Introduction to the volume, and definition and use of the term ‘tectono-sedimentary element’

The present volume is rooted in a map of sedimentary successions of the Arctic Region by Grantz et al. (2011), and contains a brief, but comprehensive compilation of geological and geophysical data characterizing all significant sedimentary successions in the Arctic, which cover 57% of the polar area north of 64°N. Two main goals have been designated: (i) to provide, based on the present-day knowledge and data, a characterization of all Arctic sedimentary successions (or sedimentary accumulations), and (ii) to supply a snapshot of hydrocarbon-related exploration in the Arctic at the end of the second decade of this millennium. To achieve these goals, we represent sedimentary successions as consisting of one or several “Tectono-Sedimentary Elements” (TSE). This concept allows delineation, mapping, and characterization of 9 categories of TSEs based of main tectonic regimes that formed accommodation space.A TSE characterization template has been developed as an efficient method of organising and presenting the most important information about stratigraphy, structure, and petroleum geology of a TSE, including most significant exploration facts. This organizational architecture is the backbone of the volume and is a key feature that distinguishes it from other similar works about the sedimentary basins.

Comparative Taxonomic Study of Launaea Cass. (Asteraceae, Cichorioideae) in Egypt

Launaea is a polymorphic genus with inter- and intraspecific inconsistencies. The study aimed to revise the classification and identification of Launaea species in Egypt. The study also aimed to assess the inter- and intraspecific variation among taxa using macro- and micromorphological characters. Numerical analysis was carried out on 156 specimens, which were collected from 63 sites in Egypt. The results revealed that L. arabica, L. capitata, L. intybacea and L. spinosa were significantly (p-value < 2.2 × 10−16 ***) discriminated from the other species at a high dissimilarity level. Launaea acanthodes was correctly identified as Lactuca orientalis. The study supported the inclusion of L. intybacea, L. massauensis and L. nudicaulis within section Microrhynchus, the separation of L. angustifolia and L. arabica in two distinct species. Two biotypes of L. nudicaulis were morphologically differentiated. Launaea fragilis subsp. fragilis showed considerable plasticity and variability in various characters; therefore, L. tenuiloba was considered to be merely an ecotype of L. fragilis. Launaea mucronata comprises two subspecies; cassiniana and mucronata, differentiated by their pappus type, conspicuous secondary ribs of the inner achenes, and the number of spines on the polar area of pollen grains.

The Antarctic Seismographic Argentinean Italian Network (ASAIN): Recording Earthquakes in the Scotia Sea Region

The Antarctic Seismographic Argentinean Italian Network (ASAIN) is a permanent broadband seismic network that has operated since 1995 in the Scotia Sea region, the Antarctic peninsula, and the polar area. It was deployed and is managed in the framework of cooperation between the National Institute of Oceanography and Applied Geophysics and Dirección Nacional del Antártico–Instituto Antártico Argentino and is financially supported by the Programma Nazionale di Ricerca in Antartide. The network consists of seven seismological stations with broadband sensors. ASAIN provides data to Incorporated Research Institutions for Seismology, Observatories and Research Facilities for European Seismology, and GEOFOrschungsNetz. It improves the worldwide seismic networks’ detection capabilities and contributes to refining regional earthquake locations released by the U.S. Geological Survey. The proximity of the seismic stations to the Antarctic continent and their continuous operation in the long term also allows for having a privileged observatory on the ice-related seismicity along the Antarctica peninsula. In this article, we discuss the historical development of ASAIN, its current configuration, and the main characteristics of the seismic stations. Finally, we also provide information on the ASAIN data exchange and the contribution to the scientific research in Antarctica.

The change of MJO teleconnection under the global warming

&lt;p&gt;Global warming&amp;#8217;s impact on the Madden-Julian Oscillation (MJO) is assessed using one of the few models capable in reproducing its key features. In a warmer climate predicted for the end of the century, it has been proved the MJO increases in amplitude and frequency, showing a more circumglobal propagation tendency. Here, we examine the MJO teleconnection and its extratropical response under the warmer climate by the time-slide experiments. The extratropics impact on different phase is shifted through the change of the mean atmospheric circulation. The strengthening of the midlatitude jet stream leads to the zonal extended wave propagation. It results the stronger variability of the atmospheric river to the America west coast. Moreover, the relationship with the NAO and PNA is weaker but the stronger fluctuation is shown in the polar area. This suggests the teleconnection of the North America weather by the tropical convection is going to change in the warming climate. It is essential to consider in the further projection and subseasonal to seasonal forecast.&lt;/p&gt;

Monitoring Polar Sea Ice Using Optical and SAR Data

With the movement and destructiveness of sea ice, conventional in situ instruments are restricted or unavailable for polar sea ice observation. Satellite remote sensing is a feasible way to monitor sea ice in the polar area. Multispectral imaging spectrometer and synthetic aperture radar are applied to monitoring the sea ice in this article with high spatial resolution, wide swath, and continuous imaging. The sea ice distribution and motion can be measured by analyzing satellite remote sensing images. The image segmentation method is presented in the article to obtain the sea ice distribution. Meanwhile, the cross-correlation algorithm to extract sea ice motion is proposed as well as the processed vector results.

Systematic relevance of pollen morphology in tribe Hylocereeae (Cactaceae)

Hylocereeae is one of the nine tribes in the subfamily Cactoideae (Cactaceae), for which the limits and recognition of genera have been controversial. Essentially, this group comprises epiphytic and hemiepiphytic genera with stems modified as climbing structures. The aim of this paper is to examine pollen attributes in representative species of genera of Hylocereeae, focusing on Selenicereus whose current circumscription comprises Hylocereus and three Weberocereus species, to find whether significant potentially apomorphic and/or autapomorphic systematic characters can be discovered. Utilizing SEM and light microscopy, 25 pollen characters were observed and measured. Tribe Hylocereeae is stenopalynous, with pollen grains isopolar and radially symmetrical monads, mostly tricolpate, except in Kimnachia, Pseudoripsalis and Weberocereus, whose pollen grains are pantocolpate. Seven attributes (five qualitative and two continuous) exhibited useful variation and were coded. The character of brevicolpate pollen grains was shared by Kimnachia ramulosa and Pseudorhipsalis amazonica. Convex quadrangular outline in the polar view was shared by Weberocereus tunilla and S. glaber. The absence of spinules on the exine was shared by S. minutiflorus and S. stenopterus. The largest pollen grain, found in Selenicereus megalanthus, might be correlated with polyploidy. Selenicereus is the taxon with the highest variation in pollen attributes, including species with an exine with or without spinules and variable polar area index and shape (subprolate or oblate-spheroidal).

Observing Polar Regions from Space: Comparison between Highly Elliptical Orbit and Medium Earth Orbit Constellations

Continuous observation of polar regions from space remains an important unsolved technical challenge of great interest for the international meteorological community. This capacity would allow achieving global continuous coverage once combined with the geostationary (GEO) satellite network. From a practical point of view, continuous coverage of polar regions with a small number of spacecraft can be obtained from a constellation of satellites either in highly elliptical orbits (HEO) or in medium Earth orbits (MEO). The study compares HEO and MEO satellite constellations for their capacity to provide continuous imaging of polar regions as function of the viewing zenith angle (VZA) and evaluates the corresponding latitude limits that ensure sufficient overlap with GEO imagery. Earlier studies assumed the latitude boundary of 60° and the VZA range 70°–85° depending on the space mission focus: meteorological purposes or communications. From the detailed analysis of meteorological retrieval requirements, this study suggests that the overlap of the GEO and polar observing systems (HEO or MEO) should occur down to the latitude band 45°–50° with a maximum VZA ranging between 60° and 64°. This coverage requirement can be met with two sets of three-satellite HEO constellations (one for each polar area) or a six-satellite MEO constellation. The 12-h Molniya and 14-, 15-, and 16-h HEO systems have been analyzed and determined to meet these revised requirements. The study demonstrates that the six-satellite 24-h MEO system can provide a suitable solution, which is also beneficial from the point of view of ionizing radiation and image acquisition geometry. Among the HEO systems, the 16-h HEO has some advantages relative to other HEO systems from the point of view of spatial coverage and space radiation.