Testing for long-term trends in climatic variables in Iran

Tabari, Hossein; Some’e, B. Shifteh; Zadeh, Mehdi Rezaeian

doi:10.1016/j.atmosres.2011.01.005

Cited by 306 publications

(124 citation statements)

References 24 publications

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“…The other advantage is its low sensitivity to abrupt breaks due to inhomogeneous time series. In this study, the 5% level of significance was considered [28,29].…”

Section: Detection Of Long-terms Trends Using Mann-kendall Testmentioning

confidence: 99%

Linkage between Water Level Dynamics and Climate Variability: The Case of Lake Hawassa Hydrology and ENSO Phenomena

Belete

Diekkrüger

Roehrig

2017

Climate

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Lake Hawassa is a topographically closed lake in the Central Main Ethiopian Rift Valley. The water level of this lake has been reported to dramatically rise without falling back to the original level. The cause of this rise is not yet sufficiently investigated and subjected to this study. This study argues that the general variability in the lake level and its resultant rise has significant linkage to the temperature variability at the Pacific Ocean. The linkage between water level dynamics and climate variability was analyzed through the application of diverse statistical techniques. It comprises the Mann-Kendall trend analysis to test monotonic variations over time; sequential regime shift index (RSI) to detect significant shifts in the mean values of time-series records of lake level; and coherence analysis to investigate the linear relationship between ENSO index and records of local hydrology. Despite the multiple rises and falls, the results of the trend analysis revealed that the lake level experienced a significant resultant upward trend with Mann-Kendall τ values of 0.558, 0.629, and 0.545 (at α = 0.05 and p < 0.01%) for monthly maximum, average and minimum values respectively. The sequential regime shift evidenced that most of the significant shifts coincide with the occurrences of ENSO events. Generally, the lake level tends to be high during El Niño and low during La Niña episodes. The typical examples are the coincidence of extreme historical maximum lake level to the strongest El Niño event of the century that occurred in 1997/98 and the lowest lake level record in the year 1975 with a strong La Niña year. The coincidence of climate regime shift in the Pacific Ocean in 1976/77 with an equivalent regime shift in the lake level is an additional confirmation for the possible climate-hydrology linkage. The likely involvement of anthropogenic factors (at least in modifying the effect of climate) is justified by the interplay between the non-trending rainfall and potential evapotranspiration and trending streamflow. The coherence analysis between 492 pairs of monthly step datasets of 3.4ENSO index and lake level changes is also found to have a significant linear relationship over frequencies ranging from 0.13 to 0.14 cycles/month or 1.56 to 1.68 cycles/year. This corresponds to a dominant average periodicity (coincident cycle) of about 7.4 months which is thought to be related to the time span of the two rainy season in the locality.

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“…The other advantage is its low sensitivity to abrupt breaks due to inhomogeneous time series. In this study, the 5% level of significance was considered [28,29].…”

Section: Detection Of Long-terms Trends Using Mann-kendall Testmentioning

confidence: 99%

Linkage between Water Level Dynamics and Climate Variability: The Case of Lake Hawassa Hydrology and ENSO Phenomena

Belete

Diekkrüger

Roehrig

2017

Climate

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“…The nonparametric Mann-Kendall test is a widely used non-parametric test for detecting trends in hydrological and meteorological time series (Tabari et al, 2011). For a time series of n observations ( , ,, , the M-K test statistic S is computed as follows: Mann (1945) and Kendall (1975) have documented that when n8, the statistic S is approximately normally distributed with zero mean and the following variance:…”

Section: Mann-kendall (M-k) Testmentioning

confidence: 99%

Analysis of the spatio-temporal patterns of dry and wet conditions in the Huai River Basin using the standardized precipitation index

Yang

2015

Atmospheric Research

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Located in a transition zone between the northern and southern climates in China, the Huai River Basin is prone to extreme events such as drought and flood. Based on the daily precipitation data at 134 stations between 1961 and 2013, this paper analyzed the spatial and temporal patterns of the dry and wet conditions in the Huai River Basin through the statistical analysis of the rainfall stations' annual and seasonal standard precipitation index (SPI) series. Annual SPI series exhibited a decreasing trend at 86 stations and an increasing trend at the remaining stations. None of the increasing trend was significant, while the decreasing trend was significant at two stations at 5% significance level (=0.05) and one station at 10% level. Seasonal-wise, there has been a prevailing trend of drying in spring and autumn, and wetting in summer and winter.The trends in the spring and summer SPI series have been mostly insignificant, while those in autumn and winter significant (=0.10) at over 30 stations. The Pettitt test results indicated that the significant transitions (=0.10) in the autumn and winter SPI series mostly occurred in the middle to late 1980's. Comparison of the average number of dry and wet years between the two sub-periods of 1961-1984 and 1990-2013 suggested a significant increase (=0.05) in the average number of severely wet years across much of the basin. Overall, significant changes have already occurred in the dry and wet conditions of the Huai River Basin, which could have profound impacts on the food and water safety situation of the region.

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“…The Mann-Kendall test is a non-parametric test and therefore does not require the data to be normally distributed. The Mann-Kendall test also has a low sensitivity to abrupt breaks due to inhomogeneous time series (Tabari, Somee, & Zadeh, 2011). The Mann-Kendall test is based on the S-statistic (Onoz & Bayazit, 2003).…”

Section: Methodsmentioning

confidence: 99%

The Bilateral Relationship Between Tourism and Dengue Occurrence: Evidence From Aruba

Oduber¹,

Ridderstaat²,

Martens³

2014

JTHM

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This study estimates the bilateral effects between seasonal patterns of dengue incidences and the recurring fluctuations of both stay-over tourism and cruise tourism. Seasonal patterns were first isolated from the series using the Census X-12 decomposition method, after which the analysis included panel data unit root testing, panel data regression, and Mahalanobis distance calculation. The results show that cruise tourism increases dengue cases in Aruba, while dengue cases themselves had no influence on the number of stay-over and cruise visitors in Aruba.The study hints for an economical duality in cruise tourism in Aruba: (1) On one hand, cruise tourists who arrive at the harbor contribute to the economy of Aruba due to their spending activities; and (2) On the other hand, cruise tourists can induce costs by increasing the risk of spreading dengue. The Mahalanobis distance showed that the sensitivity of dengue cases to cruise tourism was the strongest during

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Testing for long-term trends in climatic variables in Iran

Cited by 306 publications

References 24 publications

Linkage between Water Level Dynamics and Climate Variability: The Case of Lake Hawassa Hydrology and ENSO Phenomena

Linkage between Water Level Dynamics and Climate Variability: The Case of Lake Hawassa Hydrology and ENSO Phenomena

Analysis of the spatio-temporal patterns of dry and wet conditions in the Huai River Basin using the standardized precipitation index

The Bilateral Relationship Between Tourism and Dengue Occurrence: Evidence From Aruba

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