Sentinel-5 Precursor (S-5P) is the first of a series of atmospheric chemistry missions within the European Commission’s Copernicus (former GMES) Programme. It was launched on 13 October 2017 with 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) and OMI (AURA) and the future Sentinel-4 and -5 series. S-5P delivers unique data regarding the sources and sinks of trace gases with a focus on the lower troposphere including the planet boundary layer due to its enhanced spatial, temporal and spectral sampling capabilities as compared to its predecessors. The S-5P satellite carries a single payload, namely TROPOMI (TROPOspheric Monitoring Instrument) which was jointly developed by The Netherlands and ESA. Covering spectral channels in the UV, visible, near- and short-wave infrared, it measures various key species including tropospheric/stratospheric ozone, NO2, SO2, CO, CH4, HCHO as well as cloud and aerosol parameters. The presentation includes on overview of the actual status of the mission and some results about the products that were released to the public since early July 2018.

The Sentinel-5 Precursor (S5P) mission represents the first in a series of atmospheric observing systems within Copernicus.
The S5P mission is a single-payload satellite in a low Earth orbit that provides daily global information on concentrations of trace gases and aerosols important for air quality, climate forcing, and the ozone layer.
The payload of the mission is the TROPOspheric Monitoring Instrument TROPOMI, which has been jointly developed by the The Netherlands and ESA, and consists of a spectrometer with spectral bands in the ultraviolet, the visible, the near-infrared and the shortwave infrared.
The S5P mission was launched on the 13th of October 2017 and has been injected into a near-polar, near sun-synchronous orbit by a ROCKOT launcher.
The initial 6 months of in-orbit operation covered spacecraft, TROPOMI and ground segment level commissioning activities (Phase E1). Since the 30th of April 2018 the instrument is measuring in the nominal operations phase E2, due to last 6.5 years.
We report on the in-flight performance of TROPOMI as derived during the entire mission so far. The presentation covers the instrument's housekeeping, the instrument health and calibration status.
Various tools have been developed and are used to continuously monitor important housekeeping parameters and calibration values: A web based portal, weekly and monthly automated monitoring reports, and dedicated analysis software for new features and issues.
The web based portal allows access to all available observation data (mps.tropomi.eu/dashboard). The data is stored in a database. Plots for different time periods can be produced as chosen by the user. The shown instrument data is processed and averaged as a special L01b calibration product.
In addition housekeeping and engineering data, for example instrument temperatures and voltages, are shown on the portal for the duration of the mission. A dedicated monitoring page shows important calibration parameters and signal monitors. Part of the monitoring parameters are derived from the continuous analysis of the tailored to purpose in-flight calibration measurements performed with internal sources. Other monitoring parameters are based on irradiance and radiance measurements.
The weekly and monthly reports show the most important engineering, housekeeping, and calibration monitoring parameters as well as the results of additional analysis not shown on the web portal. These reports are manually inspected by a calibration scientist.

The presentation on TROPOMI performance monitoring will cover among other topics optical degradation, electronic drifts and detector degradation. Special attention will be paid to the instruments response and recovery to non-nominal situations such as orbit maintenance platform manoeuvres.

The Sentinel-5 Precursor (S5P) platform was launched from Northern Russia on October 13, 2017 carrying the TROPOspheric Monitoring Instrument (TROPOMI). With a spatial resolution of 7x3.5 km², TROPOMI provides improved information on natural and anthropogenic emissions of trace gases and aerosols, with an unprecedented level of details.
BIRA-IASB and DLR have the joint responsibility of developing and maintaining the SO2 retrieval algorithm and its implementation into the S5P operational processor (Theys et al., 2017).
In this paper, the current S5P SO2 algorithm will be presented and TROPOMI SO2 results will be illustrated for several degassing volcanoes and anthropogenic sources. Validation results of the TROPOMI SO2 product with available concurrent satellite and ground-based measurements are shown. Plans for future work will also be addressed. In particular, a new scheme to derive an effective SO2 layer height (LH) from the TROPOMI spectra will be highlighted for a number of volcanic events.

N. Theys, I. De Smedt, H. Yu, T. Danckaert, J. van Gent, C. Hörmann, T. Wagner, P. Hedelt, H. Bauer, F. Romahn, M. Pedergnana, D. Loyola, M. Van Roozendael : Sulfur dioxide operational retrievals from TROPOMI onboard Sentinel-5 Precursor: Algorithm Theoretical Basis, Atmos. Meas. Tech., 10, 119-153, doi:10.5194/amt-10-119-2017, 2017.

The TROPOspheric Monitoring Instrument (TROPOMI) aboard of the Sentinel 5 Precursor (S5P) satellite is the first of the European Space Agency’s Sentinel missions to monitor air quality and climate change as part of the Copernicus programme. Since November 2017, TROPOMI provides unique global measurements of key atmospheric composition species at an unprecedented spatial resolution of 7 x 7 km2, that together with an orbit swath width of 2600 km, allows for daily global coverage. Among the observed species is methane, the second most important greenhouse gas, which can be inferred from TROPOMI measurements of backscatter radiances in the near-infrared (NIR, 675-775 nm) and shortwave-infrared (SWIR, 2305-2385 nm) spectral range. For data acquisition, we use the RemoTec full- physics retrieval algorithm, which is developed at SRON (Netherlands Institute for Space Research) for the operational processing of the TROPOMI methane total column product. In this work, we present results on the methane product from more than one year of TROPOMI measurements. The product is validated with collocated ground-based measurements of methane at nine different sites from the TCCON network (Total Carbon Column Observing Network). We show that there is a very good agreement with a mean bias that is lower than 5 ppb and a station-to-station variability lower than 6 ppb. This validation of the data product together with the comparison of the proxy methane product from the Japanese GOSAT satellite has served as a benchmark to set up the optimal retrieval settings and to select ancillary datasets (e.g. the regularization scheme and the molecular absorption cross sections). The accuracy together with the high spatial and temporal coverage of TROPOMI has allowed us to zoom in on local methane enhancements. We show first case studies where we analyse in detail the temporal and spatial variability of methane concentrations over several regions on the United States.

The Sentinel-5 Precursor (S5P) was successfully launched on the 13th of October 2017, with on board the TROPOspheric Monitoring Instrument (TROPOMI). With a spatial resolution about 15 times finer than OMI, TROPOMI has started to provide important information on natural and anthropogenic emissions of trace gases and aerosols, with an unprecedented level of details. The prototype of the tropospheric HCHO retrieval algorithm has been developed at BIRA-IASB and implemented at the German Aerospace Center (DLR) in the S5P operational processor UPAS-2 (De Smedt et al., 2018). The TROPOMI formaldehyde (HCHO) L2 product has been released to the public in October 2018, one year after launch.

In this work, we present more than one year of HCHO observations with TROPOMI, with a special focus on the heat wave of summer 2018 over Northern latitudes and on the particularly long wildfire season over North America. We first compare the TROPOMI HCHO observations with the 14-years QA4ECV OMI dataset (http://doi.org/10.18758/71021031) and assess their mutual consistency. Second, we address the impact of the heat weave that occurred in Northern latitudes last summer (and associated droughts, wildfires and extreme temperatures) on NMVOC emissions during that period. How do the biogenic emissions – traced by HCHO columns - compare to previous Northern latitude summers? What are the TROPOMI capabilities for watching wildfire plumes that occurred e.g. in California, Colorado, Siberia, or in Scandinavian and Iberian Peninsulas? How better the urban concentrations can be detected with TROPOMI?
De Smedt, I., Theys, N., Yu, H., Danckaert, T., Lerot, C., Compernolle, S., Van Roozendael, M., Richter, A., Hilboll, A., Peters, E., Pedergnana, M., Loyola, D., Beirle, S., Wagner, T., Eskes, H., van Geffen, J., Boersma, K. F., and Veefkind, P.: Algorithm theoretical baseline for formaldehyde retrievals from S5P TROPOMI and from the QA4ECV project, Atmos. Meas. Tech., 11, 2395-2426, https://doi.org/10.5194/amt-11-2395-2018, 2018

Vertical column abundances of H₂O and HDO are simultaneously retrieved from reflectance measurements in the 2.3 μm spectral range from the Tropospheric Monitoring Instrument (TROPOMI) aboard ESA's Sentinel 5-P mission using the Shortwave Infrared CO Retrieval (SICOR) algorithm, which utilises a profile scaling approach. Information about isotopic fractionation in the atmosphere allows to conclude on the atmospheric transport of air parcels and by that is highly relevant, for example, for investigations of the hydrological cycle. Preliminary results of TROPOMI H₂O/HDO retrievals are presented. Compared to ground-based measurements by the Total Carbon Column Observing Network (TCCON), the standard retrieval approach yields biases both for the retrieved columns of H₂O and HDO and a-posteriori computed δD. This contribution discusses possible corrections for these biases, and assesses whether retrievals improve by applying the new molecular spectroscopic database obtained within the ESA project Scientific Exploitation of Operational Missions - Improved Atmospheric Spectroscopy Databases (SEOM-IAS).