Changes in rainfall characteristics in northern Nigeria

Tarhule, Aondover; Woo, Ming‐ko

doi:10.1002/(sici)1097-0088(199809)18:11<1261::aid-joc302>3.0.co;2-z

Cited by 100 publications

(33 citation statements)

References 18 publications

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“…A test of abrupt changes in a time series is viewed as complementary to the analysis of gradual trends [33]. The non-parametric Pettitt test is used to examine whether a change-point exists and to locate the change point with no assumptions made about the distribution of the variable [34]; this has been widely applied to examine the occurrence of abrupt change in climatic records.…”

Section: Methods For Detecting Changes Trend Testmentioning

confidence: 99%

Spatial and Temporal Variations of Precipitation Extremes and Seasonality over China from 1961~2013

Tao

Wang

Song

et al. 2018

Water

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Using the 0.5 • × 0.5 • gridded Chinese ground precipitation dataset from 1961-2013, spatial and temporal variations in precipitation extremes, total precipitation, the seasonality of precipitation and their linkages in the context of climate change are investigated using the Mann-Kendall trend test, Pettitt change-point test and correlation analysis. The investigation focuses on four extreme indices, i.e., the annual maximum number of consecutive dry days (CDD), the annual maximum number of consecutive wet days (CWD), the annual total precipitation when daily precipitation is greater than 95th percentile (R95pTOT), and the maximum 1-day precipitation (RX1day). The results show that precipitation extremes increased in northwestern China, especially Xinjiang, Tibet and Qinghai (CWD, R95pTOT and RX1day), and scattered parts of southeastern China (R95pTOT and RX1day), but decreased over considerable parts of southwestern China (CWD) and some small parts of northern China (CWD, R95pTOT and RX1day); the spatial patterns of the trends in precipitation extremes and that of total precipitation exhibit considerable similarity over China, which indicates the close relationship between changes in precipitation extremes and total precipitation; change points are detected in different periods ranging from early 1970s to early 2000s for different regions and extreme precipitation indices, and the spatial patterns of the abrupt changes of extreme indices are similar to those of the trends in extreme indices; the concentration index (CI) is strongly positively correlated with R95pTOT and RX1day in most areas in northern China (from the northeast to the northwest) and southwestern China (including Sichuan, Chongqing Guizhou and Guangxi), which means for these regions, the temporal heterogeneity of daily precipitation over a year is dominated by heavy rainfall amounts. The seasonality index of precipitation (SI) is positively related to R95pTOT and RX1day over most areas above 30 • N, indicating that heavy precipitation events have a better chance to occur in places with a strong seasonal variation in annual precipitation in these areas, but for most areas below 30 • N, the positive relationship is not significant.

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Section: Methods For Detecting Changes Trend Testmentioning

confidence: 99%

Spatial and Temporal Variations of Precipitation Extremes and Seasonality over China from 1961~2013

Tao

Wang

Song

et al. 2018

Water

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“…To address this concern, the non-parametric Pettitt test was applied to identify the abrupt change point [44]. Pettitt test has been widely applied in detecting abrupt change points in climate factors and hydrologic processes [45][46][47][48][49]. It tests the null hypothesis H 0 : the time series follows the same distribution, against the alternative hypothesis H 1 : before and after time t, the two parts of the time series follow different distribution functions [44].…”

Section: Trend Analysismentioning

confidence: 99%

“…It tests the null hypothesis H 0 : the time series follows the same distribution, against the alternative hypothesis H 1 : before and after time t, the two parts of the time series follow different distribution functions [44]. The change point t represents the point when there is an abrupt jump that partitions the time series into two parts [46,50]. One of the advantages of Pettitt test is that it makes no assumption neither on the form of the distribution nor on the location of change.…”

Section: Trend Analysismentioning

confidence: 99%

Responses of Natural Vegetation Dynamics to Climate Drivers in China from 1982 to 2011

Liu

Lei

2015

Remote Sensing

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This study investigated the spatiotemporal variation of vegetation growth and the influence of climatic drivers from 1982 to 2011 across China using datasets from the Normalized Difference Vegetation Index (NDVI) and climatic drivers. Long term trends, significance and abrupt change points of interannual NDVI time series were analyzed. We applied both simple regression and multi-regression models to quantify the effects of climatic drivers on vegetation growth and compare their relative contributions. Results show that on average, the growing season NDVI significantly increased by 0.0007 year −1 , with 76.5% of the research area showed increasing NDVI from 1982 to 2011. Seasonally, NDVI increased at high rates during the spring and autumn while changed slightly during the summer. At a national scale, the growing season NDVI was significantly and positively correlated to temperature and precipitation, with temperature being the dominant factor. At regional scales, the growing season NDVI was dominated by increasing temperature in most forest-covered areas in southern China and dominated by precipitation in most grassland in northern China. Within the past three decades, the increasing trend of national mean NDVI abruptly changed in 1994, slowing down from 0.0008 year −1 to 0.0003 year −1 . To be regional specific, the growing season NDVI in forest covered southern China has accelerated together with temperature since mid 1990s, while parts of the grassland in northern China have undergone stalled NDVI trends corresponding to slowed temperature increment and dropped precipitation since around 2000. Typical region analysis suggested that apart from

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“…Statistical significance was determined using the Mann-Kendall ranked τ statistic (Tarhule and Woo, 1998). A trend is indicated as 'significant' if it has at least 95% significance using this test.…”

Section: Extreme Intensitymentioning

confidence: 99%

Trends in extreme daily rainfall across the South Pacific and relationship to the South Pacific Convergence Zone

Griffiths

Salinger

Leleu

2003

Intl Journal of Climatology

115

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Daily rainfall records from 22 high-quality stations located in the South Pacific were analysed, over the common period 1961-2000, in order to assess whether extreme rainfall events have altered in their frequency or magnitude. A comprehensive spatial coverage across the South Pacific was provided, analysing a range of indices of extreme precipitation, which reflect both high rainfall events and drought. Clear spatial patterns emerged in the trends of extreme rainfall indices, with a major discontinuity across the diagonal section of the South Pacific Convergence Zone (SPCZ).Stations located between 180 and 155°W exhibit a greater number of significant abrupt changes in extreme climate than elsewhere in the South Pacific, and the majority of climatic jumps occur in the 1970s or 1980s (coincident with a displacement northeastward of the diagonal part of the SPCZ and a large local increase in mean annual temperature). Notably, all significant abrupt changes in an extreme rainfall intensity index occurred in the late 1970s or early 1980s, and in every case the index showed an increase in extremity following the change point, regardless of station location. For the stations located south of the SPCZ, this may also be linked to the observed warming since the 1970s. Significant abrupt changes in mean precipitation were also identified around the mid 1940s, for two longer, century-scale records, which again correspond to a major displacement of the diagonal section of the SPCZ.An indicator of the diagonal SPCZ position is significantly temporally correlated with an extreme rainfall intensity index, at two locations either side of the diagonal section of the SPCZ, at decadal time scales or longer. This suggests that the displacement of the diagonal portion of the SPCZ on decadal time scales influences not only mean precipitation, but also daily rainfall extremes.

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Changes in rainfall characteristics in northern Nigeria

Cited by 100 publications

References 18 publications

Spatial and Temporal Variations of Precipitation Extremes and Seasonality over China from 1961~2013

Spatial and Temporal Variations of Precipitation Extremes and Seasonality over China from 1961~2013

Responses of Natural Vegetation Dynamics to Climate Drivers in China from 1982 to 2011

Trends in extreme daily rainfall across the South Pacific and relationship to the South Pacific Convergence Zone

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