Search results for "forest"
showing 10 items of 3780 documents
Nature and origin of the hematite-bearing plains of Terra Meridiani based on analyses of orbital and Mars Exploration rover data sets
2006
The ~5 km of traverses and observations completed by the Opportunity rover from Endurance crater to the Fruitbasket outcrop show that the Meridiani plains consist of sulfate-rich sedimentary rocks that are largely covered by poorly-sorted basaltic aeolian sands and a lag of granule-sized hematitic concretions. Orbital reflectance spectra obtained by Mars Express OMEGA over this region are dominated by pyroxene, plagioclase feldspar, crystalline hematite (i.e., concretions), and nano-phase iron oxide dust signatures, consistent with Pancam and Mini-TES observations. Mossbauer Spectrometer observations indicate more olivine than observed with the other instruments, consistent with preferentia…
Alpha Particle X-Ray Spectrometer (APXS): Results from Gusev crater and calibration report
2006
The chemical composition of rocks and soils on Mars analyzed during the Mars Exploration Rover Spirit Mission was determined by X-ray analyses with the Alpha Particle X-Ray Spectrometer (APXS). Details of the data analysis method and the instrument calibration are presented. Measurements performed on Mars to address geometry effects and background contributions are shown. Cross calibration measurements among several instrument sensors and sources are discussed. An unintentional swap of the two flight instruments is evaluated. New concentration data acquired during the first 470 sols of rover Spirit in Gusev Crater are presented. There are two geological regions, the Gusev plains and the Col…
Mineralogy and chemistry of cobbles at Meridiani Planum, Mars, investigated by the Mars Exploration Rover Opportunity
2010
Numerous loose rocks with dimensions of a few centimeters to tens of centimeters and with no obvious physical relationship to outcrop rocks have been observed along the traverse of the Mars Exploration Rover Opportunity. To date, about a dozen of these rocks have been analyzed with Opportunity’s contact instruments, providing information about elemental chemistry (Alpha Particle X‐ray Spectrometer), iron mineralogy and oxidation states (Mossbauer Spectrometer) and texture (Microscopic Imager). These "cobbles" appear to be impact related, and three distinct groups can be identified on the basis of chemistry and mineralogy. The first group comprises bright fragments of the sulfate‐rich bedroc…
Influence des facteurs naturels sur la maturation du raisin, en 1979, à Pomerol et Saint-Emilion
1981
<p style="text-align: justify;">Les vignobles de Pomerol et Saint-Emilion sont implantés sur des sols dérivant de roches-mères variées; ils produisent des vins de haute qualité mais différents suivant leur origine géologique.</p><p style="text-align: justify;">Dans les meilleurs crus, nous avons pu vérifier que les variations mésoclimatiques sont très faibles et ont peu d'influence sur les caractères des vins. Par contre, en 1979, une relation a été mise en évidence entre les conditions de l'alimentation en eau de la vigne (étroitement liées aux propriétés physiques des sols) et la constitution des raisins à maturité (<em>V. vinifera</em> var. Merlot noir).<…
Modeling the mobility of glyphosate from two contrasting agricultural soils in laboratory column experiments
2019
Glyphosate (GLP) currently is one of the most widely used herbicides worldwide. The persistence of GLP and its major metabolite, aminomethylphosphonic acid (AMPA) in the environment has been described by other authors. This study was aimed at comparing the GLP and AMPA behavior in sandy and loamy sand soils after spiking with enhanced (445 µg g−1) concentrations of GLP in herbicide KLINIK® (Nufarm, Austria) and bioaugmentation followed by 40 days weathering and a consistent three-stage leaching in a laboratory column experiment. Soil samples were obtained from mineral topsoil (0–10 cm) within former agricultural lands where soil parent material was formed by glacigenic deposits. The total a…
The effects of habitat degradation on metacommunity structure of wood-inhabiting fungi in European beech forests
2013
Intensive forest management creates habitat degradation by reducing the variation of forest stands in general, and by removing old trees and dead wood in particular. Non-intervention forest reserves are commonly believed to be the most efficient tool to counteract the negative effects on biodiversity, but actual knowledge of the conservation efficiency is limited, especially for recent reserves. The structure of ecological communities is often described with measures of nestedness, beta diversity and similarity between communities. We studied whether these measures differ among forest reserves with different management histories. For this purpose, we used a large data set of wood-inhabiting…
www.climateofburundi.org
2010
Daily rainfall and air temperature data were collected by IGEBU. For a given station, the number of missing daily rainfall data, MRDm (days), was determined for each month of the recording period. The monthly rainfall depth, Pm (mm), and the monthly number of rainy days, NRDm (days),were determined for each month with a complete record of daily rainfall data. For a given month, Pm was obtained by summing the daily rainfall depth values and NRDm was obtained by counting the number of days of the month characterized by a daily rainfall depth greater than zero. The number of missing daily temperature data, MTDm (days), was also determined for each month of the recording period. The mean of the…
A comparison of HONO budgets for two measurement heights at a field station within the boreal forest in Finland
2015
Atmospheric concentrations of nitrous acid (HONO), one of the major precursors of the hydroxyl radical (OH) in the troposphere, significantly exceed the values predicted by the assumption of a photostationary state (PSS) during daytime. Therefore, additional sources of HONO were intensively investigated in the last decades. This study presents budget calculations of HONO based on simultaneous measurements of all relevant species, including HONO and OH at two different measurement heights, i.e. 1 m above the ground and about 2 to 3 m above the canopy (24 m above the ground), conducted in a boreal forest environment. We observed mean HONO concentrations of about 6.5 × 108 molecules cm−3 (26 p…
The summertime Boreal forest field measurement intensive (HUMPPA-COPEC-2010): an overview of meteorological and chemical influences
2011
This paper describes the background, instrumentation, goals, and the regional influences on the HUMPPACOPEC intensive field measurement campaign, conducted at the Boreal forest research station SMEAR II (Station for Measuring Ecosystem-Atmosphere Relation) in Hyyti¨al¨a, Finland from 12 July–12 August 2010. The prevailing meteorological conditions during the campaign are examined and contrasted with those of the past six years. Back trajectory analyses show that meteorological conditions at the site in 2010 were characterized by a higher proportion of southerly flow than in the other years studied. As a result the summer of 2010 was anomalously warm and high in ozone making the campaign rel…
Summertime total OH reactivity measurements from boreal forest during HUMPPA-COPEC 2010
2012
Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyyti¨al¨a (Latitude 61510 N; Longitude 24170 E) in July and August 2010 using the Comparative Reactivity Method (CRM). The CRM – total OH reactivity method – is a direct, in-situ determination of the total loss rate of hydroxyl radicals (OH) caused by all reactive species in air. During the intensive field campaign HUMPPA-COPEC 2010 (Hyyti¨al¨a United Measurements of Photochemistry and Particles in Air – Comprehensive Organic Precursor Emission and Concentration study) the total OH reactivity was monitored both inside (18 m) and directly above the forest canopy (24 m) for the first time. The compariso…