NUMERICAL MODEL ON METHANE EMISSIONS FROM AGRICULTURE SECTOR

2020 ◽  
Vol 02 (01) ◽  
pp. 2050003
Author(s):  
J. B. SHUKLA ◽  
SHYAM SUNDAR ◽  
ASHISH KUMAR MISHRA ◽  
RAM NARESH
Keyword(s):  
Numerical Simulation ◽  
Growth Rate ◽  
Global Warming ◽  
Logistic Models ◽  
Atmospheric Temperature ◽  
Atmospheric Methane ◽  
Rice Paddies ◽  
Atmospheric Concentration ◽  
Agriculture Sector ◽  
Equilibrium Level

Atmospheric methane, emitted from agriculture sector such as production of rice paddies and farming of livestock populations, is one of the important factors responsible for increasing the average atmospheric temperature leading to global warming. It is, therefore, crucial to comprehend the dynamics of methane emission and its effect on global warming. In this paper, a nonlinear mathematical model is proposed and analyzed to study the increase of average atmospheric temperature (or average global warming temperature) caused by emission of methane due to various processes involved in the production of rice paddies and farming of livestock populations simultaneously. In the modeling process, six variables are considered, namely, the cumulative biomass density of rice paddies, the cumulative density of livestock populations, the cumulative density of methane formed by various processes involved in the production of rice paddies, the cumulative density of methane formed by various processes involved in the farming of livestock populations, the atmospheric concentration of methane and the average atmospheric temperature. It is assumed that both the cumulative biomass densities of rice paddies and livestock populations follow logistic models with their respective growth rates and carrying capacities. The growth rate of concentration of methane in the atmosphere is assumed to be directly proportional to the cumulative densities of various processes involved in the production of rice paddies as well as in the farming of livestock populations. This growth rate also increases with a constant rate from various natural sources such as wetlands, etc. The growth rate of average global warming temperature is assumed to be proportional to the increased level of methane concentration in the atmosphere from its equilibrium value. It is also assumed that this temperature decreases with a rate proportional to its enhanced level from its equilibrium level caused by various natural factors such as rain fall, snowfall, etc. The proposed model is analyzed using the stability theory of differential equations and numerical simulation. The analysis shows that as the emission of methane from various processes involved in the production of rice paddies and farming of livestock populations increase, the average global warming temperature increases considerably from its equilibrium level. The numerical simulation of the model confirms the analytical results.

scholarly journals Role of OH variability in the stalling of the global atmospheric CH<sub>4</sub> growth rate from 1999 to 2006

2016 ◽  
Vol 16 (12) ◽  
pp. 7943-7956 ◽  
Author(s):  
Joe McNorton ◽  
Martyn P. Chipperfield ◽  
Manuel Gloor ◽  
Chris Wilson ◽  
Wuhu Feng ◽  
...  
Keyword(s):  
Growth Rate ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Atmospheric Temperature ◽  
Atmospheric Methane ◽  
Chemical Transport Model ◽  
Large Variability ◽  
Model Driven ◽  
Stagnation Period ◽  
Global Mean

Abstract. The growth in atmospheric methane (CH4) concentrations over the past 2 decades has shown large variability on a timescale of several years. Prior to 1999 the globally averaged CH4 concentration was increasing at a rate of 6.0 ppb yr−1, but during a stagnation period from 1999 to 2006 this growth rate slowed to 0.6 ppb yr−1. From 2007 to 2009 the growth rate again increased to 4.9 ppb yr−1. These changes in growth rate are usually ascribed to variations in CH4 emissions. We have used a 3-D global chemical transport model, driven by meteorological reanalyses and variations in global mean hydroxyl (OH) concentrations derived from CH3CCl3 observations from two independent networks, to investigate these CH4 growth variations. The model shows that between 1999 and 2006 changes in the CH4 atmospheric loss contributed significantly to the suppression in global CH4 concentrations relative to the pre-1999 trend. The largest factor in this is relatively small variations in global mean OH on a timescale of a few years, with minor contributions of atmospheric transport of CH4 to its sink region and of atmospheric temperature. Although changes in emissions may be important during the stagnation period, these results imply a smaller variation is required to explain the observed CH4 trends. The contribution of OH variations to the renewed CH4 growth after 2007 cannot be determined with data currently available.

scholarly journals An examination of enhanced atmospheric methane detection methods for predicting performance of a novel multiband uncooled radiometer imager

2020 ◽  
Vol 13 (10) ◽  
pp. 5359-5367
Author(s):  
Cody M. Webber ◽  
John P. Kerekes
Keyword(s):  
Brightness Temperature ◽  
Matched Filter ◽  
Atmospheric Temperature ◽  
Detection Methods ◽  
Absorption Feature ◽  
Atmospheric Methane ◽  
Atmospheric Concentration ◽  
Index Method ◽  
Methane Absorption ◽  
Methane Detection

Abstract. To evaluate the potential for a new uncooled infrared radiometer imager to detect enhanced atmospheric levels of methane, three different analysis methods were examined. A single-pixel brightness temperature to noise-equivalent delta temperature (NEdT) comparison study performed using data simulated from MODTRAN6 revealed that a single thermal band centered on the 7.68 µm methane feature leads to a detectable brightness temperature difference exceeding the sensor noise level for a plume of about 17 ppm at ambient atmospheric temperature compared to an ambient plume with no enhanced methane present. Application of a normalized differential methane index method, a novel approach for methane detection, demonstrated how a simple two-band method can be utilized to detect a plume of methane that is 10 ppm above ambient atmospheric concentration and −10 K from ambient atmospheric temperature with an 80 % hit rate and 17 % false alarm rate. This method was capable of detecting methane with similar levels of success as the third method, a proven multichannel method, matched filter. The matched-filter approach was performed with six spectral channels. Results from these examinations suggest that given a high enough concentration and temperature contrast, a multispectral system with a single band allocated to a methane absorption feature can detect enhanced levels of methane.

scholarly journals Role of OH variability in the stalling of the global atmospheric CH<sub>4</sub> growth rate from 1999 to 2006

2016 ◽  
Author(s):  
J. McNorton ◽  
M. P. Chipperfield ◽  
M. Gloor ◽  
C. Wilson ◽  
W. Feng ◽  
...  
Keyword(s):  
Growth Rate ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Atmospheric Temperature ◽  
Atmospheric Methane ◽  
Chemical Transport Model ◽  
Large Variability ◽  
Model Driven ◽  
Stagnation Period ◽  
Global Mean

Abstract. The growth in atmospheric methane (CH4) concentrations over the past two decades has shown large variability on a timescale of many years. Prior to 1999 the globally averaged CH4 concentration was increasing at a rate of 6.0 ppb/yr, but during a stagnation period from 1999 to 2006 this growth rate slowed to 0.6 ppb/yr. Since 2007 the growth rate has again increased to 4.9 ppb/yr. These changes in growth rate are usually ascribed to variations in CH4 emissions. We have used a 3-D global chemical transport model, driven by meteorological reanalyses and variations in global mean hydroxyl (OH) concentrations derived from CH3CCl3 observations from two independent networks, to investigate these CH4 growth variations. The model shows that between 1999 and 2006, changes in the CH4 atmospheric loss contributed significantly to the suppression in global CH4 concentrations relative to the pre-1999 trend. The largest factor in this is relatively small variations in global mean OH on a timescale of a few years, with minor contributions of atmospheric transport of CH4 to its sink region and atmospheric temperature. Although changes in emissions may be important during the stagnation period, these results imply a smaller variation is required to explain the observed CH4 trends. The contribution of OH variations to the renewed CH4 growth after 2007 cannot be determined with data currently available.

Growth and Performance of Agriculture Sector in India

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Naresh Singla ◽  
Mamandeep Kaur
Keyword(s):  
Growth Rate ◽  
Capital Formation ◽  
The Other ◽  
Agricultural Credit ◽  
Agricultural Growth ◽  
Indian Economy ◽  
Agriculture Sector ◽  
Food Grain ◽  
And Performance ◽  
Agricultural Labourers

The growth of agriculture and allied sectors is critical for the Indian economy as about 49 percent of the population is directly or indirectly dependent on agriculture. During the last decade and so, the agriculture sector has undergone profound changes resulting in sharp deceleration in its growth. The study has attempted to analyze growth and performance of the agriculture sector in India since 1980-81 and tries to comprehend some of the factors responsible for the deceleration in growth. The study has shown that agriculture sector has been able to show tremendous improvement in expansion of area and production of food grain and non-food grain crops. However, there are so many underlying factors responsible for slowdown of the agricultural growth. Some of the factors identified include: Increase in area under non-agriculture uses, excessive dependence on rain fed farming, increase in number of agricultural labourers, reducing size of the operation holdings, over use of agri-inputs, inequity in the distribution of agriculture credit along with sharp deceleration in public gross capital formation in agriculture etc. The study pointed in order to achieve higher growth rate, there is a need to enhance the gross capital formation in agriculture sector particularly on irrigation so that more area can be brought under assured irrigation. Bringing equity in distribution of agricultural credit coupled with judicious and need-based agricultural inputs are some of the other recommendations drawn based upon the study.

Identifying agronomic practices with higher yield and lower global warming potential in rice paddies: a global meta-analysis

2021 ◽  
Vol 322 ◽  
pp. 107663
Author(s):  
Ping Liao ◽  
Yanni Sun ◽  
Xiangcheng Zhu ◽  
Haiyuan Wang ◽  
Yong Wang ◽  
...  
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Meta Analysis ◽  
Rice Paddies ◽  
Agronomic Practices

scholarly journals Sensitivity of wetland methane emissions to model assumptions: application and model testing against site observations

2012 ◽  
Vol 9 (7) ◽  
pp. 2793-2819 ◽  
Author(s):  
L. Meng ◽  
P. G. M. Hess ◽  
N. M. Mahowald ◽  
J. B. Yavitt ◽  
W. J. Riley ◽  
...  
Keyword(s):  
Soil Ph ◽  
High Latitude ◽  
Large Range ◽  
Rice Paddy ◽  
Temporal Variations ◽  
Methane Emissions ◽  
Biogeochemical Model ◽  
Atmospheric Methane ◽  
Rice Paddies ◽  
Community Land Model

Abstract. Methane emissions from natural wetlands and rice paddies constitute a large proportion of atmospheric methane, but the magnitude and year-to-year variation of these methane sources are still unpredictable. Here we describe and evaluate the integration of a methane biogeochemical model (CLM4Me; Riley et al., 2011) into the Community Land Model 4.0 (CLM4CN) in order to better explain spatial and temporal variations in methane emissions. We test new functions for soil pH and redox potential that impact microbial methane production in soils. We also constrain aerenchyma in plants in always-inundated areas in order to better represent wetland vegetation. Satellite inundated fraction is explicitly prescribed in the model, because there are large differences between simulated fractional inundation and satellite observations, and thus we do not use CLM4-simulated hydrology to predict inundated areas. A rice paddy module is also incorporated into the model, where the fraction of land used for rice production is explicitly prescribed. The model is evaluated at the site level with vegetation cover and water table prescribed from measurements. Explicit site level evaluations of simulated methane emissions are quite different than evaluating the grid-cell averaged emissions against available measurements. Using a baseline set of parameter values, our model-estimated average global wetland emissions for the period 1993–2004 were 256 Tg CH4 yr−1 (including the soil sink) and rice paddy emissions in the year 2000 were 42 Tg CH4 yr−1. Tropical wetlands contributed 201 Tg CH4 yr−1, or 78% of the global wetland flux. Northern latitude (>50 N) systems contributed 12 Tg CH4 yr−1. However, sensitivity studies show a large range (150–346 Tg CH4 yr−1) in predicted global methane emissions (excluding emissions from rice paddies). The large range is sensitive to (1) the amount of methane transported through aerenchyma, (2) soil pH (±100 Tg CH4 yr−1), and (3) redox inhibition (±45 Tg CH4 yr−1). Results are sensitive to biases in the CLMCN and to errors in the satellite inundation fraction. In particular, the high latitude methane emission estimate may be biased low due to both underestimates in the high-latitude inundated area captured by satellites and unrealistically low high-latitude productivity and soil carbon predicted by CLM4.

scholarly journals Numerical stability analysis of a vortex ring with swirl

2019 ◽  
Vol 878 ◽  
pp. 5-36 ◽  
Author(s):  
Yuji Hattori ◽  
Francisco J. Blanco-Rodríguez ◽  
Stéphane Le Dizès
Keyword(s):  
Numerical Simulation ◽  
Growth Rate ◽  
Direct Numerical Simulation ◽  
Vortex Ring ◽  
Stokes Equations ◽  
Base Flow ◽  
Critical Layer ◽  
Navier Stokes ◽  
Instability Mode ◽  
Navier Stokes Equations

The linear instability of a vortex ring with swirl with Gaussian distributions of azimuthal vorticity and velocity in its core is studied by direct numerical simulation. The numerical study is carried out in two steps: first, an axisymmetric simulation of the Navier–Stokes equations is performed to obtain the quasi-steady state that forms a base flow; then, the equations are linearized around this base flow and integrated for a sufficiently long time to obtain the characteristics of the most unstable mode. It is shown that the vortex rings are subjected to curvature instability as predicted analytically by Blanco-Rodríguez & Le Dizès (J. Fluid Mech., vol. 814, 2017, pp. 397–415). Both the structure and the growth rate of the unstable modes obtained numerically are in good agreement with the analytical results. However, a small overestimation (e.g. 22 % for a curvature instability mode) by the theory of the numerical growth rate is found for some instability modes. This is most likely due to evaluation of the critical layer damping which is performed for the waves on axisymmetric line vortices in the analysis. The actual position of the critical layer is affected by deformation of the core due to the curvature effect; as a result, the damping rate changes since it is sensitive to the position of the critical layer. Competition between the curvature and elliptic instabilities is also investigated. Without swirl, only the elliptic instability is observed in agreement with previous numerical and experimental results. In the presence of swirl, sharp bands of both curvature and elliptic instabilities are obtained for $\unicode[STIX]{x1D700}=a/R=0.1$, where $a$ is the vortex core radius and $R$ the ring radius, while the elliptic instability dominates for $\unicode[STIX]{x1D700}=0.18$. New types of instability mode are also obtained: a special curvature mode composed of three waves is observed and spiral modes that do not seem to be related to any wave resonance. The curvature instability is also confirmed by direct numerical simulation of the full Navier–Stokes equations. Weakly nonlinear saturation and subsequent decay of the curvature instability are also observed.

scholarly journals Melting ice: "Warning Signs"

2007 ◽  
Vol 8 ◽  
pp. 66-73
Author(s):  
Ghana S. Malla
Keyword(s):  
Global Warming ◽  
Sea Level Rise ◽  
Sea Level ◽  
Atmospheric Temperature ◽  
Warning Signs ◽  
Warning Sign ◽  
Gradual Change ◽  
Liquid Form ◽  
Greenhouse Gasses ◽  
The Times

Melting ice is one of the concerns of world climate scientists and planners. It is the gradual change of ice in the liquid form caused by increase in atmospheric temperature. Global Warming is the increase in atmospheric temperature caused by greenhouse effects (C02, CH4, N20 and CFCs). Increase in temperature of atmosphere by 1oC that has been occurred since 1860 AD (IPCC, 1996). Scientists predicted that the Earth would warm by 1.4 to 5.8oC by 2100. In case of Nepal, increase of temperature was recorded 0.06oC per year (DHM). Sea level rise causes by melting ice is recent warning sign. The Times Center, 2007 estimated sea level rise would be 51 -140 cm by 2100 AD. It affects wide variety of ecosystem, water resources, agriculture, life and livelihoods of people in the world. However, its impact is largely unpredictable and uncertainty. There were series of glacial outburst in Nepal since 1964, destroying ecosystem of surrounding region caused by global warming. Therefore, IPCC member's countries with United State of America (USA) must act quickly to reduce greenhouse gasses to overcome threat of melting ice. The Journal of AGRICULTURE AND ENVIRONMENT Vol. 8, 2007, pp. 66-73

scholarly journals Dynamics of morbidity of mental disorders of neurotic origin in the Ternopil region in the context of global warmin

2021 ◽  
Vol 11 (6) ◽  
pp. 186-191
Author(s):  
S. N. Vadzyuk ◽  
T. V. Kharkovska
Keyword(s):  
Growth Rate ◽  
Global Warming ◽  
Mental Disorders ◽  
Correlation Coefficient ◽  
Heat Waves ◽  
Scientific Data ◽  
Educational Process ◽  
Archival Data ◽  
Primary Analysis ◽  
Average Annual Temperature

Relevance: Over the last century, the modern climate is characterized by an average annual increase in global air temperature. According to existing scientific data, heat waves are often accompanied by mental, behavioral disorders that are combined with mood swings and increased anxiety. That is why the analysis of the incidence of mental disorders of the neurotic spectrum in the Ternopil region in the context of global warming is relevant.Materials and methods: To analyze the incidence of mental disorders of the neurotic spectrum, the archival data of the Ternopil Regional Clinical Psychoneurological Hospital for 10 years, from 2010 to 2019 were analyzed. The average annual air temperatures were determined according to the archival data of hydrometeorological observations by the meteorological station of the city of Ternopil during 2010-2019. The growth rate of these indicators was estimated by the time series method. Pearson's correlation coefficient was used to measure the degree of linear dependence between two variables, namely the rate of hospitalization growth and the average annual temperature in the region. Tables and graphs are built using Microsoft Excel and Microsoft Word.Results: The primary analysis of the incidence of mental disorders of the neurotic spectrum in Ternopil region showed that the percentage growth rate for the year ranged from -19.55% to + 20.62% and it was difficult to determine the direction of this phenomenon. In this regard, we carried out the alignment of the series by increasing the period and determining the arithmetic mean of the data for three years, respectively, we obtained data showing that for 10 years the prevalence of mental disorders of the neurotic spectrum in Ternopil region increased, the growth rate ranged from + 1.66% to + 6.32%.Conclusions: Analyzing the obtained results, we found that in the conditions of global warming in Ternopil region there is a dynamics of growth in the incidence of mental disorders of neurotic origin. Also, by calculating the correlation coefficient, a direct correlation between the increase in the average annual temperature and the increase in morbidity rates was proved. The data obtained should be taken into account in the development of protocols for the prevention and treatment of mental illness associated with the effects of climate change, and will also be used in the educational process at the Departments of Physiology, Pathological Physiology and Psychiatry.

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