scholarly journals Global biogenic volatile organic compound emissions in the ORCHIDEE and MEGAN models and sensitivity to key parameters

2016 ◽  
Vol 16 (22) ◽  
pp. 14169-14202 ◽  
Author(s):  
Palmira Messina ◽  
Juliette Lathière ◽  
Katerina Sindelarova ◽  
Nicolas Vuichard ◽  
Claire Granier ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Regional Scale ◽  
High Sensitivity ◽  
Geographical Differences ◽  
Area Index ◽  
Tropical Regions ◽  
Global Emission ◽  
Volatile Organic ◽  
Almost All ◽  
Global Emissions

Abstract. A new version of the biogenic volatile organic compounds (BVOCs) emission scheme has been developed in the global vegetation model ORCHIDEE (Organizing Carbon and Hydrology in Dynamic EcosystEm), which includes an extended list of biogenic emitted compounds, updated emission factors (EFs), a dependency on light for almost all compounds and a multi-layer radiation scheme. Over the 2000–2009 period, using this model, we estimate mean global emissions of 465 Tg C yr−1 for isoprene, 107.5 Tg C yr−1 for monoterpenes, 38 Tg C yr−1 for methanol, 25 Tg C yr−1 for acetone and 24 Tg C yr−1 for sesquiterpenes. The model results are compared to state-of-the-art emission budgets, showing that the ORCHIDEE emissions are within the range of published estimates. ORCHIDEE BVOC emissions are compared to the estimates of the Model of Emissions of Gases and Aerosols from Nature (MEGAN), which is largely used throughout the biogenic emissions and atmospheric chemistry community. Our results show that global emission budgets of the two models are, in general, in good agreement. ORCHIDEE emissions are 8 % higher for isoprene, 8 % lower for methanol, 17 % higher for acetone, 18 % higher for monoterpenes and 39 % higher for sesquiterpenes, compared to the MEGAN estimates. At the regional scale, the largest differences between ORCHIDEE and MEGAN are highlighted for isoprene in northern temperate regions, where ORCHIDEE emissions are higher by 21 Tg C yr−1, and for monoterpenes, where they are higher by 4.4 and 10.2 Tg C yr−1 in northern and southern tropical regions compared to MEGAN. The geographical differences between the two models are mainly associated with different EF and plant functional type (PFT) distributions, while differences in the seasonal cycle are mostly driven by differences in the leaf area index (LAI). Sensitivity tests are carried out for both models to explore the response to key variables or parameters such as LAI and light-dependent fraction (LDF). The ORCHIDEE and MEGAN emissions are differently affected by LAI changes, with a response highly depending on the compound considered. Scaling the LAI by a factor of 0.5 and 1.5 changes the isoprene global emission by −21 and +8 % for ORCHIDEE and −15 and +7 % for MEGAN, and affects the global emissions of monoterpenes by −43 and +40 % for ORCHIDEE and −11 and +3 % for MEGAN. Performing a further sensitivity test, forcing ORCHIDEE with the MODIS LAI, confirms the high sensitivity of the ORCHIDEE emission module to LAI variation. We find that MEGAN is more sensitive to variation in the LDF parameter than ORCHIDEE. Our results highlight the importance and the need to further explore the BVOC emission estimate variability and the potential for using models to investigate the estimated uncertainties.

scholarly journals Global biogenic volatile organic compound emissions in the ORCHIDEE and MEGAN models and sensitivity to key parameters

2015 ◽  
Vol 15 (23) ◽  
pp. 33967-34033 ◽  
Author(s):  
P. Messina ◽  
J. Lathière ◽  
K. Sindelarova ◽  
N. Vuichard ◽  
C. Granier ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Regional Scale ◽  
Geographical Differences ◽  
Area Index ◽  
Tropical Regions ◽  
Global Emission ◽  
Emission Estimate ◽  
Emission Change ◽  
Almost All ◽  
Global Vegetation

Abstract. A new version of the BVOC emission scheme has been developed in the global vegetation model ORCHIDEE (Organizing Carbon and Hydrology in Dynamic EcosystEm), including an extended list of biogenic emitted compounds, updated emission factors (EFs), a dependency on light for almost all compounds and a multi-layer radiation scheme. For the 2000–2009 period, we estimate with this model, mean global emissions of 465 Tg C yr-1 for isoprene, 107.5 Tg C yr-1 for monoterpenes, 38 Tg C yr-1 for methanol, 25 Tg C yr-1 for acetone and 24 Tg C yr-1 for sesquiterpenes. The model results are compared to state-of-the-art emission budgets, showing that the ORCHIDEE emissions are within the range of published estimates. ORCHIDEE BVOC emissions are compared to the estimates of the Model of Emissions of Gases and Aerosols from Nature (MEGAN), largely used throughout the biogenic emissions and atmospheric chemistry community. Our results show that global emission budgets are, in general, in good agreement between the two models. ORCHIDEE emissions are 8 % higher for isoprene, 8 % lower for methanol, 17 % higher for acetone, 18 % higher for monoterpenes and 39 % higher for sesquiterpenes compared to MEGAN estimates. At the regional scale, the largest differences between ORCHIDEE and MEGAN are highlighted for isoprene in northern temperate regions, with the ORCHIDEE emissions being higher by 21 Tg C yr-1, and for monoterpenes being higher by 10 and 18 Tg C yr-1 in northern and southern tropical regions compared to MEGAN. The geographical differences, between the two models, are mainly associated with different EF and PFT distribution, while differences in the seasonal cycle are mostly driven by differences in the Leaf Area Index (LAI). Sensitivity tests are carried out for both models to explore the response to key variables or parameters such as LAI and Light Dependent Fraction (LDF). The ORCHIDEE and MEGAN emissions are differently affected by LAI changes, with a response highly sensitive to the considered compound. When the LAI is scaled by a factor of 0.5 (1.5), the global emission change is −21 % (+8 %) for ORCHIDEE and −15 % (+7 %) for MEGAN regarding isoprene, and is −43 % (+40 %) for ORCHIDEE and −11 % (+3 %) for MEGAN regarding monoterpenes. We find that MEGAN is more sensitive to variation of LDF parameter than ORCHIDEE. Our results highlight the importance and the need to further explore the BVOC emission estimate variability and the interest of using models to investigate the estimate uncertainties.

scholarly journals Implementation of the biogenic emission model MEGAN(v2.1) into the ECHAM6-HAMMOZ chemistry climate model. Basic results and sensitivity tests

2016 ◽  
Author(s):  
Alexandra-Jane Henrot ◽  
Tanja Stanelle ◽  
Sabine Schröder ◽  
Colombe Siegenthaler ◽  
Domenico Taraborrelli ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Climate Model ◽  
High Sensitivity ◽  
Emission Model ◽  
Terrestrial Vegetation ◽  
Biogenic Emission ◽  
Tropical Regions ◽  
Global Emission ◽  
Empirical Coefficients ◽  
The Impact

Abstract. A biogenic emission scheme based on the Model of Emissions of Gases and Aerosols from Nature (MEGAN) version 2.1 (Guenther et al., 2012) has been integrated into the ECHAM6-HAMMOZ chemistry climate model in order to calculate the emissions from terrestrial vegetation of 32 compounds. The estimated annual global total for the simulation period (2000–2012) is 634 Tg C yr−1. Isoprene is the main contributor to the average emission total accounting for 66 % (417 Tg C yr−1), followed by several monoterpenes (12 %), methanol (7 %), acetone (3.6 %) and ethene (3.6 %). Regionally, most of the high annual emissions are found to be associated to tropical regions and tropical vegetation types. In order to evaluate the implementation of the biogenic model in ECHAM-HAMMOZ, global and regional BVOC emissions of the reference simulation were compared to previous published experiment results with the MEGAN model. Several sensitivity simulations were performed to study the impact of different model input and parameters related to the vegetation cover and the ECHAM6 climate. BVOC emissions obtained with the biogenic model are within the range of previous published estimates. The large range of emission estimates can be attributed to the use of different input data and empirical coefficients within different setups of the MEGAN model. The biogenic model shows a high sensitivity to the changes in plant functional type (PFT) distributions and associated emission factors for most of the compounds. The global emission impact for isoprene is about −9 %, but reaches +75 % for α-pinene when switching to PFT-dependent emission factor distributions. Isoprene emissions show the highest sensitivity to soil moisture impact, with a global decrease of 12.5 % when the soil moisture activity factor is included in the model parameterization. Nudging ECHAM6 climate towards ERA-Interim reanalysis has impact on the biogenic emissions, slightly lowering the global total emissions and their interannual variability.

scholarly journals Influence of the spatial resolution of satellite-derived vegetation parameters on the biogenic Volatile Organic Compounds (VOC) emission modeling

2014 ◽  
Vol 6 (1) ◽  
Author(s):  
Carlos Silveira ◽  
Oxana Tchepel
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Spatial Resolution ◽  
Atmospheric Chemistry ◽  
Vegetation Index ◽  
Meteorological Data ◽  
Area Index ◽  
Voc Emission ◽  
Volatile Organic ◽  
Vegetation Parameters

AbstractVegetation is a natural source of Volatile Organic Compounds (VOC) that plays an important role in atmospheric chemistry. The main objective of the current study is to implement a model to quantify process-based VOC emissions from plants that focuses on the relationship between the sensitivity of VOC emission estimates to spatial resolution data, based on scientific knowledge and vegetation dynamics derived from satellite observations. The Normalized Difference Vegetation Index (NDVI) and Leaf Area Index (LAI) were elected to examine this issue using different resolutions of satellite-derived products: 22m from the DEIMOS-1 satellite, and 250m and 1000m provided by MODIS. The study is focused on an area of 80×80km2 in Portugal for 2011. Detailed land cover and meteorological data are also included in the emission quantification algorithm. The primary outcomes were determined using a multi-scale analysis showing spatial and temporal variations in the vegetation parameters and modeling results. The results confirm that the emissions model is highly sensitive to the spatial resolution of the satellite-derived data, resulting in about a 30% difference in total isoprene emissions for the study area.

scholarly journals Impact of climate variability and land use changes on global biogenic volatile organic compound emissions

2005 ◽  
Vol 5 (5) ◽  
pp. 10613-10656 ◽  
Author(s):  
J. Lathière ◽  
D. A. Hauglustaine ◽  
A. Friend ◽  
N. De Noblet-Ducoudré ◽  
N. Viovy ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Leaf Age ◽  
Tropical Deforestation ◽  
Light Extinction ◽  
Biogenic Emissions ◽  
Vegetation Model ◽  
Area Index ◽  
Tropical Regions ◽  
Global Emissions

Abstract. A biogenic emissions scheme is incorporated in the global dynamic vegetation model ORCHIDEE (Organizing Carbon and Hydrology in Dynamic EcosystEms) in order to calculate global biogenic emissions of isoprene, monoterpenes, methanol, acetone, acetaldehyde, formaldehyde and formic and acetic acids. Important parameters such as the leaf area index are fully determined by the global vegetation model and the influences of light extinction (for isoprene emissions) and leaf age (for isoprene and methanol emissions) are also taken into account. We study the interannual variability of biogenic emissions using the satellite-based climate forcing ISLSCP-II as well as relevant CO2 atmospheric levels, for the 1983–1995 period. Mean global emissions of 460 TgC/year for isoprene, 117 TgC/year for monoterpenes, 106 TgC/year for methanol and 42 TgC/year for acetone are predicted. The mean global emission of all biogenic compounds is 752±16 TgC/yr with extremes ranging from 717 TgC/yr in 1986 to 778 TgC/yr in 1995, that is a 8.5% increase between both. This variability differs significantly from one region to another and among the regions studied, biogenic emissions anomalies were the most variable in Europe and the least variable in Indonesia (isoprene and monoterpenes) and North America (methanol). Year-to-year variability also reveals a strong correlation of emissions in tropical regions with El Niño events, particularly for isoprene, for which the tropical regions are a major source. Two scenarios of land use changes are considered using the 1983 climate and atmospheric CO2 conditions, to study the sensitivity of biogenic emissions to vegetation alteration, namely tropical deforestation and European afforestation. Global biogenic emissions are highly affected by tropical deforestation, with a 29% decrease in isoprene emission and a 22% increase in methanol emission. Global emissions are not significantly affected by European afforestation, but on a European scale, total biogenic VOCs emissions increase by 54%.

scholarly journals Impact of climate variability and land use changes on global biogenic volatile organic compound emissions

2006 ◽  
Vol 6 (8) ◽  
pp. 2129-2146 ◽  
Author(s):  
J. Lathière ◽  
D. A. Hauglustaine ◽  
A. D. Friend ◽  
N. De Noblet-Ducoudré ◽  
N. Viovy ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Changes ◽  
Leaf Age ◽  
Tropical Deforestation ◽  
Light Extinction ◽  
Biogenic Emissions ◽  
Vegetation Model ◽  
Area Index ◽  
Global Emission ◽  
Global Emissions

Abstract. A biogenic emissions scheme has been incorporated in the global dynamic vegetation model ORCHIDEE (Organizing Carbon and Hydrology in Dynamic EcosystEms) in order to calculate global biogenic emissions of isoprene, monoterpenes, methanol, acetone, acetaldehyde, formaldehyde and formic and acetic acids. Important parameters such as the leaf area index are fully determined by the global vegetation model and the influences of light extinction (for isoprene emissions) and leaf age (for isoprene and methanol emissions) are also taken into account. We study the interannual variability of biogenic emissions using the satellite-based climate forcing ISLSCP-II as well as relevant CO2 atmospheric levels, for the 1983–1995 period. Mean global emissions of 460 TgC/yr for isoprene, 117 TgC/yr for monoterpenes, 106 TgC/yr for methanol and 42 TgC/yr for acetone are predicted. The mean global emission of all biogenic compounds is 752±16 TgC/yr with extremes ranging from 717 TgC/yr in 1986 to 778 TgC/yr in 1995, that is a 8.5% increase between both. This variability differs significantly from one region to another and among the regions studied, biogenic emissions anomalies were the most variable in Europe and the least variable in Indonesia (isoprene and monoterpenes) and North America (methanol). Two scenarios of land use changes are considered using the 1983 climate and atmospheric CO2 conditions, to study the sensitivity of biogenic emissions to vegetation alteration, namely tropical deforestation and European afforestation. Global biogenic emissions are highly affected by tropical deforestation, with a 29% decrease in isoprene emission and a 22% increase in methanol emission. Global emissions are not significantly affected by European afforestation, but on a European scale, total biogenic VOCs emissions increase by 54%.

scholarly journals Global Emissions of Perfluorocyclobutane (PFC-318, c-C<sub>4</sub>F<sub>8</sub>) Resulting from the Use of Hydrochlorofluorocarbon-22 (HCFC-22) Feedstock to Produce Polytetrafluoroethylene (PTFE) and related Fluorochemicals

2021 ◽  
Author(s):  
Jens Mühle ◽  
Lambert J. M. Kuijpers ◽  
Kieran M. Stanley ◽  
Matthew Rigby ◽  
Luke M. Western ◽  
...  
Keyword(s):  
Developing Countries ◽  
Emission Factor ◽  
Climate Impact ◽  
Manufacturing Processes ◽  
Atmospheric Measurements ◽  
Global Emission ◽  
Facility Level ◽  
Highly Correlated ◽  
Almost All ◽  
Global Emissions

Abstract. Emissions of the potent greenhouse gas perfluorocyclobutane (c-C4F8, PFC-318, octafluorocyclobutane) into the global atmosphere inferred from atmospheric measurements have been increasing sharply since the early 2000s. We find that these inferred emissions are highly correlated with the production of hydrochlorofluorocarbon-22 (HCFC-22, CHClF2) for feedstock (FS) uses, because almost all HCFC-22 FS is pyrolyzed to produce (poly)tetrafluoroethylene ((P)TFE, Teflon) and hexafluoropropylene (HFP), a process in which c-C4F8 is a known by-product, causing a significant fraction of global c-C4F8 emissions. We find a global emission factor of ~0.003 kg c-C4F8 per kg of HCFC-22 FS pyrolyzed. Mitigation of these c-C4F8 emissions, e.g., through process optimization, abatement, or different manufacturing processes, such as electrochemical fluorination, could reduce the climate impact of this industry. While it has been shown that c-C4F8 emissions from developing countries dominate global emissions, more atmospheric measurements and/or detailed process statistics are needed to quantify country to facility level c-C4F8 emissions.

scholarly journals Telemedicine in Spine Surgery: Global Perspectives and Practices

2021 ◽  
pp. 219256822110223
Author(s):  
Grant Riew ◽  
Francis Lovecchio ◽  
Dino Samartzis ◽  
Philip K. Louie ◽  
Niccole Germscheid ◽  
...  
Keyword(s):  
Spine Surgery ◽  
Descriptive Statistics ◽  
South American ◽  
Geographical Differences ◽  
Cross Sectional ◽  
Global Perspectives ◽  
Phone Calls ◽  
Initial Appointment ◽  
Almost All

Study Design: Cross-sectional, anonymous, international survey. Objectives: The COVID-19 pandemic has resulted in the rapid adoption of telemedicine in spine surgery. This study sought to determine the extent of adoption and global perspectives on telemedicine in spine surgery. Methods: All members of AO Spine International were emailed an anonymous survey covering the participant’s experiences with and perceptions of telemedicine. Descriptive statistics were used to depict responses. Responses were compared among regions. Results: 485 spine surgeons participated in the survey. Telemedicine usage rose from <10.0% to >39.0% of all visits. A majority of providers (60.5%) performed at least one telemedicine visit. The format of “telemedicine” varied widely by region: European (50.0%) and African (45.2%) surgeons were more likely to use phone calls, whereas North (66.7%) and South American (77.0%) surgeons more commonly used video ( P < 0.001). North American providers used telemedicine the most during COVID-19 (>60.0% of all visits). 81.9% of all providers “agreed/strongly agreed” telemedicine was easy to use. Respondents tended to “agree” that imaging review, the initial appointment, and postoperative care could be performed using telemedicine. Almost all (95.4%) surgeons preferred at least one in-person visit prior to the day of surgery. Conclusion: Our study noted significant geographical differences in the rate of telemedicine adoption and the platform of telemedicine utilized. The results suggest a significant increase in telemedicine utilization, particularly in North America. Spine surgeons found telemedicine feasible for imaging review, initial visits, and follow-up visits although the vast majority still preferred at least one in-person preoperative visit.

scholarly journals High Intraspecific Genetic Diversity ofNocardia brasiliensis, a Pathogen Responsible for Cutaneous Nocardiosis Found in France: Phylogenetic Relationships by Usingsodandhsp65Genes

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
D. Kosova-Maali ◽  
E. Bergeron ◽  
Y. Maali ◽  
T. Durand ◽  
J. Gonzalez ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Genetic Characterization ◽  
Haplotype Diversity ◽  
Species Level ◽  
Genotype 1 ◽  
Tropical Regions ◽  
High Bootstrap ◽  
Almost All ◽  
A New Species ◽  
Immunocompetent Patients

This study aims at genetic characterization and phylogenetic relationships ofNocardia brasiliensisfocusing by using housekeepingrrs,hsp65,andsodAgenes.N. brasiliensisis the species responsible for 80% of cases of actinomycetoma, one form of cutaneous nocardiosis which occurs mainly in tropical regions reaching immunocompetent patients in which the disease can lead to amputation. We analyze 36 indigenous cases ofN. brasiliensisthat happened in France. Phylogenetic analysis targetingrrsgene showed no robustness at phylogenetic nodes level. However, the use of a concatenation ofhsp65andsodAgenes showed that the tested strains surprisingly ranked in 3 well-defined genotypes. Genotypes 2 and 3 were phylogenetically closer to each other and both diverged from genotype 1 sustained by a high bootstrap of 81%. This last genotype hosts all the cases of pulmonary forms (3), the sole cerebral form, and almost all the cases of immunocompromised patients (3 out of 4). Moreover, excepting one of them, all the strains belonging to this group present a susceptibility to imipenem which is not the case in the other genotypes that rarely count among them strains being susceptible to this drug. The haplotype diversity (Hd) ofhsp65(0.927) andsodA(0.885) genes was higher than that ofrrs(0.824). For this gene, we obtained 16 polymorphic sites whereas, forhsp65andsodAgenes, up to 27 and 29 were identified, respectively. This study reveals that these two genes have an important genetic discriminatory power for the evaluation of the intraspecies genetic variability ofN. brasiliensisand they may be useful for identification purposes at species level. This study also reveals the possible existence of a new species harbored by genotype 1.

Mechanism of anteroposterior axis specification in vertebrates. Lessons from the amphibians

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 285-302 ◽  
Author(s):  
J.M. Slack ◽  
D. Tannahill
Keyword(s):  
Molecular Markers ◽  
Expression Patterns ◽  
Signal Transduction Pathway ◽  
Homeobox Gene ◽  
Neural Induction ◽  
High Sensitivity ◽  
Neural Plate ◽  
Mesoderm Induction ◽  
Inducing Factors ◽  
Almost All

Interest in the problem of anteroposterior specification has quickened because of our near understanding of the mechanism in Drosophila and because of the homology of Antennapedia-like homeobox gene expression patterns in Drosophila and vertebrates. But vertebrates differ from Drosophila because of morphogenetic movements and interactions between tissue layers, both intimately associated with anteroposterior specification. The purpose of this article is to review classical findings and to enquire how far these have been confirmed, refuted or extended by modern work. The “pre-molecular” work suggests that there are several steps to the process: (i) Formation of anteroposterior pattern in mesoderm during gastrulation with posterior dominance. (ii) Regional specific induction of ectoderm to form neural plate. (iii) Reciprocal interactions from neural plate to mesoderm. (iv) Interactions within neural plate with posterior dominance. Unfortunately, almost all the observable markers are in the CNS rather than in the mesoderm where the initial specification is thought to occur. This has meant that the specification of the mesoderm has been assayed indirectly by transplantation methods such as the Einsteckung. New molecular markers now supplement morphological ones but they are still mainly in the CNS and not the mesoderm. A particular interest attaches to the genes of the Antp-like HOX clusters since these may not only be markers but actual coding factors for anteroposterior levels. We have a new understanding of mesoderm induction based on the discovery of activins and fibroblast growth factors (FGFs) as candidate inducing factors. These factors have later consequences for anteroposterior pattern with activin tending to induce anterior, and FGF posterior structures. Recent work on neural induction has implicated cAMP and protein kinase C (PKC) as elements of the signal transduction pathway and has provided new evidence for the importance of tangential neural induction. The regional specificity of neural induction has been reinvestigated using molecular markers and provides conclusions rather similar to the classical work. Defects in the axial pattern may be produced by retinoic acid but it remains unclear whether its effects are truly coordinate ones or are concentrated in certain regions of high sensitivity. In general the molecular studies have supported and reinforced the “pre-molecular ones”. Important questions still remain: (i) How much pattern is there in the mesoderm (how many states?) (ii) How is this pattern generated by the invaginating organizer? (iii) Is there one-to-one transmission of codings to the neural plate? (iv) What is the nature of the interactions within the neural plate? (v) Are the HOX cluster genes really the anteroposterior codings?

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