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 An Examination of Enhanced Atmospheric Methane Detection Methods for Predicting Performance of a Novel Multiband Uncooled Radiometer Imager

2020 ◽  
Author(s):  
Cody M. Webber ◽  
John P. Kerekes
Keyword(s):  
Ambient Temperature ◽  
Matched Filter ◽  
Detection Methods ◽  
Absorption Feature ◽  
Atmospheric Methane ◽  
Index Method ◽  
Methane Absorption ◽  
Novel Approach ◽  
Temperature Contrast ◽  
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 NEdT comparison study performed using data simulated from MODTRAN6 revealed a single thermal band centered on the 7.68 μm methane feature is capable of detecting the in band temperature contrast between a plume of about 17 ppm at ambient temperature and background levels of methane at ambient temperature. 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 15 ppm above ambient and −10 K from ambient temperature with 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 methane.

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 The Hubble PanCET program: Transit and Eclipse Spectroscopy of the Hot-Jupiter WASP-74b

2021 ◽  
Vol 162 (6) ◽  
pp. 271
Author(s):  
Guangwei Fu ◽  
Drake Deming ◽  
Erin May ◽  
Kevin Stevenson ◽  
David K. Sing ◽  
...  
Keyword(s):  
Rayleigh Scattering ◽  
Hubble Space Telescope ◽  
Absorption Feature ◽  
Spectral Library ◽  
Data Set ◽  
Space Telescope ◽  
Methane Absorption ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract Planets are like children with each one being unique and special. A better understanding of their collective properties requires a deeper understanding of each planet. Here we add the transit and eclipse spectra of hot-Jupiter WASP-74b into the ever growing data set of exoplanet atmosphere spectral library. With six transits and three eclipses using the Hubble Space Telescope and Spitzer Space Telescope (Spitzer), we present the most complete and precise atmospheric spectra of WASP-74b. We found no evidence for TiO/VO nor super-Rayleigh scattering reported in previous studies. The transit shows a muted water feature with strong Rayleigh scattering extending into the infrared. The eclipse shows a featureless blackbody-like WFC3/G141 spectrum and a weak methane absorption feature in the Spitzer 3.6 μm band. Future James Webb Space Telescope follow-up observations are needed to confirm these results.

scholarly journals Exploiting stagnant conditions to derive robust emission ratio estimates for CO<sub>2</sub>, CO and volatile organic compounds in Paris

2016 ◽  
Vol 16 (24) ◽  
pp. 15653-15664 ◽  
Author(s):  
Lamia Ammoura ◽  
Irène Xueref-Remy ◽  
Felix Vogel ◽  
Valérie Gros ◽  
Alexia Baudic ◽  
...  
Keyword(s):  
Extreme Values ◽  
Background Level ◽  
Atmospheric Temperature ◽  
Atmospheric Concentration ◽  
Low Wind Speed ◽  
Volatile Organic ◽  
Regional Background Level ◽  
Autumn And Winter ◽  
The City ◽  
Emission Ratios

Abstract. We propose an approach to estimate urban emission ratios that takes advantage of the enhanced local urban signal in the atmosphere at low wind speed. We apply it to estimate monthly ratios between CO2, CO and some VOCs from several atmospheric concentration measurement datasets acquired in the centre of Paris between 2010 and 2014. We find that this approach is not very sensitive to the regional background level definition and that, in the case of Paris, it samples all days (weekdays and weekends) and all hours of the day evenly. A large seasonal variability of the ΔCO ∕ ΔCO2 ratio in Paris is shown, with a difference of around 60 % between the extreme values and a strong anti-correlation (r2 = 0.75) with atmospheric temperature. The comparison of the ratios obtained for two short measurement campaigns conducted in two different districts and two different periods (autumn and winter) shows differences ranging from −120 to +63 %. A comparison with a highly resolved regional emission inventory suggests some spatial variations of the ratio within the city.

scholarly journals Methane-Oxidizing Bacteria in a California Upland Grassland Soil: Diversity and Response to Simulated Global Change

2005 ◽  
Vol 71 (5) ◽  
pp. 2642-2652 ◽  
Author(s):  
Hans-Peter Horz ◽  
Virginia Rich ◽  
Sharon Avrahami ◽  
Brendan J. M. Bohannan
Keyword(s):  
Relative Abundance ◽  
Environmental Changes ◽  
Atmospheric Temperature ◽  
Global Changes ◽  
The Novel ◽  
Type Ii ◽  
Atmospheric Methane ◽  
Antagonistic Interaction ◽  
Methane Oxidizing Bacteria ◽  
Upland Grassland

ABSTRACT We investigated the diversity of methane-oxidizing bacteria (i.e., methanotrophs) in an annual upland grassland in northern California, using comparative sequence analysis of the pmoA gene. In addition to identifying type II methanotrophs commonly found in soils, we discovered three novel pmoA lineages for which no cultivated members have been previously reported. These novel pmoA clades clustered together either with clone sequences related to “RA 14” or “WB5FH-A,” which both represent clusters of environmentally retrieved sequences of putative atmospheric methane oxidizers. Conservation of amino acid residues and rates of nonsynonymous versus synonymous nucleotide substitution in these novel lineages suggests that the pmoA genes in these clades code for functionally active methane monooxygenases. The novel clades responded to simulated global changes differently than the type II methanotrophs. We observed that the relative abundance of type II methanotrophs declined in response to increased precipitation and increased atmospheric temperature, with a significant antagonistic interaction between these factors such that the effect of both together was less than that expected from their individual effects. Two of the novel clades were not observed to respond significantly to these environmental changes, while one of the novel clades had an opposite response, increasing in relative abundance in response to increased precipitation and atmospheric temperature, with a significant antagonistic interaction between these factors.

scholarly journals Trends of MSU Brightness Temperature in the Middle Troposphere Simulated by CMIP5 Models and Their Sensitivity to Cloud Liquid Water

2015 ◽  
Vol 32 (5) ◽  
pp. 1029-1041
Author(s):  
Xuanze Zhang ◽  
Xiaogu Zheng ◽  
Zhian Sun ◽  
San Luo
Keyword(s):  
Brightness Temperature ◽  
Liquid Water ◽  
Weighting Function ◽  
Atmospheric Temperature ◽  
Temperature Trend ◽  
Cmip5 Models ◽  
Transfer Model ◽  
Weighting Functions ◽  
Cloud Liquid Water ◽  
Middle Troposphere

AbstractOnly a climate model that is able to simulate well the historical atmospheric temperature trend can be used for estimating the future atmospheric temperature trends on different emission scenarios. Satellite-based Microwave Sounding Unit (MSU) brightness temperature in the middle troposphere (T2) is an important analog of midtropospheric atmospheric temperature. So, there is the need to compare the atmospheric temperature trend simulated by the fifth phase of the Coupled Model Intercomparison Project (CMIP5) historical realizations and the observed MSU T2. There are two approaches for estimating modeled MSU T2: apply a global-mean static weighting function to generate the weighted average of the modeled temperature at all atmospheric layers and simulate satellite-view MSU T2 using the model’s output as input into a radiative transfer model (RTM).In this paper, the two approaches for estimating modeled MSU T2 are evaluated. For each CMIP5, it is shown that there exists a model-simulated static weighting function, such that the MSU T2 trend using the weighting function is equivalent to that calculated by RTM. The effect of modeled cloud liquid water on MSU T2 trends in CMIP5 simulations is investigated by comparing the modeled cloud liquid water vertical profile and the weighting function. Moreover, it is found that warming trends of MSU T2 for CMIP5 simulations calculated by the RTM are about 15% less than those using the two traditional static weighting functions. By comparing the model-derived weighting function with the two traditional weighting functions, the reason for the systematical biases is revealed.

scholarly journals Cloud Photogrammetry from Space

2015 ◽  
Vol XL-7/W3 ◽  
pp. 247-254 ◽  
Author(s):  
K. Zakšek ◽  
A. Gerst ◽  
J. von der Lieth ◽  
G. Ganci ◽  
M. Hort
Keyword(s):  
Brightness Temperature ◽  
Spatial Resolution ◽  
Space Station ◽  
Atmospheric Temperature ◽  
Multiple Cameras ◽  
International Space ◽  
Earth Observations ◽  
Atmospheric Temperature Profile ◽  
Short Time ◽  
Short Time Evolution

The most commonly used method for satellite cloud top height (CTH) compares brightness temperature of the cloud with the atmospheric temperature profile. Because of the uncertainties of this method, we propose a photogrammetric approach. As clouds can move with high velocities, even instruments with multiple cameras are not appropriate for accurate CTH estimation. Here we present two solutions. The first is based on the parallax between data retrieved from geostationary (SEVIRI, HRV band; 1000 m spatial resolution) and polar orbiting satellites (MODIS, band 1; 250 m spatial resolution). The procedure works well if the data from both satellites are retrieved nearly simultaneously. However, MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection in the atmosphere we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. CTH is then estimated by intersection of corresponding lines-of-view from MODIS and interpolated SEVIRI data. The second method is based on NASA program Crew Earth observations from the International Space Station (ISS). The ISS has a lower orbit than most operational satellites, resulting in a shorter minimal time between two images, which is needed to produce a suitable parallax. In addition, images made by the ISS crew are taken by a full frame sensor and not a push broom scanner that most operational satellites use. Such data make it possible to observe also short time evolution of clouds.

scholarly journals Measurement of Solar Absolute Brightness Temperature Using a Ground-Based Multichannel Microwave Radiometer

2021 ◽  
Vol 13 (15) ◽  
pp. 2968
Author(s):  
Lianfa Lei ◽  
Zhenhui Wang ◽  
Yingying Ma ◽  
Lei Zhu ◽  
Jiang Qin ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Brightness Temperature ◽  
Microwave Radiation ◽  
Atmospheric Temperature ◽  
Solar Observation ◽  
The Sun ◽  
Temperature And Humidity ◽  
Microwave Radiometers ◽  
Humidity Profiles ◽  
Absolute Brightness

Ground-based multichannel microwave radiometers (GMRs) can observe the atmospheric microwave radiation brightness temperature at K-bands and V-bands and provide atmospheric temperature and humidity profiles with a relatively high temporal resolution. Currently, microwave radiometers are operated in many countries to observe the atmospheric temperature and humidity profiles. However, a theoretical analysis showed that a radiometer can be used to observe solar radiation. In this work, we improved the control algorithm and software of the antenna servo control system of the GMR so that it could track and observe the sun and we use this upgraded GMR to observe solar microwave radiation. During the observation, the GMR accurately tracked the sun and responded to the variation in solar radiation. Furthermore, we studied the feasibility for application of the GMR to measure the absolute brightness temperature (TB) of the sun. The results from the solar observation data at 22.235, 26.235, and 30.000 GHz showed that the GMR could accurately measure the TB of the sun. The derived solar TB measurements were 9950 ± 334, 10,351 ± 370, and 9217 ± 375 K at three frequencies. In a comparison with previous studies, we obtained average percentage deviations of 9.1%, 5.3%, and 4.5% at 22.235, 26.235, and 30.0 GHz, respectively. The results demonstrated that the TB of the sun retrieved from the GMR agreed well with the previous results in the literature. In addition, we also found that the GMR responded to the variation in sunspots and a positive relationship existed between the solar TB and the sunspot number. According to these results, it was demonstrated that the solar observation technique can broaden the field usage of GMR.

scholarly journals Recent Developments in Modulation Spectroscopy for Methane Detection Based on Tunable Diode Laser

2019 ◽  
Vol 9 (14) ◽  
pp. 2816 ◽  
Author(s):  
Fei Wang ◽  
Shuhai Jia ◽  
Yonglin Wang ◽  
Zhenhua Tang
Keyword(s):  
Semiconductor Lasers ◽  
Frequency Modulation ◽  
Near Infrared ◽  
Infrared Region ◽  
Tunable Diode Laser ◽  
Tone Frequency ◽  
Modulation Spectroscopy ◽  
Methane Absorption ◽  
Recent Developments ◽  
Methane Detection

In this review, methane absorption characteristics mainly in the near-infrared region and typical types of currently available semiconductor lasers are described. Wavelength modulation spectroscopy (WMS), frequency modulation spectroscopy (FMS), and two-tone frequency modulation spectroscopy (TTFMS), as major techniques in modulation spectroscopy, are presented in combination with the application of methane detection.

scholarly journals Mapping methane plumes at very high spatial resolution with the WorldView-3 satellite

2021 ◽  
Author(s):  
Elena Sánchez-García ◽  
Javier Gorroño ◽  
Itziar Irakulis-Loitxate ◽  
Daniel J. Varon ◽  
Luis Guanter
Keyword(s):  
Coal Mining ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Methane Emissions ◽  
High Signal ◽  
Absorption Feature ◽  
Industrial Emissions ◽  
Methane Absorption ◽  
Very High Spatial Resolution ◽  
Very High

Abstract. The detection of methane emissions from industrial activities has been identified as an effective climate change mitigation strategy. These industrial emissions, such as from oil and gas (O&amp;G) extraction and coal mining, typically occur as large plumes of highly concentrated gas. Different satellite missions have recently shown potential to map such methane plumes from space. In this work, we report on the great potential of the WorldView-3 (WV-3) satellite mission for methane mapping. This relies on its unique very high spatial resolution (up to 3.7 m) data in the shortwave infrared part of the spectrum, which is complemented by a good spectral sampling of the methane absorption feature at 2300 nm and a high signal to noise ratio. The proposed retrieval methodology is based on the calculation of methane concentration enhancements from pixel-wise estimates of methane transmittance at WV-3 SWIR band 7 (2235–2285 nm), which is positioned at a highly-sensitive methane absorption region. A sensitivity analysis based on end-to-end simulations has helped to understand retrieval errors and detection limits. The results have shown the good performance of WV-3 for methane mapping, especially over bright and homogeneous areas. The potential of WV-3 for methane mapping has been further tested with real data, which has led to the detection of 26 independent point emissions over different methane hotspot regions such as the O&amp;G extraction fields in Algeria and Turkmenistan, and the Shanxi coal mining region in China. In particular, the detection of very small leaks (< 100 kg/h) from oil pipelines in Turkmenistan shows the game-changing potential of WV-3 to map industrial methane emissions from space.

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