat 10), EOS/AQUA and Sentinel -1, 2, 3 (in the future). The system will deliver on a routine basis the variety of structural and functional properties of this sea, based on data provided by relevant satellites and supported by hydro-biological models. Among them: the solar radiation influx to the sea’s waters in various spectral intervals, energy balances of the short- and long-wave radiation at the Baltic Sea surface and in the upper layers of the atmosphere over the Baltic, sea surface temperature distribution, dynamic states of the water surface, concentrations of chlorophyll a and other phytoplankton pigments in the Baltic waters, spatial distributions of algal blooms, the occurrence of coastal upwelling events, and the characteristics of primary production of organic matter and photosynthetically released oxygen in the water and many others. The structure of the system and preliminary results will be presented.


2021 ◽  
Author(s):  
C. Dutheil ◽  
H. E. M. Meier ◽  
M. Gröger ◽  
F. Börgel

AbstractThe Baltic Sea is one of the fastest-warming semi-enclosed seas in the world over the last decades, yielding critical consequences on physical and biogeochemical conditions and on marine ecosystems. Although long-term trends in sea surface temperature (SST) have long been attributed to trends in air temperature, there are however, strong seasonal and sub-basin scale heterogeneities of similar magnitude than the average trend which are not fully explained. Here, using reconstructed atmospheric forcing fields for the period 1850–2008, oceanic climate simulations were performed and analyzed to identify areas of homogenous SST trends using spatial clustering. Our results show that the Baltic Sea can be divided into five different areas of homogeneous SST trends: the Bothnian Bay, the Bothnian Sea, the eastern and western Baltic proper, and the southwestern Baltic Sea. A classification tree and sensitivity experiments were carried out to analyze the main drivers behind the trends. While ice cover explains the seasonal north/south warming contrast, the changes in surface winds and air-sea temperature anomalies (along with changes in upwelling frequencies and heat fluxes) explain the SST trends differences between the sub-basins of the southern part of the Baltic Sea. To investigate future warming trends climate simulations were performed for the period 1976–2099 using two RCP scenarios. It was found that the seasonal north/south gradient of SST trends should be reduced in the future due to the vanishing of sea ice, while changes in the frequency of upwelling and heat fluxes explained the lower future east/west gradient of SST trend in fall. Finally, an ensemble of 48 climate change simulations has revealed that for a given RCP scenario the atmospheric forcing is the main source of uncertainty. Our results are useful to better understand the historical and future changes of SST in the Baltic Sea, but also in terms of marine ecosystem and public management, and could thus be used for planning sustainable coastal development.


1966 ◽  
Vol 6 (44) ◽  
pp. 267-287 ◽  
Author(s):  
C. M. Platt

AbstractMeteorological observations were made on Lewis Glacier, Mount Kenya, during the “long rains” in April 1960. General meteorological observations indicated rather similar conditions to those found in other months. Ablation occurred on each day but amounts were generally small. Rather more accumulation occurred than is expected during the dry season, but again amounts were small. The net accumulation over a to day period was only 0.38 cm. water-equivalent, although about 30 cm. new snow (about 10 cm. water-equivalent) was lying when the expedition arrived. Detailed observations of short-wave radiation, temperature, wind and humidity with estimates of long-wave radiation were used to calculate the heat balance at the surface of the upper ablation region. Agreement between calculated and measured ablation was reasonably good. Over the periods considered, radiation accounted for 89.5 per cent of ablation, turbulent exchange from the air for 8.0 per cent and evaporation for 2.5 per cent. Subsurface melting was taken into account and the formation of ice bands in terms of such melting is discussed.


Author(s):  
V. F. Dubravin ◽  
M. V. Kapustina ◽  
Zh. I. Stont

Based hydrometeorological data of the MARNET monitoring network, with the sampling interval of 1-hour, from 2003—2016, provided by the German Oceanographic Data Centre (BSH / DOD (M41)), the contributions of the irregular daily variability, the regular daily variability, the synoptic variability, the irregular intra-annual variability, the regular seasonal variability and the interannual component in the total temporal variability of the sensible and latent heat fluxes were estimated. The intra-annual and inter-annual variability of the specific contribution of the daily component of the sensible and latent heat fluxes are computed. It is shown that the structure of time variations of the fluxes in the southern part of the Baltic Sea depends on both, the station location and the nature of the flux itself.


2020 ◽  
Author(s):  
Tatiana Bukanova ◽  
Irina Chubarenko

<p>We examine three hypotheses of formation of waters of the Cold Intermediate Layer (CIL) in the Baltic Sea: the coldest baltic waters are formed (1) at the beginning of spring warming in the Arkona and Bornholm basins, (2) in the centers of mesoscale vortexes (similar to those in the Black Sea), and (3) in the convergence zones of alongshore fronts while cooling over shelves (as in the Mediterranean Sea).</p><p>In search of the coldest surface water we analyzed the dynamics of sea surface temperature (SST) in the Baltic Proper for February-April 2003-2019 from satellite imagery of infrared sensors (MODIS-Terra/Aqua and VIIRS-Suomi-NPP), and microwave sensors (AMSR-E-Aqua, AMSR-2-GCOM-W1, and WindSat-Coriolis).</p><p>Long-term mean SST maps (for February, March, April 2003-2019) show patterns that indicate rather quick, abrupt re-structuring of thermohaline fields in late March - early April, especially evident in the Arkona and Bornholm basins. This supports the idea that seasonal transfer from two-layered winter-time vertical water stratification to the summer-time three-layered stratification is driven in the Baltic Sea not by the direct heat fluxes through the surface, but rather by the large-scale north-south water exchange.</p><p>Coastal fronts may persist for a few weeks, however their location is changeable. Stable frontal zones and vortexes are not observed under long-term SST averaging. However the sequential warming of waters from south to north direction due to geographical reasons is clearly seen with long-term averaging.</p><p>The features of spring differential warming development above shallows and along shore can be observed only from daily SST maps (not from annually averaged maps).</p><p>Investigations are supported by the Russian Foundation for Basic Research, grant No. 19-05-00717 (in part of data analysis) and the State Assignment No 0149-2019-0013 (in part of satellite data collecting and processing).</p>


Boreas ◽  
2002 ◽  
Vol 31 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Christian Christiansen ◽  
Helmar Kunzendorf ◽  
Kay-Christian Emeis ◽  
Rudolf Endler ◽  
Ulrich Struck ◽  
...  

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