Casadio S.,Serco |
Arino O.,Earth Observation Directorate |
Remote Sensing of Environment | Year: 2012
A method for the monitoring of night-time gas flaring of off-shore oil/gas extraction platforms using measurements of the Along Track Scanning Radiometer (ATSR) and the Synthetic Aperture Radar (SAR) is presented and discussed in detail. The positions of off-shore extraction sites are accurately estimated by using SAR data, while the flaring activity is estimated from night-time shortwave infrared (SWIR) radiance measured by ATSR. The North Sea area has been selected as test case and related flaring activity from 1991 to 2010 has been analysed at single site and at North Sea area scales. Results indicate a decline in the overall flaring activity during the time period considered in this work, although single sites can show positive flaring trends. The ATSR derived flaring time series has been compared to the crude oil production data provided by the US Energy Information Administration (EIA), showing very good agreement in terms of trend and seasonal behaviour. We present a simple inversion scheme aimed at the evaluation of the flame parameters (temperature and size) from night-time shortwave, middle and thermal infrared ATSR measurements, and results are discussed in detail. Finally, the possibility to estimate flaring efficiency from satellite measurements and from detailed technical information on flaring devices is envisaged. The proposed approach can be easily extended to other areas in which gas flaring from off-shore oil and gas extraction are an important economic and environmental factor. © 2012 Elsevier Inc.
Rast M.,Earth Observation Directorate |
Johannessen J.,Nansen Environmental and Remote Sensing Center |
Mauser W.,Ludwig Maximilians University of Munich
Surveys in Geophysics | Year: 2014
Water is our most precious and arguably most undervalued natural resource. It is essential for life on our planet, for food production and economic development. Moreover, water plays a fundamental role in shaping weather and climate. However, with the growing global population, the planet's water resources are constantly under threat from overuse and pollution. In addition, the effects of a changing climate are thought to be leading to an increased frequency of extreme weather causing floods, landslides and drought. The need to understand and monitor our environment and its resources, including advancing our knowledge of the hydrological cycle, has never been more important and apparent. The best approach to do so on a global scale is from space. This paper provides an overview of the major components of the hydrological cycle, the status of their observations from space and related data products and models for hydrological variable retrievals. It also lists the current and planned satellite missions contributing to advancing our understanding of the hydrological cycle on a global scale. Further details of the hydrological cycle are substantiated in several of the other papers in this Special Issue. © 2014 Springer Science+Business Media Dordrecht.
Casadio S.,Serco |
Arino O.,Earth Observation Directorate
Advances in Space Research | Year: 2011
The South Atlantic Anomaly (SAA) has been monitored for 19 years using the Along Track Scanning Radiometer (ATSR) series of instruments onboard the ERS-1, ERS-2 and ENVISAT ESA satellites. The time evolution of the night-time particle induced noise in the short wavelength infrared (SWIR, 1.6 μm) and visible (VIS, 0.55 μm) channels of the ATSR instrument series have been analysed. The monthly location and extension of the SAA are inferred by fitting a two-dimensional, elliptical Gaussian function to the coordinates of the night-time hot spots detected over the SAA region. The location of the centre of the SAA is found to drift westwards with an average drift rate of about 0.24 deg/year and northward with an average drift rate of about 0.12 deg/year. Irregularities are found where the drift speed is inverted and the SAA moves eastward and southward. Results indicate that, as expected, the retrieved values of SAA's strength and extension are anti-correlated with the solar activity expressed by the solar flux at 10.7 cm (F10.7). Finally, the peak-to-peak amplitude of the seasonal variation of the SAA strength, estimated from monthly VIS data, is found to be 30% of the average value with the annual to semiannual amplitude ratio of 1.38. © 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
Padovani P.,European Southern Observatory |
Giommi P.,Earth Observation Directorate |
Rau A.,Max Planck Institute for Extraterrestrial Physics
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2012
We study the quasi-simultaneous near-IR, optical, ultraviolet and X-ray photometry of 11 γ -ray selected blazars for which redshift estimates larger than 1.2 have been recently provided. Four of these objects turn out to be high-power blazars with the peak of their synchrotron emission between ~3 × 10 15 and ~10 16 Hz, and therefore of a kind predicted to exist but never seen before. This discovery has important implications for our understanding of physical processes in blazars, including the so-called 'blazar sequence', and might also help in constraining the extragalactic background light through γ -ray absorption since two sources are strongly detected even in the 10-100 GeV Fermi-LAT band. Based on our previous work and their high powers, these sources are very likely high-redshift flat-spectrum radio quasars, with their emission lines swamped by the non-thermal continuum. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS.
Berger M.,Earth Observation Directorate |
Moreno J.,University of Valencia |
Johannessen J.A.,Nansen Environmental and Remote Sensing Center |
Johannessen J.A.,University of Bergen |
And 2 more authors.
Remote Sensing of Environment | Year: 2012
The spatial and temporal characteristics of the new Sentinel missions, primarily designed to provide routine multidisciplinary observations for operational services, are also very suitable for addressing some of the challenges associated with advancing Earth System sciences. The Sentinels are ensuring long-term observational commitment and will operate a range of instruments with different spectral bands and spatial resolutions with global coverage and high revisit times. The complexity of Earth System models has been increasing gradually and most simulations of future climate and Earth system evolution are based on coupled models that include aspects of physics, bio/geo-chemistry, anthropogenic impacts and even recently some elements of socioeconomic factors. Sentinels will provide unique observations to describe such coupled atmosphere, oceans, land and cryosphere and the exchanges among them into Earth System models. This paper emphasizes the indispensable value of the data provided by the family of Sentinel constellations in the context of the urgent need for improved process understanding of the Earth system. © 2012 Elsevier Inc.