scholarly journals Deriving column-integrated thermospheric temperature with the N<sub>2</sub> Lyman–Birge–Hopfield (2,0) band

2021 ◽  
Author(s):  
Clayton Cantrall ◽  
Tomoko Matsuo
Keyword(s):  
Rotational Temperature ◽  
Mass Density ◽  
Principal Component ◽  
Instrumental Performance ◽  
Heating Rates ◽  
Band Shape ◽  
Emission Data ◽  
Channel Ratio ◽  
Ratio Approach ◽  
Level 2

Abstract. This paper presents a new technique to derive thermospheric temperature from space-based disk observations of far ultraviolet airglow. The technique, guided by findings from principal component analysis of synthetic daytime LBH disk emissions, uses a ratio of the emissions in two spectral channels that together span the Lyman–Birge–Hopfield (LBH) (2,0) band to determine the change in band shape with respect to a change in the rotational temperature of N2. The benefits of the two-channel ratio approach include an elimination of representativeness error as absolute LBH intensities are not required in the derivation procedure and a reduced impact of systematic measurement error caused by variations in the instrumental performance across the LBH band system as a fully resolved system is also not required. It is shown that the derived temperature should, in general, be interpreted as a column-integrated property as opposed to a temperature at a specified altitude without utilization of a priori information of the thermospheric temperature profile. The two-channel ratio approach is demonstrated using NASA GOLD Level 1C disk emission data for the period of 2–8 November 2018 during which a small geomagnetic storm has occurred. Due to the lack of independent thermospheric temperature observations, the efficacy of the approach is validated through comparisons of the column-integrated temperature derived from GOLD Level 1C data with version 2 of the GOLD Level 2 temperature product as well as temperatures from first principle and empirical models. The storm-time thermospheric response manifested in the column-integrated temperature is also shown to corroborate well with hemispherically integrated Joule heating rates, ESA SWARM mass density at 460 km, and GOLD Level 2 column O / N2 ratio.

scholarly journals Deriving column-integrated thermospheric temperature with the N<sub>2</sub> Lyman–Birge–Hopfield (2,0) band

2021 ◽  
Vol 14 (11) ◽  
pp. 6917-6928
Author(s):  
Clayton Cantrall ◽  
Tomoko Matsuo
Keyword(s):  
Rotational Temperature ◽  
Mass Density ◽  
Radiative Transfer Model ◽  
Band Model ◽  
Transfer Model ◽  
Emission Data ◽  
Channel Ratio ◽  
Ratio Approach ◽  
Spectral Channels ◽  
Level 2

Abstract. This paper presents a new technique to derive thermospheric temperature from space-based disk observations of far ultraviolet airglow. The technique, guided by findings from principal component analysis of synthetic daytime Lyman–Birge–Hopfield (LBH) disk emissions, uses a ratio of the emissions in two spectral channels that together span the LBH (2,0) band to determine the change in band shape with respect to a change in the rotational temperature of N2. The two-channel-ratio approach limits representativeness and measurement error by only requiring measurement of the relative magnitudes between two spectral channels and not radiometrically calibrated intensities, simplifying the forward model from a full radiative transfer model to a vibrational–rotational band model. It is shown that the derived temperature should be interpreted as a column-integrated property as opposed to a temperature at a specified altitude without utilization of a priori information of the thermospheric temperature profile. The two-channel-ratio approach is demonstrated using NASA GOLD Level 1C disk emission data for the period of 2–8 November 2018 during which a moderate geomagnetic storm has occurred. Due to the lack of independent thermospheric temperature observations, the efficacy of the approach is validated through comparisons of the column-integrated temperature derived from GOLD Level 1C data with the GOLD Level 2 temperature product as well as temperatures from first principle and empirical models. The storm-time thermospheric response manifested in the column-integrated temperature is also shown to corroborate well with hemispherically integrated Joule heating rates, ESA SWARM mass density at 460 km, and GOLD Level 2 column O/N2 ratio.

Use of Multivariate Analysis to Determine Temperature from Low-Resolution Infrared Spectra of Carbon Dioxide

2000 ◽  
Vol 54 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Michael P. Szczepanski ◽  
Augustus W. Fountain
Keyword(s):  
Carbon Dioxide ◽  
Chemical Species ◽  
Principal Component Regression ◽  
Principal Component ◽  
Industrial Applications ◽  
Low Resolution ◽  
Band Shape ◽  
Temperature Spectra ◽  
Plume Temperature ◽  
Industrial Monitoring

The remote optical monitoring of gaseous contaminants is important for both military and industrial applications. An important parameter for quantifying chemical species and for predicting plume dynamics is the temperature. While in some industrial monitoring situations it may be practical to independently measure the temperature of stack emissions, for compliance monitoring and military chemical reconnaissance a remote optical means of estimating gas plume temperature is required. It was noticed that the band shape of low-resolution spectra of carbon dioxide in equilibrium with an exhaust plume was very sensitive to temperature. Spectra of carbon dioxide were acquired under controlled laboratory conditions in 5° increments from 20 to 200 °C. Various multivariate models were used to predict the temperature. It was found that partial least-squares (PLS) was unable to effectively model the simultaneous changes in amplitude and bandwidth with temperature. However, principal component regression (PCR) was found to be well correlated with temperature and allowed cross-validated prediction within 4% error.

Shock Spectrum Ratios Applied to the Comparison of Pulse Signatures

1980 ◽  
Vol 102 (1) ◽  
pp. 64-76
Author(s):  
J. R. Houghton
Keyword(s):  
Acoustic Emission ◽  
Transfer Functions ◽  
Time Window ◽  
Relative Size ◽  
Emission Data ◽  
Relative Damage ◽  
New Type ◽  
Ratio Approach ◽  
Spectrum Ratio ◽  
The Fourier Transform

Two extensions of the shock spectrum technique are developed for use in pulse signature analysis. A shock spectrum ratio is proposed and compared to the Fourier transfer function for the detection of small perturbations on a larger pulse shape. The shock spectrum ratio is shown to have good sensitivity to the relative size of the perturbation. The shock spectrum ratio approach is extended to a new type of spectrum named “slot transform.” This specialized transform is shown to have several advantages with respect to the Fourier transform in the development of magnitude transfer functions. The transform was developed for analysis of digitized acoustic emission pulses where a rectangular time window is preferred. These two extensions of shock spectrum methods are tested on experimental data from high g shock tests and acoustic emission measurements from damaged and undamaged ball bearings. Deconvolution of the acoustic emission data was necessary before the shork spectrum, ratio was capable of indicating the relative damage of the bearings.

scholarly journals Solar cycle, seasonal, and asymmetric dependencies of thermospheric mass density disturbances due to magnetospheric forcing

2019 ◽  
Vol 37 (5) ◽  
pp. 989-1003 ◽  
Author(s):  
Andres Calabia ◽  
Shuanggen Jin
Keyword(s):  
Solar Cycle ◽  
High Frequency ◽  
Polar Region ◽  
Rotation Axis ◽  
Mass Density ◽  
Principal Component ◽  
Geomagnetic Variation ◽  
The South ◽  
The North ◽  
Possible Cause

Abstract. Short-term upper atmosphere variations due to magnetospheric forcing are very complex, and neither well understood nor capably modeled due to limited observations. In this paper, mass density variations from 10 years of GRACE observations (2003–2013) are isolated via the parameterization of annual, local solar time (LST), and solar cycle fluctuations using a principal component analysis (PCA) technique. The resulting residual disturbances are investigated in terms of magnetospheric drivers. The magnitude of high-frequency (δ < 10 d) disturbances reveals unexpected dependencies on the solar cycle, seasonal, and an asymmetric behavior with smaller amplitudes in June in the south polar region (SPR). This seasonal modulation might be related to the Russell–McPherron (RM) effect. Meanwhile, we find a similar pattern, although less pronounced, in the northern and equatorial regions. A possible cause of this latitudinal asymmetry might be the irregular shape of the Earth's magnetic field (with the north dip pole close to Earth's rotation axis, and the south dip pole far from that axis). After accounting for the solar cycle and seasonal dependencies by regression analysis to the magnitude of the high-frequency perturbations, the parameterization in terms of the disturbance geomagnetic storm-time index Dst shows the best correlation, whereas the geomagnetic variation Am index and merging electric field Em are the best predictors in terms of time delay. We test several mass density models, including JB2008, NRLMSISE-00, and TIEGCM, and find that they are unable to completely reproduce the seasonal and solar cycle trends found in this study, and show a clear overestimation of about 100 % during low solar activity periods.

Near-Infrared Spectral Analysis of Gas Mixtures

2002 ◽  
Vol 56 (5) ◽  
pp. 593-598 ◽  
Author(s):  
Maria A. Van Agthoven ◽  
Go Fujisawa ◽  
Philip Rabbito ◽  
Oliver C. Mullins
Keyword(s):  
Principal Component Analysis ◽  
Spectral Analysis ◽  
Gas Flow ◽  
Near Infrared ◽  
Mass Density ◽  
Principal Component ◽  
Gas Mixtures ◽  
Complex Mixtures ◽  
Natural Gases ◽  
Infrared Spectral

The analysis by near-infrared spectroscopy (NIR) of a series of gas mixtures approximating natural gases is reported. Wide variations of gas pressure and temperature are used in accord with conditions found in various utilitarian gas flow streams. The NIR analysis of CH4 and CO2 composition is found to be straightforward and depends only on compound mass density, but not explicitly on temperature, pressure, or composition. Linearity of the spectra of more complex mixtures is maintained, but the NIR analysis is more complex. Principal component analysis is shown to resolve composition for those gas mixtures.

Key Parameters Affecting Quantitative Analysis of STEM-EDS Spectrum Images

2010 ◽  
Vol 16 (3) ◽  
pp. 259-272 ◽  
Author(s):  
Chad M. Parish ◽  
Luke N. Brewer
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Principal Component ◽  
Detector Resolution ◽  
X Ray ◽  
Number Of Factors ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Quantitative Analyses ◽  
Accuracy Of Results ◽  
Level 2

AbstractIn this article, we use simulated and experimental data to explore how three operator-controllable parameters—(1) signal level, (2) detector resolution, and (3) number of factors chosen for analysis—affect quantitative analyses of scanning transmission electron microscopy–energy dispersive X-ray spectroscopy spectrum images processed by principal component analysis (PCA). We find that improvements in both signal level and detector resolution improve the precision of quantitative analyses, but that signal level is the most important. We also find that if the rank of the PCA solution is not chosen properly, it may be possible to improperly fit the underlying data and degrade the accuracy of results. Additionally, precision is degraded in the case when too many factors are included in the model.

scholarly journals Characterization of the Upper Atmosphere from Neutral and Electron Density Observations

2020 ◽  
Author(s):  
Andres Calabia ◽  
Shuanggen Jin
Keyword(s):  
Hemispheric Asymmetry ◽  
Satellite Communication ◽  
Aerodynamic Drag ◽  
Mass Density ◽  
Principal Component ◽  
Artificial Satellites ◽  
Satellite Systems ◽  
Driver Response ◽  
Main Driver ◽  
Electromagnetic Signals

Abstract Upper-atmospheric processes under different space weather conditions are still not well understood, and the existing models are far away from the desired operational requirements due to the lack of in-situ measurements input. The ionospheric perturbation of electromagnetic signals affects the accuracy and reliability of Global Navigation Satellite Systems (GNSS), satellite communication infrastructures, and Earth observation techniques. Furthermore, the variable aerodynamic drag, due to variable thermospheric mass density, disturbs orbital tracking, collision analysis, and re-entry calculations of Low Earth Orbit (LEO) objects, including manned and unmanned artificial satellites. In this paper, we use the Principal Component Analysis (PCA) technique to study and compare the main driver-response relationships and spatial patterns of total electron content (TEC) estimates from 2003 to 2018, and total mass density (TMD) estimates at 475 km altitude from 2003 to 2015. Comparison of the first TEC and TMD PCA mode shows a very similar response to solar flux, but annual cycle shown by TEC is approximately one order of magnitude larger. A clear hemispheric asymmetry is shown in the global distribution of TMD, with higher values in the southern hemisphere than in the northern hemisphere. The hemispheric asymmetry is not visible in TEC. The persistent processes including a favorable solar wind input and particle precipitation over the southern magnetic dip may produce a higher thermospheric heating, which results in the hemispheric asymmetry in TMD.

scholarly journals Leaf morphological strategies of seedlings and saplings of Rhizophora mangle (Rhizophoraceae), Laguncularia racemosa (Combretaceae) and Avicennia schaueriana (Acanthaceae) from Southern Brazil

2016 ◽  
Vol 64 (1) ◽  
pp. 305 ◽  
Author(s):  
Andressa Pelozo ◽  
Maria Regina T. Boeger ◽  
Carolina Sereneski-de-Lima ◽  
Patricia Soffiatti
Keyword(s):  
Mass Density ◽  
Rhizophora Mangle ◽  
Principal Component ◽  
Anatomical Study ◽  
Dry Mass ◽  
Laguncularia Racemosa ◽  
Initial Growth ◽  
Spongy Parenchyma ◽  
Mangrove Species ◽  
Avicennia Schaueriana

The initial phase of a plant life cycle is a short and critical period, when individuals are more vulnerable to environmental factors. The morphological and anatomical study of seedlings and saplings leaf type, enables the understanding of species strategies of fundamental importance in their establishment and survival. The objective of this study was to analyze the structure of seedlings and saplings leaf types of three mangrove species, Avicennia schaueriana, Laguncularia racemosa, Rhizophora mangle, to understand their early life adaptive strategies to the environment. A total of 30 fully expanded cotyledons (A. schaueriana and L. racemosa), 30 leaves of seedlings, and 30 leaves of saplings of each species were collected from a mangrove area in Guaratuba Bay, Paraná State, Brazil. Following standard methods, samples were prepared for morphological (leaf dry mass, density, thickness) and anatomical analysis (epidermis and sub-epidermal layers, stomata types, density of salt secretion glands, palisade and spongy parenchyma thickness). To compare leaf types among species one-way ANOVA and Principal Component Analysis were used, while Cluster Analysis evaluated differences between the species. We observed significant structural differences among species leaf types. A. schaueriana showed the thickest cotyledons, while L. racemosa presented a dorsiventral structure. Higher values of the specific leaf area were observed for seedlings leaves of A. schaueriana, cotyledons of L. racemosa and saplings leaves of A. schaueriana and R. mangle. Leaf density was similar to cotyledons and seedlings leaves in A. schaueriana and L. racemosa, while R. mangle had seedlings leaves denser than saplings. A. schaueriana and R. mangle showed hypostomatic leaves, while L. racemosa amphistomatic; besides, A. chaueriana showed diacytic stomata, while L. racemosa anomocytic, and R. mangle ciclocytic. Seedling leaves were thicker in R. mangle (535 µm) and L. racemosa (520 µm) than in A. schaueriana (470.3 µm); while saplings leaves were thicker in L. racemosa (568.3 µm) than in A. schaueriana seedlings (512.4 µm) and R. mangle (514.6 µm). Besides, seedlings leaves palisade parenchyma showed increasing thickness in L. racemosa (119.2 µm) < A. schaueriana (155.5 µm) < R. mangle (175.4 µm); while in saplings leaves as follows R. mangle (128.4 µm) < A. schaueriana (183.4 µm) < L. racemosa (193.9 µm). Similarly, seedlings leaves spongy parenchyma thickness values were as follows A. schaueriana (182.6 µm) = R. mangle (192.8 µm) < L. racemosa (354.4 µm); while in saplings were A. schaueriana (182.6 µm) = R. mangle (187.3 µm) < L. racemosa (331.3 µm). The analyzed traits, in different combinations, represent morphological adjustments of leaf types to reduce water loss, eliminate salt excess, increase the absorption of light, allowing a higher efficiency on the maintenance of physiological processes in this initial growth stage.

scholarly journals Characterization of particulate matter in iron ore mining region of Itabira, Minas Gerais, Brazil

2021 ◽  
Author(s):  
Ana Carolina Vasques Freitas ◽  
Rose-Marie Belardi ◽  
Henrique de Melo Jorge Barbosa
Keyword(s):  
Particulate Matter ◽  
Air Quality ◽  
Fine Particulate Matter ◽  
Monitoring Network ◽  
Principal Component ◽  
Opencast Mining ◽  
Residential Areas ◽  
Emission Data ◽  
Particulate Matter Emission ◽  
The City

Itabira has in its territory the largest complex of opencast mining in the world, which is located close to residential areas of the city. The air quality-monitoring network installed in the city is the main source of particulate matter emission data. However, these air quality stations only cover the areas near the mines and does not measure fine particulate matter. Thus, a first field campaign was carried out to characterize the particulate matter in the city and to compare the Hi-Vol data from air quality stations with the dichotomous air sampler data. Results of trajectories cluster analysis showed a long-range transport of aerosols during the sampling days from northeast (84% of the trajectories), east-southeast (12%) and south-southwest (3%) directions. Regarding to the meteorological conditions during the sampling days, negative correlations were seen between coarse particulate matter from mostly air quality stations and all meteorological parameters (but temperature). Results of the X-ray fluorescence and principal component analyses showed that the main trace elements in the coarse and fine modes are Iron and Sulfur, associated with emissions from mining activities, air mass transport from regional iron and steelmaking industry activities, vehicle emissions, local and regional biomass burning and natural biogenic emissions. This work represents the first assessment of source apportionment done in the city. Comparisons with other studies for some Brazilian larger cities showed that Itabira has comparable contributions of sulfur, iron and elements, such as copper, selenium, chromium, nickel, vanadium and lead.

Statistical pattern recognition in paleontology using SIMCA-MACUP

1994 ◽  
Vol 68 (4) ◽  
pp. 689-703 ◽  
Author(s):  
Kuo-Yen Wei
Keyword(s):  
Pattern Recognition ◽  
Reference Sample ◽  
Principal Component ◽  
Statistical Pattern Recognition ◽  
Statistical Pattern ◽  
External Variables ◽  
History Of ◽  
Predicted Values ◽  
Component Models ◽  
Level 2

This paper describes a pattern recognition method, Soft Independent Modeling of Class Analogy-Modeling And Classification Using Partial least squares (SIMCA-MACUP), and demonstrates its application to two common paleontological problems—identification and prediction. SIMCA-MACUP performs statistical pattern recognition at four hierarchical levels. At level 1, SIMCA builds disjoint principal component models to characterize multivariate data patterns of several classes. At level 2, new, unknown objects are either classified into one of the classes, or recognized as outliers. At levels 3 and 4, the MACUP method models the relationship between external (dependent) variables and internal (independent) variables, and allows prediction of the values of external variables of new objects which are classified at level 2.The applicability of the SIMCA-MACUP has been demonstrated in a case study of the Pliocene planktic foraminiferal clade Globoconella. Two morphotypes of the clade Globorotalia (Globoconella) puncticulata and Globorotalia (Globoconella) inflata were characterized in a reference sample with SIMCA. Ancestral forms of the two morphotypes were traced through the early phylogenetic history of the clade, resulting in a reconstruction of the branching pattern of the divergence of G. inflata from G. puncticulata. The apertural height and apertural width of specimens in the ancestral stocks were then treated as if there were two “external” variables, and predicted using MACUP. The predicted values show slight discrepancy from the observed values. The deviation is size-dependent, indicating a decoupling of the apertural shape from the size of foraminifers during the branching process.

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