Homogeneity analysis of precipitation series in Iran

Talaee, P. Hosseinzadeh; Kouchakzadeh, M; Some’e, B. Shifteh

doi:10.1007/s00704-013-1074-y

Cited by 26 publications

(12 citation statements)

References 20 publications

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“…Nonetheless, its properties have been chiefly studied for normal distribution [1,12,13]. The von Neumann ratio (VN) is the most widely applied test for checking a time series for the existence of homogeneity [9,14].…”

Section: Checking the Normality And Homogeneity Of Rainfalls Seriesmentioning

confidence: 99%

“…Furthermore, rainfall affects both the temporal and spatial patterns of climate variability. In the rainfall seasonality analysis in Iran, Talaee et al (2014) noted that rainfall showed a decreasing trend in Iran in the previous years [1,2]. Some researchers [3][4][5][6][7] recognized indirect indications of trend and long-term variability of rainfall.…”

Section: Introductionmentioning

confidence: 99%

“…In the non-trended seasonal patterns, the absolute seasonal least squares methods (ASLSM) are used on the data from each station individually. Likewise, the homogeneity tests could be divided into two groups: absolute tests and relative tests [1,[9][10][11][12][13]. In this study, homogeneity tests were used: Pettit (1979), SNHT-Standard Normal Homogeneity Test (1986), Buishand (1982) and von Neumann (1941) tests [14,15].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Trend and Homogeneity Analysis of Precipitation in Iran

Javari

2016

Climate

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Abstract:The main objective of this study is to examine trend and homogeneity through the analysis of rainfall variability patterns in Iran. The study presents a review on the application of homogeneity and seasonal time series analysis methods for forecasting rainfall variations. Trend and homogeneity methods are applied in the time series analysis from collecting rainfall data to evaluating results in climate studies. For the homogeneity analysis of monthly, seasonal and annual rainfall, homogeneity tests were used in 140 stations in the 1975-2014 period. The homogeneity of the monthly and annual rainfall at each station was studied using the autocorrelation (ACF), and the von Neumann (VN) tests at a significance level of 0.05. In addition, the nature of the monthly and seasonal rainfall series in Iran was studied using the Kruskal-Wallis (KW) test, the Thumb test (TT), and the least squares regression (LSR) test at a significance level of 0.05. The present results indicate that the seasonal patterns of rainfall exhibit considerable diversity across Iran. Rainfall seasonality is generally less spatially coherent than temporal patterns in Iran. The seasonal variations of rainfall decreased significantly throughout eastern and central Iran, but they increased in the west and north of Iran during the studied interval. The present study comparisons among variations of patterns with the seasonal rainfall series reveal that the variability of rainfall can be predicted by the non-trended and trended patterns.

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Section: Checking the Normality And Homogeneity Of Rainfalls Seriesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Trend and Homogeneity Analysis of Precipitation in Iran

Javari

2016

Climate

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“…The highest number of inhomogeneity in monthly streamflow series was found in February based on the von Neumann ratio test. Homogeneity analysis of precipitation series in Iran indicated that the total number of inhomogeneity was more in clod season months or winter months than in warm season months (Hosseinzadeh Talaee et al, 2014). It was previously reported that in the semi-arid regions, the variability of the streamflow time series was usually larger in warm season months than in clod season months mainly due to the natural and anthropogenic changes (e.g., Hereford and Webb, 1992; Barlow et al, 2001;Das et al, 2011).…”

Section: Resultsmentioning

confidence: 87%

“…Several researches have applied the statistical homogeneity tests and clustering approach for the hydro-climatic time series (e.g., Conrad and Pollak, 1950;Wijngaard et al, 2003;Kahya et al, 2008;Sahin and Cigizoglu, 2010;Dikbas et al, 2013;Hosseinzadeh Talaee et al, 2014;Seyam and Othman, 2015;Omar et al, 2017). For examples, Wijngaard et al (2003) used the statistical homogeneity tests to analyze the climatic variables in the European continent and reported that about 25% of the precipitation series and 94% of the temperature series were labelled 'suspect ' or 'doubtful' over the period 1901-1999.…”

Section: Introductionmentioning

confidence: 99%

Homogeneity analysis of streamflow records in arid and semi-arid regions of northwestern Iran

Kazemzadeh

Malekian

2018

J. Arid Land

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Homogeneity analysis of the streamflow time series is essential to hydrological modeling, water resources management and climate change studies. In this study, five absolute homogeneity tests and one clustering approach were used to determine the homogeneity status of the streamflow time series (over the period 1960-2010) in 14 hydrometric stations of three important basins (i.e., Aras River Basin, Urmia Lake Basin and Sefid-Roud Basin) in northwestern Iran. Results of the Buishand range test, von Neumann ratio test, cumulative deviation test, standard normal homogeneity test and Pettitt test for monthly streamflow time series detected that about 42.26%, 38.09%, 33.33%, 39.28% and 68.45% of the streamflow time series were inhomogeneous at the 0.01 significance level, respectively. Streamflow time series of the stations located in the eastern parts of the study area or within the Urmia Lake Basin were mostly homogeneous. In contrast, streamflow time series in the stations of the Aras River Basin and Sefied-Roud Basin showed inhomogeneity at annual scales. Based on the overall classification for the monthly and annual streamflow series, we determined that about 45.60%, 11.53% and 42.85% of the time series were categorized into the 'useful', 'doubtful' and 'suspect' classes according to the five absolute homogeneity tests. We also found the homogeneity patterns of the streamflow time series by using the clustering approach. The results suggested the effectiveness of the clustering approach for homogeneity analysis of the streamflow time series in addition to the absolute homogeneity tests. Moreover, results of the absolute homogeneity tests and clustering approach indicated obvious decreasing change points of the streamflow time series in the 1990s over the three basins, which were mostly related to the hydrological droughts.

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Trend analysis and change point detection of seasonal and annual precipitation in Iran

Salehi

Dehghani

Mortazavi

et al. 2019

Intl Journal of Climatology

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The aim of this study was to analyse spatial and temporal homogeneity and trends in seasonal and annual precipitation and their fluctuations during 1957–2016 in Iran. For testing homogeneity, the Pettitt‐Whitney–Mann, the Standard Normal Homogeneity or Alexandersson's SNHT, Buishand's and the Von Neumann tests were used and for trend analysis, Mann‐Kendall and Sequential Mann‐Kendall tests were used. Homogeneity tests showed that most of the seasonal and annual precipitation time series were homogeneous and the change point was detected only at a few stations. Results indicated that in general, there was an upward trend during 1957–1986, followed by a significant downward trend during 1987–2016. The sequential Mann‐Kendall test detected several possible change points over time, although most of them were found statistically non‐significant at 95% confidence level. Upward and downward trends started in annual and seasonal precipitation after 1960 and 1990, respectively, at most stations, except in spring. In spring, an upward trend started after 1990 at some stations which showed a shift in precipitation from winter to spring. Also, the Sen's slope estimator indicated a higher downward trend in the northern parts of Iran. Two findings are worthy of note based on the results of this study. First, in general, a significant downward trend occurred in the whole country after1990. Second, a shift in precipitation from winter to spring was detected at some stations in different homogeneous regions.

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Homogeneity analysis of precipitation series in Iran

Cited by 26 publications

References 20 publications

Trend and Homogeneity Analysis of Precipitation in Iran

Trend and Homogeneity Analysis of Precipitation in Iran

Homogeneity analysis of streamflow records in arid and semi-arid regions of northwestern Iran

Trend analysis and change point detection of seasonal and annual precipitation in Iran

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