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Observations of the lunar luminescence are reported for a dozen of specific Moon features using the line-depth method with a high resolution spectroscopic technique. The data indicate a variation of the Moon proper emission as a function of the phase angle which is interpreted as a proof of the thermoluminescent origin of this emission. 相似文献
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This study investigates whether there has been a decline in fish stocks of a coral reef in Thailand, and if so, whether that decline is due to small-scale fishing. The research methods used included fish sampling by UVC, interviews and questionnaires with key informants and artisanal fishers. The results confirmed that there has been a decline in piscivores and carnivores (though not herbivores), and the main perceived threat came not from artisanal but from commercial fishing. Recommendations are to replace the largely unrestricted fishery with a more regulated regime backed by effective enforcement. 相似文献
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Marie-Lise Delgard Bruno Deflandre Jonathan Deborde Marion Richard Céline Charbonnier Pierre Anschutz 《Aquatic Geochemistry》2013,19(3):241-259
From 1989 to 2007, a severe decline in Zostera noltii meadows was reported in the Arcachon Bay, with an accelerated regression after 2005. We investigated the inter-annual variability of the biogeochemistry of the sediment in an area affected by seagrass decline. In late summer and in winter of the years 2006, 2010, and 2011, sediment cores were collected at low tide on vegetated and adjacent non-vegetated sediments located in the eastern part of the Arcachon Bay. The geochemical analyses of sediment solid-phase organic carbon, reactive P and Fe, and the pore water concentrations of Fe2+, DIP, and NH4 + are presented. The changes in the chemistry of sediment and pore water between 2006 and 2010 are interpreted as a consequence of the decrease in the Z. noltii biomass between 2006 and 2010. The absence of significant seasonal variations in biomass throughout the growth period (March–September) in 2011 is most likely related to the regression of Z. noltii meadow that strongly affects the study area. In contrast to the healthy meadow in 2006, the declining meadow favored the dissolution of sedimentary particulate phosphorus in winter. In late summer, the low biomass of seagrass resulted in a net release of ammonium in the pore water of the upper 20 cm of sediment. This study clearly shows that seagrass decay may enhance nutrient release in sediments, resulting in a significant supply of phosphorus to the water column of a magnitude comparable to annual inputs to the lagoon from the rivers and the tidal pump. 相似文献
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Marie-Lise Bernard Jack Molini Rose-Helen Petit Franois Beauducel Gilbert Hammouya Guy Marion 《Journal of Volcanology and Geothermal Research》2006,150(4):395-409
This paper presents the first remote measurements of La Soufrière gas emissions since the fumarolic and seismic reactivation in 1992. The chemical composition of the plumes has been measured from May 2003 to September 2004 using an Open Path Fourier Transform InfraRed (OP-FTIR) spectrometer, up to 15 m downwind the South Crater. HCl is clearly detected (concentration between 2.4 and 12 ppmv) whereas SO2 and H2S generally remain below the detection limit of the OP-FTIR. Direct measurements of SO2 and H2S near the South Crater with a Lancom III analyzer show a fast decrease of their concentrations with the distance. Calculated Cl / S mass ratios are high: from 9.4 ± 1.7 at 15 m from the vent to 2.8 ± 0.6 at 140 m. The enrichment in HCl of the gas emitted at La Soufrière, observed since 1998, corresponds to the degassing of a magma enriched in Cl and depleted in S. This result agrees with isotopic measurements which suggest a magmatic origin of the gases. Readjustments inside the volcanic system may have taken place during the seismic activity beginning in 1992 and enhance the transfer of magmatic gases to the summit. 相似文献
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M.L. Chanin 《Planetary and Space Science》1983,31(7):811-812
Some of the more significant results of the international ozone comparison campaign held in France in June 1981 are elucidated and compared with results of preceeding intercomparisons. 相似文献
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Experiment data of the vertical distribution of sodium density measured by lidar are compared with the horizontal structures observed by photogrammetry on the sodium emissive layer. The gravity wave induced variations seen in the vertical distribution are used to define a 2-dimensional model of the layer, which is shown to explain the observed horizontal patterns. It is strongly suggested that the structures currently seen on OH can be also related to gravity waves and that their sporadic occurrence in specific angular directions is explained by the wave characteristic and by wave or wind induced chemistry. 相似文献
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This paper presents preliminary results of a cooperative franco-sovietic program to study the polar atmosphere by the lidar technique. Atomic sodium concentration has been measured together with the neutral atmospheric temperature by means of the absorption method. The total sodium content is 6.109 atom cm?2 during February and March 1976. High values of the temperature (～210 K) have been measured at the mesopause level. 相似文献
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