High temporal resolution mapping of total suspended matter in Belgian coastal waters with SEVIRI data: a feasibility study

This study aims to investigate the potential of The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) of the ‘Meteosat Second Generation’ (MSG) geostationary satellite system for suspended matter mapping in Belgian Coastal Waters. The SEVIRI radiometer has 12 spectral channels with a spatial resolution of 3km in all channels except the High Resolution Visual (HRV) channel, where the resolution is 1km. Data is available in near real time every 15 minutes. A test data set was obtained from the SEVIRI Archive of the Royal Meteorological Institute of Belgium reflectance values using a simple atmospheric correction algorithm. Total suspended matter is then estimated from reflectance at the higher spatial resolution offered by the HRV band. This preliminary study provides the basis for generation of geostationary ocean colour sensors opens the perspective of studying high frequency dynamics of the coastal ecosystem (resuspension of bottom sediments, growth and decay of algal blooms) as well as mitigating the problems of cloudiness encountered with the current generation of polar-orbiters (MODIS, MERIS, SeaWiFS). This sensitivity, wavelengths needed for atmospheric correction and the use of a high spatial resolution broadband channel

Optimization and quality control of suspended particulate matter concentration measurement using turbidity measurements

The dry weight concentration of suspended particulate material, [SPM] (units: mg L?1), is measured by passing a known volume of seawater through a preweighed filter and reweighing the filter after drying. This is apparently a simple procedure, but accuracy and precision of [SPM] measurements vary widely depending on the measurement protocol and experience and skills of the person filtering. We show that measurements of turbidity, T (units: FNU), which are low cost, simple, and fast, can be used to optimally set the filtration volume, to detect problems with the mixing of the sample during subsampling, and to quality control [SPM]. A relationship between T and ?optimal filtration volume?, Vopt, is established where Vopt is the volume at which enough matter is retained by the filter for precise measurement, but not so much that the filter clogs. This relationship is based on an assessment of procedural uncertainties in the [SPM] measurement protocol, including salt retention, filter preparation, weighing, and handling, and on a value for minimum relative precision for replicates. The effect of filtration volume on the precision of [SPM] measurement is investigated by filtering volumes of seawater ranging between one fifth and twice Vopt. It is shown that filtrations at Vopt maximize precision and cost effectiveness of [SPM]. Finally, the 90% prediction bounds of the T versus [SPM] regression allow the quality control of [SPM] determinations. In conclusion it is recommended that existing [SPM] gravimetric measurements be refined to include measurement of turbidity to improve their precision and quality control

In situ determination of the remote sensing reflectance: an inter-comparison

Inter-comparison of data products from simultaneous measurements performed with independent systems and methods is a viable approach to assess the consistency of data and additionally to investigate uncertainties. Within such a context the inter-comparison called Assessment of In Situ Radiometric Capabilities for Coastal Water Remote Sensing Applications (ARC) was carried out at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea to explore the accuracy of in situ data products from various in- and above-water optical systems and methods. Measurements were performed under almost ideal conditions, including a stable deployment platform, clear sky, relatively low sun zenith angles and moderately low sea state. Additionally, all optical sensors involved in the experiment were inter-calibrated through absolute radiometric calibration performed with the same standards and methods. Inter-compared data products include spectral water-leaving radiance Lw (λ), above-water downward irradiance Ed(0+,λ) and remote sensing reflectance Rrs(λ). Data products from the various measurement systems/methods were directly compared to those from a single reference system/method. Results for Rrs(λ) indicate spectrally averaged values of relative differences comprised between -1 and +6%, while spectrally averaged values of absolute differences vary from approximately 6% for the above-water systems/methods to 9% for buoy-based systems/methods. The agreement between Rrs(λ) spectral relative differences and estimates of combined uncertainties of the inter-compared systems/methods is noteworthy

A SWIR based algorithm to retrieve total suspended matter in extremely turbid waters

In ocean colour remote sensing, the use of Near Infra Red (NIR) spectral bands for the retrieval of Total Suspended Matter (TSM) concentration in turbid and highly turbid waters has proven to be successful. In extremely turbid waters (TSMN 100 mgL−1) however, these bands are less sensitive to increases in TSM. Here it is proposed to use Short Wave Infra Red (SWIR) spectral bands between 1000 and 1300 nm for these extreme cases. This SWIR spectral region is subdivided into two regions, SWIR-I (1000 nm to 1200 nm) and SWIR-II (1200 nm to 1300 nm) which correspond to local minima in the pure water absorption spectrum. For both spectral regions the water reflectance signal was measured in situ with an ASD spectrometer in three different extremely turbid estuarine sites: Scheldt (Belgium), Gironde (France), and Río de la Plata (Argentina), along with the TSMconcentration.A measurable water reflectance was observed for all sites in SWIR-I, while in the SWIR-II region the signal was not significant compared to the Signal-to-Noise Ratio (SNR) of current Ocean Colour (OC) sensors. For the spectral band at 1020 nm (present in Ocean and Land Colour Instrument ? OLCI, onboard Sentinel-3) and at 1071 nm, an empirical single band TSM algorithm is defined which is valid for both the Gironde and Scheldt estuarine sites. This means that a single algorithm can be applied for both sites without expensive recalibration.The relationship between TSM and SWIR reflectance at 1020 and 1071 nm is linear and did not show any saturation for the concentrations measured here (up to 1400 mg L−1), while saturation was observed for the NIR wavelengths, as expected. Hence, for extremely turbid waters it is advised to switch from NIR to SWIR-I wavelengths to estimate TSM concentration. This was demonstrated for an airborne hyperspectral dataset (Airborne Prism Experiment, APEX) from the Gironde estuary having several spectral bands in the SWIR-I. The empirical single band SWIR TSM algorithm was applied to the atmospherically corrected scene providing a TSM concentration map of the Gironde from mouth to more upstream with concentrations expected in this region ranging from a few to several hundreds mg L−1. These results, i.e. the existence of a single relationship for the Scheldt and Gironde, not showing any decrease of sensitivity, highlights the importance of having SWIR bands in future ocean colour sensors for studying extremely turbid rivers, coastal areas and estuaries in the world. A further implication of these results is that there is a TSMlimit for application of atmospheric correction algorithms which assume zero SWIR marine reflectance. That limit is defined here as function of wavelength and sensor noise level.Fil: Knaeps, E.. Flemish Institute for Technological Research (VITO); BélgicaFil: Ruddick, K. G.. Flemish Institute for Technological Research ; BélgicaFil: Doxaran, D.. Laboratoire d; FranciaFil: Dogliotti, Ana Inés. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Nechad, B.. Royal Belgian Institute for Natural Sciences (RBINS); BélgicaFil: Raymaekers, D.. Flemish Institute for Technological Research; BélgicaFil: Sterckx, S.. Flemish Institute for Technological Research; Bélgic

Just One? Solo Dining, Gender and Temporal Belonging in Public Spaces

In recent years, various lifestyle websites have offered tips on eating out alone as well as lists of the best restaurants for solo dining in major cities of the world. Utilising the theoretical concepts of participation units, territories of the self (Goffman 1972[1971]) and belonging (Author B2011, 2013), this paper explores the challenges that spatio-temporal conventions pose for women solo diners in particular. Through the lens of solo dining, we explore being alone and belonging in shared public spaces, and the gendered nature of aloneness and respectability. The papercontributes to existing theory by examining the influence that time has on a woman solo diner’s ‘single’ participation unit, her ability to lay claim to public space and her relationship with the surrounding social environment. The paper concludes by exploring what the new trend of solo dining can offer and the consequences this has for how sociologists conceptualise sociality inpublic spaces