Identification and characterization of water quality transients using wavelet analysis. I. Wavelet analysis methodology

1997 ◽  
Vol 36 (5) ◽  
pp. 325-335 ◽  
Author(s):  
Kathleen Dohan ◽  
Paul H. Whitfield
Keyword(s):  
Water Quality ◽  
Time Series ◽  
Wavelet Analysis ◽  
Wavelet Transforms ◽  
Transient Event ◽  
Frequency Decomposition ◽  
Analysis Methodology ◽  
Transient Events ◽  
Identification And Characterization

The methodology used in the identification and characterization of transient water quality events using wavelet transforms is described. The use of wavelets in the analysis of transient events is a distinct improvement over the methods which have been used previously, as wavelets are better suited to aperiodic processes than frequency decomposition. The methods presented here allow us to identify the location, duration and magnitude of a transient event in a water quality time series.

Identification and characterization of water quality transients using wavelet analysis. II. Application to electronic water quality data

1997 ◽  
Vol 36 (5) ◽  
pp. 337-348 ◽  
Author(s):  
Paul H. Whitfield ◽  
Kathleen Dohan
Keyword(s):  
Water Quality ◽  
Quality Data ◽  
Data Sets ◽  
Water Quality Data ◽  
Periodic Processes ◽  
Small Streams ◽  
Transient Events ◽  
Identification And Characterization

Two wavelet transform techniques for identifying water quality transients are applied to example data sets from two small streams. Temperature and conductance represent the range of properties from periodic processes to transient events. Both methods were successful in identifying the location, duration and magnitude of the transient events in these data sets. The methods may be refined to automate the detection and classification of transient events.

Trend analysis methodology for water quality time series

1991 ◽  
Vol 2 (2) ◽  
pp. 169-200 ◽  
Author(s):  
A. Ian McLeod ◽  
Keith W. Hipel ◽  
Byron A. Bodo
Keyword(s):  
Water Quality ◽  
Time Series ◽  
Trend Analysis ◽  
Analysis Methodology

WAVELET ANALYSIS OF TIME-SERIES: COHERENT STRUCTURES, CHAOS AND NOISE

1999 ◽  
Vol 09 (03) ◽  
pp. 455-471 ◽  
Author(s):  
W. J. STASZEWSKI ◽  
K. WORDEN
Keyword(s):  
Time Series ◽  
Wavelet Analysis ◽  
Coherent Structures ◽  
Wavelet Transforms ◽  
Time Series Data ◽  
Series Data ◽  
Different Types ◽  
Analyze Time Series Data ◽  
Analyze Time Series ◽  
Analysis Of Time Series

The continuous and orthogonal wavelet transforms are used to analyze time-series data. The analysis involves signal decomposition into scale components using both Grossman–Morlet and Daubechies type wavelets. A number of simulated and experimental data vectors exhibiting different types of coherent structures, chaos and noise is analyzed. The study shows that wavelet analysis provides a unifying framework for the description of many phenomena in time-series.

scholarly journals Variação da Linha de Costa na Região da Ilha dos Guarás – PA Através de Análise de Série Temporal de Imagens de Satélites (Coastline Changes Using Sattelite Images time series in Guarás Island Region – Pará State, Brazil)

2012 ◽  
Vol 4 (5) ◽  
pp. 922
Author(s):  
Luis Americo Conti
Keyword(s):  
Time Series ◽  
Spatial Data ◽  
Satellite Images ◽  
Coastal Protection ◽  
Island Region ◽  
Temporal Gis ◽  
High Resolution Satellite Images ◽  
Geospatial Tools ◽  
Identification And Characterization

Este trabalho apresenta uma analise da variação da linha de costa na região da Ilha dos Guarás, Município de Mariteua-PA ao longo das ultimas 3 décadas. Foi analisada uma seqüência de imagens de satélite de alta resolução da área e estabelecido um projeto em Sistema de Informações geográficas (SIG) visando a identificação e caracterização da linha de costa e estabelecendo padrões de mudanças. Os caso estudado mostrou que ferramentas geoespaciais como o “digital shoreline analyst” (DAS) podem ferramentas ser de grande importância na manipulação, análise e modelagem de dados costeiros, principalmente aplicados a estudos de conservação e monitoramento. A Ilha dos Guarás, em especial, apresentou um comportamento bastante peculiar com uma tendência de acreção nas porções laterais (Leste e Oeste) em oposição a uma tendência menos clara de erosão na porção central. Tais processos parecem ter sido mais determinantes na conformação da estrutura costeira da Ilha até o inicio da década de 2000 quando se tornou consideravelmente menos intenso.   Palavras Chave: Linha de costa, sensoriamento remoto, dinâmica costeira, modelagem  Coastline Changes Using Sattelite Images time series in Guarás Island Region – Pará State, Brazil  ABSTRACTThis work analyzes the coastline changes in the Ilha dos Guarás, Para State, Brazil. A sequence high resolution satellite images from 1985 to 2011 of the areas were analyzed in order to develop a systematic Geographic Information Systems (GIS) approach for the identification and characterization of the shoreline characteristics and how they change over the time. The main goal of our work is the proposal of a unified database to incorporate both spectral and spatial data in a temporal GIS framework. The examples analyzed showed that geospatial tools such as the Digital Shoreline Analyst (DSA) used could became a powerful tool for handling and analyzed data focused on the environmental monitoring and the coastal protection and conservation. The Guarás Island showed a peculiar dynamic with two areas of intense accretion in the flanks of the island in opposition of the central portion of the island submitted to a unstable erosional process. These processes were more severe until the beginning of the 21th century when it became considerable less intense.   Keywords: Coastline, Remote Sensing, Coastal dynamics, shoreline modelling

scholarly journals Temporal variability of two contrasting transient pollution events in a pastoral stream

2010 ◽  
Vol 61 (4) ◽  
pp. 1053-1063
Author(s):  
P. T. Yillia ◽  
N. Kreuzinger ◽  
K. K. Mwetu
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Base Flow ◽  
Channel Processes ◽  
Total N ◽  
Transient Event ◽  
Relative Contribution ◽  
Transient Events ◽  
Pollution Events ◽  
Total P

Two transient pollution events were monitored in a pastoral stream in southwestern Kenya to evaluate their relative contribution to diffuse pollution. Peak loads of pollutants during storm-induced transients were within 3–4 orders of magnitude higher than the short-lived (30–60 minutes) diurnal episodes provoked by in-stream activities of people and livestock. Transient yields were striking during storm-induced events; 778,000, 8,400, 550 and 100 kg day−1 for suspended solids, BOD5, total P and total N, respectively, compared to wet weather base flow (150, 30, 0.8 and 1.4 kg day−1, for the same parameters, respectively). Two forms of concentration-discharge relationships were observed: increases in concentration for turbidity, suspended solids, BOD5, total P and the faecal indicator bacteria at the peak of the stream hydrograph, and concurrent decreases in concentration for conductivity and total N. Following each storm-induced transient event, a marked improvement in water quality was observed within 48–72 hrs of the receding limb of the stream hydrograph before the next base low was established. It was concluded that storm-induced transients are exceedingly important for the mobilization of pollutants from diffuse sources but both transient events affect stream-channel processes, especially water quality, with the possibility of attendant consequences on the health of riparian inhabitants.

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