Monitoring land subsidence induced by groundwater change using satellite gravimetry and radar interferometry measurements. Case study: Surabaya city, Indonesia

Land subsidence is considered a potential hazard often occurring in densely populated urban areas due to increasing freshwater demands from groundwater pumping. The Gravity Recovery and Climate Experiment (GRACE) satellite gravimetry combined with Sentinel 1 interferometric satellite radar measurement has provided the possibility to monitor land subsidence induced by groundwater change. This study monitored land subsidence induced by groundwater change through satellite observations over Surabaya City, Indonesia, from 2014 to 2019. Persistent Scattered InSAR (PSInSAR) measurement was used to monitor land subsidence by using 114 SLC pairs. As for the groundwater perspective, Global Land Data Assimilation System (GLDAS v.2.2), which contains the Groundwater Storage Anomaly (GWS) derived from GRACE satellite observation, was used to understand groundwater’s spatial and temporal variation. The results show a satisfactory agreement of satellite radar measurement with ground measurement (R = 0.96, RMSE = 4.92cm), while satellite gravimetry measurement showed reasonably good agreement with radar measurement as well (R = 0.25). Regarding the magnitude and occurrence of land subsidence over Surabaya City, the result shows that, over the past 5 years, the southern part of the city had the highest subsidence ranging from -10 mm/year to -40 mm/year. Therefore, the results conclude the capability of both satellite gravimetry and radar measurements to monitor land subsidence over an urban area. Thus, this information could be considered as an important decision-making process for disaster management purposes.

Use of X-Band Radars to Monitor Small Garbage Islands

The aim of this work is to verify and demonstrate the possibility of using X-band radars to identify, discriminate, characterize and follow small floating aggregations of marine litter (Small Garbage Islands—SGIs) made up mainly of plastic debris. To this end, a radar measurement campaign was carried out on a series of controlled releases into the sea of SGI modules assembled in the lab using the waste collected along a beach near the port of Livorno, in Tuscany, where the X-band radar of the Institute of Bioeconomy (IBE) of the National Research Council (CNR) is installed. The results of this first measurement campaign, which are illustrated in this preliminary work, are of interest to the entire scientific community that operates in the field of macroplastics analysis and monitoring, opening a new experimental avenue for the use of X-band radars also to monitor plastic waste at sea. Furthermore, the results obtained suggest good prospects for the use of X-band radars also for the study of coastal hydrodynamics on a local scale as well as in areas where it would be difficult to carry out measurements employing other technologies.

Crowded Space: A Review on Radar Measurements for Space Debris Monitoring and Tracking

Space debris monitoring is nowadays a priority for worldwide space agencies, due to the serious threat that these objects present. More and more efforts have been made to extend the network of available radar systems devoted to the control of space. A meticulous review has been done in this paper, in order to find and classify the considerable amounts of data provided by the scientific community that deal with RADAR measurement for the debris monitoring and tracking. The information gathered is organized based on the volume of found data and classified taking into account the geographical location of the facilities.

Design of a New Technology to Evaluate the Rocket Forecast Path of a Real-Time Object Under a Multi-Dimensional Graphic Scheme

This article provides a quick and precise algorithm for improving the accuracy of the ballistic path forecast. In order to assess projectile approach corners in every measurement moment the algorithm is focused on the six degree freedom path rules (6DOF). The algorithm uses DFP to fix the nonlinear equations and Doppler trajectory sample data comprising the projectile only location cords to rebuild the linear data. The radar data can therefore be obtained via the projectile. At the end of the radar measurement, “position coordinates of the test” and “angular reconstruction displacements” serve as the initial value for the track calculation for the extrapolation of the path impact. The numerical simulations validate the technique suggested and show that the projected effect value is very consistent with the actual technique. Moreover, other algorithm artillery trajectory can be anticipated, and the suggested algorithm can also be used with other trajectory designs such as 4DOF or 5DOF.