Abstract:The assessment of climate dynamics and the impact of land drainage systems on lakeland blind drainage area was the problem studied in the paper. The research area was located based on relative stability of non-climatic physiographic characteristics and water management practices over a longer time-scale. Thus, the influence of non-climatic factors on water storage could be omitted. The study site was situated in Warmia region in the Dopływ spod Nowej Wsi catchment (27.53 km 2 ). One of local seepage ponds called Bagna Ramuckie within the aforementioned catchment was investigated. The study covered the time period since the first half of the 19 th century to the year 2005. The decisive factors affecting processes of increase and decrease of pond water surface area in considered spatial units were the trends of air temperature over the long time scale. It was indicated that natural enlargement of water surface area in the pond occurred after 40-years long period of air temperature decrease and the decline followed 20-year-long period of air temperature rise. Precipitation did not show any trends for long periods but typical cyclic changes of precipitation over a short time-scale. These pluvial cycles stimulated or destimulated processes of water surface changes additionally over short periods. The first episode of water surface decrease in the seepage pond occurred when air temperature rise trend coincided with intensive land drainage and changes in some land management patterns (the 2 nd half of the 19 th century). Nevertheless, during the 20 th century water management practices were rather stable and did not have any impact on rise or decline of seepage pond water surface area.
This paper presents the methodology of taking measurements of active surface energy balance components using the Bowen method. It discusses the applied measurement system, an important part of which are HMD 50U/50Y measurement sensors from Vaisala, adapted to work in the field. Their operation is a source of data for determining vertical profiles of temperature and water vapour pressure. These data are used to determine the turbulence components of the energy balance, i.e., sensible and latent heat. Measurements taken during the vegetative season on rape field showed that intensive evaporation occurred in the period until the end of June and that its decrease coincided with the decrease in the value of the degree of plant development determined on the basis of LAI records. In spring, during the period of intensive plant development, the decade sums of evaporation reached 30 mm, after which their quantities fell to the range of 10–15 mm. They became higher only in the periods of precipitation, when the water from the interception was available.
The potential absorption of solar energy in photovoltaic thermal (PVT) hybrid solar collectors at different tilt angles was compared in the present study. The optimal tilt angles were tested in three variants: during 1 day, 1 year and a period of 30 years. Simulations were performed based on actual weather data for 30 years, including average hourly total radiation, insolation and air temperature. The apparent movement of the Sun across the sky, solar radiation properties, and the electrical and thermal efficiency of a PVT collector were also taken into account in the simulation model. The optimal orientation of the absorber surface was determined by solving an optimization task. The results of the study indicate that in the long-term perspective, the collector’s performance is maximized when the absorber is positioned toward the south at an elevation angle of 34.1°.
The Wietrzychowice Cultural Park protects one of the last preserved megalithic barrows of the Funnel Beaker Culture people at the Kuyavia Lakeland (Central Poland). Archaeological excavations of the lake palaeolittoral zone were conducted on the nearby Karaśnia Lake shore. Numerous Mesolithic and Neolithic remains were excavated including: flint artefacts, potsherds, arrowheads, and mammal bones with traces of human processing. The SM9G2 core from the Śmieły site covers gyttias and peats with the Holocene history of Karaśnia Lake. The age-depth model is based on 3 AMS and 3 LSC radiocarbon dates as well as cultural remains. The bottom section of the core (275-190cm b.g.l.) includes the record of the early to mid-Holocene layers that fall on the Mesolithic and Neolithic in the region. The multi-proxy study (geochemistry, plant macrofossils, pollen, Mollusca, Cladocera and Chironomidae analyses) were conducted on the Mesolithic-Neolithic section of the core. Additionally, Chironomidae subfossil analysis was conducted on the SM1 core from another part of the Karaśnia Lake shore zone, documenting the mid-Holocene age of the lake littoral shore development.
The paper describes gap filling procedures for active surface heat balance structure data recorded for fields of rape, maize, spring and winter wheat and an apple orchard. The balance components were determined based on the Bowen ratio requiring direct measurements of net radiation, soil heat flux, temperature and water vapour pressure profiles. The latter is used to determine vertical gradients and the Bowen ratio, with sensible and latent heat fluxes calculated from the heat balance equation. Missing data are filled in from regression dependencies between individual balance components at various measurement sites. The regression data set comprised results recorded over 24 h, before the gap in measurements and after 24 h. Multiple regressions were determined from a 48-h measurement set. Regression was applied to establish missing values of net radiation (Rn), soil heat flux (G) and latent heat (LE), while sensible heat was calculated from the active surface heat balance equation. Relatively the greatest differences were found for latent heat and soil fluxes, with both estimated values deviating by 13% from the measured daily average, for net radiation the relative difference was 10% and for sensible heat -6%. This method successfully filled gaps in measured heat balance data from April to September.
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