Browsing by Author "Smith, R. G."
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Item Metadata only ACE2- Global Digital Elevation Model.(European Space Agency, 2010) Smith, R. G.; Berry, P. A. M.; Benveniste, J.Item Metadata only ACE2: the new global digital elevation model(Springer, 2010) Berry, P. A. M.; Smith, R. G.; Benveniste, J.Item Metadata only Analysis of EnviSat RA-2 burst echoes over lake surfaces.(European Space Agency, 2010) Witheridge, S.; Berry, P. A. M.; Smith, R. G.Item Metadata only An enhanced ocean and coastal zone retracking technique for gravity field computation.(Springer, 2010) Berry, P. A. M.; Freeman, Jennifer A.; Smith, R. G.Item Metadata only EnviSat altimetry for river and lakes monitoring(IEEE, 2012) Berry, P. A. M.; Smith, R. G.; Benveniste, J.Item Metadata only The ESA near real time river and lake system.(European Space Agency, 2009) Wheeler, J.; Benveniste, J.; Berry, P. A. M.; Smith, R. G.Item Metadata only Evaluation of the differences between the SRTM and satellite radar altimetry height measurements and the approach taken for the ACE2 GDEM in areas of large disagreement.(Royal Society of Chemistry, 2011) Smith, R. G.; Berry, P. A. M.Item Metadata only Global analysis of EnviSat Burst echoes over inland water.(2012-05) Berry, P. A. M.; Smith, R. G.; Benveniste, J.Satellite radar altimeters have an established and increasingly vital role in monitoring the Earth’s surface inland water resources. This paper analyzes two years of EnviSat burst echoes (which have 3.9-m nominal along-track separation) over rivers, lakes, and ephemeral water globally to assess the increase in monitoring potential afforded by the higher pulse repetition frequency (PRF) of the next generation of synthetic aperture radar altimeters and investigate spatial burst correlation. Burst echoes at 1800 Hz are successfully retracked with no waveform averaging. The conclusion is that the higher PRF allows detection and measurement of water bodies on a far finer spatial scale because water is a very bright reflector at Ku-band and land in general is relatively poor, with pools of water a few tens of meters across being successfully identified.Item Metadata only A global assessment of the EnviSat -RA2 performance over non-ocean surfaces.(European Space Agency, 2010) Berry, P. A. M.; Smith, R. G.Item Metadata only Global inland water monitoring from Satellite Radar Altimetry - A glimpse into the future.(European Space Agency, 2010) Berry, P. A. M.; Smith, R. G.; Witheridge, S.; Wheeler, J.Item Metadata only Inland water monitoring from multi-mission Satellite Radar Altimetry- current status and future capability(European Space Agency, 2009) Berry, P. A. M.; Wheeler, J.; Smith, R. G.Item Metadata only Lake volume change by drainage basin from Satellite Radar Altimetry.(European Space Agency, 2009) Chamelo, P.; Berry, P. A. M.; Smith, R. G.Item Metadata only Near-global validation of the SRTM DEM using satellite radar altimetry(IEEE, 2007-01-01) Berry, P. A. M.; Garlick, J. D.; Smith, R. G.Item Metadata only Rainforest canopy mapping - A unique snapshot from the new GDEM, ACE2(European Space Agency, 2010) Smith, R. G.; Berry, P. A. M.Item Metadata only Real-time remote sensing driven river basin modeling using radar altimetry.(Copernicus Publications, 2011) Pereira-Cardenal, S. J.; Riegels, N. D.; Berry, P. A. M.; Smith, R. G.; Yakovlev, A.; Siegfried, T. U.; Bauer-Gottwein, P.Item Metadata only Real-time remote sensing driven river basin modelling using radar altimetry.(Copernicus Publications, 2010) Pereira-Cardenal, S. J.; Riegels, N. D.; Berry, P. A. M.; Smith, R. G.; Yakovlev, A.; Siegfried, T. U.; Bauer-Gottwein, P.Item Open Access Risk Assessment of Sharing Cyber Threat Intelligence(Springer, 2020-09) Boiten, Eerke Albert; Smith, R. G.; Albakri, AdhamSharing Cyber Threat Intelligence (CTI) is advocated to get better defence against new sophisticated cyber-attacks. CTI may contain critical information about the victim infrastructure, existing vulnerabilities and business processes so sharing CTI may carry a risk. However, evaluating the risk of sharing CTI da-tasets is challenging due to the nature of the CTI context which is associated with the evolution of the threat landscape and new cyber attacks that are difficult to evaluate. In this paper, we present a quantitative risk model to assess the risk of sharing CTI datasets enabled by sharing with different entities in various situa-tions. The model enables the identification of the threats and evaluation of the impacts of disclosing this information. We present two use cases that help to de-termine the risk level of sharing a CTI dataset and consequently the mitigation techniques to enable responsible sharing. Risk identification and evaluation have been validated using experts’ opinions.Item Metadata only River Monitoring from Satellite Radar Altimetry in the Zambezi River Basin(Copernicus Publications, 2012-07) Michailovsky, C.; McEnnis, S.; Berry, P. A. M.; Smith, R. G.; Bauer-Gottwein, P.Satellite radar altimetry can be used to monitor surface water levels from space. While current and past altimetry missions were designed to study oceans, retracking the waveforms returned over land allows data to be retrieved for smaller water bodies or narrow rivers. The objective of this study is the assessment of the potential for river monitoring from radar altimetry in terms of water level and discharge in the Zambezi River basin. Retracked Envisat altimetry data were extracted over the Zambezi River basin using a detailed river mask based on Landsat imagery. This allowed for stage measurements to be obtained for rivers down to 80m wide with an RMSE relative to in situ levels of 0.32 to 0.72m at different locations. The altimetric levels were then converted to discharge using three different methods adapted to different data-availability scenarios: first with an in situ rating curve available, secondly with one simultaneous field measurement of cross-section and discharge, and finally with only historical discharge data available. For the two locations at which all three methods could be applied, the accuracies of the different methods were found to be comparable, with RMSE values ranging from 4.1 to 6.5% of the mean annual in situ gauged amplitude for the first method and from 6.9 to 13.8% for the second and third methods. The precision obtained with the different methods was analyzed by running Monte Carlo simulations and also showed comparable values for the three approaches with standard deviations found between 5.7 and 7.2% of the mean annual in situ gauged amplitude for the first method and from 8.7 to 13.0% for the second and third methods.Item Metadata only Terrestrial water storage from GRACE and satellite altimetry in the Okavango Delta (Botswana)(Springer, 2010) Andersen, O. B.; Krogh, P. E.; Bauer-Gottwein, P.; Leiriao, S.; Smith, R. G.; Berry, P. A. M.Item Metadata only The utilisation of digital elevation models in the monitoring of global wetlands(European Space Agency, 2009) Smith, R. G.; Berry, P. A. M.