Abstract: This paper is issued from one chapter of Ismael Keddar PhD thesis. I Keddar was supervised by F Bonadonna as main supervisor and S F Dobson as co-supervisor, and stopped the research career after defending his thesis in 2014. In 2015, SF Dobson fraudulently published this chapter deleting my name from the authorship (as it was in the thesis manuscript) and without informing me. The direction of my lab (the CEFE-CNRS), the IPEV, and the CNRS itself were informed, and sustained me. A legal case has been opened by CNRS.

Abstract: This paper is devoted to the simultaneous determination of the coseismic and postseismic gravitational changes caused by the great 2004 December 26 Sumatra–Andaman earthquake from the time-variable global gravity fields recovered by the Gravity Recovery And Climate Experiment (GRACE) mission. Furthermore, a complete modelling of the elasto-gravitational response of a self-gravitating, spherically layered, elastic earth model is carried out using a normal-modes summation for comparison with the observed coseismic gravitational change. Special attention is paid to the ocean mass redistribution. Special care is paid during the inversion of the data to avoid contamination of tectonic gravity changes by ocean tidal model errors, seasonal and interannual signals originating from continental hydrology and oceanic circulation as well as contamination of the coseismic gravity change by the postseismic relaxation. We use a 4.6-yr-long time-series of global gravity solutions including 26 months of postseismic data, provided by the Groupe de Recherche en Géodésie Spatiale (GRGS). For comparison, the Release-04 solutions of the Center for Space Research (CSR) are also investigated after a spectral windowing or a Gaussian spatial smoothing. Results are shown both in terms of geoid height changes and gravity variations. Coseismic and postseismic gravitational changes estimated from the different gravity solutions are globally similar, although their spatial extent and amplitude depend on the type of filter used in the processing of GRACE fields. The highest signal-to-noise ratio is found with the GRGS solutions. The postseismic signature has a spectral content closer to the GRACE bandwidth than the coseismic signature and is therefore better detected by GRACE. The coseismic signature consists mainly of a strong gravity decrease east of the Sunda trench, in the Andaman Sea. A gravity increase is also detected at a smaller scale, west of the trench. The model for the coseismic gravity changes agrees well with the coseismic signature estimated from GRACE, regarding the overall shape and orientation, location with respect to the trench and order of magnitude. Coseismic gravity changes are followed by a postseismic relaxation that are well fitted by an increasing exponential function with a mean relaxation time of 0.7 yr. The total postseismic gravity change consists of a large-scale positive anomaly centred above the trench and extending over 15° of latitude along the subduction. After 26 months, the coseismic gravity decrease has been partly compensated by the postseismic relaxation, but a negative anomaly still remains south of Phuket. A dominant gravity increase extends over 15° of latitude west of the trench, being maximal south of the epicentre area. By investigating analyses of two global hydrology models and one ocean general circulation model, we show that our GRACE estimates of the coseismic and postseismic gravitational changes are almost not biased by interannual variations originating from continental hydrology and ocean circulation in the subduction area and in the central part of the Andaman Sea, while they are biased by several μGal in the Malay Peninsula

Abstract: This paper investigates the impact of ground albedo neutrons in the terrestrial radiation field and their seasonal variations. A modeling methodology is proposed, it is based on ATMORAD (atmospheric shower modeling) and GEANT4 simulations taking into account the soil characteristics and hydrogen content. This method was validated thanks to neutron measurements performed in two high altitude stations located in medium geomagnetic latitude and Antarctica (Pic-du-Midi and Concordia, respectively). Thus, the chemical rock composition, the density, the water content and the snow pack impacts to neutron spectrum were investigated. Simulated and measured spectra were compared. Analyses show that variations are dominant in the thermal domain (i.e. En <;0.5 eV) and lesser degree in epithermal and evaporation domains (i.e. 0.5 eV <; En <;0.1 MeV and 0.1 MeV <; En <;20 MeV, respectively). The last part investigates the impact induced by the evaporation neutron contribution to Single Event Rate (more impacted by the ground albedo neutron). Results show that evaporation neutrons contribution to the total SER should be assessed for high-sensitive technologies.

Abstract: This paper describes the assembly of an updated quasi-global dataset of higher-frequency sea level information obtained from tide gauges operated by many agencies around the world. We believe that the construction of such a dataset is fundamental to scientific research in sea level variability and also to practical aspects of coastal engineering. A first version of the dataset was used in approximately a dozen published studies, and this second version is about twice the size, containing longer and more geographically representative sea level records. The dataset has acquired a digital object identifier and may be obtained from several sources. The paper mentions some of the merits of and deficiencies with the present version and takes a forward look at how the dataset may be updated in the future.

Abstract: This paper demonstrates an inversion of surface CO2 fluxes using concentrations derived from assimilation of satellite radiances. Radiances come from the Atmospheric Infrared Sounder (AIRS) and are assimilated within the system of the European Centre for Medium-Range Weather Forecasts. We evaluate the quality of the inverted fluxes by comparing simulated concentrations with independent airborne measurements. As a benchmark we use an inversion based on surface flask measurements and another using only the global concentration trend. We show that the AIRS-based inversion is able to improve the match to the independent data compared to the prior estimate but that it usually performs worse than either the flask-based or trend-based inversion.