A review of last interglacial sea-level proxies in the western Atlantic and southwestern Caribbean, from Brazil to Honduras

We use a standardized template for Pleistocene sea-level data to review last interglacial (Marine Isotope Stage 5 – MIS 5) sea-level indicators along the coasts of the western Atlantic and southwestern Caribbean, on a transect spanning from Brazil to Honduras and including the islands of Aruba, Bonaire, and Curaçao. We identified six main types of sea-level indicators (beach deposits, coral reef terraces, lagoonal deposits, marine terraces, Ophiomorpha burrows, and tidal notches) and produced 55 standardized data points, each constrained by one or more geochronological methods. Sea-level indicators are well preserved along the Brazilian coasts, providing an almost continuous north-to-south transect. However, this continuity disappears north of the Rio Grande do Norte Brazilian state. According to the sea-level index points (discrete past position of relative sea level in space and time) the paleo sea-level values range from ∼ 5.6 to 20 m above sea level (a.s.l.) in the continental sector and from ∼ 2 to 10 m a.s.l. in the Caribbean islands. In this paper, we address the uncertainties surrounding these values. From our review, we identify that the coasts of northern Brazil, French Guiana, Suriname, Guyana, and Venezuela would benefit from a renewed study of Pleistocene sea-level indicators, as it was not possible to identify sea-level index points for the last interglacial coastal outcrops of these countries. Future research must also be directed at improving the chronological control at several locations, and several sites would benefit from the re-measurement of sea-level index points using more accurate elevation measurement techniques. The database compiled in this study is available in spreadsheet format at the following link: https://doi.org/10.5281/zenodo.5516444 (Version 1.02; Rubio-Sandoval et al., 2021).

UPDATES OF ‘AW3D30’ ALOS GLOBAL DIGITAL SURFACE MODEL IN ANTARCTICA WITH OTHER OPEN ACCESS DATASETS

In 2016, the first processing of the semi-global digital surface models (DSMs) utilizing all the archives of stereo imageries derived from the Panchromatic Remote sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS) was successfully completed. The dataset was freely released to the public in 30 m grid spacing as the ‘ALOS World 3D - 30m (AW3D30)’, which was generated from its original version processed in 5 m or 2.5 m grid spacing. The dataset has been updated since then to improve the absolute/relative height accuracies with additional calibrations. However, the most significant update that should be applied for improving the data usability is the filling of void areas, which correspond to approx. 10% of semiglobal coverage, mostly due to cloud covers. In 2020, we completed the filling process by using other open-access digital elevation models (DEMs) such as Shuttle Radar Topography Mission (SRTM) DEM, Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM (ASTER GDEM), ArcticDEM, etc., except for Antarctica. In this paper, we report on the filling process of the remaining voids in Antarctica by using other open-access DEMs such as Reference Elevation Model of Antarctica (REMA) DSM, TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X, TDX) 90m DEM, and ASTER GDEM to complete the void-free semi-global AW3D30 datasets.

EXPERIMENTAL STUDIES OF GEODETIC MONITORING ACCURACY OF UPPER SURFACE OF ENGINEERING OBJECTS AND CONSTRUCTIONS

The development of totally new methods for geodetic monitoring of engineering objects and con-structions in emergency state is a relevant scientific and technical task of geodesy. The results of such studies allow to ensure prompt and reliable data of the condition of a spatial object for the purpose of its safe exploitation. The article presents experimental studies of a quadcopter model according to the developed by the author method for geodetic monitoring of engineering objects and constructions based on the multi-agent system theory. The article describes the test model of quadcopter and mean square error calculation of elevation measurement in the laboratory conditions of the station. Based on the experiment results the article makes the conclusion about the possibility of measurement by the described method. The suggested method is possible in situations when measurements by man are im-possible and the object of geo-monitoring is an inaccessible place.

Analysis of abnormal expansion of pipe system and optimization of structural stress in 350MW unit

A 350MW power plant main steam and reheat hot steam pipe subsidence occurred in part of the pipe section, through field inspection, calculation and checking analysis, combined with pipeline support and hanger adjustment, load testing and elevation measurement and other means, the settlement of the pipe system to optimize the overall stress state of the pipe system. Through the thermal displacement of the pipe system support lifting point, the selection and calculation of the pipe system support hanger and the overall design state stress check of the pipe system, the design state is basically consistent with the check state. Through to the key node load tests have shown that small spring hanger selection is the primary cause of section settling, combined with the spring adjustment space and calculation results are part of the hanger. Finally, the settlement of pipeline is realized, main steam pipe at the same time a stress and secondary stress were achieved about 15% of the decline, piping stress has been further optimized.

Late Roman Forest in the Delta of the River Po (Italy): Remote Sensing and 3D Maps Computation for Palaeoenvironmental Reconstruction

Literary and historical sources provide information about Late Roman forests in the Delta of the River Po, in the district of Ferrara (Italy), between Vicus Aventiae (Voghenza), Sandalo, Gambulaga, Caput Gauri (Codigoro) and Castrum Cumiacli (Comacchio). Toponymy, archaeological excavations and geoarchaeological studies support the palaeoenvironmental reconstruction of this land. In this work, after a brief examination of the ancient texts, we are going to introduce some new data concerning archaeobotanical evidence, detected by remote sensing in combination with direct surveys (on land and underwater). On the technical side, we are going to present a geomatic application for underwater measurements of ancient trunks related to discoveries in the palaeo-watercourses of the River Po (geomatic measurements, thanks to remote sensing surveys, allows us to have detailed length and diameters of trunks and trees, which are not always visible and detectable while diving) together with some satellite elevation measurement of the river banks and 3D map supported by geocomputation. Thanks to botanical data, we are able to illustrate the local context of the paleoenvironmental/archaeological sites, offering a reconstruction of the landscape and of the use of the wood.

Feasibility study of high-precision trigonometric elevation replacing second-order level in tunnel penetration control survey

Based on the principle of trigonometric elevation measurement and the law of error propagation, the trigonometric elevation formula is derived in this paper. The factors that cause the trigonometric measurement error are analyzed accurately. It is considered that the use of a high-precision total station for the trigonometric elevation measurement under opposite conditions can reach the second-order level measurement accuracy.

The Improvement and application of elevation measurement method with total station

In this paper, by analyzing the limitations of the traditional trigonometric elevation method, and on the basis of establishing a mathematical model of trigonometric elevation, a convenient and fast trigonometric elevation method without instrument height and prism height is improved, and the operation steps of the method are introduced in detail. The accuracy analysis was evaluated and the method was applied to actual engineering. The results show that under the premise of ensuring the measurement accuracy, this method not only reduces the range of measurement error sources, but also improves the measurement efficiency.