Search results for "Eddy"

3D magnetic and thermal fields for in the transformer with homogenised amorphous C-core under high frequency

2017

Linking photosynthesis and sun-induced fluorescence at sub-daily to seasonal scales

2018

Abstract Due to its close link to the photosynthetic process, sun-induced chlorophyll fluorescence (F) opens new possibilities to study dynamics of photosynthetic light reactions and to quantify CO2 assimilation rates. Although recent studies show that F is linearly related to gross primary production (GPP) on coarse spatial and temporal scales, it is argued that this relationship may be mainly driven by seasonal changes in absorbed photochemical active radiation (APAR) and less by the plant light use efficiency (LUE). In this work a high-resolution spectrometer was used to continuously measure red and far-red fluorescence and different reflectance indices within a sugar beet field during t…

Retrieval of daily gross primary production over Europe and Africa from an ensemble of SEVIRI/MSG products

2018

The main goal of this paper is to derive a method for a daily gross primary production (GPP) product over Europe and Africa taking the full advantage of the SEVIRI/MSG satellite products from the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) sensors delivered from the Satellite Application Facility for Land Surface Analysis (LSA SAF) system. Special attention is paid to model the daily GPP response from an optimized Montheith's light use efficiency model under dry conditions by controlling water shortage limitations from the actual evapotranspiration and the potential evapotranspiration (PET). The PET was parameterized using the mean daily air temperatur…

Applicability and consequences of the integration of alternative models for CO<sub>2</sub> transfer velocity into a process-based lake mo…

2019

Abstract. Freshwater lakes are important in carbon cycling, especially in the boreal zone where many lakes are supersaturated with the greenhouse gas carbon dioxide (CO2) and emit it to the atmosphere, thus ventilating carbon originally fixed by the terrestrial system. The exchange of CO2 between water and the atmosphere is commonly estimated using simple wind-based parameterizations or models of gas transfer velocity (k). More complex surface renewal models, however, have been shown to yield more correct estimates of k in comparison with direct CO2 flux measurements. We incorporated four gas exchange models with different complexity into a vertical process-based physico-biochemical lake mo…

Study of Mass Oxygen Transfer in a Biotrickling Filter for Air Pollution Control

2012

Biotrickling filtration is a potential and cost effective alternative for the treatment of volatile organic compound (VOC) emissions in air, so it is necessary to deepen into the key aspects of design and operation for the optimization of this technology. One of these factors is the oxygen mass transfer of the process. This study would facilitate the selection of the packing material and the mathematical modelling and simulation of bioreactors. Four plastic packing materials with a different specific surface area have been evaluated in terms of oxygen mass transfer. For the tested range of superficial liquid velocities, data show a relationship between the kLa and the superficial liquid vel…

Lysimeter assessment of the Simplified Two-Source Energy Balance model and eddy covariance system to estimate vineyard evapotranspiration

2019

Abstract Estimation of crop water needs plays a key role in the water resource management in arid and semi-arid regions. Actual evapotranspiration (ETa) becomes the key term in both water and energy balances at this point. In this work we focus on vineyard due to the significance of this crop for La Mancha region, Spain, with the greatest concentration of vineyards in the world. Eddy-covariance (EC) technique has been traditionally used for ground observations of ETa. One of the aims of this work is to assess the feasibility of an EC system under the challenging conditions of a small drip-irrigated vineyard in a semi-arid environment. Two-source energy balance modelling allows for ETa estim…

Biotrickling filter modeling for styrene abatement. Part 1: Model development, calibration and validation on an industrial scale

2017

Abstract A three-phase dynamic mathematical model based on mass balances describing the main processes in biotrickling filtration: convection, mass transfer, diffusion, and biodegradation was calibrated and validated for the simulation of an industrial styrene-degrading biotrickling filter. The model considered the key features of the industrial operation of biotrickling filters: variable conditions of loading and intermittent irrigation. These features were included in the model switching from the mathematical description of periods with and without irrigation. Model equations were based on the mass balances describing the main processes in biotrickling filtration: convection, mass transfe…

Partitioning net carbon dioxide fluxes into photosynthesis and respiration using neural networks

2020

Abstract The eddy covariance (EC) technique is used to measure the net ecosystem exchange (NEE) of CO2 between ecosystems and the atmosphere, offering a unique opportunity to study ecosystem responses to climate change. NEE is the difference between the total CO2 release due to all respiration processes (RECO), and the gross carbon uptake by photosynthesis (GPP). These two gross CO2 fluxes are derived from EC measurements by applying partitioning methods that rely on physiologically based functional relationships with a limited number of environmental drivers. However, the partitioning methods applied in the global FLUXNET network of EC observations do not account for the multiple co‐acting…

Simple eddy current compensation by additional gradient pulses

2018

Are remote sensing evapotranspiration models reliable across South American ecoregions?

2021

Many remote sensing-based evapotranspiration (RSBET) algorithms have been proposed in the past decades and evaluated using flux tower data, mainly over North America and Europe. Model evaluation across South America has been done locally or using only a single algorithm at a time. Here, we provide the first evaluation of multiple RSBET models, at a daily scale, across a wide variety of biomes, climate zones, and land uses in South America. We used meteorological data from 25 flux towers to force four RSBET models: Priestley–Taylor Jet Propulsion Laboratory (PT-JPL), Global Land Evaporation Amsterdam Model (GLEAM), Penman–Monteith Mu model (PM-MOD), and Penman–Monteith Nagler model (PME-VI).…