Review #2 of “Technical Note: A simple theoretical model framework to describe plant stomatal “sluggishness” in response to elevated ozone concentrations” by Chris Huntingford et al.

2018 ◽  
Author(s):  
Anonymous
Keyword(s):  
Theoretical Model ◽  
Technical Note ◽  
Model Framework ◽  
Ozone Concentrations ◽  
Elevated Ozone ◽  
Simple Theoretical Model

scholarly journals Technical Note: A simple theoretical model framework to describe plant stomatal sluggishness in response to elevated ozone concentrations

2018 ◽  
Author(s):  
Chris Huntingford ◽  
Rebecca J. Oliver ◽  
Lina M. Mercado ◽  
Stephen Sitch
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Model Development ◽  
Technical Note ◽  
Climate Impacts ◽  
Terrestrial Vegetation ◽  
Stomatal Response ◽  
Model Framework ◽  
Elevated Ozone

Abstract. Elevated levels of tropospheric Ozone [O3] causes damage to terrestrial vegetation, affecting leaf stomatal functioning and reducing photosynthesis. Climatic impacts under future raised atmospheric Greenhouse Gas (GHG) concentrations will also impact on the Net Primary Productivity (NPP) of vegetation, which might for instance alter viability of some crops. Together, ozone damage and climate change may adjust the current ability of terrestrial vegetation to offset a significant fraction of carbon dioxide (CO2) emissions. Climate impacts on the land surface are well studied, but arguably large-scale modelling of raised surface level [O3] effects is less advanced. To date most models representing ozone damage use either [O3] concentration or, more recently, flux-uptake related reduction of stomatal opening, estimating suppressed land-atmosphere water and CO2 fluxes. However there is evidence that for some species, [O3] damage can also cause an inertial sluggishness of stomatal response to changing surface meteorological conditions. In some circumstances e.g. droughts, this loss of stomata control can cause them to be more open than without ozone interference. The extent of this effect may be dependent on magnitude and cumulated time of exposure to raised [O3], suggesting experiments to analyze this require operation over long timescales such as full growing seasons. To both aid model development and provide empiricists with a system on to which measurements can be mapped, we present a parameter-sparse framework specifically designed to capture sluggishness. This contains a single time-delay parameter τO3, characterising the timescale for stomata to catch up with the level of opening they would have with- out damage. The larger the value of this parameter, the more sluggish the modelled stomatal response. Through variation of τO3, we find it is possible to have qualitatively similar responses to factorial experiments with and without raised [O3], when comparing to measurement timeseries presented in the literature. This low-parameter approach lends itself to the inclusion of ozone-induced inertial effects being incorporated in the terrestrial vegetation component of Earth System Models (ESMs).

scholarly journals Technical note: A simple theoretical model framework to describe plant stomatal “sluggishness” in response to elevated ozone concentrations

2018 ◽  
Vol 15 (17) ◽  
pp. 5415-5422 ◽  
Author(s):  
Chris Huntingford ◽  
Rebecca J. Oliver ◽  
Lina M. Mercado ◽  
Stephen Sitch
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Net Primary Productivity ◽  
Model Development ◽  
Technical Note ◽  
Climate Impacts ◽  
Terrestrial Vegetation ◽  
Stomatal Response ◽  
Model Framework ◽  
Elevated Ozone

Abstract. Elevated levels of tropospheric ozone, O3, cause damage to terrestrial vegetation, affecting leaf stomatal functioning and reducing photosynthesis. Climatic impacts under future raised atmospheric greenhouse gas (GHG) concentrations will also impact on the net primary productivity (NPP) of vegetation, which might for instance alter viability of some crops. Together, ozone damage and climate change may adjust the current ability of terrestrial vegetation to offset a significant fraction of carbon dioxide (CO2) emissions. Climate impacts on the land surface are well studied, but arguably large-scale modelling of raised surface level O3 effects is less advanced. To date most models representing ozone damage use either O3 concentration or, more recently, flux-uptake-related reduction of stomatal opening, estimating suppressed land–atmosphere water and CO2 fluxes. However there is evidence that, for some species, O3 damage can also cause an inertial “sluggishness” of stomatal response to changing surface meteorological conditions. In some circumstances (e.g. droughts), this loss of stomata control can cause them to be more open than without ozone interference. To both aid model development and provide empiricists with a system on to which measurements can be mapped, we present a parameter-sparse framework specifically designed to capture sluggishness. This contains a single time-delay parameter τO3, characterizing the timescale for stomata to catch up with the level of opening they would have without damage. The larger the value of this parameter, the more sluggish the modelled stomatal response. Through variation of τO3, we find it is possible to have qualitatively similar responses to factorial experiments with and without raised O3, when comparing to reported measurement time series presented in the literature. This low-parameter approach lends itself to the inclusion of ozone-induced inertial effects being incorporated in the terrestrial vegetation component of Earth system models (ESMs).

scholarly journals Incumbent and Entrant Bidding in Scoring Rule Auctions: A Study on Italian Canteen Services

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Riccardo Camboni ◽  
Paola Valbonesi
Keyword(s):  
Theoretical Model ◽  
Production Cost ◽  
Specific Information ◽  
Scoring Rule ◽  
The Public ◽  
Simple Theoretical Model ◽  
Original Dataset

AbstractWe empirically investigate incumbents’ and entrants’ bids on an original dataset of 192 scoring rule auctions for canteen services in Italy. Our findings show that winning rebates are lower (i.e., prices paid by the public buyer are higher) when the contract is awarded to the incumbent supplier. This result is not explained by the observable characteristics of the auction or the service awarded. We develop a simple theoretical model showing that the result is consistent with a setting in which the buyer exploits specific information on the incumbent supplier’s production cost.

scholarly journals Market Choices Driven by Reference Groups: A Comparison of Analytical and Simulation Results on Random Networks

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 1007
Author(s):  
Michał Ramsza
Keyword(s):  
Theoretical Model ◽  
Reference Group ◽  
Third Party ◽  
Qualitative Behavior ◽  
Reference Groups ◽  
Group Influence ◽  
Simple Theoretical Model ◽  
High Connectivity ◽  
Simulation Results ◽  
Two Equilibria

The present paper reports simulation results for a simple model of reference group influence on market choices, e.g., brand selection. The model was simulated on three types of random graphs, Erdos–Renyi, Barabasi–Albert, and Watts–Strogatz. The estimates of equilibria based on the simulation results were compared to the equilibria of the theoretical model. It was verified that the simulations exhibited the same qualitative behavior as the theoretical model, and for graphs with high connectivity and low clustering, the quantitative predictions offered a viable approximation. These results allowed extending the results from the simple theoretical model to networks. Thus, by increasing the positive response towards the reference group, the third party may create a bistable situation with two equilibria at which respective brands dominate the market. This task is easier for large reference groups.

scholarly journals Current and future occurrences of health-relevant, compound heat and ozone pollution events in six European ozone-temperature regions 

2021 ◽  
Author(s):  
Sally Jahn ◽  
Elke Hertig
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Large Scale ◽  
Coupled Model ◽  
Ground Level ◽  
Future Climate Change ◽  
Ozone Pollution ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
Elevated Ozone

<p>Air pollution and heat events present two major health risks, both already independently posing a significant threat to human health and life. High levels of ground-level ozone (O<sub>3</sub>) and air temperature often coincide due to the underlying physical relationships between both variables. The most severe health outcome is in general associated with the co-occurrence of both hazards (e.g. Hertig et al. 2020), since concurrent elevated levels of temperature and ozone concentrations represent a twofold exposure and can lead to a risk beyond the sum of the individual effects. Consequently, in the current contribution, a compound approach considering both hazards simultaneously as so-called ozone-temperature (o-t-)events is chosen by jointly analyzing elevated ground-level ozone concentrations and air temperature levels in Europe.</p><p>Previous studies already point to the fact that the relationship of underlying synoptic and meteorological drivers with one or both of these health stressors as well as the correlation between both variables vary with the location of sites and seasons (e.g. Otero et al. 2016; Jahn, Hertig 2020). Therefore, a hierarchical clustering analysis is applied to objectively divide the study domain in regions of homogeneous, similar ground-level ozone and temperature characteristics (o-t-regions). Statistical models to assess the synoptic and large-scale meteorological mechanisms which represent main drivers of concurrent o-t-events are developed for each identified o-t-region.</p><p>Compound elevated ozone concentration and air temperature events are expected to become more frequent due to climate change in many parts of Europe (e.g. Jahn, Hertig 2020; Hertig 2020). Statistical projections of potential frequency shifts of compound o-t-events until the end of the twenty-first century are assessed using the output of Earth System Models (ESMs) from the sixth phase of the Coupled Model Intercomparison Project (CMIP6).</p><p><em>Hertig, E. (2020) Health-relevant ground-level ozone and temperature events under future climate change using the example of Bavaria, Southern Germany. Air Qual. Atmos. Health. doi: 10.1007/s11869-020-00811-z</em></p><p><em>Hertig, E., Russo, A., Trigo, R. (2020) Heat and ozone pollution waves in Central and South Europe- characteristics, weather types, and association with mortality. Atmosphere. doi: 10.3390/atmos11121271</em></p><p><em>Jahn, S., Hertig, E. (2020) Modeling and projecting health‐relevant combined ozone and temperature events in present and future Central European climate. Air Qual. Atmos. Health. doi: 10.1007/s11869‐020‐009610</em></p><p><em>Otero N., Sillmann J., Schnell J.L., Rust H.W., Butler T. (2016) Synoptic and meteorological drivers of extreme ozone concentrations over Europe. Environ Res Lett. doi: 10.1088/ 1748-9326/11/2/024005</em></p>

scholarly journals Theoretical Bounds on Electron Energy Filtering in Disordered Nanomaterials

2019 ◽  
Author(s):  
Amro Dodin ◽  
Brian F. Aull ◽  
Roderick R. Kunz ◽  
Adam Willard
Keyword(s):  
Theoretical Model ◽  
Electron Energy ◽  
Energy Levels ◽  
Additional Source ◽  
Discrete Energy ◽  
Energy Filtering ◽  
Simple Theoretical Model ◽  
Particle Polydispersity ◽  
Electron Energy Filtering ◽  
Individual Nanoparticles

This manuscript presents a theoretical model for determining the electron energy filtering properties of nanocomposite materials. Individual nanoparticles can serve as energy filters for tunneling electrons due their discretized energy levels. Nanomaterials comprised of many individual nanoparticles can in principle serve the same purpose, however, particle polydispersity can lead to an additional source of energetic broadening. We describe a simple theoretical model that includes the effects of discrete energy levels and inhomogeneous broadening. We use this model to identify the material parameters needed for effective energy filtering by quantum dot solids.

Sign in / Sign up

Export Citation Format

Share Document