Comparative Studies for the Assessment of the Quality of Near-Real-Time GPS-Derived Atmospheric Parameters

Abstract Accurate and frequent sampling of atmospheric parameters, such as water vapor, is important for enabling reliable weather forecasts and global climate studies over a wide range of spatial and temporal scales. Recent developments in global positioning system data processing have allowed the estimation of zenith total delay (ZTD), the delay of the neutral atmosphere, with a high degree of accuracy using continuously operating GPS networks. From this delay integrated water vapor can be derived by means of additional meteorological information, in particular observed pressure or numerical weather prediction model pressure. Comparisons with other independent techniques must be performed to evaluate the quality of atmospheric parameters directly estimated or retrieved from the GPS system. In this work the accuracy of GPS atmospheric parameter, namely, zenith total delay, delivered in near–real time from a European ground-based network of permanent GPS receivers has been assessed. It is compared to other GPS solutions, radiosonde profiles, and High-Resolution Limited-Area Model (HIRLAM)-derived ZTD. Intercomparisons between results from different GPS analysis centers in the framework of the Targeting Optimal Use of GPS Humidity Measurements in Meteorology (TOUGH) project show a mean ZTD station bias at the level of ±6 mm with a related standard deviation of about 7–8 mm. In the comparison with radiosondes, an overall ZTD bias of about 7 mm with a standard deviation of 9 mm is detected. Finally, the comparison of ZTD near–real time against the HIRLAM models has an average bias of about −4.8 mm and a standard deviation of 11.5 mm

smart Emergency Response System (smartERS) – the Oil Spill use case

Thanks to the huge progress within the last 50 years in Earth Observation, Geospatial science and ICT technology, mankind is facing, for the first time, the opportunity to effectively respond to natural and artificial emergencies such as: earthquake, flood, oil spill, etc. Responding to an emergency requires to find, access, exchange, and of course understand many types of geospatial information provided by several types of sensors. Majors oil spills emergencies as, the Gulf of Mexico (Macondo/Deepwater Horizon) in 2010, the sinking of the oil tanker Prestige in 2002, have offered lessons learned and identified challenges to be addressed. Interoperability provides the principles and technologies to address those challenges. Since years interoperability has been developing based on traditional Service Oriented Architecture, request/response communication style, and implemented through Spatial Data Infrastructures. The experience handling oil spill responses shows that emergency services based on SDIs have some limitations, mainly due to their real-time peculiarity. Moreover despite the effort that Private Sector and Public Administration have been putting since years, the goal to provide an exhaustive picture of the situation during an Emergency Response is still far to be reached. We argue that to achieve this goal, we have to frame the problem in a different way. Emergency Response is not just sensing; it should be smart enough to encompass intelligent actions such as, automatically and dynamically acquire context driven information. The gaol of this paper is to define what a “smart Emergency Response System” (smartERS) should be.JRC.G.3-Maritime affair

Lessons for radar: Waveform diversity in echolocating mammals

Copyright © 2008 IEEEEcholocating mammals such as bats, whales and dolphins have been using waveform diversity for over 50 million years. Synthetic systems such as sonar and radar have existed for fewer than 100 years. Given the extraordinary capability of echolocating mammals it seems self-evident that designers of radar (and sonar) systems may be able to learn lessons that may potentially revolutionize current radar-based capability leading to truly autonomous navigation, collision avoidance, and automatic target classification. Echolocating mammals have been little studied in relation to the operation of radar and sonar systems. In this article, we introduce a range of strategies employed by bats and consider how these might be exploitable in the radar systems of tomorrow. Specifically, we concentrate on the functions necessary for autonomous navigation. Echolocating mammals are known to vary their waveforms via modification to the pulse-repetition frequency (PRF), also known to biologists as pulse-repetition rate (PRR), power, and frequency content of their transmitted waveforms. This has enabled them to evolve highly sophisticated orientation techniques and the ability to successfully forage for food. Moreover, recent developments in technology mean that it is now possible to replicate these parametric variations in synthetic sensing systems such as radar and sonar.Michele Vespe, Gareth Jones and Chris J. Bake

Tidal modulation of plate motions

While mantle convection is a fundamental ingredient of geodynamics, the driving mechanism of plate tectonics remains elusive. Are plates driven only from the thermal cooling of the mantle or are there further astronomical forces acting on them? GPS measurements are now accurate enough that, on long baselines, both secular plate motions and periodic tidal displacements are visible. The now >20 year-long space geodesy record of plate motions allows a more accurate analysis of the contribution of the horizontal component of the body tide in shifting the lithosphere. We review the data and show that lithospheric plates retain a non-zero horizontal component of the solid Earth tidal waves and their speed correlates with tidal harmonics. High-frequency semidiurnal Earth's tides are likely contributing to plate motions, but their residuals are still within the error of the present accuracy of GNSS data. The low-frequency body tides rather show horizontal residuals equal to the relative motion among plates, proving the astronomical input on plate dynamics. Plates move faster with nutation cyclicities of 8.8 and 18.6 years that correlate to lunar apsides migration and nodal precession. The highfrequency body tides are mostly buffered by the high viscosity of the lithosphere and the underlying mantle, whereas low-frequency horizontal tidal oscillations are compatible with the relaxation time of the low-velocity zone and can westerly drag the lithosphere over the asthenospheric mantle. Variable angular velocities among plates are controlled by the viscosity anisotropies in the decoupling layer within the low-velocity zone. Tidal oscillations also correlate with the seismic release

Terrain modelling by kinematical GPS survey

This work presents the first results of an experiment aiming to derive a high resolution Digital Terrain Model (DTM) by kinematic GPS surveying. The accuracy of the DTM depends on both the operational GPS precision and the density of GPS samples. The operational GPS precision, measured in the field, is about 10cm. A Monte Carlo analysis is performed to study the dependence of the DTM error on the sampling procedure. The outcome of this analysis is that the accuracy of the topographic reconstruction is less than 1m even in areas with a density of samples as low as one sample per 100m², and becomes about 30cm in areas with at least one sample per 10m². The kinematic GPS technique gives a means for a fast and accurate mapping of terrain surfaces with an extension of a few km². Examples of application are the investigation of archaeological sites and the stability analysis of landslide prone areas

High resolution map of migrants in the EU

This report describes a data set generated from the harmonization and spatial processing of official census statistics collected from National Statistical Institutes in 8 EU Member States (France, Germany, Ireland, Italy, Netherlands, Portugal, Spain and UK). The dataset provides a map at high spatial resolution of the population with migrant background in these Member States. The uniqueness of the data set resides both the high level of spatial resolution (cells of 100 by 100 m) and the large geographical coverage which is including almost 45 thousand local administrative units. From this data set it is possible to calculate indicators of concentration of migrants, diversity and spatial residential segregation which can support comparative research and policies on the local aspect of the integration of migrants in the EU.JRC.E.6-Demography, Migration and Governanc