Examinando por Autor "Pommereau, J. P."

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Ground-based validation of the Copernicus Sentinel-5P TROPOMI NO2 measurements with the NDACC ZSL-DOAS, MAX-DOAS and Pandonia global networks
(European Geoscience Union (EGU), 2021-01-22) Verhoelst, T.; Compernolle, S.; Pinardi, G.; Lambert, J. C.; Eskes, H. J.; Eichmann, K. U.; Fjaeraa, A. M.; Granville, J.; Niemeijer, S.; Cede, A.; Tiefengraber, M.; Hendrick, F.; Pazmiño, A.; Bais, A.; Bazureau, A.; Folkert Boersma, K.; Bognar, K.; Dehn, A.; Donner, S.; Elokhov, A.; Gebetsberger, M.; Goutail, F.; Grutter de la Mora, M.; Gruzdev, A.; Gratsea, M.; Hansen, G. H.; Irie, H.; Jepsen, N.; Kanaya, Y.; Karagkiozidis, D.; Kivi, R.; Kreher, K.; Levelt, P. F.; Liu, C.; Müller, M.; Piters, Ankie; Pommereau, J. P.; Portafaix, T.; Prados Roman, C.; Puentedura, O.; Querel, R.; Remmers, J.; Richter, A.; Rimmer, J.; Rivera Cárdenas, C.; Saavedra de Miguel, L.; Sinyakov, V. P.; Stremme, W.; Strong, K.; Van Roozendael, M.; Pepijn Veefkind, J.; Wagner, T.; Wittrock, F.; Yela González, M.; Zehner, C.; Navarro-Comas, Mónica; Navarro-Comas, Mónica; European Space Agency (ESA); French Institut National des Sciences de l'Univers (INSU); Centre National D'Etudes Spatiales (CNES); Centre National de la Recherche Scientifique (CNRS); Institut polaire français Paul Emile Victor (IPEV); Belgian Science Policy Office (BELSPO); Verhoelst, T. [0000-0003-0163-9984]; Compernolle, S. [0000-0003-0872-0961]; Pinardi, G. [0000-0001-5428-916X]; Eskes, H. [0000-0002-8743-4455]; Bais, A. [0000-0003-3899-2001]; Folkert Boersma, K. [0000-0002-4591-7635]; Bognar, K. [0000-0003-4619-2020]; Donner, S. [0000-0001-8868-167X]; Elokhov, A. [0000-0003-4725-9186]; Grutter de la Mora, M. [0000-0001-9800-5878]; Gruzdev, A. [0000-0003-3224-1012]; Karagkiozidis, D. [0000-0002-3595-0538]; Kivi, R. [0000-0001-8828-2759]; Liu, C. [0000-0002-3759-9219]; Müller, M. [0000-0001-5284-5425]; Pommereau, J. P. [0000-0002-8285-9526]; Prados Roman, C. [0000-0001-8332-0226]; Puentedura, O. [0000-0002-4286-1867]; Querel, R. [0000-0001-8792-2486]; Richter, A. [0000-0003-3339-212X]; Rivera Cárdenas, C. [0000-0002-8617-265X]; Stremme, W. [0000-0003-0791-3833]; Strong, K. [0000-0001-9947-1053]; Pepijn Veefkind, J. [0000-0003-0336-6406]
This paper reports on consolidated ground-based validation results of the atmospheric NO2 data produced operationally since April 2018 by the TROPOspheric Monitoring Instrument (TROPOMI) on board of the ESA/EU Copernicus Sentinel-5 Precursor (S5P) satellite. Tropospheric, stratospheric, and total NO2 column data from S5P are compared to correlative measurements collected from, respectively, 19 Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS), 26 Network for the Detection of Atmospheric Composition Change (NDACC) Zenith-Scattered-Light DOAS (ZSL-DOAS), and 25 Pandonia Global Network (PGN)/Pandora instruments distributed globally. The validation methodology gives special care to minimizing mismatch errors due to imperfect spatio-temporal co-location of the satellite and correlative data, e.g. by using tailored observation operators to account for differences in smoothing and in sampling of atmospheric structures and variability and photochemical modelling to reduce diurnal cycle effects. Compared to the ground-based measurements, S5P data show, on average, (i) a negative bias for the tropospheric column data, of typically −23 % to −37 % in clean to slightly polluted conditions but reaching values as high as −51 % over highly polluted areas; (ii) a slight negative median difference for the stratospheric column data, of about −0.2 Pmolec cm−2, i.e. approx. −2 % in summer to −15 % in winter; and (iii) a bias ranging from zero to −50 % for the total column data, found to depend on the amplitude of the total NO2 column, with small to slightly positive bias values for columns below 6 Pmolec cm−2 and negative values above. The dispersion between S5P and correlative measurements contains mostly random components, which remain within mission requirements for the stratospheric column data (0.5 Pmolec cm−2) but exceed those for the tropospheric column data (0.7 Pmolec cm−2). While a part of the biases and dispersion may be due to representativeness differences such as different area averaging and measurement times, it is known that errors in the S5P tropospheric columns exist due to shortcomings in the (horizontally coarse) a priori profile representation in the TM5-MP chemical transport model used in the S5P retrieval and, to a lesser extent, to the treatment of cloud effects and aerosols. Although considerable differences (up to 2 Pmolec cm−2 and more) are observed at single ground-pixel level, the near-real-time (NRTI) and offline (OFFL) versions of the S5P NO2 operational data processor provide similar NO2 column values and validation results when globally averaged, with the NRTI values being on average 0.79 % larger than the OFFL values.
Restringido
Measurement of dust optical depth using the solar irradiance sensor (SIS) onboard the ExoMars 2016 EDM
(Elsevier, 2017-01-20) Toledo, D.; Arruego, I.; Jiménez, J. J.; Gómez, L.; Yela González, M.; Rannou, P.; Pommereau, J. P.; Apéstigue, Víctor; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO)
"The solar irradiance sensor (SIS) was included in the DREAMS package onboard the ExoMars 2016 Entry Descent and Landing Demonstrator Module, and has been selected in the METED meteorological station onboard the ExoMars 2020 Lander. This instrument is designed to measure at different time intervals the scattered flux or the sum of direct flux and scattered flux in UVA (315-400 nm) and NIR (700-1100 nm) bands. For SIS'16, these measurements are performed by a total of 3 sensors per band placed at the faces of a truncated tetrahedron with face inclination angles of 60. The principal goal of SIS'16 design is to perform measurements of the dust opacity in UVA and NIR wavelengths ranges, crucial parameters in the understanding of the Martian dust cycle. The retrieval procedure is based on the use of radiative transfer simulations to reproduce SIS observations acquired during daytime as a function of dust opacity. Based on different sensitivity analysis, the retrieval procedure also requires to include as free parameters (1) the, dust effective radius; (2) the dust effective variance; and (3) the imaginary part of the refractive index of dust particles in UVA band. We found that the imaginary part of the refractive index of dust particles does not have a big impact on NIR signal, and hence we can kept constant this parameter in the retrieval of dust opacity at this channel. In addition to dust opacity measurements, this instrument is also capable to detect and characterize clouds by looking at the time variation of the color index (CI), defined as the ratio between the observations in NIR and UVA channels, during daytime or twilight. By simulating CI signals with a radiative transfer model, the cloud opacity and cloud altitude (only during twilight) can be retrieved. Here the different retrieval procedures that are used to analyze SIS measurements, as well as the results obtained in different sensitivity analysis, are presented and discussed."
Restringido
The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season
(Elsevier, 2018-02-01) Bettanini, C.; Esposito, F.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, Enrico; Ferri, F.; Marty, Laurent; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, Edoardo; Ari-Matti, H.; Montmessin, F.; Wilson, Colin; Arruego, I.; Abbaki. S.; Bellucci, G.; Berthelier, J. J.; Calcutt, S.; Forget, F.; Genzer, M.; Gilbert, Pierre; Haukka, H.; Jiménez, Juan J.; Jiménez, Salvador; Josset, J. L.; Karatekin, Özgür; Landis, G.; Lorenz, Ralph; Martínez Oter, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Patel, M.; Pommereau, J. P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Rennó, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vázquez, L.; Apéstigue, Víctor; Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF)
"The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) instrument on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and its direction, but also on solar irradiance, dust opacity and atmospheric electrification; this comprehensive set of parameters would assist the quantification of risks and hazards for future manned exploration missions mainly related to the presence of airborne dust. Schiaparelli landing on Mars was in fact scheduled during the foreseen dust storm season (October 2016 in Meridiani Planum) allowing DREAMS to directly measure the characteristics of such extremely harsh environment. DREAMS instrument’s architecture was based on a modular design developing custom boards for analog and digital channel conditioning, power distribution, on board data handling and communication with the lander. The boards, connected through a common backbone, were hosted in a central electronic unit assembly and connected to the external sensors with dedicated harness. Designed with very limited mass and an optimized energy consumption, DREAMS was successfully tested to operate autonomously, relying on its own power supply, for at least two Martian days (sols) after landing on the planet. A total of three flight models were fully qualified before launch through an extensive test campaign comprising electrical and functional testing, EMC verification and mechanical and thermal vacuum cycling; furthermore following the requirements for planetary protection, contamination control activities and assay sampling were conducted before model delivery for final integration on spacecraft. During the six months cruise to Mars following the successful launch of ExoMars on 14th March 2016, periodic check outs were conducted to verify instrument health check and update mission timelines for operation. Elaboration of housekeeping data showed that the behaviour of the whole instrument was nominal during the whole cruise. Unfortunately DREAMS was not able to operate on the surface of Mars, due to the known guidance anomaly during the descent that caused Schiaparelli to crash at landing. The adverse sequence of events at 4 km altitude anyway triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. The spare models of DREAMS are currently in use at university premises for the development of autonomous units to be used in cubesat mission and in probes for stratospheric balloons launches in collaboration with Italian Space Agency."