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This work presents a practical approach to reconstructing past and present discharge and water depth time series for operational monitoring of small-sized ungauged watersheds using remotely sensed and freely accessible datasets in conjunction with hydrological models. The methodology was applied to the Tsiribihina watershed in Madagascar. Mostly, satellite data are used, such as water levels from satellite altimetry missions and rainfall from the African Rainfall Climatology 2 product. In contrast, the Modelo de Grandes Bacias is calibrated using historical discharge measurements to simulate distributed discharge in the basin. Rating curves are computed by crossing the altimetry information of water height with the simulated discharge outputs. These rating curves enable the conversion of water levels, discharge and depth interchangeably. Present-day discharge and depth can thus be estimated in near real time with any update of satellite rainfall data and/or water level gained by altimetry missions currently flying in operational mode.

As a consequence of inexpensive sensors, ubiquitous tracking devices, and abundant digital storage, by 2019 smarter cities have become platforms for increasing levels of operational monitoring and ...

As part of the Copernicus program, Sentinel-2 is the optical imaging mission designed for the operational monitoring of land and coastal areas. It offers a unique combination of global coverage with a wide field of view, a high revisit capability (5 days with two satellites), a high resolution and multi-spectral imagery. CNES, the French Space Agency, was involved in the commissioning of both Sentinel-2 satellites and is currently working in collaboration with ESA on their long-term monitoring. This paper reviews all the techniques used to ensure an absolute calibration of the 13 spectral bands to better than 5% (the target is 3%) at TOA level. After a brief description of the mission and its related radiometric calibration scheme, we show how standard vicarious calibration methods based on acquisitions over natural targets (oceans, deserts, and Antarctica during winter) are used to check and improve the accuracy of the absolute calibration coefficients. Finally, the verification scheme, exploiting photometer in-situ measurements over the La Crau plain in France and Gobabeb in Namibia, is described. The paper concludes with a summary that includes spectral coherence, agreement between the results obtained with various calibration methods and temporal evolution.

This paper reports ongoing exploration of X-band radar as an operational monitoring tool for coastal infrastructure development. Data have been continually gathered since 2013, helping a major ener...

This study proposes an enhanced damping estimation procedure for flexible cable-supported bridges based on operational modal analysis (OMA). The OMA approach combines the natural excitation techniq...

This article presents the results of routine satellite oil spill monitoring in the Eastern Black Sea 2011–2013 and the Northern & Middle Caspian Sea 2009–2013 by analysing synthetic aperture radar SAR images acquired by space-borne SARs on board the European Environmental Satellite, Canadian SAR-equipped Radarsat-1, and Radarsat-2. The focus of operational monitoring is to provide information that assists in adequate responses, as well as further investigates the problem of recent oil pollution in these seas. A number of state-of-the-art technologies developed by Research and Development Centre SCANEX have been used to address this problem. For example, GeoMixer allows the integration and combination of all information needed for analysis by integrating all detected and verified spills and combining annual oil spill distribution maps and comparing them. Distributions of oil spills in the Black Sea and in the Caspian Sea are quite different, i.e. in their spatial patterns. In the Black Sea, the most important source of oil pollution is tank washing in the open sea producing spills of 20–100 km2 or more and illegal discharges. In the Caspian Sea, most of the detected oil spills in the northern and middle sections are from small ship-made discharges ≤10 km2 related to cargo traffic and fisheries. Despite the oil exploration and production LUKOIL and others in the Northern Caspian, no oil spills related to oil production have been detected. An ill-estimated source is natural oil seeping, mainly in the southern part of the Caspian. It is therefore concluded that the distribution of oil spills in a particular sea may depend strongly on a number of causes, including ship and tanker traffic.

Vegetation monitoring has been performed using remotely sensed images to secure food production, prevent fires, and protect natural ecosystems. Recent satellite sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS), provide frequent wide-scale coverage in multiple areas of the spectrum, allowing the estimation of a wide range of specialized vegetation indices (VIs), each offering several advantages. It is not, however, clear which VI performs better during operational monitoring of wide-scale vegetation patches, such as CORINE Land Cover (CLC) classes. The aim of this work was to investigate the performance of several VIs in operational monitoring of vegetation condition of CLC vegetation types, using Terra MODIS data. Comparison among the VIs within each CLC class was conducted using the sensitivity ratio, a statistical measure that has not been used to compare VIs and does not require calibration curves between each VI and a biophysical parameter. In addition, the VI’s sensitivity t...

The high risk of oil and gas exploration in the sea must expect a high-quality level of safety insurance to prevent environmental damage. This safety insurance can be supported and provided though satellite monitoring. In the period from 23 June to 5 July 2007, Sakhalin Energy Investment Company Ltd. completed the installation of the Piltun-Astokhskoye-B production platform topsides on the gravity base structure in the Piltun-Astokhskoye Field on the shelf to the northeast of Sakhalin Island. Operational monitoring of this event was based on acquisition of Envisat and Radarsat-1 synthetic aperture radar (SAR) images and was aimed at monitoring ship activity, oil spills and environmental parameters (wind, waves and sea ice). By combining and providing the quasi-real-time information derived from SAR images, an accurate understanding of activity during the tow-out, positioning and installation, as well as environmental conditions, can be obtained in a cost-effective manner. This paper discusses the approach used and presents the results of this monitoring.

This article covers the importance of employing a cross-platform and cross-application log management approach rather than a siloed approach to collecting and reviewing logs for simplifying security and operational monitoring as well as compliance initiatives.

Fire products derived from NOAA-AVHRR channel 3 images and DMSP-OLS are compared to determine the most appropriate AVHRR channel 3 thresholds and methods for operational monitoring of fire in Kalimantan, Indonesia. The results indicate that about 77% of AVHRR fire cells derived from a temperature threshold of 321 deg K applied to channel 3 daytime images corresponded with DMSP-OLS fire cells at monthly or longer time scales. However, lower temperature thresholds produced slightly greater correspondence between the two sensors on the same date. By contrast, a contextual algorithm produced a lower correspondence (approximately 50%) between fire products from the two sensors. Although the number and extent of DMSP-OLS fire cells was much greater than fire-cells derived from AVHRR channel 3, the spatial distribution of the two products was broadly similar in the study area.

Operational sea surface temperature (SST) monitoring was tested with the study of large-scale SST features in Indonesia from July 1981 to June 1985. Digital data were provided by digitizing 208 weekly SST charts of NOAA-NESS. The pixel size corresponded to 1 ° 15' longitude and latitude. These data displayed a 0·5 deg K. r.m.s. error compared with 1985 in situ measurements. Iterative interactive factorial analyses combined with a parallelepiped classifier as a clustering technique enhanced the SST spatio-temporal features. The study area was divided into zones in which pixels had similar SST profiles and dates of occurrence of thermal anomalies were pointed out. Sea fronts and upwellings were mapped through spatio-temporal analyses of thermal gradients. This study stresses the possibility of operational SST monitoring for Indonesia, allowing simple data manipulation with hardware easily maintained locally.

A simulated air traffic control task was used to study the effects of prolonged monitoring on some of the behaviours (complex discriminations, interpretations, decisions, memory for actions taken) frequently associated with operational monitoring tasks, but seldom examined in laboratory vigilance studies. Forty-eight subjects performed the monitoring task under relatively high taskload conditions for 2h. Two types of critical events were employed. Simple events consisted of a readily detectible alphanumeric change; complex events (detection of two aircraft at the same altitude on the same flight path) required considerable information processing for detection. Behaviours following detection of each type of event enabled acquisition of data on short-term memory, decision time and errors, procedural errors, and motor movement time. Time to detect aircraft at the same altitude was found to increase significantly over the 2 h as did failures to detect these events; detection time for the simpler type...