Climatic impact on atmospheric turbidity at some Indian stations

Data from four Indian BAPMoN stations in different climatic regions were analysed using principal component analysis (PCA) for the evaluation of climatic impact upon turbidity. Spectral analysis (FFT) of the data for these stations has helped to bring out the sub-seasonal, seasonal and annual cycles. It is found that the atmospheric turbidity is predominantly controlled by climatic factors through surface fluxes, transport of dust or rain washout and is mainly a lower tropospheric phenomenon. The performance of the PCA regression model is found satisfactorily in reproducing the annual cycle and long period variations.

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Long-term runoff forecast using BP neural network based on climatic factors and mutual information method in the Qujiang Catchment of China

10.5194/egusphere-egu2020-12734 ◽

2020 ◽

Author(s):

Huihui Dai

Keyword(s):

Neural Network ◽

Principal Component Analysis ◽

Mutual Information ◽

Bp Neural Network ◽

Climatic Factors ◽

Principal Component ◽

Component Analysis ◽

Information Method ◽

Runoff Forecast

The formation of runoff is extremely complicated, and it is not good enough to forecast the future runoff only by using the previous runoff or meteorological data. In order to improve the forecast precision of the medium and long-term runoff forecast model, a set of forecast factor group is selected from meteorological factors, such as rainfall, temperature, air pressure and the circulation factors released by the National Meteorological Center&#160; using the method of mutual information and principal component analysis respectively. Results of the forecast in the Qujiang Catchment suggest the climatic factor-based BP neural network hydrological forecasting model has a better forecasting effect using the mutual information method than using the principal component analysis method.

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Archetypal analysis of Southern Hemisphere extreme circulation events

10.5194/egusphere-egu2020-4375 ◽

2020 ◽

Author(s):

James Risbey ◽

Didier Monselesan

Keyword(s):

Principal Component Analysis ◽

Southern Hemisphere ◽

Principal Component ◽

Temperature Extremes ◽

Archetypal Analysis ◽

Long Period ◽

Circulation Types ◽

Circulation Patterns ◽

Extreme Flow ◽

Flow States

Archetypal analysis of Southern Hemisphere extreme circulation eventsThis work conducts an archetypal analysis (AA) of midtropospheric flow in the Southern Hemisphere. &#160;The analysis identifies the archetypical extreme flow states and compares them with the leading modes of variability from Principal Component Analysis (PCA) methods. &#160;In particular, we examine long-lived extreme circulation patterns and events from both AA and PCA, together with their synoptic signatures and surface impacts. &#160;The long-lived circulation types are efficient at generating surface temperature extremes and exhibit long period variability. &#160;Case studies of documented surface extreme events show that they correspond clearly to the midtropospheric flow archetypes.&#160;

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The applicability of principal component analysis to the separation of multiple plane-wave signals

Bulletin of the Seismological Society of America ◽

10.1785/bssa0650030627 ◽

1975 ◽

Vol 65 (3) ◽

pp. 627-635

Author(s):

Z. A. Der ◽

E. A. Flinn

Keyword(s):

Principal Component Analysis ◽

Plane Wave ◽

Principal Component ◽

Component Analysis ◽

Eigenvalue Decomposition ◽

Long Period ◽

Multiple Plane

abstract It is shown that principal component analysis (eigenvector-eigenvalue decomposition of array spectral matrices) can be used for the approximate separation of superposed plane-wave signals only if at least one of the following conditions is satisfied: Application of the method for such cases is demonstrated on composited long-period seismograms using recordings from the D ring and center element of ASA.

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On nearly-commensurable periods in the restricted problem of three bodies, with calculations of the long-period variations in the interior 2:1 case

Symposium - International Astronomical Union ◽

10.1017/s0074180900105480 ◽

1966 ◽

Vol 25 ◽

pp. 197-222 ◽

Cited By ~ 4

Author(s):

P. J. Message

Keyword(s):

Periodic Solution ◽

Periodic Solutions ◽

Large Amplitude ◽

Restricted Problem ◽

Small Amplitude ◽

Minor Planets ◽

Long Period ◽

Numerical Integrations ◽

Period Variations ◽

The Mean

An analytical discussion of that case of motion in the restricted problem, in which the mean motions of the infinitesimal, and smaller-massed, bodies about the larger one are nearly in the ratio of two small integers displays the existence of a series of periodic solutions which, for commensurabilities of the typep+ 1:p, includes solutions of Poincaré'sdeuxième sortewhen the commensurability is very close, and of thepremière sortewhen it is less close. A linear treatment of the long-period variations of the elements, valid for motions in which the elements remain close to a particular periodic solution of this type, shows the continuity of near-commensurable motion with other motion, and some of the properties of long-period librations of small amplitude.To extend the investigation to other types of motion near commensurability, numerical integrations of the equations for the long-period variations of the elements were carried out for the 2:1 interior case (of which the planet 108 “Hecuba” is an example) to survey those motions in which the eccentricity takes values less than 0·1. An investigation of the effect of the large amplitude perturbations near commensurability on a distribution of minor planets, which is originally uniform over mean motion, shows a “draining off” effect from the vicinity of exact commensurability of a magnitude large enough to account for the observed gap in the distribution at the 2:1 commensurability.

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Scanning x-ray fluorescence microscopy and principal component analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133394 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1752-1753

Author(s):

Brian Cross

Keyword(s):

Principal Component Analysis ◽

Fluorescence Microscopy ◽

Spatial Resolution ◽

High Speed ◽

Image Acquisition ◽

Principal Component ◽

Fluorescence Microscope ◽

Acquisition Rate ◽

X Ray ◽

Speed Up

A relatively new entry, in the field of microscopy, is the Scanning X-Ray Fluorescence Microscope (SXRFM). Using this type of instrument (e.g. Kevex Omicron X-ray Microprobe), one can obtain multiple elemental x-ray images, from the analysis of materials which show heterogeneity. The SXRFM obtains images by collimating an x-ray beam (e.g. 100 μm diameter), and then scanning the sample with a high-speed x-y stage. To speed up the image acquisition, data is acquired "on-the-fly" by slew-scanning the stage along the x-axis, like a TV or SEM scan. To reduce the overhead from "fly-back," the images can be acquired by bi-directional scanning of the x-axis. This results in very little overhead with the re-positioning of the sample stage. The image acquisition rate is dominated by the x-ray acquisition rate. Therefore, the total x-ray image acquisition rate, using the SXRFM, is very comparable to an SEM. Although the x-ray spatial resolution of the SXRFM is worse than an SEM (say 100 vs. 2 μm), there are several other advantages.

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A German version of the Intermittent Claudication Questionnaire (ICQ): cultural adaptation and validation

VASA ◽

10.1024/0301-1526/a000218 ◽

2012 ◽

Vol 41 (5) ◽

pp. 333-342 ◽

Cited By ~ 3

Author(s):

Kirchberger ◽

Finger ◽

Müller-Bühl

Keyword(s):

Principal Component Analysis ◽

Intermittent Claudication ◽

Completion Time ◽

Short Form ◽

Principal Component ◽

Component Analysis ◽

German Version ◽

Average Completion Time ◽

Sf 36 ◽

Related Quality

Background: The Intermittent Claudication Questionnaire (ICQ) is a short questionnaire for the assessment of health-related quality of life (HRQOL) in patients with intermittent claudication (IC). The objective of this study was to translate the ICQ into German and to investigate the psychometric properties of the German ICQ version in patients with IC. Patients and methods: The original English version was translated using a forward-backward method. The resulting German version was reviewed by the author of the original version and an experienced clinician. Finally, it was tested for clarity with 5 German patients with IC. A sample of 81 patients were administered the German ICQ. The sample consisted of 58.0 % male patients with a median age of 71 years and a median IC duration of 36 months. Test of feasibility included completeness of questionnaires, completion time, and ratings of clarity, length and relevance. Reliability was assessed through a retest in 13 patients at 14 days, and analysis of Cronbachs alpha for internal consistency. Construct validity was investigated using principal component analysis. Concurrent validity was assessed by correlating the ICQ scores with the Short Form 36 Health Survey (SF-36) as well as clinical measures. Results: The ICQ was completely filled in by 73 subjects (90.1 %) with an average completion time of 6.3 minutes. Cronbachs alpha coefficient reached 0.75. Intra-class correlation for test-retest reliability was r = 0.88. Principal component analysis resulted in a 3 factor solution. The first factor explained 51.5 of the total variation and all items had loadings of at least 0.65 on it. The ICQ was significantly associated with the SF-36 and treadmill-walking distances whereas no association was found for resting ABPI. Conclusions: The German version of the ICQ demonstrated good feasibility, satisfactory reliability and good validity. Responsiveness should be investigated in further validation studies.

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