scholarly journals A review: anomaly based versus full-field based weather analysis and forecasting

2021 ◽  
pp. 1-52
Author(s):  
Weihong Qian ◽  
Jun Du ◽  
Yang Ai
Keyword(s):  
Model Prediction ◽  
Heavy Rain ◽  
Societal Impact ◽  
Seasonal Forecasts ◽  
Field Methods ◽  
Weather System ◽  
Full Field ◽  
Diagnostic Parameters ◽  
Weather Events ◽  
Typhoon Tracks

AbstractComparisons between anomaly and full-field methods have been carried out in weather analysis and forecasting over the last decade. Evidence from these studies has demonstrated the superiority of anomaly to full-field in the following four aspects: depiction of weather systems, anomaly forecasts, diagnostic parameters and model prediction. To promote the use and further discussion of the anomaly approach, this article summarizes those findings.After examining many types of weather events, anomaly weather maps show at least five advantages in weather system depiction: (1) less vagueness in visually connecting the location of an event with its associated meteorological conditions; (2) clearer and more complete depictions of vertical structures of a disturbance; (3) easier observation of time and spatial evolution of an event and its interaction or connection with other weather systems; (4) simplification of conceptual models by unifying different weather systems into one pattern; and (5) extension of model forecast length due to earlier detection of predictors. Anomaly verification is also mentioned. The anomaly forecast is useful for raising one’s awareness of potential societal impact. Combining the anomaly forecast with an ensemble is emphasized, where a societal impact index is discussed. For diagnostic parameters, two examples are given: an anomalous convective instability index for convection, and seven vorticity and divergence related parameters for heavy rain. Both showed positive contributions from the anomalous fields. For model prediction, the anomaly version of the beta-advection model consistently outperformed its full-field version in predicting typhoon tracks with clearer physical explanation. Application of anomaly global models to seasonal forecasts is also reviewed.

scholarly journals Anomaly-Based Weather Analysis versus Traditional Total-Field-Based Weather Analysis for Depicting Regional Heavy Rain Events

2016 ◽  
Vol 31 (1) ◽  
pp. 71-93 ◽  
Author(s):  
Weihong Qian ◽  
Ning Jiang ◽  
Jun Du
Keyword(s):  
Heavy Rain ◽  
Total Field ◽  
Structure Approach ◽  
Rain Area ◽  
Diagnostic Parameters ◽  
Weather Events ◽  
Pros And Cons ◽  
Rain Events ◽  
Abnormal Weather ◽  
Atmospheric Variables

Abstract Although the use of anomaly fields in the forecast process has been shown to be useful and has caught forecasters’ attention, current short-range (1–3 days) weather analyses and forecasts are still predominantly total-field based. This paper systematically examines the pros and cons of anomaly- versus total-field-based approaches in weather analysis using a case from 1 July 1991 (showcase) and 41 cases from 1998 (statistics) of heavy rain events that occurred in China. The comparison is done for both basic atmospheric variables (height, temperature, wind, and humidity) and diagnostic parameters (divergence, vorticity, and potential vorticity). Generally, anomaly fields show a more enhanced and concentrated signal (pattern) directly related to surface anomalous weather events, while total fields can obscure the visualization of anomalous features due to the climatic background. The advantage is noticeable in basic atmospheric variables, but is marginal in nonconservative diagnostic parameters and is lost in conservative diagnostic parameters. Sometimes a mix of total and anomaly fields works the best; for example, in the moist vorticity when anomalous vorticity combines with total moisture, it can depict the heavy rain area the best when comparing to either the purely total or purely anomalous moist vorticity. Based on this study, it is recommended that anomaly-based weather analysis could be a valuable supplement to the commonly used total-field-based approach. Anomalies can help a forecaster to more quickly identify where an abnormal weather event might occur as well as more easily pinpoint possible meteorological causes than a total field. However, one should not use the anomaly structure approach alone to explain the underlying dynamics without a total field.

A review of automated methods for the collection and analysis of photoelastic data

1998 ◽  
Vol 33 (2) ◽  
pp. 75-91 ◽  
Author(s):  
A Ajovalasit ◽  
S Barone ◽  
G Petrucci
Keyword(s):  
Experimental Stress ◽  
Field Methods ◽  
Spectral Content ◽  
Full Field ◽  
Experimental Stress Analysis ◽  
Phase Stepping ◽  
Speed Up ◽  
Photoelastic Data ◽  
The Fourier Transform ◽  
Automated Methods

Photoelasticity is one of the most widely used full-field methods for experimental stress analysis. However, the collection of photoelastic parameters can be a long and tedious process. The advent of automated photoelastic systems has allowed the experimentalists to speed up the rate of analysis and to perform more complex investigations. This paper provides a survey of recent methods of automated photoelasticity developed in the last 20 years, i.e. methods of the fringe centres, half-fringe photoelasticity, phase-stepping photoelasticity, methods based on the Fourier transform, spectral content analysis (SCA) and RGB (red, green, blue) photoelasticity.

Shear-enhanced compaction band identification at the laboratory scale using acoustic and full-field methods

2014 ◽  
Vol 67 ◽  
pp. 240-252 ◽  
Author(s):  
Elli-Maria Charalampidou ◽  
Stephen A. Hall ◽  
Sergei Stanchits ◽  
Gioacchino Viggiani ◽  
Helen Lewis
Keyword(s):  
Laboratory Scale ◽  
Field Methods ◽  
Full Field ◽  
Compaction Band

Forecasting an Unusual Weather Event in Colorado: 15 October 1980

1982 ◽  
Vol 63 (10) ◽  
pp. 1142-1150 ◽  
Author(s):  
John F. Weaver ◽  
John M. Brown
Keyword(s):  
Heavy Rain ◽  
Heavy Precipitation ◽  
Severe Weather ◽  
Time Data ◽  
Short Term ◽  
Weather Event ◽  
Weather System ◽  
Light Rain ◽  
Term Forecast ◽  
Surface Data

On 15 October 1980, a weather system that had been to the west of Colorado was forecast to move into the state, and to bring with it light to moderate snow in the Rockies, and generally light rain and thundershower activity over the plains to the east. In most regions this forecast was adequate. However, substantially heavier activity (including a small tornado, large hail, heavy rain, and snow) also occurred in some areas. In this paper we show how all relevant real-time data, when properly merged, could have enabled formulation of a useful short-term forecast. In addition we point out how mesonet surface data gathered after the fact could have helped narrow down the forecast area of severe weather and heavy precipitation.

A pair of new moisture-dynamic diagnostic parameters for heavy rain location

2017 ◽  
Vol 130 (3) ◽  
pp. 325-331 ◽  
Author(s):  
Kai Yuan ◽  
Zhiwei Zhu ◽  
Ming Li
Keyword(s):  
Heavy Rain ◽  
Diagnostic Parameters

scholarly journals The cyclonic activity and frequency of dangerous weather phenomena over the territory of Belarus

2019 ◽  
pp. 79-93
Author(s):  
Katsiaryna M. Sumak ◽  
Inna G. Semenova
Keyword(s):  
Heavy Rain ◽  
Weather Conditions ◽  
Summer Period ◽  
Severe Convection ◽  
Weather Events ◽  
Atmospheric Fronts ◽  
Significant Damage ◽  
Wet Snow ◽  
The Republic ◽  
The Impact

In recent decades in the world, and in the Republic of Belarus in particular, the question of the impact of weather conditions on the development of sectors of the economy and life of the population has become acute. The sudden changes in weather conditions can lead to adverse and dangerous weather phenomena that cause significant damage to the country’s economy. This paper examines the frequency of dangerous weather phenomena in cyclones of different trajectories that moved through the territory of the Republic of Belarus during the period of 1995–2015. It is identified that southern and western cyclones caused dangerous weather events over the territory of Belarus. The interannual and seasonal frequency of cyclones causing dangerous weather phenomena in Belarus was analyzed. It is shown that the largest number of southern and western cyclones was characteristic mainly for the summer period, as well as the transitional seasons of the year, therefore the dangerous weather phenomena were associated mainly with the development of severe convection on atmospheric fronts. Such phenomena as very heavy rain, snowfall and wind had the highest frequency in cyclones, as in southern as western trajectories. The share of strong sticking of wet snow and large hail were isolated cases and these phenomena were recorded locally over the territory of country.

scholarly journals Maximum-Entropy Based Estimates of Stress and Strain in Thermoelastic Random Heterogeneous Materials

2020 ◽  
Vol 141 (2) ◽  
pp. 321-348
Author(s):  
Maximilian Krause ◽  
Thomas Böhlke
Keyword(s):  
Maximum Entropy ◽  
Heterogeneous Materials ◽  
Entropy Method ◽  
Distribution Functions ◽  
Internal Stresses ◽  
Field Methods ◽  
Common Procedure ◽  
Full Field ◽  
Mean Values ◽  
Special Cases

Abstract Mean-field methods are a common procedure for characterizing random heterogeneous materials. However, they typically provide only mean stresses and strains, which do not always allow predictions of failure in the phases since exact localization of these stresses and strains requires exact microscopic knowledge of the microstructures involved, which is generally not available. In this work, the maximum entropy method pioneered by Kreher and Pompe (Internal Stresses in Heterogeneous Solids, Physical Research, vol. 9, 1989) is used for estimating one-point probability distributions of local stresses and strains for various classes of materials without requiring microstructural information beyond the volume fractions. This approach yields analytical formulae for mean values and variances of stresses or strains of general heterogeneous linear thermoelastic materials as well as various special cases of this material class. Of these, the formulae for discrete-phase materials and the formulae for polycrystals in terms of their orientation distribution functions are novel. To illustrate the theory, a parametric study based on Al-Al2O3 composites is performed. Polycrystalline copper is considered as an additional example. Through comparison with full-field simulations, the method is found to be particularly suited for polycrystals and materials with elastic contrasts of up to 5. We see that, for increasing contrast, the dependence of our estimates on the particular microstructures is increasing, as well.

scholarly journals Stochastic evaluation of stress and strain distributions in duplex steel

2021 ◽  
Author(s):  
Maximilian Krause ◽  
Thomas Böhlke
Keyword(s):  
Crystallographic Texture ◽  
Mean Field ◽  
Local Fields ◽  
Stress And Strain ◽  
X Ray Diffraction ◽  
Field Methods ◽  
Full Field ◽  
X Ray ◽  
Duplex Steel ◽  
Duplex Steels

AbstractAustenite–ferrite duplex steels generally consist of two differently textured polycrystalline phases with different glide mechanisms. For estimating the effective mechanical behavior of heterogeneous materials, there exist well established approaches, two of which are the classes of mean-field and full-field methods. In this work, the local fields resulting from these different approaches are compared using analytical calculations and full-field simulations. Duplex steels of various textures measured using X-ray diffraction are considered. Special emphasis is given to the influence of the crystallographic texture on the stress and strain distributions.

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