Trends analysis of rainfall and rainfall extremes in Sarawak, Malaysia using modified Mann–Kendall test

Sa’adi, Zulfaqar; Shahid, Shamsuddin; Ismail, Tarmizi; Chung, Eun‐Sung; Wang, Xiao Jun

doi:10.1007/s00703-017-0564-3

Cited by 184 publications

(90 citation statements)

References 61 publications

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“…The secular trends of concurrent extremes are estimated by simple linear regression, and their significances are evaluated by the nonparametric modified Mann-Kendall (mMK) test that considers the autocorrelation in the time series (Hamed and Rao, 1998), and has been widely used in hydrological and climatological studies Lau, 2018, 2019;Sa'adi et al, 2019).…”

Section: Methodsmentioning

confidence: 99%

Changes of concurrent drought and heat extremes in the arid and semi‐arid regions of China during 1961–2014

Luo

2019

Atmospheric Science Letters

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Arid and semi‐arid regions of China (ASRC) are increasingly threatened by drought. Especially when drought and heat extremes coincide, the resultant impact would be even more harmful to human society and the natural environment. This study investigates the spatio‐temporal changes in concurrent drought and heat extremes in ASRC during 1961–2014. Summer heat extremes quantified by hot day (HD), warm night (WN), daytime (DHW), and nighttime heatwave (NHW) are examined. On average, the concurrent nighttime events (concurrent drought‐WN and drought‐NHW) increases by 2.7 times faster than daytime ones (concurrent drought‐HD and drought‐DHW), and they appear more frequently in eastern than western ASRC. We also find that all four types of concurrent events have been significantly increased over the past decades. Compared to daytime (i.e., HD and DHW), the concurrent events at nighttime (i.e., WN and NHW) increased even more rapidly. During the study period, concurrent drought‐DHW (drought‐NHW) climbed up at the rate of 0.03 (0.08) events decade−1 and concurrent drought‐HD (drought‐WN) increased by 0.17 (0.45) days decade−1. Geographically, eastern ASRC exhibited a more pronounced increasing trend than the west. Given the increasing threats of concurrent events, we suggest that more attention should be paid to these compound events in future climate change studies.

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Section: Methodsmentioning

confidence: 99%

Changes of concurrent drought and heat extremes in the arid and semi‐arid regions of China during 1961–2014

Luo

2019

Atmospheric Science Letters

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“…About 95% of its basin is steep mountains terrain rising to a height of 2,135 m [18]. The climate of Kelantan River basin is dominated by two monsoons like other parts of the Malaysia, northeast monsoon (Nov-Mar) and southwest monsoon (May-Sep) [19], [20]. The Kelantan River basin is influenced strongly by the northeast monsoon when most of the average annual rainfall (2,500 mm) occurs [21].…”

Section: Study Area and Datasetsmentioning

confidence: 99%

Flood susceptibility assessment in Kelantan river basin using copula

Nashwan

Ismail

Ahmed

2018

IJET

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Bivariate frequency analysis of flood variables of different station locations of Kelantan river basin was conducted using copula for the assessment of the geographical distribution of flood risk. Seven univariate distribution functions of flood variables were fitted with flood variables such as peak flow, flood volume, and flood duration to find the best-fitted distributions. The joint dependent structures of flood variables were modeled using Gumbel copula. The results of the study revealed that different variables fit with different distributions. The correlation analysis among variables showed a strong association. Joint distribution functions of peak-flow and volume, peak-flow and duration, and volume and duration revealed that the joint return periods were much higher than univariate return periods of same flood variables. The flood risk analysis based on joint return period of flood variables revealed the highest risk of devastating flood in the downstream. The locations identified as highly susceptible to flood risk by joint distributing of flood variables had experienced most severe floods in recent history, which indicates the effectiveness of the method for the analysis of flood risk. It is expected that this procedure can be helpful for better assessment of flood impacts.

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“…The significance of the trend was tested using the Sen's slope method. These methods are widely used for trend estimation, and justification for their use appears in numerous publications [38,39,[90][91][92]. The Mann-Kendall statistic ( ) for a time series 1 , 2 , … , is calculated as,…”

Section: Trend Analysismentioning

confidence: 99%

Trend Dynamics of GRACE Terrestrial Water Storage in the Nile River Basin

Hasan¹,

Tarhule²

2019

Preprint

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GRACE-derived Terrestrial Water Storage Anomalies (TWSA) continue to be used in an expanding array of studies to analyze numerous processes and phenomena related to terrestrial water storage dynamics, including groundwater depletions, lake storage variations, snow, and glacial mass changes, as well as floods, droughts, among others. So far, however, few studies have investigated how the factors that affect total water storage (e.g., precipitation, runoff, soil moisture, evapotranspiration) interact and combine over space and time to produce the mass variations that GRACE detects. This paper is an attempt to fill that gap and stimulate needed research in this area. Using the Nile River Basin as case study, it explicitly analyzes nine hydroclimatic and anthropogenic processes, as well as their relationship to TWS in different climatic zones in the Nile River Basin. The analytic method employed the trends in both the dependent and independent variables applying two geographically multiple regression (GMR) approaches: (i) an unweighted or ordinary least square regression (OLS) model in which the contributions of all variables to TWS variability are deemed equal at all locations; and (ii) a geographically weighted regression (GWR) which assigns a weight to each variable at different locations based on the occurrence of trend clusters, determined by Moran’s cluster index. In both cases, model efficacy was investigated using standard goodness of fit diagnostics. The OLS showed that trends in five variables (i.e., precipitation, runoff, surface water soil moisture, and population density) significantly (p<0.0001) explain the trends in TWSA for the basin at large. However, the models R2 value is only 0.14. In contrast, the GWR produced R2 values ranging between 0.40 and 0.89, with an average of 0.86 and normally distributed standard residuals. The models retained in the GWR differ by climatic zone. The results showed that all nine variables contribute significantly to the trend in TWS in the Tropical region; population density is an important contributor to TWSA variability in all zones; ET and Population density are the only significant variables in the semiarid zone. This type of information is critical for developing robust statistical models for reconstructing time series of proxy GRACE anomalies that predate the launch of the GRACE mission and for gap-filling between GRACE and GRACE-FO.

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Trends analysis of rainfall and rainfall extremes in Sarawak, Malaysia using modified Mann–Kendall test

Cited by 184 publications

References 61 publications

Changes of concurrent drought and heat extremes in the arid and semi‐arid regions of China during 1961–2014

Changes of concurrent drought and heat extremes in the arid and semi‐arid regions of China during 1961–2014

Flood susceptibility assessment in Kelantan river basin using copula

Trend Dynamics of GRACE Terrestrial Water Storage in the Nile River Basin

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