212 research outputs found

    Long term measurement network for FIFE

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    The objectives were: to obtain selected instruments which were not standard equipment on the Portable Automated Mesometeorological (PAM) and Data Control Platform (DCP) stations; to assist in incorporation of these instruments onto the PAM and DCP stations; to help provide routine maintenance of the instruments; to conduct periodic instrument calibrations; and to repair or replace malfunctioning instruments when possible. All of the objectives were or will be met soon. All instruments and the necessary instrument stands were purchased or made and were available for inclusion on the PAM and DCP stations before the beginning of the IFC-1. Due to problems beyond control, the DCP stations experienced considerable difficulty in becoming operational. To fill some of the gaps caused by the DCP problems, Campbell CR21-X data loggers were installed and the data collected on cassette tapes. Periodic checks of all instruments were made, to maintain data quality, to make necessary adjustments in certain instruments, to replace malfunctioning instruments, and to provide instrument calibration. All instruments will be calibrated before the beginning of the 1988 growing season as soon as the weather permits access to all stations and provides conditions that are not too harsh to work in for extended periods of time

    Measurement of surface physical properties and radiation balance for KUREX-91 study

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    Biophysical properties and radiation balance components were measured at the Streletskaya Steppe Reserve of the Russian Republic in July 1991. Steppe vegetation parameters characterized include leaf area index (LAI), leaf angle distribution, mean tilt angle, canopy height, leaf spectral properties, leaf water potential, fraction of absorbed photosynthetically active radiation (APAR), and incoming and outgoing shortwave and longwave radiation. Research results, biophysical parameters, radiation balance estimates, and sun-view geometry effects on estimating APAR are discussed. Incoming and outgoing radiation streams are estimated using bidirectional spectral reflectances and bidirectional thermal emittances. Good agreement between measured and modeled estimates of the radiation balance were obtained

    Calibration of field reference panel and radiometers used in FIFE 1989

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    Remote sensing of the earth's surface features involves the measurement of reflected solar radiation and the interpretation of the data in biophysical terms. Reflected radiation is a function of the surface properties and incident solar irradiance. The amount of radiation reflected from a surface is compared to the amount of solar radiation received at the surface as a means of comparing information from different times of day as well as for different days of the year. Thus, it is imperative to calibrate the instruments used to measure the incoming and reflected radiation

    Measuring and modeling near surface reflected and emitted radiation fluxes at the FIFE site

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    Research was conducted during the four Intensive Field Campaigns (IFC) of the FIFE project in 1987. The research was done on a tall grass prairie with specific measurement sites on and near the Konza Prairie in Kansas. Measurements were made to help meet the following objectives: determination of the variability in reflected and emitted radiation fluxes in selected spectral wavebands as a function of topography and vegetative community; development of techniques to account for slope and sun angle effects on the radiation fluxes; estimation of shortwave albedo and net radiation fluxes using the reflected and emitted spectral measurements described; estimation of leaf and canopy spectral properties from calculated normalized differences coupled with off-nadir measurements using inversion techniques; estimation of plant water status at several locations with indices utilizing plant temperature and other environmental parameters; and determination of relationships between estimated plant water status and measured soil water content. Results are discussed

    Measuring and modeling near-surface reflected and emitted radiation fluxes at the FIFE site

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    Information is presented pertaining to the measurement and estimation of reflected and emitted components of the radiation balance. Information is included about reflectance and transmittance of solar radiation from and through the leaves of some grass and forb prairie species, bidirectional reflectance from a prairie canopy is discussed and measured and estimated fluxes are described of incoming and outgoing longwave and shortwave radiation. Results of the study showed only very small differences in reflectances and transmittances for the adaxial and abaxial surfaces of grass species in the visible and infrared wavebands, but some differences in the infrared wavebands were noted for the forbs. Reflectance from the prairie canopy changed as a function of solar and view zenith angles in the solar principal plane with definite asymmetry about nadir. The surface temperature of prairie canopies was found to vary by as much as 5 C depending on view zenith and azimuth position and on the solar azimuth. Aerodynamic temperature calculated from measured sensible heat fluxes ranged from 0 to 3 C higher than nadir-viewed temperatures. Models were developed to estimate incoming and reflected shortwave radiation from data collected with a Barnes Modular Multiband Radiometer. Several algorithms for estimating incoming longwave radiation were evaluated and compared to actual measures of that parameter. Net radiation was calculated using the estimated components of the shortwave radiation streams, determined from the algorithms developed, and from the longwave radiation streams provided by the Brunt, modified Deacon, and the Stefan-Boltzmann models. Estimates of net radiation were compared to measured values and found to be within the measurement error of the net radiometers used in the study

    Biophysical characterization and surface radiation balance

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    The Kursk 1991 Experiment (KUREX-91) was conducted as one of a suite of international studies to develop capabilities to monitor global change. The studies were designed specifically to understand the earth's land-surface vegetation and atmospheric boundary layer interaction. An intensive field campaign was conducted at a site near Kursk, Russia during the month of July in 1991 by a team of international scientists to aid in the understanding of land-surface-atmosphere interactions in an agricultural/grassland setting. We were one of several teams of scientists participating at KUREX-91 at the Streletskaya Steppe Researve near Kursk, Russia. The main goals of our research were to: (1) characterize biophysical properties of the prairie vegetation; and (2) to characterize radiation regime through measurements and from estimates derived from canopy bidirectional reflectance data. Four objectives were defined to achieve these goals: (1) determine dependence of leaf optical properties on leaf water potential of some dominant species in discrete wavebands in the visible, near-infrared, and mid-infrared (spanning 0.4-2.3 microns range); (2) characterize the effective leaf area index (LAI) and leaf angle distribution of prairie vegetation; (3) characterize the radiation regime of the prairie vegetation through measures of the radiation balance components; and (4) examine, develop, and test methods for estimating albedo, APAR, and LAI from canopy bidirectional reflectance data. Papers which were the result of the research efforts are included

    Comparison of Measured and Modeled Radiation, Heat, and Water Vapor Fluxes: Fife Pilot Study (CAMaC Progress Report 87-7)

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    Mémoire de fin d'étude du diplôme de conservateur d'Elydia Barret, promotion 22 portant sur les humanités numériques, publié par les Collections numériques de l’Enssib en janvier 2014 : http://www.enssib.fr/bibliotheque-numerique/notices/64711-quel-role-pour-les-bibliotheques-dans-les-humanites-numeriques Les humanités numériques sont nées au tournant du XXIe siècle avec l’arrivée de l’internet qui ouvre un nouveau chapitre dans l’histoire des rapports des technologies numériques et des scien..

    Comunidades de macroinvertebrados bentónicos y evaluación de la calidad del agua en humedales altoandinos de Callali-Oscollo, Arequipa-Cusco, Perú

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    High Andean wetlands are fragile systems, vulnerable to human activity and climate change. In the Arequipa region (Peru), there are high Andean lotic and lentic systems currently affected by livestock raising, fish farming, and dams. The aim of the study was to evaluate the aquatic invertebrate community in the Callalli-Oscollo wetlands and the possible impact of human activities. Samples were taken from November 2017 to October 2018 at four sampling stations in lotic environments and two in lentic environments. Macroinvertebrates were identified to the family level. The following were determined to evaluate community structure: richness, relative abundance, Shannon-Wiener diversity, Simpson dominance, Pielou evenness, and true diversity. The indices ABI, BMWP/Bol and nPeBMWP were applied to evaluate the ecological quality of the environments sampled. Thirty families were recorded in lotic environments, the most abundant being Chironomidae, Naididae, Limnesiidae, Elmidae, Baetidae and Lumbriculidae. The ecological quality was good, except at the station associated to the dam, where it was doubtful. Twenty-six families were recorded in lentic environments, the most abundant being Cyprididae, Naididae and Corixidae. The macroinvertebrate communities in high Andean environments reflect ecosystem conditions. Environments associated to human activity have lower ecological quality.Los humedales altoandinos son sistemas frágiles, vulnerables a la actividad humana y al cambio climático. La región de Arequipa (Perú) posee ecosistemas lóticos y lénticos altoandinos con impactos por la ganadería, piscicultura y represamiento. Se evaluó la comunidad de macroinvertebrados acuáticos de los humedales de Callalli-Oscollo y el posible efecto de las actividades humanas. Desde noviembre de 2017 a octubre de 2018 se realizaron muestreos en 4 estaciones en ambientes lóticos y 2 en lénticos. Los macroinvertebrados se identificaron a nivel de familia. Para evaluar la estructura comunitaria se registró la riqueza, la abundancia relativa, la diversidad de Shannon-Wiener, la dominancia de Simpson, la equidad de Pielou y la diversidad verdadera. Se aplicaron los índices ABI, BMWP/Bol y nPeBMWP para evaluar la calidad ecológica de los ambientes lóticos. En éstos se registraron 30 familias, siendo las más abundantes Chironomidae, Naididae, Limnesiidae, Elmidae, Baetidae y Lumbriculidae. La calidad ecológica fue buena, con excepción de la estación vinculada a la presa que fue dudosa. Los ambientes lénticos registraron 26 familias, siendo las más abundantes Cyprididae, Naididae y Corixidae. Las comunidades de macroinvertebrados en ambientes altoandinos reflejan el estado del ecosistema. Los ambientes vinculados con la actividad humana registran menor calidad ecológica.Fil: Coayla Peñaloza, Pastor. Universidad Nacional de San Agustin; PerúFil: Cheneaux Díaz, André Alexander. Universidad Nacional de San Agustin; PerúFil: Moreno Salazar, Claudia Viviana. Universidad Nacional de San Agustin; PerúFil: Cruz Remache, Cynthia Elizabeth. Universidad Nacional de San Agustin; PerúFil: Colque Rondón, Eusebio Walter. Universidad Nacional de San Agustin; PerúFil: Damborenea, Maria Cristina. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Cátedra de Zoología de Invertebrados I; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin
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