The information system of the French Peatland Observation Service: Service National d'Observation Tourbières – A valuable tool to assess the impact of global changes on the hydrology and biogeochemistry of temperate peatlands through long term monitoring

Mitigating and adapting to global changes requires a better understanding of the response of the Biosphere to these environmental variations. Human disturbances and their effects act in the long term (decades to centuries) and consequently, a similar time frame is needed to fully understand the hydrological and biogeochemical functioning of a natural system. To this end, the ‘Centre National de la Recherche Scientifique’ (CNRS) promotes and certifies long-term monitoring tools called national observation services or ‘Service National d'Observation’ (SNO) in a large range of hydrological and biogeochemical systems (e.g., cryosphere, catchments, aquifers). The SNO investigating peatlands, the SNO ‘Tourbières’, was certified in 2011 ( https://www.sno-tourbieres.cnrs.fr/ ). Peatlands are mostly found in the high latitudes of the northern hemisphere and French peatlands are located in the southern part of this area. Thus, they are located in environmental conditions that will occur in northern peatlands in coming decades or centuries and can be considered as sentinels. The SNO Tourbières is composed of four peatlands: La Guette (lowland central France), Landemarais (lowland oceanic western France), Frasne (upland continental eastern France) and Bernadouze (upland southern France). Thirty target variables are monitored to study the hydrological and biogeochemical functioning of the sites. They are grouped into four datasets: hydrology, fluvial export of organic matter, greenhouse gas fluxes and meteorology/soil physics. The data from all sites follow a common processing chain from the sensors to the public repository. The raw data are stored on an FTP server. After operator or automatic processing, data are stored in a database, from which a web application extracts the data to make them available ( https://data-snot.cnrs.fr/data-access/ ). Each year at least, an archive of each dataset is stored in Zenodo, with a digital object identifier (DOI) attribution ( https://zenodo.org/communities/sno_tourbieres_data/ ).     

Infrared spectrophotometry of Comet IRAS-Araki-Alcock (1983d): a bare nucleus revealed?

Spectra of the central core and surrounding coma of Comet IRAS-Araki-Alcock (1983d) were obtained at 8–13 μm on 11 May and 2–4 μm on 12 May 1983. Spatially resolved measurements at 10 μm with a 4-arcsec beam showed that the central core was more than 100 times brighter than the inner coma only 8 arcsec away; for radially outflowing dust, the brightness ratio would be a factor of 8. The observations of the central core are consistent with direct detection of a nucleus having a radius of approximately 5 km. The temperature of the sunlit hemisphere was > 300 K. Spectra of the core are featureless, while spectra of the coma suggest weak silicate emission. The spectra show no evidence for icy grains. The dust producton rate on 11.4 May was ～ 10⁵ g/sec, assuming that the gas flux from the dust-producing areas on the nucleus was ～ 10^?5 g/cm²/sec.     

Distinguishing the Regional Atmospheric Controls on Precipitation Isotopic Variability in the Central-Southeast Portion of Brazil

Precipitation isotope ratios (O and H) record the history of water phase transitions and fractionation processes during moisture transport and rainfall formation. Here, we evaluated the isotopic composition of precipitation over the central-southeastern region of Brazil at different timescales. Monthly isotopic compositions were associated with classical effects (rainfall amount, seasonality, and continentality), demonstrating the importance of vapor recirculation processes and different regional atmospheric systems (South American Convergence Zone-SACZ and Cold Fronts-CF). While moisture recycling and regional atmospheric processes may also be observed on a daily timescale, classical effects such as the amount effect were not strongly correlated (δ¹⁸O-precipitation rate r ≤ –0.37). Daily variability revealed specific climatic features, such as δ¹⁸O depleted values (~ –6‰ to –8‰) during the wet season were associated with strong convective activity and large moisture availability. Daily isotopic analysis revealed the role of different moisture sources and transport effects. Isotope ratios combined with d-excess explain how atmospheric recirculation processes interact with convective activity during rainfall formation processes. Our findings provide a new understanding of rainfall sampling timescales and highlight the importance of water isotopes to decipher key hydrometeorological processes in a complex spatial and temporal context in central-southeastern Brazil.     

GIScience Journals Ranking and Evaluation: An International Delphi Study

Researchers’ fame in most scientific fields is closely linked to their publishing capacity, both in terms of quantity and quality. In GIScience, as in other fields, this situation demands that the researcher evaluate and to be very familiar with the scientific journals in which they could publish. Some specialized journals (e.g. Journal of Citation Reports or JCR) are devoted to ranking these reviews according to various methods and criteria. Compared to other scientific communities, GIScience is relatively new and constantly evolving. Therefore, the journals of this field do not benefit from any real formal ranking yet. The objective of this paper is to present the process and results of a study aimed at addressing this gap. More specifically, the challenge is to elaborate an importance ranking of the scientific journals in the field of GIScience. To do so, both a qualitative (Delphi study carried out with 40 international experts) and a quantitative (JCR impact factor) approach has been implemented. This triangulation method leads to an early global ranking of the journals of this field.     

Properties and Comparison of Some Kriging Sub-model Aggregation Methods

Mathematical Geosciences - Kriging is a widely employed technique across computer experiments, machine learning and geostatistics. An important challenge for kriging is its high costs when dealing...     

Ocean bottom refraction seismograph (OBRS)

This paper describes a pop-up ocean bottom seismograph designed primarily for refraction surveys both on the continental shelf and in deep sea. Its development is the extension of our system based on seismic detectors located on the sea floor with radio transmission of seismic signals and used for seismic refraction studies on the continental shelf. The seismic detectors (vertical geophone or hydrophone and two orthogonally mounted horizontal geophones) are located outside of the pressure vessel on the main frame. Optionally, the seismic sensors may be decoupled from the main frame assembly. This decoupling is performed by a mobile arm positioning the separate three component sensor package on the sea floor.Contribution No. 455 of the Département Scientifique, Centre Océanologique de Bretagne.     

Nouvelles données sur le téphra de Sarliève et le téphra CF7, marqueurs chrono-stratigraphiques de Grande Limagne (Massif central,France)

A trachytic tephra, discovered in the ancient lake of Sarliève, ‘Grande Limagne’, has been dated using the thermoluminescence technique. The obtained age, 16±4 ka ($\text{2}\text{σ}$), is older than that of the trachytic volcanoes of the Cha??ne des Puys, the ashes of which have already been locally recognised in the region. Its analysis confirms its originality. In the course of the comparisons made to search for its spring, it appears that the wide-dispersion tephra CF7, beforehand correlated by hypothesis to the Puy de Clierzou, probably originates from the Kilian crater or the Puy de Vasset. To cite this article: D. Miallier et al., C. R. Geoscience 336 (2004).