Wavelet analysis of the complex precipitation series in the Northern Jiansanjiang Administration of the Heilongjiang land reclamation, China

2016 ◽  
Vol 7 (4) ◽  
pp. 796-809 ◽  
Author(s):  
Dong Liu ◽  
Qiang Fu ◽  
Tianxiao Li ◽  
Yuxiang Hu ◽  
Khan M. Imran ◽  
...  
Keyword(s):  
Wavelet Analysis ◽  
Land Reclamation ◽  
Southern Oscillation ◽  
Annual Precipitation ◽  
Major Influence ◽  
Precipitation Series ◽  
Analysis Method ◽  
Variation Characteristics ◽  
Precipitation Variation ◽  
Jiansanjiang Administration

Due to interference from natural factors and the intensity of human activities, the complex characteristics of the regional precipitation process have become increasingly evident, which creates a challenge for the rational development and utilisation of precipitation resources. In this perspective of complexity diagnosis, the multi-timescale variation characteristics of precipitation were analysed in the Northern Jiansanjiang Administration of Heilongjiang land reclamation, China, by the wavelet analysis method. The results showed that the most complex precipitation series was at Qinglongshan Farm. There are five significant main periods of approximately 2, 3, 4, 9 and 12 years in the seasonal and annual precipitation of Qinglongshan Farm; these periodic variation characteristics are almost identical to the periods of the EI Niño-Southern Oscillation phenomena and sunspot activity, which illustrates that climate change has a major influence on the local precipitation variation characteristics. At the same time, precipitation in summer and autumn has similar periods and a similar variation trend to the annual precipitation at Qinglongshan Farm, which indicates that the local annual precipitation variation characteristics are mainly affected by summer and autumn precipitation variation. In contrast with the harmonic analysis method based on Fourier transform, wavelet analysis has a significant advantage in terms of accurately identifying the main cycle of the hydrological time series.

scholarly journals Wavelet analysis for seasonal precipitation variations of Yuanmou dry-hot valley in recent 50 years

MAUSAM ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. 663-672
Author(s):  
L. N. SUN ◽  
J. Y. WANG ◽  
B. ZHANG
Keyword(s):  
Wavelet Analysis ◽  
Time Scales ◽  
Periodic Oscillation ◽  
Landscape Patterns ◽  
Annual Precipitation ◽  
Seasonal Precipitation ◽  
Short Term ◽  
Time Frequency ◽  
Precipitation Variation ◽  
Meyer Wavelet

The dry-hot valley is a special kind of degradation ecosystem region in Hengduan Mountains. Variations of seasonal precipitation have important influnces on its landscape patterns and agricultural activities. Based on the monthly and annual precipitation data from 1956 to 2006, the multi-time scales characteristics of seasonal and annual variations of precipitation in the past 50a in the Yuanmou County had been analyzed using Meyer wavelet analysis in this paper. The periodic oscillation of precipitation variation and the points of abrupt change at different time scales along the time series are discovered and the main periods of every serial are confirmed. It was showed that the periodic oscillation of 8-12a and 4-6a for the seasonal and annual precipitation variation are obvious. The time-frequency local change characteristic of Meyer wavelet analysis can demonstrate the fine structures of precipitation and the method provides a new way in analyzing climate multi-time scales characteristics and forecasting short-term climate. The localization characteristics of time -frequency for wavelet analysis can demonstrate the detailed structures of rainfall. The wavelet analysis can be an alternative approach to analyze climate multi-time scales characteristics and forecast short-term climate variations. The research on the regularity of seasonal precipitation variation in the dry-hot valley region has a great guidance meaning to the agriculture production and resilience in flood prevention.  

scholarly journals Entropy-based analysis and regionalization of annual precipitation variation in Iran during 1960–2010 using ensemble empirical mode decomposition

2018 ◽  
Vol 20 (2) ◽  
pp. 468-485 ◽  
Author(s):  
Kiyoumars Roushangar ◽  
Farhad Alizadeh
Keyword(s):  
Empirical Mode Decomposition ◽  
Ensemble Empirical Mode Decomposition ◽  
Multiscale Entropy ◽  
Annual Precipitation ◽  
Precipitation Series ◽  
Self Organizing Map ◽  
Intrinsic Mode Functions ◽  
Mode Decomposition ◽  
Entropy Variation ◽  
Precipitation Variation

Abstract This study proposes an ensemble empirical mode decomposition (EEMD)-based multiscale entropy (EME) approach. The proposed model is used to analyze and gage variability of the annual precipitation series and spatially classify raingauges in Iran. For this end, historical annual precipitation data during 1960–2010 from 31 raingauges are decomposed using EEMD. Decomposed series of precipitation series present different periods and trends. Next, entropy concept is applied to the components obtained from EEMD to measure dispersion of multiscale components. It is observed that entropy values of intrinsic mode functions (IMFs) 1–5 and residual component show different behaviors. IMF 5 and residual components have highest values of entropy, whereas IMF 3 and 4 present highest entropy variation among all components. Based on spatial distribution of EME values, EME 3 and 1 have a downward variation from north to south, whereas EME 1 presents increasing variation. Spatial classification of raingauges is performed using EME values as input data to self-organizing map (SOM) and k-means clustering techniques. Finally, spatial structure of annual precipitation variation is investigated. It is observed that EME values have a downward trend with latitude, whereas it is observed that EME shows an upward relationship with longitude in Iran.

scholarly journals The correlation between three teleconnections and leptospirosis incidence in the Kandy District, Sri Lanka, 2004–2019

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
N. D. B. Ehelepola ◽  
Kusalika Ariyaratne ◽  
A. M. S. M. C. M. Aththanayake ◽  
Kamalanath Samarakoon ◽  
H. M. Arjuna Thilakarathna
Keyword(s):  
Time Series ◽  
Sri Lanka ◽  
Wavelet Analysis ◽  
Southern Oscillation ◽  
Population Data ◽  
Enso Modoki ◽  
Cross Correlation Analysis ◽  
Teleconnection Indices ◽  
Weather Parameters ◽  
Time Lagged

Abstract Background Leptospirosis is a bacterial zoonosis. Leptospirosis incidence (LI) in Sri Lanka is high. Infected animals excrete leptospires into the environment via their urine. Survival of leptospires in the environment until they enter into a person and several other factors that influence leptospirosis transmission are dependent upon local weather. Past studies show that rainfall and other weather parameters are correlated with the LI in the Kandy district, Sri Lanka. El Niño Southern Oscillation (ENSO), ENSO Modoki, and the Indian Ocean Dipole (IOD) are teleconnections known to be modulating rainfall in Sri Lanka. There is a severe dearth of published studies on the correlations between indices of these teleconnections and LI. Methods We acquired the counts of leptospirosis cases notified and midyear estimated population data of the Kandy district from 2004 to 2019, respectively, from weekly epidemiology reports of the Ministry of Health and Department of Census and Statistics of Sri Lanka. We estimated weekly and monthly LI of Kandy. We obtained weekly and monthly teleconnection indices data for the same period from the National Oceanic and Atmospheric Administration (NOAA) of the USA and Japan Agency for Marine-Earth Science and Technology (JAMSTEC). We performed wavelet time series analysis to determine correlations with lag periods between teleconnection indices and LI time series. Then, we did time-lagged detrended cross-correlation analysis (DCCA) to verify wavelet analysis results and to find the magnitudes of the correlations detected. Results Wavelet analysis displayed indices of ENSO, IOD, and ENSO Modoki were correlated with the LI of Kandy with 1.9–11.5-month lags. Indices of ENSO showed two correlation patterns with Kandy LI. Time-lagged DCCA results show all indices of the three teleconnections studied were significantly correlated with the LI of Kandy with 2–5-month lag periods. Conclusions Results of the two analysis methods generally agree indicating that ENSO and IOD modulate LI in Kandy by modulating local rainfall and probably other weather parameters. We recommend further studies about the ENSO Modoki and LI correlation in Sri Lanka. Monitoring for extreme teleconnection events and enhancing preventive measures during lag periods can blunt LI peaks that may follow.

scholarly journals Energy Analysis Method Based on Wavelet Transform for Sensor Fault Diagnosis

2011 ◽  
Vol 2-3 ◽  
pp. 117-122 ◽  
Author(s):  
Peng Peng Qian ◽  
Jin Guo Liu ◽  
Wei Zhang ◽  
Ying Zi Wei
Keyword(s):  
Wavelet Transform ◽  
Fault Diagnosis ◽  
Wavelet Analysis ◽  
Energy Analysis ◽  
Sensor Faults ◽  
Analysis Method ◽  
Sensor Fault ◽  
Fault Type ◽  
Ideal Tool ◽  
Non Stationary Signal

Wavelet analysis with its unique features is very suitable for analyzing non-stationary signal, and it can also be used as an ideal tool for signal processing in fault diagnosis. The characteristics of the faults and the necessary information on the diagnosis can be constructed and extracted respectively by wavelet analysis. Though wavelet analysis is specialized in characteristics extraction, it can not determine the fault type. So this paper has proposed an energy analysis method based on wavelet transform. Experiment results show the method is very effective for sensor fault diagnosis, because it can not only detect the sensor faults, but also determine the fault type.

scholarly journals Responses of groundwater to precipitation variability and ENSO in the Vietnamese Mekong Delta

2021 ◽  
Author(s):  
Phong V. V. Le ◽  
Hai V. Pham ◽  
Luyen K. Bui ◽  
Anh N. Tran ◽  
Chien V. Pham ◽  
...  
Keyword(s):  
Water Resources ◽  
Climate Variability ◽  
Time Scales ◽  
Groundwater Level ◽  
Southern Oscillation ◽  
Mekong Delta ◽  
Precipitation Variability ◽  
Annual Precipitation ◽  
Aquifer Recharge ◽  
Deep Aquifers

Abstract Groundwater is a critical component of water resources and has become the primary water supply for agricultural and domestic uses in the Vietnamese Mekong Delta (VMD). Widespread groundwater level declines have occurred in the VMD over recent decades, reflecting that extraction rates exceed aquifer recharge in the region. However, the impacts of climate variability on groundwater system dynamics in the VMD remain poorly understood. Here, we explore recent changes in groundwater levels in shallow and deep aquifers from observed wells in the VMD and investigate their relations to the annual precipitation variability and El Niño–Southern Oscillation (ENSO). We show that groundwater level responds to changes in annual precipitation at time scales of approximately 1 year. Moreover, shallow (deep) groundwater in the VMD appears to correlate with the ENSO over intra-annual (inter-annual) time scales. Our findings reveal a critical linkage between groundwater level changes and climate variability, suggesting the need to develop an understanding of the impacts of climate variability across time scales on water resources in the VMD.

Mine Ventilator Fault Diagnosis Based on Harmonic Wavelet Analysis

2011 ◽  
Vol 143-144 ◽  
pp. 613-617
Author(s):  
Shuang Xi Jing ◽  
Yong Chang ◽  
Jun Fa Leng
Keyword(s):  
Fault Diagnosis ◽  
Wavelet Analysis ◽  
Frequency Domain ◽  
Vibration Signal ◽  
Wavelet Function ◽  
Frequency Region ◽  
Analysis Method ◽  
Vibration Signals ◽  
Harmonic Wavelet ◽  
Frequency Components

Harmonic wavelet function, with the strict box-shaped characteristic of spectrum, has strong ability of identifying signal in frequency domain, and can extract weak components form vibration signals in frequency domain. Using harmonic wavelet analysis method, the selected frequency region and other frequency components of vibration signal of mine ventilator were decomposed into independent frequency bands without any over-lapping or leaking. Simulation and diagnosis example show that this method has good fault diagnosis effect, and the ventilator fault is diagnosed successfully.

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