scholarly journals Cloud characteristics, thermodynamic controls and radiative impacts during the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) experiment

2017 ◽  
Vol 17 (23) ◽  
pp. 14519-14541 ◽  
Author(s):  
Scott E. Giangrande ◽  
Zhe Feng ◽  
Michael P. Jensen ◽  
Jennifer M. Comstock ◽  
Karen L. Johnson ◽  
...  
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Department Of Energy ◽  
Cloud Characteristics ◽  
Radiative Impacts ◽  
Atmospheric Radiation Measurement ◽  
Dry Seasons ◽  
Basin Region ◽  
Cloud Regimes ◽  
Wet And Dry Seasons

Abstract. Routine cloud, precipitation and thermodynamic observations collected by the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) and Aerial Facility (AAF) during the 2-year US Department of Energy (DOE) ARM Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign are summarized. These observations quantify the diurnal to large-scale thermodynamic regime controls on the clouds and precipitation over the undersampled, climatically important Amazon basin region. The extended ground deployment of cloud-profiling instrumentation enabled a unique look at multiple cloud regimes at high temporal and vertical resolution. This longer-term ground deployment, coupled with two short-term aircraft intensive observing periods, allowed new opportunities to better characterize cloud and thermodynamic observational constraints as well as cloud radiative impacts for modeling efforts within typical Amazon wet and dry seasons.

scholarly journals Cloud Characteristics, Thermodynamic Controls and Radiative Impacts During the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) Experiment

2017 ◽  
Author(s):  
Scott E. Giangrande ◽  
Zhe Feng ◽  
Michael P. Jensen ◽  
Jennifer Comstock ◽  
Karen L. Johnson ◽  
...  
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Short Term ◽  
Cloud Characteristics ◽  
Cloud Regime ◽  
Radiative Impacts ◽  
Dry Seasons ◽  
Thermodynamic Regime ◽  
Basin Region ◽  
Wet And Dry Seasons

Abstract. Routine cloud, precipitation and thermodynamic observations collected by the ARM Mobile Facility (AMF) and Aerial Facility (AAF) during the two-year DOE ARM Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign are summarized. These observations quantify the diurnal to large-scale thermodynamic regime controls on the clouds and precipitation over the undersampled, climatically important, Amazon basin region. The extended ground deployment of cloud-profiling instrumentation enabled a unique look at multiple cloud regime controls at high temporal and vertical resolution. This longer-term ground deployment coupled with two short-term aircraft intensive observing periods allowed new opportunities to better characterize cloud and thermodynamic observational constraints as well as cloud radiative impacts for modeling efforts within typical Amazon ‘wet’ and ‘dry’ seasons.

Spatial distribution of Serengeti wildebeest in relation to resources

1999 ◽  
Vol 77 (8) ◽  
pp. 1223-1232 ◽  
Author(s):  
John F Wilmshurst ◽  
John M Fryxell ◽  
Brian P Farm ◽  
ARE Sinclair ◽  
Chris P Henschel
Keyword(s):  
Spatial Distribution ◽  
Energy Intake ◽  
Large Scale ◽  
Spatial Scales ◽  
Mechanistic Model ◽  
Large Herbivores ◽  
Serengeti Ecosystem ◽  
Dry Seasons ◽  
Behavioural Factors ◽  
Wet And Dry Seasons

We investigated the spatial distribution of radio-marked wildebeest (Connochaetes taurinus) in the Serengeti ecosystem in relation to the distribution of their food resources, comparing patterns in the wet and dry seasons and at local and landscape spatial scales. A mechanistic model of ruminant energy optimization predicted that wildebeest should maximize energy intake on swards 3 cm high and maintain energy balance on swards between 3 and 10 cm high. At the ecosystem scale, wildebeest preferred short and intermediate-height grass of moderate greenness during both the wet and dry seasons. This was consistent with the model prediction which suggests that large-scale movements by wildebeest are motivated, at least partially, by an energy-maximizing strategy. At the local scale, however, wildebeest showed spatial selectivity only on the basis of grass greenness, not on grass height. This differed from model expectations and may have resulted from wildebeest exploiting ephemeral green flushes of grass caused by localized rainfall in their movement radius. According to these results, the influence of other nutritional or behavioural factors on wildebeest distributions is not rejected, yet they suggest the potentially important role of an energy intake maximizing strategy on movement patterns. Our findings show that wildebeest movements are broadly similar to those of other large herbivores that migrate in response to resource gradients.

scholarly journals A BRIEF OBSERVATION OF THE FORMATION OF COHERENT STRUCTURES AND TURBULENCE OVER A RAIN FOREST AREA IN CENTRAL AMAZÔNIA: THE ATTO-CLAIRE/IOP – 1/2012 EXPERIMENT

2017 ◽  
Vol 35 (3) ◽  
Author(s):  
Newton Silva de Lima ◽  
Julio Tota da Silva ◽  
Maurício José Alves Bolzam ◽  
Alan Dos Santos Ferreira ◽  
Matheus Da Rocha Pietzsch
Keyword(s):  
Coherent Structures ◽  
Large Scale ◽  
Inflection Point ◽  
Terra Firme ◽  
Central Amazonia ◽  
Intensive Observation ◽  
Dry Seasons ◽  
Box Plot ◽  
Observation Period ◽  
Wet And Dry Seasons

ABSTRACT. This work used micrometeorological measurements of temperature and wind in order to characterize the turbulence due to wind in a terra firme forest in central Amazonia as part of the ATTO-CLAIRE / IOP-1 (2012) (Amazon Tall Tower Observatory – Cooperative LBA Airborne Regional Experiment / Intensive Observation Period – 2012 / LBA – Large Scale Biosphere-Atmosphere Experiment in the Amazon). This research was conducted at the Uatumã ATTO Sustainable Development Reserve in the State of Amazonas, Brazil, from February to September, 2012, and used data from February 26 to September 07, 2012, dates that partially encompass the wet and dry seasons, respectively. The ATTO site has 5 towers: one that is 320m, and four that are 80 m in height, and this research was conducted on an 80 m triangular tower. A total of ten 3D and 2D ultrasonic anemometers were installed on the tower, and the importance of these instruments used for flux measurements is also evident when taking into account the fact that the dissemination and diffusion of seeds and chemical composts in the forest happens through the action of turbulent fluxes. In order to understand the wind profile, the inflection point of the wind velocity, and coherent structures (ECs) and local turbulence, box-plot diagrams, quadrant analyses, wavelet potential spectrum, and energy potential analyses were conducted. The turbulence characterized at the ATTO had a roll or ramp structure during the study period, which represents favorable conditions for the maintenance of the forest during the wet and dry seasons in the Central Amazon. Keywords: inflection point, ramp, wavelet, turbulence. RESUMO. Este trabalho faz uso de medidas micrometeorológicas de temperatura e vento, com finalidade de caracterizar a turbulência aerotransportada em uma floresta de terra firme na Amazônia Central, realizadas no experimento ATTO-CLAIRE / IOP-1 (2012) (Amazon Tall Tower Observatory – Cooperative LBA Airborne Regional Experiment / Intensive Observation Period – 2012 / LBA – Large Scale Biosphere-Atmosphere Experiment in Amazônia), no sítio do ATTO, na Reserva de Desenvolvimento Sustentável do Uatumã – AM (Brasil) nos meses de fevereiro a setembro de 2012, com dados analisados a partir do dia 26 de fevereiro de 2012 até o dia 7 de setembro de 2012, entre as estações úmida e seca na Amazônia Central, no complexo de torres altas composta de 5 (cinco) torres; uma de 320 m e 4 (quatro) de 80 m. Este trabalho foi realizado na torre triangular (80 m). Foram instalados 10 (dez) anemômetros ultrassônicos de 3D e 2D. Equipamentos necessários em método de fluxos, visto que, a disseminação e difusão de sementes e compostos químicos da floresta, faz-se também por fluxos turbulentos. Para compreensão do perfil de vento, ponto de inflexão do perfil da velocidade do vento, estruturas coerentes e a turbulência local, para tal desenvolveu-se a partir dos dados processados, diagrama de caixa (box-plot ), análise de quadrantes, espectro de potência em ondeletas, espectro de energia. A turbulência caracterizada no ATTO, foi de estruturas do tipo “rolo” ou rampa, para o período estudado, condições favoráveis para manutenção da floresta em período úmido-seco na Amazônia Central.Palavras-chave: ponto de inflexão, rampa, ondeleta, turbulência.

scholarly journals VIROLOGICAL AND SEROLOGICAL DIAGNOSIS OF RABIES IN BATS FROM AN URBAN AREA IN THE BRAZILIAN AMAZON

2015 ◽  
Vol 57 (6) ◽  
pp. 497-503 ◽  
Author(s):  
Rubens Souza de OLIVEIRA ◽  
Lanna Jamile Corrêa da COSTA ◽  
Fernanda Atanaena Gonçalves de ANDRADE ◽  
Wilson UIEDA ◽  
Luzia Fátima Alves MARTORELLI ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Urban Area ◽  
Amazon Basin ◽  
Common Species ◽  
Urban Context ◽  
Serum Samples ◽  
Tissue Samples ◽  
Dry Seasons ◽  
The Brain ◽  
Wet And Dry Seasons

The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.

scholarly journals Distinct Impacts of Aerosols on an Evolving Continental Cloud Complex during the RACORO Field Campaign

2016 ◽  
Vol 73 (9) ◽  
pp. 3681-3700 ◽  
Author(s):  
Yun Lin ◽  
Yuan Wang ◽  
Bowen Pan ◽  
Jiaxi Hu ◽  
Yangang Liu ◽  
...  
Keyword(s):  
Convective Cloud ◽  
Department Of Energy ◽  
Atmospheric Radiation Measurement ◽  
Aerosol Cloud Interactions ◽  
Absorbing Aerosols ◽  
The Individual ◽  
Moisture Conditions ◽  
Aerosol Effects ◽  
Cloud Regimes ◽  
Cloud Complex

Abstract A continental cloud complex, consisting of shallow cumuli, a deep convective cloud (DCC), and stratus, is simulated by a cloud-resolving Weather Research and Forecasting Model to investigate the aerosol microphysical effect (AME) and aerosol radiative effect (ARE) on the various cloud regimes and their transitions during the Department of Energy Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) campaign. Under an elevated aerosol loading with AME only, a reduced cloudiness for the shallow cumuli and stratus resulted from more droplet evaporation competing with suppressed precipitation, but an enhanced cloudiness for the DCC is attributed to more condensation. With the inclusion of ARE, the shallow cumuli are suppressed owing to the thermodynamic effects of light-absorbing aerosols. The responses of DCC and stratus to aerosols are monotonic with AME only but nonmonotonic with both AME and ARE. The DCC is invigorated because of favorable convection and moisture conditions at night induced by daytime ARE, via the so-called aerosol-enhanced conditional instability mechanism. The results reveal that the overall aerosol effects on the cloud complex are distinct from the individual cloud types, highlighting that the aerosol–cloud interactions for diverse cloud regimes and their transitions need to be evaluated to assess the regional and global climatic impacts.

Impact of Dynamics and Atmospheric State on Cloud Vertical Overlap

2008 ◽  
Vol 21 (8) ◽  
pp. 1758-1770 ◽  
Author(s):  
Catherine M. Naud ◽  
Anthony Del Genio ◽  
Gerald G. Mace ◽  
Sally Benson ◽  
Eugene E. Clothiaux ◽  
...  
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Vertical Motion ◽  
General Circulation Models ◽  
Department Of Energy ◽  
Smooth Transition ◽  
Atmospheric Radiation Measurement ◽  
Atmospheric State ◽  
Active Research ◽  
Wind Shears

Abstract The observation and representation in general circulation models (GCMs) of cloud vertical overlap are the objects of active research due to their impacts on the earth’s radiative budget. Previous studies have found that vertically contiguous cloudy layers show a maximum overlap between layers up to several kilometers apart but tend toward a random overlap as separations increase. The decorrelation length scale that characterizes the progressive transition from maximum to random overlap changes from one location and season to another and thus may be influenced by large-scale vertical motion, wind shear, or convection. Observations from the U.S. Department of Energy Atmospheric Radiation Measurement program ground-based radars and lidars in midlatitude and tropical locations in combination with reanalysis meteorological fields are used to evaluate how dynamics and atmospheric state influence cloud overlap. For midlatitude winter months, strong synoptic-scale upward motion maintains conditions closer to maximum overlap at large separations. In the tropics, overlap becomes closer to maximum as convective stability decreases. In midlatitude subsidence and tropical convectively stable situations, where a smooth transition from maximum to random overlap is found on average, large wind shears sometimes favor minimum overlap. Precipitation periods are discarded from the analysis but, when included, maximum overlap occurs more often at large separations. The results suggest that a straightforward modification of the existing GCM mixed maximum–random overlap parameterization approach that accounts for environmental conditions can capture much of the important variability and is more realistic than approaches that are only based on an exponential decay transition from maximum to random overlap.

scholarly journals AWARE: The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment

2020 ◽  
Vol 101 (7) ◽  
pp. E1069-E1091 ◽  
Author(s):  
Dan Lubin ◽  
Damao Zhang ◽  
Israel Silber ◽  
Ryan C. Scott ◽  
Petros Kalogeras ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Cloud Microphysics ◽  
Surface Energy Budget ◽  
Department Of Energy ◽  
The Arctic ◽  
Atmospheric Radiation ◽  
Radiation Measurement ◽  
West Antarctic ◽  
Atmospheric Radiation Measurement

Abstract The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment (AWARE) performed comprehensive meteorological and aerosol measurements and ground-based atmospheric remote sensing at two Antarctic stations using the most advanced instrumentation available. A suite of cloud research radars, lidars, spectral and broadband radiometers, aerosol chemical and microphysical sampling equipment, and meteorological instrumentation was deployed at McMurdo Station on Ross Island from December 2015 through December 2016. A smaller suite of radiometers and meteorological equipment, including radiosondes optimized for surface energy budget measurement, was deployed on the West Antarctic Ice Sheet between 4 December 2015 and 17 January 2016. AWARE provided Antarctic atmospheric data comparable to several well-instrumented high Arctic sites that have operated for many years and that reveal numerous contrasts with the Arctic in aerosol and cloud microphysical properties. These include persistent differences in liquid cloud occurrence, cloud height, and cloud thickness. Antarctic aerosol properties are also quite different from the Arctic in both seasonal cycle and composition, due to the continent’s isolation from lower latitudes by Southern Ocean storm tracks. Antarctic aerosol number and mass concentrations are not only non-negligible but perhaps play a more important role than previously recognized because of the higher sensitivities of clouds at the very low concentrations caused by the large-scale dynamical isolation. Antarctic aerosol chemical composition, particularly organic components, has implications for local cloud microphysics. The AWARE dataset, fully available online in the ARM Program data archive, offers numerous case studies for unique and rigorous evaluation of mixed-phase cloud parameterization in climate models.

Environmental changes in southeastern Amazonia during the last 25,000 yr revealed from a paleoecological record

2012 ◽  
Vol 77 (1) ◽  
pp. 138-148 ◽  
Author(s):  
Barbara Hermanowski ◽  
Marcondes Lima da Costa ◽  
Hermann Behling
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Environmental Changes ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Early Holocene ◽  
Tropical Atlantic ◽  
Inter Tropical Convergence Zone ◽  
Savanna Vegetation ◽  
Dry Seasons

New pollen, micro-charcoal, sediment and mineral analyses of a radiocarbon-dated sediment core from the Serra Sul dos Carajás (southeast Amazonia) indicate changes between drier and wetter climatic conditions during the past 25,000 yr, reflected by fire events, expansion of savanna vegetation and no-analog Amazonian forest communities. A cool and dry last glacial maximum (LGM) and late glacial were followed by a wet phase in the early Holocene lasting for ca. 1200 yr, when tropical forest occurred under stable humid conditions. Subsequently, an increasingly warm, seasonal climate established. The onset of seasonality falls within the early Holocene warm period, with possibly longer dry seasons from 10,200 to 3400 cal yr BP, and an explicitly drier phase from 9000 to 3700 cal yr BP. Modern conditions with shorter dry seasons became established after 3400 cal yr BP. Taken together with paleoenvironmental evidence from elsewhere in the Amazon Basin, the observed changes in late Pleistocene and Holocene vegetation in the Serra Sul dos Carajás likely reflect large-scale shifts in precipitation patterns driven by the latitudinal displacement of the Inter-Tropical Convergence Zone and changes in sea-surface temperatures in the tropical Atlantic.

Temporal variations of CH4/CO2/CO fluxes in the central Amazon rainforest

2020 ◽  
Author(s):  
Shujiro Komiya ◽  
Jost Lavric ◽  
David Walter ◽  
Santiago Botia ◽  
Alessandro Araujo ◽  
...  
Keyword(s):  
Amazon Basin ◽  
Temporal Variations ◽  
Dry Season ◽  
Amazon Rainforest ◽  
Eddy Covariance Method ◽  
Co Concentration ◽  
Dry Seasons ◽  
Co Concentrations ◽  
Wet And Dry Seasons

<p>Amazon rainforests and soils contain large amounts of carbon, which is under pressure from ongoing climate and land use change in the Amazon basin. It is estimated that methane (CH<sub>4</sub>), an important greenhouse gas, is largely released from the flooded wetlands of the Amazon, but the trends and balances of CH<sub>4 </sub>in the Amazon rainforest are not yet well understood. In addition, the change in atmospheric CH<sub>4</sub> concentration is strongly associated with a change in carbon monoxide (CO) concentration, often caused by the human-induced combustion of biomass that usually peaks during dry season. Understanding the long-term fluctuations in the fluxes of greenhouse gases in the Amazon rainforest is essential for improving our understanding of the carbon balance of the Amazon rainforest.</p><p>Since March 2012, we have continuously measured atmospheric CO<sub>2</sub>/CH<sub>4</sub>/CO concentrations at five levels (79, 53, 38, 24, and 4 m a.g.l.) using two wavelength-scanned cavity ring-down spectroscopy analyzers (G1301 and G1302, Picarro Inc., USA), which are automatically calibrated on site every day. In addition, we measured the CO<sub>2</sub> flux by the eddy covariance method at the same tower. We estimated the CO<sub>2</sub>/CH<sub>4</sub>/CO fluxes by combining the vertical profile of the CO<sub>2</sub>/CH<sub>4</sub>/CO concentrations with the flux gradient method. Our results generally show no major difference in CO<sub>2</sub> flux between the wet and dry seasons except for year 2017, when an elevated CO<sub>2</sub> uptake was documented during the dry season despite the lowest precipitation between 2014 and 2018. The CH<sub>4</sub> flux showed the largest CH<sub>4</sub> emission during the dry season in year 2016. Further results will be analyzed and discussed in the presentation.</p>

scholarly journals Impacts of Emerging Agricultural Practices on Groundwater Quality in Kahe Catchment, Tanzania

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2263 ◽  
Author(s):  
Lwimbo ◽  
Komakech ◽  
Muzuka
Keyword(s):  
Groundwater Quality ◽  
Large Scale ◽  
Agricultural Practices ◽  
Pesticides Residues ◽  
Average Value ◽  
Intensive Use ◽  
Shallow Wells ◽  
Dry Seasons ◽  
Deep Boreholes ◽  
Wet And Dry Seasons

This paper assesses the impacts of farmers’ intensive use of agrochemicals (fertilizers and pesticides) on groundwater quality in the Kahe catchment. Samples were collected during the wet and dry seasons of the year 2018 and analyzed for the presence of agrochemicals in the water. Groundwater chemistry was dominated by magnesium-sodium-bicarbonate (Mg-Na-HCO3−). The cations levels were in the trend of Mg2+ >Na+ > Ca2+ > K+, whereas anions were HCO3− > Cl− > SO42− for both seasons. The NO3− had an average value of about 18.40 ± 4.04 and 7.6 ± 1.7 mg/L in the wet and dry season, respectively. Elevated levels of nitrate, sulfate, phosphate, and ammonium were found in water samples collected near the large-scale sugarcane plantation in the catchment. For both seasons, Pb, Cd, Fe, Mn, Zn and Cu concentrations averaged approximately 0.08 ± 0.03, 0.11 ± 0.03, 0.16 ± 0.02, 0.11 ± 0.01, 0.46 ± 0.05, and 0.55 ± 0.02 mg/L, respectively. On the other hand, the concentrations were higher in shallow wells than in the deep boreholes. Pesticides’ residues were below the detection limit in all sampled groundwater. The findings from this study provide important information for intervention in groundwater quality management in Kahe Catchment, Tanzania.

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