scholarly journals Clues for our missing respiration model

2019 ◽  
Vol 222 (3) ◽  
pp. 1167-1170 ◽  
Author(s):  
Michael G. Ryan ◽  
Shinichi Asao
Keyword(s):  
Respiration Model

scholarly journals A Multi–Level Approach for Simulation of Storage and Respiration of Produce

2019 ◽  
Vol 9 (6) ◽  
pp. 1052
Author(s):  
Mahmoud Elhalwagy ◽  
Nolan Dyck ◽  
Anthony Straatman
Keyword(s):  
Discrete Element Modelling ◽  
Elementary Volume ◽  
Respiration Model ◽  
Digital Generation ◽  
Flow Heat ◽  
Multi Level ◽  
Simulation Parameters ◽  
And Storage ◽  
Ultimate Purpose ◽  
Generation Procedure

A produce gas respiration model and fruit-stack geometric digital generation approach is used with commercial CFD software (ANSYS CFXTM) to conduct shape-level simulations of the fluid flow, heat and respiration processes that occur during the storage of produce, with the ultimate purpose of providing detailed information that can be used to develop closure coefficients for volume-averaged simulations. A digital generation procedure is used to develop an accurate representation of the shapes of the different produce. The produce shapes are then implemented into a discrete element modelling tool to generate a randomly-distributed stack of produce in a generic container, which is then utilized as a representative elementary volume (REV) for simulations of airflow and respiration. Simulations are first conducted on single pieces of produce and compared to a recently published experimental data for tomatoes and avocadoes to generate coefficients for the respiration model required for the shape-level simulations on the REV. The results of the shape-level simulation are then processed to produce coefficients that can be used for volume-averaged (porous-continuum-level) calculations, which are much more practical for simulations of large areas of storage comprised of hundreds or thousands of boxes of different commodities. The results show that the multi-level approach is a viable means for developing the simulation parameters required to study refrigeration, ripening and storage/transport of produce.

scholarly journals TR eSpire – a biophysical TR ee Stem respiration model

2019 ◽  
Vol 225 (5) ◽  
pp. 2214-2230 ◽  
Author(s):  
Roberto L. Salomón ◽  
Linus De Roo ◽  
Jacek Oleksyn ◽  
Dirk J. W. De Pauw ◽  
Kathy Steppe
Keyword(s):  
Stem Respiration ◽  
Respiration Model

A Study of MODIS-Based Ecosystem Respiration Model in a Semi-Arid Grassland of Inner Mongolia

2020 ◽  
Author(s):  
Haimei Jiang ◽  
Haotian Ye ◽  
Yong Hao
Keyword(s):  
Land Surface ◽  
Inner Mongolia ◽  
Vegetation Index ◽  
Ecosystem Respiration ◽  
Water Index ◽  
Growing Seasons ◽  
Land Surface Water ◽  
Respiration Model ◽  
The Difference ◽  
Semi Arid

<p>Eddy covariance data from Xilinhaote National Climatological Observatory in Xilin Gol League during growing seasons of 2010—2013 as well as MODIS data were used to validate an ecosystem respiration model based on enhanced vegetation index (EVI), land surface water index (LSWI) and land surface temperature (LST) in a semi-arid grassland of Inner Mongolia. The limitations of this remote sensing respiration model were also discussed. The results indicate that this model can successfully simulate the variations of nocturnal ecosystem respiration (Reco) in the growing seasons and between different years. The simulated nocturnal Reco also agreed remarkably with the observed Reco (R2=0.90, RMSE=0.02 mgCO2/(m2·s)). Moreover, the observed nocturnal Reco showed a good linear correlation with EVIs×Ws (R2=0.63), in which EVIs and Ws are response functions of EVI and LSWI on photosynthesis, respectively. The response of nocturnal Reco to LST was also found following the L-T equation (R2=0.39). In addition, the difference between responses of nocturnal Reco to EVIs×Ws and LST in the early, middle and late stages of the growing season is indicated as one principal source of the deviations of model results.</p>

Impact of using various prior flux models on the posterior NEE derived from the Jena Carboscope regional inversion system

2020 ◽  
Author(s):  
Saqr Munassar ◽  
Christoph Gerbig ◽  
Frank-Thomas Koch ◽  
Christian Rödenbeck
Keyword(s):  
Fossil Fuel ◽  
A Priori ◽  
Net Ecosystem Exchange ◽  
Observation System ◽  
Mixing Ratio ◽  
British Petroleum ◽  
Respiration Model ◽  
Atmospheric Data ◽  
The Impact ◽  
Fossil Fuel Emissions

<p>Regional flux estimates over Europe have been calculated using the two-step inverse system of the Jena CarboScope Regional inversion (CSR) to estimate the annual CO<sub>2</sub> budgets for recent years, in cooperation with the research project VERIFY. The CSR system assimilates observational datasets of CO<sub>2</sub> mixing ratio provided by the Integrated Carbon Observation System (ICOS) across the European domain to optimize Net Ecosystem Exchange (NEE) fluxes computed from biosphere models at a spatial resolution of 0.25 degree. Ocean fluxes are assumed to be constant over time. Fossil fuel emissions are obtained from EDGAR_v4.3 and updated based on British Petroleum (BP) statistics. Therefore, only biosphere-atmosphere exchange fluxes are considered to be optimized against the atmospheric data.</p><p>In this study we focus on the impact of using a-priori fluxes from different biosphere and ocean models on the annual CO<sub>2</sub> budget of posterior fluxes. Results calculated using the Vegetation and Photosynthesis Respiration Model (VPRM) and Simple Biosphere/Carnegie-Ames Stanford Approach (SiBCASA) models show a consistent posterior interannual variability, largely independent of which prior fluxes are used, even though those prior fluxes show considerable differences on annual scales.</p>

scholarly journals Euphausiid respiration model revamped: Latitudinal and seasonal shaping effects on krill respiration rates

2014 ◽  
Vol 291 ◽  
pp. 233-241 ◽  
Author(s):  
Nelly Tremblay ◽  
Thorsten Werner ◽  
Kim Huenerlage ◽  
Friedrich Buchholz ◽  
Doris Abele ◽  
...  
Keyword(s):  
Respiration Rates ◽  
Respiration Model

scholarly journals The Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM): a parsimonious, satellite data-driven model of high-latitude CO<sub>2</sub> exchange

2015 ◽  
Vol 8 (2) ◽  
pp. 979-1027 ◽  
Author(s):  
K. A. Luus ◽  
J. C. Lin
Keyword(s):  
Eddy Covariance ◽  
North American ◽  
High Latitude ◽  
Growing Season ◽  
Growing Season Length ◽  
The North ◽  
Air Temperatures ◽  
High Latitude Region ◽  
Respiration Model ◽  
Photosynthesis And Respiration

Abstract. We introduce the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), a remote-sensing based approach for generating accurate, high resolution (≥1 km2, three-hourly) estimates of net ecosystem CO2 exchange (NEE). PolarVPRM simulates NEE using polar-specific vegetation classes, and by representing high-latitude influences on NEE. We present a description, validation, and error analysis (first-order Taylor expansion) of PolarVPRM, followed by an examination of per-pixel trends (2001–2012) in model output for the North American terrestrial region north of 55° N. PolarVPRM was validated against eddy covariance observations from nine North American sites, of which three were used in model calibration. PolarVPRM performed well over all sites. Model intercomparisons indicated that PolarVPRM showed slightly better agreement with eddy covariance observations relative to existing models. Trend analysis (2001–2012) indicated that warming air temperatures and drought stress in forests increased growing season rates of respiration, and decreased rates of net carbon uptake by vegetation when air temperatures exceeded optimal temperatures for photosynthesis. Concurrent increases in growing season length at Arctic tundra sites allowed increases in photosynthetic uptake over time by tundra vegetation. PolarVPRM estimated that the North American high-latitude region changed from a carbon source (2001–2004) to sink (2005–2010) to source (2011–2012) in response to changing environmental conditions.

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