scholarly journals Contribution of Satellite Measurements to the Modeling and Monitoring of the Quality of Coastal Seawater

10.5772/53375 ◽  
2013 ◽  
Author(s):  
Houma Fouzia ◽  
Bachouche Samir ◽  
Bachari Nour El Islam ◽  
Belkessa Rabah
Keyword(s):  
Satellite Measurements ◽  
Coastal Seawater

scholarly journals Evaluation of Total Ozone Column from Multiple Satellite Measurements in the Antarctic Using the Brewer Spectrophotometer

2021 ◽  
Vol 13 (8) ◽  
pp. 1594
Author(s):  
Songkang Kim ◽  
Sang-Jong Park ◽  
Hana Lee ◽  
Dha Hyun Ahn ◽  
Yeonjin Jung ◽  
...  
Keyword(s):  
Satellite Data ◽  
Total Ozone ◽  
Spatiotemporal Pattern ◽  
Satellite Measurements ◽  
Austral Spring ◽  
Total Ozone Column ◽  
Brewer Spectrophotometer ◽  
The Antarctic ◽  
Ozone Column

The ground-based ozone observation instrument, Brewer spectrophotometer (Brewer), was used to evaluate the quality of the total ozone column (TOC) produced by multiple polar-orbit satellite measurements at three stations in Antarctica (King Sejong, Jang Bogo, and Zhongshan stations). While all satellite TOCs showed high correlations with Brewer TOCs (R = ~0.8 to 0.9), there are some TOC differences among satellite data in austral spring, which is mainly attributed to the bias of Atmospheric Infrared Sounder (AIRS) TOC. The quality of satellite TOCs is consistent between Level 2 and 3 data, implying that “which satellite TOC is used” can induce larger uncertainty than “which spatial resolution is used” for the investigation of the Antarctic TOC pattern. Additionally, the quality of satellite TOC is regionally different (e.g., OMI TOC is a little higher at the King Sejong station, but lower at the Zhongshan station than the Brewer TOC). Thus, it seems necessary to consider the difference of multiple satellite data for better assessing the spatiotemporal pattern of Antarctic TOC.

Sea-urchin Embryo Bioassay for in situ Evaluation of the Biological Quality of Coastal Seawater

2001 ◽  
Vol 52 (1) ◽  
pp. 29-32 ◽  
Author(s):  
R. Beiras ◽  
E. Vázquez ◽  
J. Bellas ◽  
J.I. Lorenzo ◽  
N. Fernández ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Coastal Seawater ◽  
Biological Quality ◽  
Sea Urchin Embryo

scholarly journals Technical Note: Validation of Odin/SMR limb observations of ozone, comparisons with OSIRIS, POAM III, ground-based and balloon-borne instruments

2008 ◽  
Vol 8 (1) ◽  
pp. 727-779
Author(s):  
F. Jégou ◽  
J. Urban ◽  
J. de La Noë ◽  
P. Ricaud ◽  
E. Le Flochmoën ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Technical Note ◽  
Atmospheric Composition ◽  
Satellite Measurements ◽  
Space Agency ◽  
Infrared Imager ◽  
Ozone Maximum ◽  
Polar Ozone ◽  
Good Agreement

Abstract. The Odin satellite carries two instruments capable of determining stratospheric ozone profiles by limb sounding: the Sub-Millimetre Radiometer (SMR) and the UV-visible spectrograph of the OSIRIS (Optical Spectrograph and InfraRed Imager System) instrument. A large number of ozone profiles measurements were performed during six years from November 2001 to present. This ozone dataset is here used to make quantitative comparisons with satellite measurements in order to assess the quality of the Odin/SMR ozone measurements. In a first step, we compare Swedish SMR retrievals version 2.1, French SMR ozone retrievals version 222 (both from the 501.8 GHz band), and the OSIRIS retrievals version 3.0, with the operational version 4.0 ozone product from POAM III (Polar Ozone Atmospheric Measurement). In a second step, we refine the Odin/SMR validation by comparisons with ground-based instruments and balloon-borne observations. We use observations carried out within the framework of the Network for Detection of Atmospheric Composition Change (NDACC) and balloon flight missions conducted by the Canadian Space Agency (CSA), the Laboratoire de Physique et de Chimie de l'Environnement (LPCE, Orléans, France), and the Service d'Aéronomie (SA, Paris, France). Coincidence criteria were 5° in latitude x in 10° longitude, and 5 h in time in Odin/POAM III comparisons, 12 h in Odin/NDACC comparisons, and 72 h in Odin/balloons comparisons. An agreement is found with the POAM III experiment (10–60 km) within −0.3±0.2 ppmv (bias±standard deviation) for SMR (v222, v2.1) and within −0.5±0.2 ppmv for OSIRIS (v3.0). Odin ozone mixing ratio products are systematically slightly lower than the POAM III data and show an ozone maximum lower by 1–5 km in altitude. The comparisons with the NDACC data (10–34 km for ozonesonde, 10–50 km for lidar, 10–60 for microwave instruments) yield a good agreement within −0.15±0.3 ppmv for the SMR data and −0.3±0.3 ppmv for the OSIRIS data. Finally the comparisons with instruments on large balloons (10–31 km) show a good agreement, within −0.7±1 ppmv.

scholarly journals A Hyperspectral Bidirectional Reflectance Model for Land Surface

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4456
Author(s):  
Qiguang Yang ◽  
Xu Liu ◽  
Wan Wu
Keyword(s):  
Land Surface ◽  
Solar Observation ◽  
Bidirectional Reflectance Distribution Function ◽  
Satellite Measurements ◽  
Bidirectional Reflectance ◽  
Reflective Spectrum ◽  
Vegetation Database ◽  
Airborne Sensors ◽  
Bidirectional Reflectance Distribution

A hyperspectral bidirectional reflectance (HSBR) model for land surface has been developed in this work. The HSBR model includes a very diverse land surface bidirectional reflectance distribution function (BRDF) database with ~40,000 spectra. The BRDF database is saved as Ross-Li parameters, which can generate hyperspectral reflectance spectra at different sensor and solar observation geometries. The HSBR model also provides an improved method for generating hyperspectral surface reflectance using multiband satellite measurements. It is shown that the land surface reflective spectrum can be easily simulated using BRDF parameters or reflectance at few preselected wavelengths. The HSBR model is validated using the U.S. Geological Survey (USGS) vegetation database and the AVIRIS reflectance product. The simulated reflective spectra fit the measurements very well with standard deviations normally smaller than 0.01 in the unit of reflectivity. The HSBR model could be used to significantly improve the quality of the reflectance products of satellite and airborne sensors. It also plays important role for intercalibration among space-based instruments and other land surface related applications.

scholarly journals An Assessment on the Coastal Seawater Quality of the Gulf of Suez, Egypt

2020 ◽  
Vol 11 (01) ◽  
pp. 34-47
Author(s):  
Manal G. Mahmoud ◽  
Ehsan Abu El-Khir ◽  
Mahmoud H. Ebeid ◽  
Laila A. Mohamed ◽  
Mamdouh A. Fahmy ◽  
...  
Keyword(s):  
Gulf Of Suez ◽  
Coastal Seawater ◽  
Seawater Quality

scholarly journals Geometric Aspects of Ground Augmentation of Satellite Networks for the Needs of Deformation Monitoring

2016 ◽  
Vol 51 (2) ◽  
pp. 75-88 ◽  
Author(s):  
Elżbieta Protaziuk
Keyword(s):  
Deformation Monitoring ◽  
Satellite Networks ◽  
Satellite Network ◽  
Accuracy Analysis ◽  
Satellite Measurements ◽  
Error Ellipse ◽  
Satellite Signal ◽  
Comparable Accuracy ◽  
Error Ellipsoid

Abstract Satellite measurements become competitive in many tasks of engineering surveys, however, in many requiring applications possibilities to apply such solutions are still limited. The possibility to widely apply satellite technologies for displacements measurements is related with new challenges; the most important of them relate to increasing requirements concerning the accuracy, reliability and continuity of results of position determination. One of the solutions is a ground augmentation of satellite network, which intention is to improve precision of positioning, ensure comparable accuracy of coordinates and reduce precision fluctuations over time. The need for augmentation of GNSS is particularly significant in situations: where the visibility of satellites is poor because of terrain obstacles, when the determined position is not precise enough or a satellites constellation does not allow for reliable positioning. Ground based source/sources of satellite signal placed at a ground, called pseudosatellites, or pseudolites were intensively investigated during the last two decades and finally were developed into groundbased, time-synchronized transceivers, that can transmit and receive a proprietary positioning signal. The paper presents geometric aspects of the ground based augmentation of the satellite networks using various quality measures of positioning geometry, which depends on access to the constellation of satellites and the conditions of the observation environment. The issue of minimizing these measures is the key problem that allows to obtain the position with high accuracy. For this purpose, the use of an error ellipsoid is proposed and compared with an error ellipse. The paper also describes the results of preliminary accuracy analysis obtained at test area and a comparison of various measures of the quality of positioning geometry.

scholarly journals Comparison of In Situ and Satellite-Derived Sea Surface Temperatures in the Gulf of Carpentaria

2007 ◽  
Vol 24 (10) ◽  
pp. 1773-1784 ◽  
Author(s):  
Ian J. Barton
Keyword(s):  
Single Channel ◽  
Pilot Project ◽  
Sea Surface ◽  
Global Ocean ◽  
Satellite Measurements ◽  
Ocean Data Assimilation ◽  
Infrared Radiometer

Abstract During 30 days in May and June 2003, the R/V Southern Surveyor was operating in the Gulf of Carpentaria, northern Australia. Measurements of sea surface temperature (SST) were made with an accurate single-channel infrared radiometer as well as with the ship’s thermosalinograph. These ship-based measurements have been used to assess the quality of the SST derived from nine satellite-borne instruments. The satellite dataset compiled during this period also allows the intercomparison of satellite-derived SST fields in areas not covered by the ship’s track. An assessment of the SST quality from each satellite instrument is presented, and suggestions for blending ground and satellite measurements into a single product are made. These suggestions are directly applicable to the international Global Ocean Data Assimilation Experiment (GODAE) High Resolution SST Pilot Project (GHRSST-PP) that is currently developing an operational system to provide 6-hourly global fields of SST at a spatial resolution close to 10 km. The paper demonstrates how the Diagnostic Datasets (DDSs) and Matchup Database (MDB) of the GHRSST-PP can be used to monitor the quality of individual and blended SST datasets. Recommendations for future satellite missions that are critical to the long-term generation of accurate blended SST datasets are included.

scholarly journals Retrieval of tropospheric NO<sub>2</sub> columns from SCIAMACHY combining measurements from limb and nadir geometries

2012 ◽  
Vol 5 (4) ◽  
pp. 5043-5105 ◽  
Author(s):  
A. Hilboll ◽  
A. Richter ◽  
A. Rozanov ◽  
Ø. Hodnebrog ◽  
A. Heckel ◽  
...  
Keyword(s):  
Systematic Bias ◽  
Satellite Measurements ◽  
Matching Algorithm ◽  
The Earth ◽  
Novel Approach ◽  
Tropospheric No2 ◽  
Invaluable Tool ◽  
Global Coverage ◽  
Sector Method

Abstract. Satellite measurements of atmospheric trace gases have proved to be an invaluable tool for monitoring the Earth system. When these measurements are to be used for assessing tropospheric emissions and pollution, as for example in the case of nadir measurements of nitrogen dioxide (NO2), it is necessary to separate the stratospheric from the tropospheric signal. The SCIAMACHY instrument offers the unique opportunity to combine its measurements in limb and nadir viewing geometries into a tropospheric data product, using the limb measurements of the stratospheric NO2 abundances to correct the nadir measurements' total columns. In this manuscript, we present a novel approach to limb/nadir matching, calculating one stratospheric NO2 value from limb measurements for every single nadir measurement, abandoning global coverage for the sake of spatial accuracy. As a comparison, modelled stratospheric NO2 columns from the Oslo CTM2 are evaluated as stratospheric correction, and both datasets are confronted with the originally used reference sector method. Our study shows that stratospheric NO2 columns from SCIAMACHY limb measurements very well reflect stratospheric conditions. The zonal variability of stratospheric NO2 is captured by our matching algorithm, and the quality of the resulting tropospheric NO2 columns improves considerably. Modelled stratospheric NO2 columns from the Oslo CTM2 agree remarkably well with the measurements. Both datasets need to be matched to the level of the nadir measurements, however, because a time and latitude dependent bias between both stratospheric datasets and the measured nadir columns can be observed over clean regions. After accounting for this systematic bias between SCIAMACHY nadir observations and the stratospheric columns, both new stratospheric correction methods provide a significant improvement to the retrieval of tropospheric NO2 columns from the SCIAMACHY instrument.

scholarly journals Improvements to the retrieval of tropospheric NO<sub>2</sub> from satellite – stratospheric correction using SCIAMACHY limb/nadir matching and comparison to Oslo CTM2 simulations

2013 ◽  
Vol 6 (3) ◽  
pp. 565-584 ◽  
Author(s):  
A. Hilboll ◽  
A. Richter ◽  
A. Rozanov ◽  
Ø. Hodnebrog ◽  
A. Heckel ◽  
...  
Keyword(s):  
Earth System ◽  
Spatial Accuracy ◽  
Satellite Measurements ◽  
Matching Algorithm ◽  
The Earth ◽  
Novel Approach ◽  
Tropospheric No2 ◽  
Invaluable Tool ◽  
Global Coverage

Abstract. Satellite measurements of atmospheric trace gases have proved to be an invaluable tool for monitoring the Earth system. When these measurements are to be used for assessing tropospheric emissions and pollution, as for example in the case of nadir measurements of nitrogen dioxide (NO2), it is necessary to separate the stratospheric from the tropospheric signal. The SCIAMACHY instrument offers the unique opportunity to combine its measurements in limb- and nadir-viewing geometries into a tropospheric data product, using the limb measurements of the stratospheric NO2 abundances to correct the nadir measurements' total columns. In this manuscript, we present a novel approach to limb/nadir matching, calculating one stratospheric NO2 value from limb measurements for every single nadir measurement, abandoning global coverage for the sake of spatial accuracy. For comparison, modelled stratospheric NO2 columns from the Oslo CTM2 are also evaluated for stratospheric correction. Our study shows that stratospheric NO2 columns from SCIAMACHY limb measurements very well reflect stratospheric conditions. The zonal variability of the stratospheric NO2 field is captured by our matching algorithm, and the quality of the resulting tropospheric NO2 columns improves considerably. Both stratospheric datasets need to be adjusted to the level of the nadir measurements, because a time- and latitude-dependent bias to the measured nadir columns can be observed over clean regions. After this offset is removed, the two datasets agree remarkably well, and both stratospheric correction methods provide a significant improvement to the retrieval of tropospheric NO2 columns from the SCIAMACHY instrument.

scholarly journals Verification of the Geomagnetic Field Models Using Historical Satellite Measurements Obtained in 1964 and 1970

2022 ◽  
Author(s):  
Anatoly Soloviev ◽  
Dmitry Peregoudov
Keyword(s):  
Geomagnetic Field ◽  
Field Model ◽  
Digital Data ◽  
Mathematical Methods ◽  
Satellite Measurements ◽  
Data Set ◽  
Geomagnetic Field Models ◽  
Improved Model ◽  
First Time

Abstract In 2019, the WDC for Solar-Terrestrial Physics in Moscow digitized the archive of observations of the Earth’s magnetic field carried out by the Soviet satellites Kosmos-49 (1964) and Kosmos-321 (1970). As a result, the scientific community for the first time obtained access to a unique digital data set, which was registered at the very beginning of the scientific space era. This article sets out three objectives. First, the quality of the obtained measurements is assessed by their comparison with the IGRF reference field model. Secondly, we assess the quality of the models, which at that time were derived from the data of these two satellites and ground-based observations. Thirdly, we propose a new, improved model of the geomagnetic field secular variation based on the scalar measurements of the Kosmos-49 and Kosmos-321 satellites using modern mathematical methods.

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