Search results for "canopy"
showing 10 items of 221 documents
Amazonian biomass burning-derived acid and nutrient deposition in the north Andean montane forest of Ecuador
2008
[1] We explored the influence of biomass burning in Amazonia and northeastern Latin America on N, C, P, S, K, Ca, Mg, Al, Mn, and Zn cycles of an Andean montane forest in south Ecuador exposed to the Amazon basin between May 1998 and April 2003. We assessed the response of the element budget of three microcatchments (8–13 ha) to the variations in atmospheric deposition between the intensive burning season and outside the burning season in Amazonia. There were significantly elevated H, N, and Mn depositions during biomass burning. Elevated H deposition during biomass burning caused elevated base metal loss from the canopy and the organic horizon and deteriorated already low base metal supply…
Surface to boundary layer coupling in the urban area of Lisbon comparing different urban canopy models in WRF
2019
Abstract This work presents a sensitivity study to evaluate different Urban Canopy Models (UCM) existing within the Weather Research and Forecasting Model (WRF) in the urban area of Lisbon, Portugal. Several hind-cast simulations were carried out for a selected period in July 2010, in which synoptic conditions favoured urban heat island formation. We aim to gain knowledge on the feedback of modified urban canopy representation in WRF on local scale meteorology and the boundary-layer dynamics over the urban area, by comparing a single layer urban canopy model (SLUCM) and a more sophisticated multi-layer building effect parametrisation (BEP). We find significant differences in the characteris…
Relationship between recruitment and mother plant vitality in the alien species Acacia cyclops A. Cunn. ex G. Don
2014
Acacia cyclops is a widespread invader in Mediterranean-climate regions. However, although its naturalization in the Mediterranean Basin dates back only a few years ago, and the invasion process has not been studied hitherto. We investigated seedlings recruitment strategy adopted by A. cyclops in a small island (Lampedusa, Italy) where its natural regeneration was strictly confined under mother plants canopy. Healthy plants (DCP), plants at incipient senescence (SCP) and dead plants (DP) were distinguished according to vitality and canopy status. Living plants were also characterized in relation to leaf C and N isotope composition. Regeneration pattern (seedlings and saplings abundance) was…
Global L-band vegetation volume fraction estimates for modeling vegetation optical depth
2021
The attenuation of microwave emissions through the canopy is quantified by the vegetation optical depth (VOD), which is related to the amount of water, the biomass and the structure of vegetation. To provide microwave-derived plant water estimates, one must account for biomass/structure contributions in order to extract the water component from the VOD. This study uses Aquarius scatterometer data to build an L-band global seasonality of vegetation volume fraction (d), representative of biomass/structure dynamics. The dynamic range of d is adapted for its application in a gravimetric moisture (Mg) retrieval model. Results show that d ranging from 0 to 3.35.10- 4 is needed for modelling physi…
Grapevine row orientation mediated temporal and cumulative microclimatic effects on grape berry temperature and composition
2021
Abstract Ambient radiation and temperature are global drivers of grapevine growth, grape yield and composition, and wine quality. Knowledge of the implications of vineyard row orientation/microclimate is required for decision-making in current and future macro- and mesoclimates. Temporal and cumulative microclimatic changes, induced by vine row orientation (NS; EW; NE-SW; NW-SE) of vertically trellised Shiraz grapevines, on berry pulp temperature and composition at different ripeness levels were investigated. Berries dynamically gained heat energy relative to: ambient climate/weather; direct canopy wall/bunch irradiance; and berry skin colour development. Berries exposed to direct solar rad…
Influence of row orientation on the canopy temperature of Sicilian vineyards
2021
Row orientation can have significant effects on grape quality as it directly affects the exposure of the fruits with indirect consequences on wine quality. In this study, a Flir i7 thermal camera was used to measure the temperature of both canopy sides of a ‘Sauvignon blanc’ vineyard trained to vertical shoot position and with north-south (NS) and east-west (EW) row orientations. Photosynthetically active radiation (PAR) measurements using a 0.8-m sensor bar were taken along with the thermal imaging camera measurements. Considering both row orientations, south and east canopy sides were those that intercepted the greatest radiant energy during the day, 57.7 and 47.5%, respectively. The EW r…
Evaluation of Small Vase and Y-trellis Orchard Systems for Peach and Nectarine Production in Mediterranean Regions
2015
Two peach planting systems, Small Vase (SV) and Y-trellis (Y), were evaluated and compared in the Mediterranean settings of Southern Italy. The two orchards were located next to each other on relatively uniform soil and terrain, and the observations included two peach (âRich Mayâ and âSummer Richâ) and two nectarine (âBig Bangâ and âNectarossâ) cultivars. In the SV system, trees were spaced at 4.5 A 2.5 m (888 trees/ha), whereas in the Y system, trees were spaced at 5.5 A 2 m (909 trees/ha) and no canopy gap was left between rows. Yield per tree; fruit size grade; unit price of sold peaches for each size grade; materials, labor and associated costs for cultural management;…
Two new planting systems for early ripening peaches (Prunus persica L. Batsch): Yield and fruit quality in four low-chill cultivars
1997
SummaryTrees of peach cvs Flordastar, Flordaprince, Flordacrest and Maravilha, low in chill requirement (Flordaprince 150; Flordacrest 350 C.U.), with a short fruit development period (Flordaprince 90; Flordacrest 110 d) and a very early ripening time (Flordastar mid May; Flordacrest first week of June), were planted in Sicily (37° 30′ Lat. N) both in a medium (667 trees per ha) and a high density (2000 trees per ha) plantation system. In the medium density planting system, the trees were trained to a Fusetto, and in the high density to a Y-shape. Both in the Fusetto and Y, the size of the trees was controlled by severe pruning soon after harvest, consisting in the shortening of most of the…
Development of a Sensor for Continuous and Accurate Monitoring of Air Flow for Open-System Whole Canopy Gas-Exchange Measurements
2007
The research describes the development and set-up of a simple and accurate solid-state device for continuous monitoring of airflow forced into an open-flow gas-exchange chamber for whole-canopy transpiration and photosynthesis measurements. The ventilation system was formed by a centrifugal fan powered by an electric motor and a PVC pipe (0.193 m inner diameter). To damp airflow turbulence, 50 cm of the main pipe was filled with a bundle of smaller PVC pipes (3 cm inner diameter). The measurement principle of the sensor is the thermal balance of an electrically heated copper plate compared to an unheated one. Calibration of the sensor was performed by two independent methods: gas dilution (…
Canopy chlorophyll content and LAI estimation from Sentine1-2: Vegetation indices and Sentine1-2 Leve1-2A automatic products comparison
2019
The aim of this work is to analyze different methodologies for the estimation of leaf area index (LAI) and canopy chlorophyll content (CCC), using the Sentine1-2 satellite. LAI and CCC are biophysical parameters indicator of crop health state and fundamental in the productivity prediction. The purpose is to define the most optimal LAI and CCC estimation method for operational use in the monitoring of agricultural areas. Moreover, the CCC and LAI automatic products obtained directly through the Sentinel Application Platform Software (SNAP) biophysical processor and Sentine1-2 images by means of an artificial neural network (ANN) are validated. On the other hand, common vegetation indices use…