Michael Eisinger

ECSIM: the simulator framework for EarthCARE

In 2013 an important ESA Core Explorer Mission, EarthCARE is scheduled to be launched. EarthCARE, (the Earth, Clouds, Aerosol and Radiation Explorer) will comprise two active (a cloud-profiling radar (CPR) and an high spectral resolution atmospheric lidar (ATLID)) and two passive (a Multi-spectral imager (MSI) and a Broad-Band Radiometer (BBR)) instruments. With these, EarthCARE will enable cloud and aerosol properties retrievals consistent with a Top-of-Atmospheric (TOA) flux accuracy of 10 Wm-2. This will be achieved by simultaneously probing the atmosphere vertically with the active instruments in synergy with the passive instruments. In order to facilitate and optimize algorithm development and to quantify the effect of different instrument configurations on the mission performance a simulator for EarthCARE (ECSIM) has been developed. ECSIM relies strongly upon a previous prototype developed by ESA/KNMI where a combination of forward and retrieval models (full End-to-End capabilities) have been included. In order to make this tool more useful within the scientific and engineering communities, the prototype simulator has been embedded into a completely reorganized architecture intended to improve a number of aspects: *Complex algorithms have been enclosed within logical entities: models. *Models are connected in a logical sequence with well-defined interfaces. *Users can customize almost every modes parameter values using configuration XML files. *Model outputs are well documented and stored in easy to access NetCDF files. *Complex simulations can be built up with a few mouse clicks. *Users can run lengthy simulations automatically iterating through different parameter values. *ECSIM can intercept and classify information and error messages from the simulations. *A database is maintained with all the information generated by the system. *It is possible to add third-party algorithms or tools to convert, analyze and visualize data extracted from generated products.

GOME-2 -- the ozone instrument onboard the European METOP satellites

Since 1995 the Global Ozone Monitoring Experiment (GOME) is measuring ozone (total column and profile), nitrogen dioxide and other minor trace gases on-board of the European Space Agency (ESA) ERS-2 satellite. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and ESA decided to fly an advanced GOME-2 instrument on the METOP satellites. Within the EUMETSAT Polar System (EPS), the GOME-2 measurements will provide the input for the ozone data record in the timeframe 2005 to 2020. The radiometric calibration of the polarisation sensitive GOME-2 instrument is significantly improved by the simultaneous measurement of s- and p-polarised light at moderate resolution and high temporal resolution. The Polarisation Monitoring Unit (PU) measures the spectral range between 312 and 790 nm in 15 narrow bands. The ground pixel size in the 960 km swath is 40 * 5km2. The paper describes in detail the polarization measurement devices and their technical capabilities.

Development status of the EarthCARE Mission and its atmospheric Lidar

The European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) are co-operating to develop as part of ESA’s Living Planet Programme, the third Earth Explorer Core Mission, EarthCARE, with the fundamental objective of improving the understanding of the processes involving clouds, aerosols and radiation in the Earth’s atmosphere. EarthCARE payload consists of two active and two passive instruments: an ATmospheric LIDar (ATLID), a Cloud Profiling Radar (CPR), a Multi-Spectral Imager (MSI) and a Broad-Band Radiometer (BBR). The four instruments data are processed individually and in a synergetic manner to produce a large range of products, which include vertical profiles of aerosols, liquid water and ice, observations of cloud distribution and vertical motion within clouds, and will allow the retrieval of profiles of atmospheric radiative heating and cooling. Operating in the UV range at 355 nm, ATLID provides atmospheric echoes with a vertical resolution up to 100 m from ground to an altitude of 40 km. Thanks to a high spectral resolution filtering, the lidar is able to separate the relative contribution of aerosol (Mie) and molecular (Rayleigh) scattering, which gives access to aerosol optical depth. Co-polarised and cross-polarised components of the Mie scattering contribution are also separated and measured on dedicated channels. This paper gives an overview of the mission science objective, the satellite configuration with its four instruments and details more specifically the implementation and development status of the Atmospheric Lidar. Manufacturing status and first equipment qualification test results, in particular for what concerns the laser transmitter development are presented.

GOME-2 ozone instrument onboard the European METOP satellites

Since 1995 the Global Ozone Monitoring Experiment (GOME) is measuring ozone (total column and profile), nitrogen dioxide and other minor trace gases on-board of the European Space Agency (ESA) ERS-2 satellite. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and ESA decided to fly an advanced GOME-2 instrument on the METOP satellites. Within the EUMETSAT Polar System (EPS), the GOME-2 measurements will provide the input for the ozone data record in the timeframe 2005 to 2020. The radiometric calibration of the polarisation sensitive GOME-2 instrument is significantly improved by the simultaneous measurement of s- and p-polarised light at moderate resolution and high temporal resolution. The Polarisation Monitoring Unit (PU) measures the spectral range between 312 and 790 nm in 15 narrow bands. The ground pixel size in the 960 km swath is 40 * 5km2. The paper describes in detail the polarisation measurement devices and their technical capabilities.

An overview of the EarthCARE mission and end-to-end simulator

The Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission aims at improving the representation and understanding of the Earths radiative balance in climate and numerical weather forecast models by acquiring vertical profiles of clouds - including vertical motion within clouds - and aerosols, as well as measuring the broadband radiances at the top of the atmosphere for flux estimates in relation of the observed clouds and aerosols fields. The EarthCARE payload comprises an High Spectral Resolution (HSR) Lidar (ATLID) operating at 355 nm and equipped with a high-spectral resolution (HSR) receiver and the Cloud Profiling Radar (CPR), a highly sensitive 94GHz cloud radar with Doppler capability. A Multi-Spectral Imager (MSI) supporting the active instruments consists of a push-broom imager with 7 channels in the visible, near infrared, short-wave infrared and thermal infrared. Finally, a Broad-Band Radiometer (BBR) measures the outgoing top-of-atmosphere radiances in a short wave channel and a total wave channel, from which the long wave contribution can be deduced. The EarthCARE end-to-end Simulator (ECSIM) encompasses the full EarthCARE observation chain from scene definition to single-instrument and synergistically derived multi-instrument Level 2 products. Level 2 retrieval algorithms can be tested in the full chain (provision of input data, algorithm performance tests by comparison of outputs with known inputs) by using a single framework with well-defined interfaces helping to harmonise algorithm developments. The CPR is developed and procured by JAXA (Japanese Aerospace Exploration Agency) and NiCT (National Institute of Information and Communications Technology) and will be embarked as an integral part of the EarthCARE satellite in the context of the ESA/JAXA cooperation for EarthCARE.

Calibration of GOME-2 data

The GOME-2 spaceborne spectrometers will provide data for the ozone product chain of the EUMETSAT Polar System (EPS), in charge of the monitoring of atmospheric ozone. The accuracy of any geophysical parameter retrieved from the GOME-2 measurements will ultimately be limited by the accuracy of the spectral and radiometric calibration of instrument data. This imposes strong accuracy and stability requirements on the instrument, the calibration activities and the ground processing. In this paper, the processing scheme for the spectral and radiometric calibration of GOME-2 data is presented.

New advanced polarization measurements of GOME-2 onboard the Metop satellites

Since 1995 the Global Ozone Monitoring Experiment (GOME) is measuring ozone (total column and profile), nitrogen dioxide and other minor trace gases on-board of the European Space Agency (ESA) ERS-2 satellite. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and ESA decided to fly an advanced GOME-2 instrument on the METOP satellites. The GOME-2 measurements will provide the input for the ozone data record in the timeframe 2005 to 2020 provided by the EUMETSAT Polar System (EPS). The radiometric calibration of the polarisation sensitive GOME-2 instrument is significantly improved by the simultaneous measurement of s- and p -polarised light at moderate resolution and high temporal resolution. The Polarisation Monitoring Device (PMD) measures the spectral range between 312 and 790 nm in 15 narrow bands. The ground pixel size in the 960 km swath is 40 x 5km2. The paper describes in detail the polarisation measurement devices and their technical capabilities.

Status of ESA's EarthCARE mission, passive instruments payload

EarthCARE is ESA’s third Earth Explorer Core Mission, with JAXA providing one instrument. The mission allows unique data product synergies to improve understanding of atmospheric cloud–aerosol interactions and Earth’s radiation balance. Retrieved data will be used to improve climate and numerical weather prediction models. EarthCARE accommodates two active instruments: an ATmospheric LIDar (ATLID) and a Cloud Profiling Radar (CPR), and two passive instruments: a Multi Spectral Imager (MSI) and a BroadBand Radiometer (BBR). The instruments will provide simultaneous, collocated imagery, allowing both individual and common data products. The active instruments provide data on microscopic levels, measured through the atmospheric depth. 3-D models of the atmospheric interactions are constructed from the data, which can be used to calculate radiation balance. The large footprint of the MSI provides contextual information for the smaller footprints of the active instruments. Data from the BBR allows the loop to be closed by providing a macroscopic measurement of the radiation balance. This paper will describe the passive instruments development status. MSI is a compact instrument with a 150 km swath providing 500 m pixel data in seven channels, whose retrieved data will give context to the active instrument measurements, as well as providing cloud and aerosol information. BBR measures reflected solar and emitted thermal radiation from the scene. To reduce uncertainty in the radiance to flux conversion, three independent view angles are observed for each scene. The combined data allows more accurate flux calculations, which can be further improved using MSI data.

The ESA-JAXA EarthCARE clouds, aerosol and radiation explorer mission: overview and development status

The EarthCARE, Earth Clouds, Aerosol and Radiation Explorer, is a joint European-Japanese mission (ESA/JAXA/NICT) which has been defined with the objective of improving the understanding of cloud-aerosol-radiation interactions so as to include them correctly and reliably in climate and numerical weather prediction models. The EarthCARE Mission has been approved for implementation as ESAs third Earth Explorer Core Mission. It is currently in its Detailed Design Phase (phase C/D) with a launch scheduled for 2018 [1]. This paper presents the EarthCARE programmatic status, the current instrument design and mission performance. The mission end-to-end simulator (E3SIM) and data processing up to level 2 (geophysical products) and related science activities will be discussed. The E3SIM supports end-to-end simulations from a scene definition to synergistic level 2 products. Level 2 retrieval algorithms can be tested in the full chain (provision of input data, algorithm performance tests by comparison of outputs with known inputs) by using a single framework with well-defined interfaces helping to harmonise algorithm developments.

End-to-end performance analysis using engineering confidence models and a ground processor prototype

The European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) are co-operating to develop the EarthCARE satellite mission with the fundamental objective of improving the understanding of the processes involving clouds, aerosols and radiation in the Earth’s atmosphere. The EarthCARE Multispectral Imager (MSI) is relatively compact for a space borne imager. As a consequence, the immediate point-spread function (PSF) of the instrument will be mainly determined by the diffraction caused by the relatively small optical aperture. In order to still achieve a high contrast image, de-convolution processing is applied to remove the impact of diffraction on the PSF. A Lucy-Richardson algorithm has been chosen for this purpose. This paper will describe the system setup and the necessary data pre-processing and post-processing steps applied in order to compare the end-to-end image quality with the L1b performance required by the science community.