Sentinel 5P Getting Ready for Launch

Under the leadership of the European Commission (EC), a series of missions in support of the Copernicus Atmosphere Monitoring Service (CAMS) is in preparation by ESA. The programme basically consists of a geostationary element called Sentinel-4 (S4) and a low-Earth orbiting element called Sentinel-5 (S5).

In view of bridging the data gap between OMI on EOS-Aura and S5 on MetOP-SG, S5 will be preceded by a slightly simplified instrument, the TROPOspheric Monitoring Instrument (TROPOMI), carried on board a dedicated, sun-synchronous and near-polar orbiting platform. This mission, called ‘Sentinel-5 Precursor’ (S5P), will be operated in loose formation with NOAA’s Suomi-NPP (SNPP) spacecraft. This concept will allow utilization of cloud image data provided by the VIIRS instrument on board SNPP for use in routine processing tasks.

The S5P mission has entered the launch preparatory period with an estimated launch in the second quarter of 2016. Tests in order to characterize essential instrument performance parameters and verify flight readiness have finished in spring 2015. An S5P Validation Team has been convened based on proposals received in response to a Calibration & Validation Announcement of Opportunity Call in 2014. A first workshop has taken place at ESTEC from 29 Sept - 01 Oct 2015.

The presentation will focus on the user aspects during mission preparation and exploitation after launch.

Independent geophysical validation is key to the quality assurance of remote sensed products by satellites. In the frame of the Sentinel-5 Precursor (S5P) mission, with the TROPOspheric Monitoring Instrument (TROPOMI) payload, the validation activities are implemented in two distinct approaches: The operational validation to secure the basic data quality for the use in the Copernicus atmospheric services is part of the S5P Mission Performance Center. Complementary to the MPC activities, ESA has issued an Announcement of Opportunity call for the validation of S5P products. A total of 37 proposals have been received from European, Canadian, US, Korean and Chinese validation scientists forming the Sentinel-5 Precursor Validation Team (S5PVT). Overall, the S5PVT activities cover all operational products with a large range of observation systems and representing major observation networks, such as TCCON, AERONET, NDAAC and EARLINET. In addition a number of campaign opportunities have been identified with the potential to contribute to the S5P validation.

The implementation aspects of the S5PVT projects will be covered in the scientific validation implementation plan. Its objective is to provide all stakeholders of the S5P mission with a reference regarding the independent validation activities proposed and planned by the science community represented in the S5PVT. The matching of the proposed S5PVT activities to the validation requirements of the operational processors and products allows the identification of potential gaps and fostering of cooperation among S5PVT teams. In addition, the implementation plan will be an essential input for the planning of the validation activities covering individual instrument, network and campaign contributions and aligning those with the overall S5P mission implementation during the commissioning and operational phase. While focussing on validation of the operational products to be provided to the Copernicus services, it will also support the scientific exploitation of the mission, giving an overview of observation capabilities that can be exploited, not only as validation, but at a later stage also in synergy with the S5P data.

The Copernicus Sentinel 5 Precursor (S5P) is the first of the Sentinels dedicated to monitoring of the atmospheric composition. The mission objectives of S5P are to monitor air quality, climate and the ozone layer, in the time period between 2016 and 2022. S5P will fly in a Sun-synchronized polar orbit with a 13:30 hr local equator crossing time.

The single payload of the S5P mission is TROPOspheric Monitoring Instrument (TROPOMI), which is developed by The Netherlands in cooperation with ESA. TROPOMI is a nadir viewing shortwave spectrometer that measures in the UV-visible wavelength range (270-500 nm), the near infrared (710-770 nm) and the shortwave infrared (2314-2382 nm). TROPOMI will have an unprecedented spatial resolution of 7x7 km² at nadir. The spatial resolution is combined with a wide swath to allow for daily global coverage.
The TROPOMI/S5P geophysical (Level 2) operational data products include nitrogen dioxide, carbon monoxide, ozone (total column, tropospheric column & profile), methane, sulphur dioxide, formaldehyde and aerosol and cloud parameters.

The main heritage for TROPOMI comes from the Ozone Monitoring Instrument (OMI) for the measurement principle, and from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) for the shortwave infrared band. Many of the lessons learned in these missions have resulted in design improvements for TROPOMI.
One of the most striking features of TROPOMI is the high spatial resolution of 7x7 km² at nadir. The high spatial resolution serves two goals: (1) emissions sources can be detected with a higher accuracy and (2) the number of cloud-free ground pixels will increase substantially. The higher spatial resolution is also combined with a significantly higher signal-to-noise ratio per ground pixel, compared to OMI. This will further enhance the capabilities of TROPOMI to detect small emissions sources.

 The S5P will fly in a so-called loose formation with the U.S. Suomi NPP (National Polar-orbiting Partnership) satellite. The primary objective for this formation flying is to use the cloud clearing capabilities of the VIIRS (Visible Infrared Imager Radiometer Suite). The temporal separation between TROPOMI and VIIRS will be less than 5 minutes. Once this formation has been established, it will enable synergistic data products and scientific research potentials.

 In this contribution we will present the TROPOMI instrument, with a focus on performance aspects, the L0-1B processor and the results from the on-ground calibration campaign.

The Sentinel 5 Precursor (S5P) mission is a sun-synchronous polar satellite system scheduled for launch in 2016. The payload of the S5P mission is the TROPOspheric Monitoring Instrument (TROPOMI) that will provide key information on air quality, climate and the ozone layer with high spatial resolution and daily global coverage.

We present an overview of the work being performed by the S5P Level 2 Working Group (L2WG) for the development of TROPOMI geophysical products including O₃, NO₂, SO₂, HCHO, CO, CH₄, as well as UV, cloud and aerosol products. The L2WG is organized in three groups covering: (i) retrieval algorithms, (ii) scientific verification, and ultimately (iii) the data processors to be used in the ground-segment for the generation of the operational S5P products.

The work on TROPOMI/S5P geophysical products is funded by ESA and national contributions from The Netherlands, Germany, Belgium and Finland.

Sentinel-5 Precursor (S-5P) will be the first of a series of atmospheric missions to be launched within the European Copernicus Programme. With the current launch window mid-April to mid-June 2016 and a nominal lifetime of 7 years, S-5P is expected to provide continuity in the availability of global atmospheric data products between its predecessor missions SCIAMACHY (Envisat), OMI (AURA), GOME(-2) and the future Sentinel-4 and -5 series.

S-5P will deliver unique data regarding the sources and sinks of trace gases with a focus on the lower Troposphere including the PBL. Due to its enhanced spatial, temporal and spectral sampling capabilities, as compared to its predecessors. The S-5P satellite will carry a single payload, TROPOMI (TROPOspheric Monitoring Instrument), which is jointly developed by The Netherlands and ESA. Covering spectral channels in the UV, visible, near- and short-wave infrared it will measure various key species including tropospheric/stratospheric ozone, NO₂, SO₂, CO, CH₄, CH₂O as well as cloud and aerosol parameters. S-5P will be operated in a loose formation with NOAA’s Suomi-NPP spacecraft carrying the high-resolution imaging instrument VIIRS. VIIRS will provide routine cloud mask data required to meet the demanding accuracy requirements, in particular for the CH₄ product.

The presentation will provide a status update of the S-5P mission focussing on the spacecraft and ground segment preparation for launch and the commissioning phase.