Linear trend analysis: a comparison of methods

Hess, Ann; Iyer, Hari; Malm, William C.

doi:10.1016/s1352-2310(01)00342-9

Cited by 205 publications

(107 citation statements)

References 12 publications

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“…Further, the method can be used on data that are not normally distributed, which is commonly the case with environmental data and it is also robust for extreme values and possible outliers (Helsel and Hirsch, 1992). The Seasonal Kendall has also been shown to be reliable in comparison with other methods for trend analysis and to maintain a high power with different trend functions (Hess et al, 2001). …”

Section: Methodsmentioning

confidence: 99%

Increasing concentrations of arsenic and vanadium in (southern) Swedish streams

Wällstedt

Björkvald

Gustafsson

2010

Applied Geochemistry

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The aim of this study was to investigate temporal trends and controlling factors of As and V in running waters throughout Sweden. For this purpose, data on stream water chemistry from 62 streams of varying catchment size and characteristics, included in the Swedish environmental monitoring programmes were evaluated. The geochemical software Visual MINTEQ was used to model the speciation and trend analyses were performed on total concentrations of As and V as well as modelled fractions (dissolved species as well as arsenate and vanadate adsorbed to ferrihydrite). The trend analyses showed increasing total concentrations of As and V in southern Sweden. Concentrations of As and V correlated significantly to Fe concentrations in 59 and 60 of the 62 streams respectively, indicating that Fe is an important determining factor for As and V concentrations in Swedish streams. This was confirmed by the geochemical modelling that indicated that the adsorbed fraction is the dominant form of As and V and that the concentrations of As and V in Swedish streams are thus highly determined by concentrations of colloidal or particulate Fe. It is therefore suggested that the increasing trends of As and V are to a large extent due to increasing concentrations of colloidal Fe, which is stabilised by increasing concentrations of DOC. Further the geochemical modelling indicates that the dissolved fraction of As and V generally is small, with the exception of a few streams with high pH and/or phosphate concentrations.

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Section: Methodsmentioning

confidence: 99%

Increasing concentrations of arsenic and vanadium in (southern) Swedish streams

Wällstedt

Björkvald

Gustafsson

2010

Applied Geochemistry

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“…The Mann-Kendall test has been extensively used to analyze linear trends in hydrological datasets (e.g. Burn and Hag Elnur, 2002;Hamed, 2008;Yip et al, 2012), proving better results than other methods (Hess et al, 2001). As recommended by Hamed and Rao (1998) time series autocorrelation was removed before performing the Mann-Kendall test to eliminate the detection of false trends.…”

Section: Trend and Change Point Analysismentioning

confidence: 99%

Recent changes to the hydrological cycle of an Arctic basin at the tundra–taiga transition

Krogh

Pomeroy

2018

Hydrol. Earth Syst. Sci.

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Abstract. The impact of transient changes in climate and vegetation on the hydrology of small Arctic headwater basins has not been investigated before, particularly in the tundrataiga transition region. This study uses weather and land cover observations and a hydrological model suitable for cold regions to investigate historical changes in modelled hydrological processes driving the streamflow response of a small Arctic basin at the treeline. The physical processes found in this environment and explicit changes in vegetation extent and density were simulated and validated against observations of streamflow discharge, snow water equivalent and active layer thickness. Mean air temperature and all-wave irradiance have increased by 3.7 • C and 8.4 W m −2 , respectively, while precipitation has decreased 48 mm (10 %) since 1960. Two modelling scenarios were created to separate the effects of changing climate and vegetation on hydrological processes. Results show that over 1960-2016 most hydrological changes were driven by climate changes, such as decreasing snowfall, evapotranspiration, deepening active layer thickness, earlier snow cover depletion and diminishing annual sublimation and soil moisture. However, changing vegetation has a significant impact on decreasing blowing snow redistribution and sublimation, counteracting the impact of decreasing precipitation on streamflow, demonstrating the importance of including transient changes in vegetation in longterm hydrological studies. Streamflow dropped by 38 mm as a response to the 48 mm decrease in precipitation, suggesting a small degree of hydrological resiliency. These results represent the first detailed estimate of hydrological changes occurring in small Arctic basins, and can be used as a reference to inform other studies of Arctic climate change impacts.

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“…The time series are tested for the presence of monotonically increasing or decreasing trends (referred as 'monotonic trends') using the Mann-Kendall and Spearman tests (Mann, 1945;Kendall, 1975;Helsel and Hirsch, 1993;Hess et al, 2001;McCuen, 2003;Kundzewicz and Robson, 2004). Similar to the Pettitt test, they are nonparametric and have similar power (Yue et al, 2002).…”

Section: Change-point and Trend Analysesmentioning

confidence: 99%

Analyses of extreme flooding in Austria over the period 1951–2006

Villarini

Smith

Serinaldi

et al. 2011

Intl Journal of Climatology

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ABSTRACT:Analyses of extreme flooding in Austria is performed using daily discharge time series from 27 stations over the period . The main research questions revolve around: (1) temporal non-stationarities in the flood record, (2) upper tail and scaling properties of the flood peak records, and (3) relation between magnitude and frequency of flooding and the North Atlantic Oscillation (NAO). Two datasets are derived from the daily discharge time series: annual maximum daily discharge and peaks-over-threshold (POT) data. The validity of the stationarity assumption in the annual maximum discharge record is assessed by investigating the presence of abrupt and slowly varying changes using nonparametric tests. The time series are tested for abrupt changes both in the mean and variance of the flood peak distributions by means of the Pettitt test. The presence of monotonic trends is investigated by means of the Mann-Kendall and Spearman tests. Violations of the stationarity assumption are associated with abrupt rather than gradual changes. These step changes generally involve river regulation through construction of dams or other major engineering works. It is not possible to make conclusive statements about the presence of an anthropogenic climate change signal in the flood peak record. Similar conclusions are obtained when focussing on the frequency of POT floods. The Generalised Extreme Value distribution is used to study the upper tail and scaling properties of annual maximum daily discharge records. The location and scale parameters exhibit power-law behaviour as a function of drainage area. The shape parameters indicate that the flood peak distributions for Austria have a heavy tail. Non-stationary modelling of the annual maximum daily discharge and POT time series is used to explore the relation between flood magnitude and frequency and NAO. The results indicate that NAO is a significant covariate in explaining the magnitude and frequency of occurrence of flooding over a large part of Austria.

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Linear trend analysis: a comparison of methods

Cited by 205 publications

References 12 publications

Increasing concentrations of arsenic and vanadium in (southern) Swedish streams

Increasing concentrations of arsenic and vanadium in (southern) Swedish streams

Recent changes to the hydrological cycle of an Arctic basin at the tundra–taiga transition

Analyses of extreme flooding in Austria over the period 1951–2006

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