Evaluation of two process-based models used to estimate global CH4 emissions from natural wetlands

2020 ◽  
Author(s):  
Tingting Li
Keyword(s):  
Coastal Wetland ◽  
Poor Performance ◽  
Wetland Type ◽  
The World ◽  
Natural Wetlands ◽  
Flux Measurements ◽  
Model Efficiency ◽  
Global Emissions ◽  
Wetland Types ◽  
Process Based Models

<p>Reliable models are required to estimate global wetland CH<sub>4</sub> emissions. This study aimed to test two process-based models, CH4MOD<sub>wetland</sub> and TEM, against the CH<sub>4</sub> flux measurements of marsh, swamps, peatland and coastal wetland sites across the world; specifically, model accuracy and generality were evaluated for different wetland types and in different continents, and then the global CH<sub>4</sub> emissions from 2000 to 2010 were estimated. Both models showed similar high correlations with the observed seasonal CH<sub>4</sub> emissions, and the regression of the observed versus computed total seasonal CH<sub>4</sub> emissions resulted in R<sup>2</sup> values of 0.78 and 0.72 by CH4MOD<sub>wetland</sub> and TEM, respectively. The CH4MOD<sub>wetland</sub> predicted more accurately in marsh, peatland and coastal wetlands, with model efficiency (EF) values of 0.22, 0.55 and 0.72, respectively; however, the model showed poor performance in swamps (EF<0). The TEM model predicted better in peatland and swamp, with EF values of 0.77 and 0.71, respectively, but it could not accurately simulate the marsh and coastal wetland (EF<0). There was a good correlation between the simulated CH<sub>4</sub> fluxes and the observed values on most continents. However, CH4MOD<sub>wetland</sub> showed no correlation with the observed values in South America and Africa. TEM showed no correlation with the observations in Europe. The global CH<sub>4</sub> emissions for the period 2000­­–2010 were estimated to be 105.31±2.72 Tg yr<sup>-1</sup> by CH4MOD<sub>wetland</sub> and 134.31±0.84 Tg yr<sup>-1</sup> by TEM. Both models simulated a similar spatial distribution of CH<sub>4</sub> emissions across the world and among continents. Marsh contributes 36%–39% to global CH<sub>4</sub> emissions. Lakes and rivers and swamp are the second and third contributors, respectively. Other wetland types account for only approximately 20% of global emissions. Based on the models’ generality, if we use the more accurate model to estimate each continent/wetland type, we obtain a new assessment of 116.99–124.74 Tg yr<sup>-1 </sup>for the global CH<sub>4</sub> emissions for the period 2000–2010.</p>

scholarly journals Evaluation of CH4MOD<sub>wetland</sub> and TEM models used to estimate global CH<sub>4</sub> emissions from natural wetlands

2020 ◽  
Author(s):  
Tingting Li ◽  
Yanyu Lu ◽  
Lingfei Yu ◽  
Wenjuan Sun ◽  
Qing Zhang ◽  
...  
Keyword(s):  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Poor Performance ◽  
Model Accuracy ◽  
Ch4 Flux ◽  
Ch4 Emissions ◽  
Natural Wetlands ◽  
Flux Measurements ◽  
Model Efficiency ◽  
Process Based Models

Abstract. Reliable models are required to estimate global wetland CH4 emissions. This study aimed to test two process-based models, CH4MODwetland and TEM, against the CH4 flux measurements of marsh, swamps, peatland and coastal wetland sites across the world; specifically, model accuracy and generality were evaluated for different wetland types and in different continents, and then the global CH4 emissions from 2000 to 2010 were estimated. Both models showed similar high correlations with the observed seasonal CH4 emissions, and the regression of the observed versus computed total seasonal CH4 emissions resulted in R2 values of 0.78 and 0.72 by CH4MODwetland and TEM, respectively. The CH4MODwetland predicted more accurately in marsh, peatland and coastal wetlands, with model efficiency (EF) values of 0.22, 0.55 and 0.72, respectively; however, the model showed poor performance in swamps (EF 

scholarly journals Evaluation of CH4MOD<sub>wetland</sub> and Terrestrial Ecosystem Model (TEM) used to estimate global CH<sub>4</sub> emissions from natural wetlands

2020 ◽  
Vol 13 (8) ◽  
pp. 3769-3788
Author(s):  
Tingting Li ◽  
Yanyu Lu ◽  
Lingfei Yu ◽  
Wenjuan Sun ◽  
Qing Zhang ◽  
...  
Keyword(s):  
Coastal Wetlands ◽  
Coastal Wetland ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Model Accuracy ◽  
Ch4 Emissions ◽  
Terrestrial Ecosystem Model ◽  
Model Efficiency ◽  
Wetland Types ◽  
Process Based Models

Abstract. Wetlands are the largest and most uncertain natural sources of atmospheric methane (CH4). Several process-based models have been developed to quantify the magnitude and estimate spatial and temporal variations in CH4 emissions from global wetlands. Reliable models are required to estimate global wetland CH4 emissions. This study aimed to test two process-based models, CH4MODwetland and Terrestrial Ecosystem Model (TEM), against the CH4 flux measurements of marsh, swamp, peatland and coastal wetland sites across the world; specifically, model accuracy and generality were evaluated for different wetland types and in different continents, and then the global CH4 emissions from 2000 to 2010 were estimated. Both models showed similar high correlations with the observed seasonal/annual total CH4 emissions, and the regression of the observed versus computed total seasonal/annual CH4 emissions resulted in R2 values of 0.81 and 0.68 for CH4MODwetland and TEM, respectively. The CH4MODwetland produced accurate predictions for marshes, peatlands, swamps and coastal wetlands, with model efficiency (EF) values of 0.22, 0.52, 0.13 and 0.72, respectively. TEM produced good predictions for peatlands and swamps, with EF values of 0.69 and 0.74, respectively, but it could not accurately simulate marshes and coastal wetlands (EF <0). There was a good correlation between the simulated CH4 fluxes and the observed values on most continents. However, CH4MODwetland showed no correlation with the observed values in South America and Africa. TEM showed no correlation with the observations in Europe. The global CH4 emissions for the period 2000–2010 were estimated to be 105.31 ± 2.72 Tg yr−1 by CH4MODwetland and 134.31 ± 0.84 Tg yr−1 by TEM. Both models simulated a similar spatial distribution of CH4 emissions globally and on different continents. Marshes contribute 36 %–39 % of global CH4 emissions. Lakes/rivers and swamps are the second and third greatest contributors, respectively. Other wetland types account for only approximately 20 % of global emissions. Based on the model applicability, if we use the more accurate model, i.e., the one that performs best as evidenced by a higher model efficiency and a lower model bias, to estimate each continent and wetland type, we obtain a new assessment of 116.99–124.74 Tg yr−1 for the global CH4 emissions for the period 2000–2010. Our results imply that performance at a global scale may conceal model uncertainty. Efforts should be made to improve model accuracy for different wetland types and regions, particularly hotspot regions, to reduce the uncertainty in global assessments.

Relationships between gregarine infection in damselflies, wetland type, and landscape characteristics

2011 ◽  
Vol 143 (5) ◽  
pp. 460-469 ◽  
Author(s):  
Julia J. Mlynarek ◽  
Daniel G. Bert ◽  
G. Haydeé Peralta-Vázquez ◽  
Joanna A. James ◽  
Mark R. Forbes
Keyword(s):  
Forest Cover ◽  
Road Density ◽  
Natural Habitats ◽  
Artificial Wetlands ◽  
Wetland Type ◽  
Landscape Characteristics ◽  
Natural Wetlands ◽  
Ischnura Verticalis ◽  
Host Parasite ◽  
Wetland Cover

AbstractAlthough human-modified landscapes are characterized by the loss of natural habitats, new habitats also can be created and exploited by many species. The importance of landscape change to invertebrate associations (particularly host-parasite associations) is understudied. Our objective was to determine whether prevalence and intensity of gregarine parasitism in the damselfly Ischnura verticalis (Say) (Odonata: Coenagrionidae) differed between 17 artificial and 7 natural wetlands in landscapes that varied in amount of forest and wetland cover and road density determined at spatial extents of 500m and 1km from each wetland. Wetlands were located in and around Ottawa, Ontario, and Gatineau, Quebec, Canada. Wetland type did not account for significant variation in principal components based on forest and wetland cover and road density at either spatial extent. Gregarine prevalence was higher in damselflies collected from natural wetlands than in those collected from artificial wetlands and was positively associated with increasing forest cover. In contrast, gregarine intensity was inversely related to road density. Our results suggest that parasitism of damselflies by gregarines is associated with wetland type and landscape characteristics, although the mechanisms producing such relationships are unknown.

scholarly journals Landscape Characteristics and Ecological Risk Assessment Based on Multi-Scenario Simulations: A Case Study of Yancheng Coastal Wetland, China

2020 ◽  
Vol 13 (1) ◽  
pp. 149
Author(s):  
Peng Tian ◽  
Luodan Cao ◽  
Jialin Li ◽  
Ruiliang Pu ◽  
Hongbo Gong ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Markov Model ◽  
Ecological Risk ◽  
Ecological Risk Assessment ◽  
Coastal Wetland ◽  
Landscape Planning ◽  
Test Accuracy ◽  
Artificial Wetlands ◽  
Wetland Landscape ◽  
Natural Wetlands

Carrying out coastal wetland landscape simulations and current and future ecological risk assessments is conducive to formulating policies for coastal wetland landscape planning and promoting the coordinated development of the social economy and ecological environment. This study used the Cellular Automaton (CA)-Markov model to simulate the landscape data of the study area under different scenarios in 2021 and 2025, and built an ecological risk assessment (ERS) index model to analyze the differences of spatio-temporal characteristics of ecological risks. The results showed that: (1) The test accuracy of the CA–Markov model was 0.9562 after passing through the consistency test. The spatial distribution data of landscapes under current utilization scenarios (CUSs), natural development scenarios (NDSs), and ecological protection scenarios (EPSs) were gained through simulations. (2) During 1991–2025, the landscape types of Yancheng coastal wetlands undertake complicated transfers and have vast transfer regions. Under CUSs and NDSs, a large number of natural wetlands are transferred to artificial wetlands. Under EPSs, the area of artificial wetlands declines and artificial wetlands are mainly transferred to natural wetlands. (3) The ecological risk of Yancheng Coastal Wetland increases, accompanied with significant spatial heterogeneity, which is manifested as low in the north area and high in the south area, and there exist some differences between sea areas and land areas. Ecological risk levels transfer violently.

scholarly journals Coastal Wetland Classification with Deep U-Net Convolutional Networks and Sentinel-2 Imagery: A Case Study at the Tien Yen Estuary of Vietnam

2020 ◽  
Vol 12 (19) ◽  
pp. 3270
Author(s):  
Kinh Bac Dang ◽  
Manh Ha Nguyen ◽  
Duc Anh Nguyen ◽  
Thi Thanh Hai Phan ◽  
Tuan Linh Giang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Coastal Wetland ◽  
Coastal Hazards ◽  
Support Vector ◽  
Wetland Classification ◽  
Natural Wetland ◽  
Convolutional Networks ◽  
Transition Areas ◽  
Wetland Types ◽  
Sentinel 2

The natural wetland areas in Vietnam, which are transition areas from inland and ocean, play a crucial role in minimizing coastal hazards; however, during the last two decades, about 64% of these areas have been converted from the natural wetland to the human-made wetland. It is anticipated that the conversion rate continues to increase due to economic development and urbanization. Therefore, monitoring and assessment of the wetland are essential for the coastal vulnerability assessment and geo-ecosystem management. The aim of this study is to propose and verify a new deep learning approach to interpret 9 of 19 coastal wetland types classified in the RAMSAR and MONRE systems for the Tien Yen estuary of Vietnam. Herein, a Resnet framework was integrated into the U-Net to optimize the performance of the proposed deep learning model. The Sentinel-2, ALOS-DEM, and NOAA-DEM satellite images were used as the input data, whereas the output is the predefined nine wetland types. As a result, two ResU-Net models using Adam and RMSprop optimizer functions show the accuracy higher than 85%, especially in forested intertidal wetlands, aquaculture ponds, and farm ponds. The better performance of these models was proved, compared to Random Forest and Support Vector Machine methods. After optimizing the ResU-Net models, they were also used to map the coastal wetland areas correctly in the northeastern part of Vietnam. The final model can potentially update new wetland types in the southern parts and islands in Vietnam towards wetland change monitoring in real time.

Performance of hazelnut cultivars and selections in southern Ontario

2020 ◽  
Vol 100 (5) ◽  
pp. 537-548
Author(s):  
Toktam Taghavi ◽  
Adam Dale ◽  
John M. Kelly ◽  
Dragan Galic ◽  
Alireza Rahemi
Keyword(s):  
New York ◽  
Cold Hardiness ◽  
Poor Performance ◽  
Southern Ontario ◽  
Production Phase ◽  
The Poor ◽  
Global Demand ◽  
The World ◽  
Health Products ◽  
Establishment Phase

The global demand for hazelnuts is increasing steadily, driven by increasing use by chocolate companies, pharmaceuticals, health products, and others. North America only produces 5% of the world crop, of which 99% is produced in Oregon (OR, USA). Most available cultivars are adapted to areas with mild winters and thus do not perform well in Ontario (ON, Canada). Our objective was to identify genotypes capable of supporting the newly formed hazelnut industry in southern Ontario. In the last several decades, selections have been identified in ON, New York (NY, USA), and Michigan (MI, USA) that may be better adapted in ON than cultivars from Europe and OR. To test our hypothesis that these new selections would outperform cultivars from Europe and OR in southern Ontario, two trials were performed to evaluate yield, nut quality, and winter hardiness. As hypothesized, selections from ON and NY such as ‘Gene’, ‘Alex’, and ‘Slate’ were winter hardy and highest yielding, followed by ‘Butler’ and ‘Gamma’ from OR; however, these selections did not perform well in other assessed parameters such as nut quality and catkin survivability. Possible explanations for the poor performance of the European and OR cultivars include (i) longer time needed to acclimatize and enter production phase relative to selections from ON, NY, and MI, and (ii) cold susceptibility during the initial establishment phase. The need to allocate resources towards survival probably delays the ability of the European and OR cultivars to enter the production phase. In conclusion, hazelnut cultivars brought from regions with a different climate need to be tested for cold hardiness.

Amphibian reproductive success as a gauge of functional equivalency of created wetlands in the Central Appalachians

2017 ◽  
Vol 44 (4) ◽  
pp. 354 ◽  
Author(s):  
Gabriel F. Strain ◽  
Philip J. Turk ◽  
Jordan Helmick ◽  
James T. Anderson
Keyword(s):  
Growth Curves ◽  
Wildlife Habitat ◽  
Breeding Habitat ◽  
Wetland Mitigation ◽  
Sufficient Evidence ◽  
Created Wetlands ◽  
Green Frog ◽  
Vegetative Cover ◽  
Wetland Type ◽  
Natural Wetlands

Context Evaluating the adequacy of created wetlands to replace the functions of lost natural wetlands is important because wetland mitigation is a major tool used to offset wetland losses. However, measurements such as vegetative cover and presence of wildlife may not provide sufficient evidence that created wetlands are functioning properly. Thus, examining the ecology of wetland biota such as that of amphibians may be a more useful surrogate for function. Aims The objectives of this study were to compare the abundance of amphibian metamorphs and survival and growth of larval amphibians in created wetlands, relative to natural wetlands. Methods Amphibian metamorphs were trapped in created and natural wetlands during the spring (April–May) and summer (June–August) of 2009 and 2010, and 165 green frog (Lithobates clamitans) larvae were raised during the spring of 2010 in laboratory aquaria containing water from created or natural wetlands. Key results Abundance of spring peeper (Pseudacris crucifer) metamorphs decreased significantly from 2009 to 2010 and abundance of green frog metamorphs increased with habitat complexity, but both were unaffected by wetland type. Detection probability of metamorphs of both species was low, increased with water temperature and declined with month of observation. Survival, growth curves and mass were similar among green frog larvae raised in created and natural wetland aquaria. Conclusions Our results suggest that the created and natural wetlands we examined function similarly with respect to providing adequate breeding habitat for green frogs and spring peepers. Implications Wetlands created to offset the loss of natural wetlands, although generally not designed for the purpose of wildlife habitat, can function as adequate breeding habitat for generalist amphibians such as green frogs and spring peepers.

Cosmic-ray fast-neutron flux measurements in the atmosphere at various latitudes

1968 ◽  
Vol 46 (10) ◽  
pp. S1023-S1026 ◽  
Author(s):  
S. A. Korff ◽  
R. B. Mendell ◽  
M. Merker ◽  
W. Sandie
Keyword(s):  
Solar Cycle ◽  
Neutron Transport ◽  
Full Range ◽  
Cosmic Ray ◽  
Leakage Flux ◽  
Transport Code ◽  
The World ◽  
Flux Measurements ◽  
High Elevations ◽  
The Relationship

We have extended in time our series of balloon flights, made at several latitudes between Hyderabad, India, and Ft. Churchill, Manitoba, to altitudes close to the top of the atmosphere. In these flights the neutrons generated by the cosmic radiation in the energy interval between 1 and 10 MeV are measured. The first set of measurements was made during the period of the minimum of solar activity, and the more recent flights carry the work into the start of the next solar cycle. A decrease in intensity at high elevations with the onset of the present solar cycle has been noted. Further data were also obtained on an airplane flight around the world over both poles, thus covering the full range of latitudes at two opposite longitudes. The relationship between the observed neutron spectrum and that derived by the use of a neutron transport code will be discussed. We shall also discuss other factors emerging from this analysis, including the numbers for radiocarbon production and the leakage flux.

scholarly journals Carbon Inequality in 2030: Per capita consumption emissions and the 1.5⁰C goal

2021 ◽  
Author(s):  
Tim Gore
Keyword(s):  
Paris Agreement ◽  
Capita Consumption ◽  
World Population ◽  
The World ◽  
Per Capita ◽  
Global Emissions ◽  
Per Capita Consumption

The world’s richest 1% are set to have per capita consumption emissions in 2030 that are still 30 times higher than the global per capita level compatible with the 1.5⁰C goal of the Paris Agreement, while the footprints of the poorest half of the world population are set to remain several times below that level. By 2030, the richest 1% are on course for an even greater share of total global emissions than when the Paris Agreement was signed. Tackling extreme inequality and targeting the excessive emissions linked to the consumption and investments of the world’s richest people is vital to keeping the 1.5⁰C Paris goal alive.

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