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In-situ automatic observations of ice thickness of seas

100%

Dou Y. , Chang X.

Metrology and Measurement Systems

2012

tom Vol. 19, nr 3

583-592

Ice thickness is one of the most critical physical indicators in the ice science and engineering. It is therefore very necessary to develop in-situ automatic observation technologies of ice thickness. This paper proposes the principle of three new technologies of in-situ automatic observations of sea ice thickness and provides the findings of laboratory applications. The results show that the in-situ observation accuracy of the monitor apparatus based on the Magnetostrictive Delay Line (MDL) principle can reach š2 mm, which has solved the "bottleneck" problem of restricting the fine development of a sea ice thermodynamic model, and the resistance accuracy of monitor apparatus with temperature gradient can reach the centimeter level and research the ice and snow substance balance by automatically measuring the glacier surface ice and snow change. The measurement accuracy of the capacitive sensor for ice thickness can also reach š4 mm and the capacitive sensor is of the potential for automatic monitoring the water level under the ice and the ice formation and development process in water. Such three new technologies can meet different needs of fixed-point ice thickness observation and realize the simultaneous measurement in order to accurately judge the ice thickness.

Influence of climate change on the ice conditions of the Curonian Lagoon

86%

Jakimavičius D. , Šarauskienė D. , Kriaučiūnienė J.

Oceanologia

2020

tom No. 62 (2)

164-172

The Curonian Lagoon is a shallow freshwater lagoon of significant environmental value in the south-eastern part of the Baltic Sea. The objective of the study was to evaluate changes of ice indices (duration, thickness and breakup dates) of this lagoon and to assess their possible tendencies in the 21st century. A methodology was developed combining the assessment of past changes (1960-2017) of ice indices and their projections in the near (2021-2040) and far (2081-2100) future periods using a hydrometeorological database, statistical methods and regression analysis as well as regional climate models and RCP scenarios. Climate change has a considerable impact on ice conditions in the Curonian Lagoon. During the historical period of 1960-2017, the Curonian Lagoon was covered with ice for 72 days a year, ice thickness reached 23 cm, whereas ice breakup was observed in the middle of March on average. According to the different scenarios, in the near and far future periods, ice duration will last 35-45 and 3-34 days, respectively. Ice thickness is projected to be 13-15 cm in the near future, whereas, at the end of the century, it is expected to decline to 0-13 cm. In the past, the lagoon ice cover remained until the middle of the third decade of February. At the end of the 21st century, RCP8.5 scenario projects the most drastic shifts: the permanent ice cover might be absent, whereas short-term ice cover is expected to melt already in the beginning of January.

Phytoplankton diversity and biomass during winter with and without ice cover in the context of climate change

72%

Lenard T. , Wojciechowska W.

Polish Journal of Ecology

2013

tom 61

nr 4

Most scenarios of the predicted climate change in Europe imply that the increasing temperature trend will be maintained in winter seasons. The presence or absence of the ice cover in winter can impact on the functioning of lake ecosystems. The research was carried out in two mesotrophic and dimictic lakes in winter with and without ice cover. The biomass and phytoplankton and its composition was analysed with reference to physical factors (PAR and temperature). The research proved that poor thermal-light conditions under the ice/snow cover favoured the development of nanoplanktonic species from the genus Cryptomonas (Cryptophyta) or Stephanodiscus (Bacillariophyceae), whereas microplanktonic species of dinoflagellates, diatoms or green algae prevailed during the ice-free winter. The highest phytoplankton biomass and species richness were recorded during ice-free winter, which affected a higher Shannon-Wiener diversity index and evenness. It has been shown that the mild winter creates good conditions for the development of phytoplankton species characteristic for the mixing periods. The lack of inverse thermal stratification during winter can lead to disturbance in the functioning of the water ecosystems throughout the year.

AVHRR images as a tool in the analysis of marine suspended matter in Polar Region

51%

Krezel A.

Oceanological Studies

1997

tom 26

nr 2-3