The EPS-SG Visible/Infrared Imaging mission is dedicated to supporting the optical imagery user needs for Numerical Weather Prediction (NWP), Nowcasting (NWC) and climate in the 2020 onwards timeframe. The VII mission is fulfilled by the METimage instrument, to be embarked on the Metop-SG-A satellites. METimage will fly in the mid-morning orbit of the Joint Polar System, whilst the early-afternoon orbits are served by the JPSS (U.S. Joint Polar Satellite System) Visible Infrared Imager Radiometer Suite (VIIRS). METimage is a cross-purpose medium resolution, multispectral optical imager, measuring radiation emitted and reflected by the Earth from a low-altitude sun synchronous orbit with a minimum swath width of 2700 km. The top of the atmosphere outgoing radiance will be sampled every 500 m (at nadir) with measurements made in 20 spectral channels ranging from 443 nm in the visible up to 13.345 μm in the thermal infrared.
The following METimage geophysical products will be generated and validated by EUMETSAT:
Cloud mask
Atmospheric motion vectors.
Cloud top height, microphysics and volcanic ash
Cloud top pressure using the oxygen-A band
Total precipitable water vapour from METimage visible/near-infrared bands.
Total precipitable water vapour from METimage thermal infra-red bands
This paper focuses on the validation activities planned for the METimage geophysical products to ensure they meet user requirements for the lifetime of the mission. The validation of level 2 variables relies on the availability of simultaneous and independent data providing the same information on the same horizontal scale. Validation methods include intercomparisons with other validated missions through simultaneous nadir overpasses (both low Earth orbit and geostationary), comparisons with ground based observations, and short term weather forecasts. The level 2 product performance will be validated with respect to user requirements for all geographic regions and seasonal variation.
The EUMETSAT Polar System - Second Generation (EPS-SG) Visible/Infrared Imaging mission supports the optical
imagery user needs for Numerical Weather Prediction (NWP), Nowcasting (NWC) and climate in the timeframe beyond
2020. The VII mission is fulfilled by the METimage instrument, to be flown onboard the Metop-SG-A satellite series.
The instrument itself is a cross-purpose medium resolution, multi-spectral optical imager, measuring radiation emitted
and reflected by the Earth from a low-altitude sun synchronous orbit with a swath width of 2700 km. Measurements will
be made in 20 spectral channels ranging from 443 nm in the visible up to 13.345 μm in the thermal infrared at a spatial
sampling distance of 500 m at nadir.
This paper focuses on the Calibration and Validation (Cal/Val) activities planned for the METimage level 1B products to
ensure that the calibrated and geolocated radiances meet the performance specifications for the lifetime of the mission.
Such methods include cross-calibration with instruments on the same platform e.g. IASI-NG and Sentinel-5
measurements, inter-comparisons with other missions during simultaneous nadir overpasses, comparisons with ground
based observations and lunar calibration. The level 1B product performance will be validated with respect to geometric,
spectral, and radiometric requirements for all geographic regions including their seasonal variability. In particular the
following specific activities are described:
• Calibration verification
• Validation of radiometry
• Geometric verification
• Image quality verification
As the commissioning phase is limited in time, the products from METimage have to be confidence checked and
validated with a concise focus on essential tests. The Cal/Val activities will extend to routine operations in order to
ensure long term stability of the calibrated radiances and continually improve the calibration throughout the lifetime of
the mission.
The EPS-SG Visible/Infrared Imaging (VII) mission is dedicated to supporting the optical imagery user needs for Numerical Weather Prediction (NWP), Nowcasting (NWC) and climate in the timeframe beyond 2020. The VII mission is fulfilled by the METimage instrument, developed by the German Space Agency (DLR) and funded by the German government and EUMETSAT. Following on from an important list of predecessors such as the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate resolution Imaging Spectro-radiometer (MODIS), METimage will fly in the mid-morning orbit of the Joint Polar System, whilst the early-afternoon orbits are served by the JPSS (U.S. Joint Polar Satellite System) Visible Infrared Imager Radiometer Suite (VIIRS). METimage itself is a cross-purpose medium resolution, multi-spectral optical imager, measuring the optical spectrum of radiation emitted and reflected by the Earth from a low-altitude sun synchronous orbit over a minimum swath width of 2700 km. The top of the atmosphere outgoing radiance will be sampled every 500 m (at nadir) with measurements made in 20 spectral channels ranging from 443 nm in the visible up to 13.345 μm in the thermal infrared. The three major objectives of the EPS-SG METimage calibration and validation activities are: • Verification of the instrument performances through continuous in-flight calibration and characterisation, including monitoring of long term stability. • Provision of validated level 1 and level 2 METimage products. • Revision of product processing facilities, i.e. algorithms and auxiliary data sets, to assure that products conform with user requirements, and then, if possible, exceed user expectations. This paper will describe the overall Calibration and Validation (Cal/Val) logic and the methods adopted to ensure that the METimage data products meet performance specifications for the lifetime of the mission. Such methods include inter-comparisons with other missions through simultaneous nadir overpasses and comparisons with ground based observations, analysis of algorithm internal diagnostics to confirm retrieval performance for geophysical products and vicarious calibration to assist with validation of the instrument on-board calibration. Any identified deficiencies in the products will lead to either an update any auxiliary data sets (e.g. calibration key data) that are used to configure the product processors or to a revision of algorithms themselves. The Cal/Val activities are mostly foreseen during commissioning but will inevitably extend to routine operations in order to take on board seasonal variations and ensure long term stability of the calibrated radiances and geophysical products. Pre-requisite to validation of products at scientific level is that the satellite and instrument itself have been verified against their respective specifications both pre-launch and during the satellite in-orbit verification phase.
The EUMETSAT Polar System (EPS) will be followed by a second generation system, EPS-SG, in the 2020-2040
timeframe and contribute to the Joint Polar System being jointly set up with NOAA. Among the various missions which
are part of EPS-SG, there are the Microwave Imager (MWI) and the Ice Cloud Imager (ICI).
The MWI frequencies are from 18 GHz up to 183 GHz. All MWI channels up to 89 GHz measure both V and H
polarisations. The primary objective of the MWI mission is to support Numerical Weather Prediction at regional and
global scales. The MWI will not only provide continuity of measurements for some heritage microwave imager channels
(e.g. SSM/I, AMSR-E) but will also include additional channels such as the 50-55 / 118 GHz bands. The combined use
of these channels will provide more information on cloud and precipitation over sea and land. The ICI will provide
measurements over the sub-millimetre spectral range contributing to an innovative characterisation of clouds over the
whole globe. The ICI has channels at 183 GHz, 325 GHz and 448 GHz with single V polarisation and two channels at
243 GHz and 664 GHz with both V and H polarisation. The ICI’s primary objectives are to support climate monitoring
and validation of ice cloud models and the parameterisation of ice clouds in weather and climate models through the
provision of ice cloud products.
The Multi-viewing ,Multi-channel, Multi-polarisation Imager (3MI) of the EUMETSAT Polar System - Second Generation (EPS-SG) is a two-dimensional push broom radiometer dedicated to aerosol characterisation for climate monitoring, air quality forecasting and Numerical Weather Prediction (NWP). The purpose of the 3MI concept is to provide a multi-spectral (from 410 to 2130 nm), multi-polarisation (-60°, 0°, and +60°), and multi-angular (10 to 14 views) image of the Earth outgoing radiance at the top of the atmosphere (TOA) in order to accurately measure the aerosol load and thereby resolve the directional anisotropy and the microphysical properties of aerosol. The 3MI heritage comes from the Polarisation and Directionality of the Earth's Reflectances (POLDER) and Polarisation and Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar (PARASOL), with 3 instruments launched since 1996.
The EUMETSAT Polar System Second Generation (EPS-SG) will continue operational meteorological measurements
from polar orbiting satellites in the mid-morning orbit in the 2020 timeframe. The Metop Second Generation (Metop-
SG) satellites will carry a payload which is primarily dedicated to operational meteorology and climate monitoring. A
core mission within this payload is an optical imager required to meet the imagery user needs for Numerical Weather
Prediction (NWP), Nowcasting (NWC) and climate applications. As NWP progresses towards operation on higher
spatial resolution grids, improved representation of atmospheric processes encompassing the whole Earth system will be
required, hence the availability of observations of clouds and aerosols as well as surface parameters will play an
increasing role in a skilful weather forecast. Imagery data will also be very important in NWC applications, particularly
in polar regions where space-borne imagery from geostationary satellites is not available.
The EPS-SG Visible/Infrared Imaging mission (VII) follows on from an important list of predecessors such as the
Advanced Very High Resolution Radiometer (AVHRR) and the Moderate resolution Imaging Spectro-radiometer
(MODIS). The VII mission is planned to be implemented by the METimage instrument, developed by Deutsches
Zentrum für Luft und Raumfahrt (DLR). METimage is a cross-purpose medium resolution, multi-spectral optical imager,
measuring the optical spectrum of radiation emitted and reflected by the Earth from a low-altitude sun synchronous orbit
over a minimum swath width of 2800 km. The spectral and radiometric performances and space-time resolution
introduce novel observing capabilities that will enhance the observation potential compared to current operational optical
imagers. These enhanced capabilities along with the evolution of the VII observation requirements are discussed.
EUMETSAT has initiated preparatory activities for the definition of the follow-on EUMETSAT Polar System (post-
EPS) needed for the timeframe 2020 onwards as a replacement for the current EUMETSAT Polar System. Based on the
first outputs of the EUMETSAT post-EPS user consultation process initiated in 2005, mission requirements for potential
post-EPS missions have been drafted. Expertise from a variety of communities was drawn upon in order to ascertain user
needs expressed in terms of geophysical variables, for operational meteorology, climate monitoring, atmospheric
chemistry, oceanography, and hydrology. Current trends in the evolution of these applications were considered in order
to derive the necessary satellite products that will be required in the post-EPS era. The increasing complexity of models
with regard to parameterisation and data assimilation, along with the trend towards coupled atmosphere, ocean and land
models, generates new requirements, particularly in the domains of clouds and precipitation, trace gases and ocean/land
surface products. Following the requirements definition, concept studies at instrument and system levels will shortly
commence with the support of the European Space Agency (ESA), together with industry and representatives of the user
and science communities. Such studies, planned for completion by end of 2008, aim at defining and trading off possible
mission and system concepts and will establish preliminary functional requirements for full or partial implementation of
post-EPS mission requirements. Cost drivers and needs for critical research and development will also be identified. The
generation of both the user and mission requirements have been supported substantially by the post-EPS Mission Experts
Team and the Application Expert Groups. Their support is gratefully acknowledged.
The Infrared Atmospheric Sounding Interferometer (IASI) , due to fly on the EPS Metop satellites from 2006 onwards, will produce hyperspectral radiance spectra, profiles of temperature and humidity at high vertical resolution in addition to columnar trace gas amounts, skin temperature, surface emissivity, and cloud products. Since IASI is not an ideal interferometer, any inhomogeneity within the instrument's field of view (FOV) changes the self-apodisation and thus modifies the spectral response. Clouds and surface variability are likely sources of such inhomogeneities that need to be known in order to correct for the changed spectral response and perform the atmospheric retrievals to the specified accuracy.
The operationally generated AVHRR (Advanced Very High Resolution Radiometer) scenes analysis is used to identify the surface or cloud types present in each IASI FOV. However, although statistically averaging the scenes analysis results to obtain mean estimates of cloud coverage and scene type within the IASI pixels increases the probability of correct classification, the geometric distribution of each scene is lost. A radiance analysis is performed on the co-located AVHRR pixels to identify localised areas of similar radiance clusters within the IASI pixels, the assumption being these clusters correspond to different scene types. Similar clusters of known scene type are then generated from the AVHRR scenes analysis data and matched to the clusters generated from the independent radiance analysis in order to classify scenes in IASI fields of view.
KEYWORDS: Transducers, Feature extraction, Global Positioning System, Embedded systems, Data conversion, Phase shifts, Interfaces, Signal processing, Received signal strength, Human-machine interfaces
A DERA classifier has been interfaced to a recreational sonar form Echo Pilot to provide a wreck location capability. In normal use, a single forward-looking beam plots the seabed contour by using super-directional techniques. The sonar monitors the amplitude of received echoes, and when this exceeds a given threshold it computes the inclination corresponding to the echo. The classifier uses the original data streams, and converts them to feature values on each ping; new classes of features have been developed to augment those usually used on A-scans.
Spectroscopic ellipsometry and Raman spectroscopy have ben sued to characterize Si/Si0.78Ge0.22 superlattices grown by molecular beam epitaxy at different substrate temperatures, 550 degrees C < Ts < 810 degrees C. The result are interpreted to give information on material and interface quality, layer thicknesses, and state of strain, and are in good agreement with XRD, SIMS and RBS investigations. The observed frequencies of zone-folded longitudinal acoustic phonons in a high quality sample agree well with those calculated using Rytov's theory of acoustic vibrations in layered media.
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