The Global Ozone Monitoring Experiment-2 (GOME-2) flies on the Metop series of satellites, the space component of the EUMETSAT Polar System. In this paper we will provide an overview of the ...instrument design, the on-ground calibration and characterization activities, in-flight calibration, and level 0 to 1 data processing. The current status of the level 1 data is presented and points of specific relevance to users are highlighted. Long-term level 1 data consistency is also discussed and plans for future work are outlined. The information contained in this paper summarizes a large number of technical reports and related documents containing information that is not currently available in the published literature. These reports and documents are however made available on the EUMETSAT web pages and readers requiring more details than can be provided in this overview paper will find appropriate references at relevant points in the text.
The Polar Multi-Sensor Aerosol product (PMAp) is based on the synergistic use of three instruments from the Metop platform, GOME-2, AVHRR, and IASI. The retrieval algorithm includes three major ...steps: a pre-identification of the aerosol class, a selection of the aerosol model, and a calculation of the Aerosol Optical Depth (AOD). This paper provides a detailed description of the PMAp retrieval, which combines information provided by the three instruments. The retrieved AOD is qualitatively evaluated, and a good temporal as well as spatial performance is observed, including for the transition between ocean and land. More quantitatively, the performance is evaluated by comparison to AERONET in situ measurements. Very good consistency is also observed when compared to other space-based data such as MODIS or VIIRS. The paper demonstrates the ability of this first generation of synergistic products to derive reliable AOD, opening the door for the development of synergistic products from the instruments to be embarked on the coming Metop Second Generation platform. PMAp has been operationally distributed in near-real-time since 2014 over ocean, and 2016 over land.
We present an assessment study of the Global Ozone Monitoring Experiment 2 (GOME‐2) reflectance for the wavelength range 270–350 nm by comparing measurements with simulations calculated using the ...vector linearized discrete ordinate radiative transfer model (VLIDORT) and Microwave Limb Sounder (MLS) ozone profiles. The results indicate wavelength‐ and cross‐track‐position‐dependent biases. GOME‐2 reflectance is overestimated by 10% near 300 nm and by 15%–20% around 270 nm. Stokes fraction measurements made by onboard polarization measurement devices are also validated directly using the VLIDORT model. GOME‐2 measurements agree well with the simulated Stokes fractions, with mean biases ranging from −1.0% to ∼2.9%; the absolute differences are less than 0.05. Cloudiness‐dependent biases suggest the existence of uncorrected stray‐light errors that vary seasonally and latitudinally. Temporal analysis indicates that reflectance degradation began at the beginning of the mission; the reflectance degrades by 15% around 290 nm and by 2.2% around 325 nm from 2007 through 2009. Degradation shows wavelength‐ and viewing‐angle‐dependent features. Preliminary validation of ozone profile retrievals with MLS, Michelson Interferometer for Passive Atmospheric Sounding, and ozonesonde reveals that the application of radiometric recalibration improves the ozone profile retrievals as well as reduces fitting residuals by 30% in band 2b.
Key Points
Wavelength and cross‐track‐position‐dependent bias in GOME‐2 reflectance in UV
Validate polarization measurements using vector radiative transfer model
The “soft” calibration improves ozone profile and SO2 retrieval
•Multi-angle, multi-spectral and polarised radiances from the Metop SG satellite.•An easy to use and well characterized polarized radiance product by EUMETSAT.•Radiometric error characterization by ...measuring sub-pixel spatial frequencies.
The Multi-viewing, Multi-channel and Multi-polarisation Imager (3MI) on board the Metop-SG satellites will observe polarised multi-spectral radiances of a single target within a very short time period from the visible to the shortwave infrared region with daily global coverage. In order to provide the users of 3MI data with an easy to use and well characterised radiance product EUMETSAT will make a geoprojected and regridded 3MI level-1C product available to users within 70 min of sensing. The paper describes the methodologies of geoprojection and regridding used for the processing of such a product. In addition, the colocation of ancillary information, in particular from the METimage 20-channel imager providing subpixel information of the radiance field and of clouds is described in detail. The latter information is provided as colocated geometric average values in the product and is also used to provide a realistic scene-dependent error introduced by the radiance regridding. Initial estimates, using a synthetic test dataset of top-of-atmosphere radiances of 3MI and METimage at native instrument resolution, provide an upper limit for the additional radiance error contribution depending on the scene homogeneity. Colocated METimage cloud-top height information is also used for parallax correction of the coregistered radiance data either to the cloud height or to the surface elevation, depending on the origin of the dominant radiance signal within the line-of-sight.
AN INTRODUCTION TO THE EUMETSAT POLAR SYSTEM Klaes, K. Dieter; Cohen, Marc; Buhler, Yves ...
Bulletin of the American Meteorological Society,
07/2007, Letnik:
88, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Polar System is the European contribution to the European–U.S. operational polar meteorological satellite system ...(Initial Joint Polar System). It serves the midmorning (3.3.) orbit 0930 Local Solar Time (LST) descending node. The EUMETSAT satellites of this new polar system are the Meteorological Operational Satellite (Metop) satellites, jointly developed with ESA. Three Metop satellites are foreseen for at least 14 years of operation from 2006 onward and will support operational meteorology and climate monitoring.
The Metop Programme includes the development of some instruments, such as the Global Ozone Monitoring Experiment, Advanced Scatterometer, and the Global Navigation Satellite System (GNSS) Receiver for Atmospheric Sounding, which are advanced instruments of recent successful research missions. Core components of the Metop payload, common with the payload on the U.S. satellites, are the Advanced Very High Resolution Radiometer and the Advanced Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (ATOVS) package, composed of the High Resolution Infrared Radiation Sounder (HIRS), Advanced Microwave Sounding Unit A (AMSU-A), and Microwave Humidity Sounder (MHS). They provide continuity to the NOAA-K, -L, -M satellite series (in orbit known as NOAA-15, -16 and -17). MHS is a EUMETSAT development and replaces the AMSU-B instrument in the ATOVS suite. The Infrared Atmospheric Sounding Interferometer (IASI) instrument, developed by the Centre National d'Etudes Spatiales, provides hyper-spectral resolution infrared sounding capabilities and represents new technology in operational satellite remote sensing.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Operational spaced-based system for aerosol and cloud determination.•Definition of the Multi-view, Multi-spectral and Multi-polarization concept.•Characterization of the system, on-ground as well as ...in-orbit.•Ground processing of the Level-1 products.
The 3MI instrument is one of the missions of the EUMETSAT Polar System Second Generation (EPS-SG) program to be launched in 2021. This polarimetric mission has a direct heritage from the POLDER mission, with improved capabilities and is implemented within a fully operational long-term framework. The spectral range was extended from the visible-near-infrared (410–910 nm) to the shortwave-infrared domain (up to 2200 nm). The spatial resolution (4 km at nadir) and the instantaneous swath (2200 × 2200 km²) were also improved compared to previous POLDER instruments. The 3MI concept of the multi-viewing, multi-spectral and multi-polarized Imaging is described, in particular how these 3 pieces of information are acquired together within a single simple instrument concept. Achieving the performance necessary to meet the mission requirements will rely on a comprehensive initial pre-launch characterization and subsequently extensive in-orbit monitoring based on a vicarious calibration strategy. The level 1 products available to the users will be geo-located Stokes vectors on the native viewing geometry (Level 1B) and geo-projected multi-directional and spectral Stokes vectors (Level 1C). Level-2 products will provide geophysical and microphysical parameters for aerosol and clouds.
The role of ozone in absorbing ultraviolet solar radiation is well known. Ozone also makes a significant contribution to the radiative balance of the upper troposphere and lower stratosphere, such ...that changes in the distribution of ozone in these atmospheric regions will affect the radiative forcing of climate,. Furthermore, tropospheric ozone is the source of the hydroxyl radical which controls the abundance and distribution of many atmospheric constituents, including greenhouse gases such as methane and hydrochlorofluorocarbons. Tropospheric ozone is produced photochemically in situ and is also transported down from the stratosphere, but the relative importance of these two sources to its global budget is poorly understood. High-quality tropospheric and lower-stratospheric ozone profile measurements are available from sondes and lidar techniques, but their geographical sampling is very limited. Complementary satellite measurements of the global ozone distribution in this height region are therefore required to quantify ozone's tropospheric budget and its participation in climate-forcing and tropospheric chemistry. Here we present direct measurements of tropospheric ozone concentrations from space, made by the European Space Agency's Global Ozone Monitoring Experiment. These results demonstrate the potential of satellite measurements to provide self-consistent tropospheric and stratospheric ozone distributions on a global scale.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This paper presents a new, simple, fast method to retrieve cloud altitude from measurements of light absorption in the strongest molecular band of oxygen (the A-band), centered at 761 nm, by the ...polarization and directionality of the earth's reflectance sensor. First, we assess the validity of the method against synthetic spectra as a function of realistic cloud scenarios and satellite observation geometries. The retrieval error estimate amounts, on average, to less than 500 m. Second, the hurricane Ileana, overpassed the August 30, 2012, off the coasts west of Mexico and Southern California, is selected as test bed for the comparison of our retrievals against independent and nearly coincident cloud data inferred with the Moderate Resolution Imaging Spectroradiometer onboard Aqua and the Global Ozone Monitoring Experiment 2 onboard MetOp-A. We find that our approach can accurately reproduce the cloud height patterns, as long as the clouds are not thin cirrus.
Community-acquired oxacillin-resistant Staphylococcus aureus (ORSA) infections are an emerging problem in the 1990s in Sydney, Australia. Laboratory data pertaining to all specimens that grew S. ...aureus between 1/1/1990 and 31/12/1999 were analysed. A total of 12,909 isolates of S. aureus were obtained. The proportions that were non-multiresistant oxacillin-resistant S. aureus (NORSA) increased from 0.09% in 1990 to 5.5% in 1999. Resistance of NORSA strains to erythromycin was 8.5%, ciprofloxacin 8.4%, tetracycline 13%, rifampicin 0.7%, and fusidic acid 5.3%. A chart review was performed for cases of NORSA infection which occurred 1/1/1998–3/5/1998. Isolates from these cases underwent E-test oxacillin MIC testing, mecA determinant PCR, phage typing and pulsed-field gel electro-phoresis. All nine of the patients with NORSA were Polynesians, and all had serious soft tissue infections. Bacter-aemia was not seen. Only one patient received vancomycin yet all recovered. Isolates from all nine patients contained the mecA determinant. Oxacillin MICs were 1–8mg/l. Strain differentiation with phage typing and pulsed-field gel electro-phoresis showed isolates from eight patients were closely related and were similar to New Zealand WSPP1 and WSPP2 strains. Medical practitioners should take specimens for culture and sensitivity from lesions where infection with S. aureus is likely. Empirical treatment of staphylococcal infections in Polynesians needs to cover NORSA. Methods to detect oxacillin resistance need to be robust.
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