The summary of research activities concerning general theory and methodology performed in Poland in the period of 2015–2018 is presented as a national report for the 27th IUGG (International Union of Geodesy and Geophysics) General Assembly. It contains the results of research on new or improved methods and variants of robust parameter estimation and their application, especially to control network analysis. Reliability analysis of the observation system and an integrated adjustment approach are also given. The identifiability (ID) index as a new measure for minimal detectable bias (MDB) in the observation system of a network, has been introduced. A new method of covariance function parameter estimation in the least squares collocation has been developed. The robustified version of the Shift-Msplit estimation, termed as Shift-M*split estimation, which enables estimation of parameter differences (robustly), without the need of prior estimation of the parameters, has been introduced. Results on the analysis of geodetic time series, particularly Earth orientation parameter time series, geocenter time series, permanent station coordinates and sea level variation time series are also provided in this review paper. The entire bibliography of related works is provided in the references.

This paper presents the numerical solution to the unsteady natural convection problem in micropolar fluid in the vicinity of a vertical plate, heat flux of which rises suddenly at a given moment. In order to solve this problem the method of finite differences was applied. The numerical results have been presented for a range of values of the dimensionless material properties and fluid Prandtl number. The analysis of the results shows that the intensity of the heat transfer in micropolar fluid is lower compared to the Newtonian fluid.

An axially symmetric, gravity driven, steady flow of a grounded polar ice sheet with a prescribed temperature field is considered.

The ice is treated as an incompressible, non-linearly viscous, anisotropic fluid, the internal structure (fabric) of which evolves as ice descends from the free surface to depth in an ice sheet. The evolution of the ice fabric is described by an orthotropic constitutive law which relates the deviatoric stress to the strain-rate, strain, and three structure tensors based on the current (rotating) principal stretch axes. The solution of the problem is constructed as a leading-order approximation derived from asymptotic expansions in a small parameter that reflects the small ratio of stress and velocity gradients in the lateral direction of the ice sheet to those in the thickness direction. Numerical simulations of the flow problem have been carried out for various sets of rheological parameters defining the limit strength of the anisotropic fabric in ice. The results of calculations illustrate the influence of the ice anisotropy, basal melt conditions and temperature field in ice on the glacier thickness and lateral span, and on the depth profiles of the flow velocity.

The Long March-2F rocket was launched on 15 September 2016 from the Jiuquan Satellite Launch Centre in China, carrying the Tiangong-2 space laboratory. The laboratory is fitted with the detector of the POLAR experiment, which was prepared jointly with Polish scientists.

Ice constitutes physically, but not legally, a separate element of polar regions, alongside with land, water and air. Lack of clear legal regulations in this respect compells the practitioners to apply often inadequate analogies. The specific status of polar permanent and floating ice calls for urgent and comprehensive legal regulation under general international law, the law of the sea and the law of polar regions, on the ground of the principle of Arctic sectors in the Northern Hemisphere and the Antarctic Treaty System in the Southern Hemisphere, with reference to the relatively rich legal doctrine, discussed in detail below.

A. B. Dobrowolski, a member of the Belgian expedition in Belgica to West Antarctica (1897-1899), after his return home became a strong supporter of Polish scientific activity in the Polar countries. His patronage - called by him the "Polar Action", was especially well marked during organization of three Polish expeditions to the Svalbard archipelago: to Bear Island during the 2nd Polar Year, 1932-33 and to Spitsbergen in 1934 and 1938. Apart from his scientific achievements in Antarctica, Dobrowolski was also widely known as an author of popular-scientific books on history of discovery and exploration in the Arctic and the Antarctic.

Polar stations became subject of keen interest of law-makers as the most effective manifestation of human activities in Antarctica. Legal procedures governing the establishment and regulations on operation and decommission of Antarctic stations are presented in this paper.

Petiole bending in detached leaves of Bryophyllum calycinum was intensively investigated in relation to polar auxin transport in petioles. When detached leaves were placed leaf blade face down, clear petiole bending was observed. On the other hand, no petiole bending was found when detached leaves were placed leaf blade face up. Indole-3-acetic acid (IAA) exogenously applied to petioles was significantly effective to induce and/or stimulate petiole bending when detached leaves were placed leaf blade face down. To clarify the mechanisms of petiole bending in detached leaves of B. calycinum when they were placed leaf blade face down, the effects of application of IAA, ethephon which is an ethylene releasing compound, inhibitors of polar auxin transport such as 2,3,5-tiiodobenzoic acid (TIBA), N-1-naphthylphthalamic acid (NPA) and 9-hydroxyfluorene-9-carboxylic acid (HFCA) and methyl jasmonate (JA-Me) were thoroughly investigated. Ethephon was not effective to enhance petiole bending, suggesting that ethylene derived from exogenously applied IAA does not play an important role in petiole bending in detachd leaves of B. calycinum. This suggestion was strongly supported by the fact that ethephon exogenously applied to petioles in intact plant of B. calycinum had no effect on inducing epinasty and/or hyponasty either (Ueda et al., 2018). Potent inhibitors of polar auxin transport, TIBA and HFCA, and JA-Me were extremely effective to inhibit petiole bending but NPA was not. Almost no petiole bending was observed in excised petiole segments without the leaf blade. Applicaton of IAA to the cut surface of petioles in the leaf blade side strongly promoted petiole bending. Polar auxin transport in excised petioles of B. calycinum was intensively investigated using radiolabeled IAA ([1-14C] IAA). Clear polar auxin transport was observed in excised petiole segments, indicating that auxin allows movement in one direction: from the leaf blade side to the stem side in petioles. When detached leaves were placed only leaf blade face down, transported 14C-IAA was reduced in the lower side of the excised petioles. These results strongly suggest that transport and/or lateral movement of endogenous auxin biosynthesized or produced in the leaf blade are necessary to induce petiole bending in detached leaves of B. calycinum. Mechanisms of petiole bending in detached leaves of B. calycinum are also discussed in relation to polar auxin transport and lateral movement of auxin.

The polarized electromagnetic waves have significant impact on the performance of adaptive antenna arrays. In this paper we investigate the effect of polarized desired and undesired signals on the performance of electronically steered beam adaptive antenna arrays. To achieve this goal, we built an analytical signal model for the adaptive array, in order to analyze, and compare the effect of polarized signals on the output SINRs (signal to interference plus noise ratios) of single-dipole, and cross-dipole adaptive antenna arrays. Based on a proof-of-concept experiment, and on MATLAB simulation results, it will be shown that cross-dipole adaptive antenna arrays exhibit better performance in comparison with single-dipole adaptive antenna arrays in presence of randomly polarized signals. However, single-dipole arrays show better performance under certain operating conditions.

Results from anthropometric measurements and examinations of physical fitness of the candidates for the Polish Polar Expeditions from 1976 till 1980 are presented. The authors suggest the necessity of introducing fixed norms of physical fitness in medical qualification of the candidates for polar expeditions.

In the paper, an extended analysis of the polarization properties of a liquid crystal cell with a biconically tapered single-mode telecommunication optical fiber was presented. These properties are a result of a sample geometry and used LC materials. They were analyzed by using two theoretical models based on the matrix decomposition methods, i.e., polar and singular-value one. By measuring Mueller matrices, information about losses, depolarization, dichroism and birefringence was obtained. In the experiment two types of tested samples filled with well-known 6CHBT and E7 liquid crystals were prepared and all optical parameters were shown as the voltage dependence. The tested samples have dichroic properties and for both models calculated PDL is similar and it increases from 2.6 to 6.6 dB for E7 and from 0.4 to 2.7 dB for 6CHBT with voltage changes within the range of 40 – 190 V. Optical losses simultaneously decrease from 30 dB to 27 dB and from 36 dB to 28 dB, respectively. The birefringence properties cannot be directly comparable due to differences between both applied models but voltage fluctuations of these parameters are not significant. These results confirm expected dichroic properties of designed device and complete knowledge about its working principles. Moreover, presented analysis validates usefulness of the singular-value decomposition model applied to dichroic optical fiber elements.

Spectral characteristics and amplitude tunability of a long period grating with a dual- resonance inside fiber loop mirror are studied in terms of applied stress caused by elongation. Inserting the polarization controller between grating and part of polarization maintaining fiber in the loop structure enables tuning of resonance and interferometric peaks. The maximum sensitivity of demonstrated sensor is of 1.943 dB/mε for the range of 1.1–4.4 mε. Combination of these two optical components allows to measure strain in a wider range comparing with sensors based on standard long period grating.

Analytical relations, describing the electrical fields of cylindrical piezoceramic radiators with circular polarization as a member of the cylindrical systems with the baffle in the inner cavity, using the related fields method in multiply connected regions were obtained. Comparative analysis of the results of numerical experiments performed on the frequency characteristics of the electric field of the radiating systems for different modes of radiation allow to establish a number of subtle effects of the formation of the electric field of radiators.