A 6-year global cloud climatology from the Atmospheric InfraRed Sounder AIRS and a statistical analysis in synergy with CALIPSO and CloudSat

We present a six-year global climatology of cloud properties, obtained from observations of the Atmospheric Infrared Sounder (AIRS) onboard the NASA Aqua satellite. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) combined with CloudSat observations, both missions launched as part of the A-Train in 2006, provide a unique opportunity to evaluate the retrieved AIRS cloud properties such as cloud amount and height. In addition, they permit to explore the vertical structure of different cloud types. AIRS-LMD cloud detection agrees with CALIPSO about 85% over ocean and about 75% over land. Global cloud amount has been estimated from 66% to 74%, depending on the weighting of not cloudy AIRS footprints by partial cloud cover from 0 to 0.3. 42% of all clouds are high clouds, and about 42% of all clouds are single layer low-level clouds. The "radiative" cloud height determined by the AIRS-LMD retrieval corresponds well to the height of the maximum backscatter signal and of the "apparent middle" of the cloud. Whereas the real cloud thickness of high opaque clouds often fills the whole troposphere, their "apparent" cloud thickness (at which optical depth reaches about 5) is on average only 2.5 km. The real geometrical thickness of optically thin cirrus as identified by AIRS-LMD is identical to the "apparent" cloud thickness with an average of about 2.5 km in the tropics and midlatitudes. High clouds in the tropics have slightly more diffusive cloud tops than at higher latitudes. In general, the depth of the maximum backscatter signal increases nearly linearly with increasing "apparent" cloud thickness. For the same "apparent" cloud thickness optically thin cirrus show a maximum backscatter about 10% deeper inside the cloud than optically thicker clouds. We also show that only the geometrically thickest opaque clouds and (the probably surrounding anvil) cirrus penetrate the stratosphere in the tropics

Psychanalyse appliquée aux représentations picturales des camps de concentration nazis

Ce travail de thèse porte sur la question de l existence de représentations, sous forme picturale (dessins, peintures ), exécutées par certains sujets pendant leur internement dans les camps de concentration nazis, dans un contexte de traumatisme extrême, considéré comme de l ordre de l irreprésentable. A partir d une étude de cas de trois sujets dessinateurs/trices, et de leur production picturale, abordée selon la méthode de la psychanalyse appliquée au sens d André Green, une réflexion peut s amorcer autour de l hypothèse d une autoconservation, différenciée, physique et psychique. Afin de la mener à bien sont résumées les représentations historiques après-coup, puis cernées la problématique du traumatisme extrême dans les camps de concentration et la création d un point de vue psychanalytique avec des auteurs tels que Freud, Férenczi, Winnicott, Roussillon, Green, Bertrand, Zaltzman, Cerf de Duzeele, Waintrater et Cupa. Les résultats amènent à constater l existence chez ces sujets d une aire intermédiaire qui leur a permis de conserver une activité représentationnelle particulière. Celle-ci constitue un travail de représentation de la surréalité déréalisante du camp, principalement utilisé dans une autoconservation psychique. Inscrit dans un fil de culture, de filiation et d historicisation, il participe d un travail de liaison intrapsychique et intersubjectif ainsi que d une lutte contre la désintrication pulsionnelle. Des fantasmes omnipotents d éternité sous-jacents aux dessins vont de pair avec, dans l activité, une coexcitation libidinale qui ouvre sur la question d une éventuelle sublimationThis thesis begins with noticing that pictorial representations (e.g. drawings or paintings etc.) in nazi concentration camps have been made by some subjets while imprisonment, in a massive traumatism, usually thinked as a non-representable situation. From a three drawers and drawings study, imcompletely by Andre Green s applied psychoanalysis method, reflexion can occur with the hypothesis of a dissociated physical and psychic self-preservation in that context. To achieve this goal, historical nazi camps differed representations, massive traumatism and creation, are detailed in a psychoanalytic viewpoint with Freud, Ferenczi, Winnicott, Roussillon, Green, Bertrand, Zaltzman, Cerf de Duzeele, Waintrater and Cupa as main authors. Results show the existence of an intermediate space that enabled these subjets to keep a specific representational activity. It s mainly a representation work of the camp overreality in a psychic self-preservation way. This work is an internal and external connection work, in a culture and filiation link, that struggles against drive defusion. Eternity and omnipotent fantasy, libidinal coexcitation underly drawings and pictorial activity. They interrogate about a possible sublimationNANTERRE-PARIS10-Bib. élec. (920509901) / SudocSudocFranceF

Assessing the effect of tandem phase Sentinel-3 OLCI Sensor uncertainty on the estimation of potential ocean chlorophyll-a trends

The Sentinel-3 tandem project represents the first time that two ocean colour satellites have been flown in the same orbit with minimal temporal separation (~30 s), thus allowing them to have virtually identical views of the ocean. This offers an opportunity for understanding how differences in individual sensor uncertainty can affect conclusions drawn from the data. Here, we specifically focus on trend estimation. Observational chlorophyll-a uncertainty is assessed from the Sentinel-3A Ocean and Land Colour Imager (OLCI-A) and Sentinel-3B OLCI (OLCI-B) sensors using a bootstrapping approach. Realistic trends are then imposed on a synthetic chlorophyll-a time series to understand how sensor uncertainty could affect potential long-term trends in Sentinel-3 OLCI data. We find that OLCI-A and OLCI-B both show very similar trends, with the OLCI-B trend estimates tending to have a slightly wider distribution, although not statistically different from the OLCI-A distribution. The spatial pattern of trend estimates is also assessed, showing that the probability distributions of trend estimates in OLCI-A and OLCI-B are most similar in open ocean regions, and least similar in coastal regions and at high northern latitudes. This analysis shows that the two sensors should provide consistent trends between the two satellites, provided future ageing is well quantified and mitigated. The Sentinel-3 programme offers a strong baseline for estimating long-term chlorophyll-a trends by offering a series of satellites (starting with Sentinel-3A and Sentinel-3B) that use the same sensor design, reducing potential issues with cross-calibration between sensors. This analysis contributes an important understanding of the reliability of the two current Sentinel-3 OLCI sensors for future studies of climate change driven chlorophyll-a trends

The dependence of contrail formation on the weather pattern and altitude in the North Atlantic

Aircraft flying through cold ice-supersaturated air produce persistent contrails which contribute to the climate impact of aviation. Here, we demonstrate the importance of the weather situation, together with the route and altitude of the aircraft through this, on estimating contrail coverage. The results have implications for determining the climate impact of contrails as well as potential mitigation strategies. Twenty-one years of re-analysis data are used to produce a climatological assessment of conditions favorable for persistent contrail formation between 200 and 300 hPa over the north Atlantic in winter. The seasonal-mean frequency of cold ice-supersaturated regions is highest near 300 hPa, and decreases with altitude. The frequency of occurrence of ice-supersaturated regions varies with large-scale weather pattern; the most common locations are over Greenland, on the southern side of the jet stream and around the northern edge of high pressure ridges. Assuming aircraft take a great circle route, as opposed to a more realistic time-optimal route, is likely to lead to an error in the estimated contrail coverage, which can exceed 50% for westbound north Atlantic flights. The probability of contrail formation can increase or decrease with height, depending on the weather pattern, indicating that the generic suggestion that flying higher leads to fewer contrails is not robust

Benefits and lessons learned from the Sentinel-3 tandem phase

During its commissioning phase, the Copernicus Sentinel-3B satellite has been placed in a tandem formation with Sentinel-3A for a period of 6 months. This configuration allowed a direct comparison of measurements obtained by the two satellites. The purpose of this paper was to present the range of analyses that can be performed from this dataset, highlighting methodology aspects and the main outcomes for each instrument. We examined, in turn, the benefit of the tandem in understanding instrument operational modes differences, in assessing inter-satellite differences, and in validating measurement uncertainties. The results highlighted the very good consistency of the Sentinel-3A and B instruments, ensuring the complete inter-operability of the constellation. Tandem comparisons also pave the way for further improvements through harmonization of the sensors (OLCI), correction of internal stray-light sources (SLSTR), or high-frequency processing of SRAL SARM data. This paper provided a comprehensive overview of the main results obtained, as well as insights into some of the results. Finally, we drew the main lessons learned from the Sentinel-3 tandem phase and provided recommendations for future missions

The Relative Humidity in an Isentropic Advection–Condensation Model: Limited Poleward Influence and Properties of Subtropical Minima

An idealized model of advection and condensation of water vapor is considered as a representation of processes influencing the humidity distribution along isentropic surfaces in the free troposphere. Results are presented for how the mean relative humidity distribution varies in response to changes in the distribution of saturation specific humidity and in the amplitude of a tropical moisture source. Changes in the tropical moisture source are found to have little effect on the relative humidity poleward of the subtropical minima, suggesting a lack of poleward influence despite much greater water vapor concentrations at lower latitudes. The subtropical minima in relative humidity are found to be located just equatorward of the inflection points of the saturation specific humidity profile along the isentropic surface. The degree of mean subsaturation is found to vary with the magnitude of the meridional gradient of saturation specific humidity when other parameters are held fixed. The atmospheric relevance of these results is investigated by comparison with the positions of the relative humidity minima in reanalysis data and by examining poleward influence of relative humidity in simulations with an idealized general circulation model. It is suggested that the limited poleward influence of relative humidity may constrain the propagation of errors in simulated humidity fields

The SURPRISE demonstrator: a super-resolved compressive instrument in the visible and medium infrared for Earth Observation

While Earth Observation (EO) data has become ever more vital to understanding the planet and addressing societal challenges, applications are still limited by revisit time and spatial resolution. Though low Earth orbit missions can achieve resolutions better than 100 m, their revisit time typically stands at several days, limiting capacity to monitor dynamic events. Geostationary (GEO) missions instead typically provide data on an hour-basis but with spatial resolution limited to 1 km, which is insufficient to understand local phenomena. In this paper, we present the SURPRISE project - recently funded in the frame of the H2020 programme – that gathers the expertise from eight partners across Europe to implement a demonstrator of a super-spectral EO payload - working in the visible (VIS) - Near Infrared (NIR) and in the Medium InfraRed (MIR) and conceived to operate from GEO platform -with enhanced performance in terms of at-ground spatial resolution, and featuring innovative on-board data processing and encryption functionalities. This goal will be achieved by using Compressive Sensing (CS) technology implemented via Spatial Light Modulators (SLM). SLM-based CS technology will be used to devise a super-resolution configuration that will be exploited to increase the at-ground spatial resolution of the payload, without increasing the number of detector’s sensing elements at the image plane. The CS approach will offer further advantages for handling large amounts of data, as is the case of superspectral payloads with wide spectral and spatial coverage. It will enable fast on-board processing of acquired data for information extraction, as well as native data encryption on top of native compression. SURPRISE develops two disruptive technologies: Compressive Sensing (CS) and Spatial Light Modulator (SLM). CS optimises data acquisition (e.g. reduced storage and transmission bandwidth requirements) and enables novel onboard processing and encryption functionalities. SLM here implements the CS paradigm and achieves a super-resolution architecture. SLM technology, at the core of the CS architecture, is addressed by: reworking and testing off-the-shelf parts in relevant environment; developing roadmap for a European SLM, micromirror array-type, with electronics suitable for space qualification. By introducing for the first time the concept of a payload with medium spatial resolution (few hundreds of meters) and near continuous revisit (hourly), SURPRISE can lead to a EO major breakthrough and complement existing operational services. CS will address the challenge of large data collection, whilst onboard processing will improve timeliness, shortening time needed to extract information from images and possibly generate alarms. Impact is relevant to industrial competitiveness, with potential for market penetration of the demonstrator and its components

Remediable institutional alignment and water service reform: Beyond rational choice

A growing body of empirical evidence fails to support rational choice expectations of superior private sector efficiency in the urban water sector. Drawing on Oliver Williamson’s work on comparative institutional analysis, I suggest that institutional adaptability explains the efficiency and effectiveness of the public sector relative to the private sector. Under private sector participation, lowly remediable institutional adaptability favours the deployment of asymmetric power and the production of outcomes unaligned to reform objectives. Conversely, institutions supporting public operations are designed to facilitate the achievement of collective goals. This makes the alignment of individual attitudes, resources and institutions under in-house service provision less resilient to sustainability-oriented change. Remediable institutional alignment undergirds the comparative advantage of public water operations, as more ample opportunities are provided for compliance, allocative efficiency and adaptive performance. I thus call for a critical realist account of the outcomes of water service reform, free of rational choice dogma

Psychoanalysis applied to pictorial representations of nazi concentration camps

Ce travail de thèse porte sur la question de l’existence de représentations, sous forme picturale (dessins, peintures…), exécutées par certains sujets pendant leur internement dans les camps de concentration nazis, dans un contexte de traumatisme extrême, considéré comme de l’ordre de l’irreprésentable. A partir d’une étude de cas de trois sujets dessinateurs/trices, et de leur production picturale, abordée selon la méthode de la psychanalyse appliquée au sens d’André Green, une réflexion peut s’amorcer autour de l’hypothèse d’une autoconservation, différenciée, physique et psychique. Afin de la mener à bien sont résumées les représentations historiques après-coup, puis cernées la problématique du traumatisme extrême dans les camps de concentration et la création d’un point de vue psychanalytique avec des auteurs tels que Freud, Férenczi, Winnicott, Roussillon, Green, Bertrand, Zaltzman, Cerf de Duzeele, Waintrater et Cupa. Les résultats amènent à constater l’existence chez ces sujets d’une aire intermédiaire qui leur a permis de conserver une activité représentationnelle particulière. Celle-ci constitue un travail de représentation de la surréalité déréalisante du camp, principalement utilisé dans une autoconservation psychique. Inscrit dans un fil de culture, de filiation et d’historicisation, il participe d’un travail de liaison intrapsychique et intersubjectif ainsi que d’une lutte contre la désintrication pulsionnelle. Des fantasmes omnipotents d’éternité sous-jacents aux dessins vont de pair avec, dans l’activité, une coexcitation libidinale qui ouvre sur la question d’une éventuelle sublimationThis thesis begins with noticing that pictorial representations (e.g. drawings or paintings etc.) in nazi concentration camps have been made by some subjets while imprisonment, in a massive traumatism, usually thinked as a non-representable situation. From a three drawers and drawings study, imcompletely by Andre Green’s applied psychoanalysis method, reflexion can occur with the hypothesis of a dissociated physical and psychic self-preservation in that context. To achieve this goal, historical nazi camps differed representations, massive traumatism and creation, are detailed in a psychoanalytic viewpoint with Freud, Ferenczi, Winnicott, Roussillon, Green, Bertrand, Zaltzman, Cerf de Duzeele, Waintrater and Cupa as main authors. Results show the existence of an intermediate space that enabled these subjets to keep a specific representational activity. It’s mainly a representation work of the camp overreality in a psychic self-preservation way. This work is an internal and external connection work, in a culture and filiation link, that struggles against drive defusion. Eternity and omnipotent fantasy, libidinal coexcitation underly drawings and pictorial activity. They interrogate about a possible sublimatio

Relations entre cirrus et humidité dans la haute troposphère à partir du sondage infrarouge et de sa synergie avec d'autres observations. Application à l'impact du trafic aérien sur le climat.

L'augmentation considérable du trafic aérien depuis quelques décennies a motivé des recherches sur l'impact des traînées de condensation sur le climat. Lorsque celles-ci persistent, elles induisent une couverture nuageuse additionnelle en cirrus dont l'impact sur le climat est difficile à quantifier. La condition physique de la persistance des trainées de condensation est la sursaturation en glace (humidité relative supérieure à la saturation), phénomène assez fréquent dans la haute troposphère et condition nécessaire pour la formation des cirrus. Dans ce contexte, les sondeurs infrarouges ont l'avantage de fournir, de manière globale et continue, des mesures conjointes de propriétés nuageuses et de profils atmosphériques de température et de vapeur d'eau. Nous utilisons dans cette étude les bases de données climatiques TIROS-N Observation Vertical Sounder (TOVS) puis Atmospheric InfraRed Sounder (AIRS). Ces deux instruments n'ont pas une résolution verticale suffisante pour détecter la présence de fines couches de sursaturation en glace. Des synergies avec d'autres types observations permettent de le mettre en évidence et de le corriger. Nous démontrons notamment à l'aide du lidar CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) que l'humidité relative de la haute troposphère dans les cirrus, déterminée par AIRS, montre un biais négatif en comparaison de mesures in situ. Ce biais est lié à la résolution verticale de AIRS et il est d'autant plus prononcé que les nuages sont géométriquement fins. Il est difficile de détecter la sursaturation car cette dernière est plus à même d'apparaître sur de fines épaisseurs. Une méthode de correction est alors proposée pour mieux estimer les fréquences d'occurrence de la sursaturation en glace à l'échelle globale. La synergie entre AIRS et des mesures aéroportées de la campagne MOZAIC (Measurement of OZone and water vapour by AIrbus in-service airCraft) nous permet de construire une probabilité d'occurrence de la sursaturation en fonction de l'humidité relative déterminée par AIRS, quelque soit la valeur de cette humidité relative. Cette probabilité permet de construire des climatologies de la sursaturation en glace. Enfin, son couplage avec la détermination conjointe des propriétés nuageuses permet d'établir des climatologies des situations atmosphériques favorables à la persistance et à l'impact sur le climat des traînées de condensation