Browsing by Author "Shamsuddin Shahid"
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Item Restricted Changes in reference evapotranspiration and its driving factors in peninsular Malaysia(Elsevier, 2020) Sahar Hadi Pour; Ahmad Khairi Abd Wahab; Shamsuddin Shahid; Zulhilmi Bin IsmailTrends in reference evapotranspiration (ETo) have been found highly diverse in different regions of the globe due to the contradictory changes in the meteorological variables that define ETo. Despite a significant impact of ETo in water resources and ecology, knowledge on the changes and the cause of the changes in ETo is very limited in tropical regions. The trends in ETo, the factors influencing the changes in ETo and the change point (year) that made the trend significant were evaluated in this study for tropical peninsular Malaysia.Item Restricted Correcting bias of satellite rainfall data using physical empirical model(Elsevier, 2021) Ghaith Falah Ziarh; Shamsuddin Shahid; Tarmizi Bin Ismail; Md Asaduzzaman; Ashraf DewanThe provision of high resolution near real-time rainfall data has made satellite rainfall products very potential for monitoring hydrological hazards. However, a major challenge in their direct-use can be problematic due to measurement error. In this study, an attempt was made to correct the bias of Global Satellite Mapping of Precipitation near-real-time (GSMaP_NRT) product. Physical factors, including topography, season, windspeed and cloud types were accounted for correcting bias. Peninsular Malaysia was used as the case study area. Gridded rainfall, developed from 80 gauges for the period 2000-2018, was used along with physical factors in a two-stage procedure.Item Restricted Physical- emipirical models for prediction of seasonal rainfall extremes of Peninsular Malaysia(Elsevier, 2020) Sahar Hadi Pour; Ahmad Khairi Abd Wahab; Shamsuddin ShahidReliable prediction of rainfall extremes is vital for disaster management, particularly in the context of increasing rainfall extremes due to global climate change. Physical-empirical models have been developed in this study using three widely used Machine Learning (ML) methods namely, Support Vector Machines (SVM), Random Forests (RF), Bayesian Artificial Neural Networks (BANN) for the prediction of rainfall and rainfall related extremes during Northeast Monsoon (NEM) in Peninsular Malaysia from synoptic predictors.Item Embargo Prediction of dissolved oxygen, biochemical oxygen demand, and chemical oxygen demand using hydrometeorological variables: case study of Selangor River, Malaysia(Springer, 2020) Sinan Q. Salih; Intisar Alakili; Ufuk Beyaztas; Shamsuddin Shahid; Zaher Mundher YaseenIn this research, three water quality (WQ) indexes, namely dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand (COD), in Selangor River of peninsular Malaysia were simulated using a stochastic model based on vector auto-regression (VAR).Item Restricted Projection of spatial and temporal changes of rainfall in Sarawak of Borneo Island using statistical downscaling of CMIP5 models(Elsevier, 2017) Zulfaqar Sa'adi; Shamsuddin Shahid; Eun-Sung Chung; Tarmizi bin IsmailThis study assesses the possible changes in rainfall patterns of Sarawak in Borneo Island due to climate change through statistical downscaling of General Circulation Models (GCM) projections. Available in-situ observed rainfall data were used to downscale the future rainfall from ensembles of 20 GCMs of Coupled Model Intercomparison Project phase 5 (CMIP5) for four Representative Concentration Pathways (RCP) scenarios, namely, RCP2.6, RCP4.5, RCP6.0 and RCP8.5. Model Output Statistics (MOS) based downscaling models were developed using two data mining approaches known as Random Forest (RF) and Support Vector Machine (SVM).Item Embargo Spatiotemporal changes in Hourly Wet Bulb Globe temperature in Peninsular Malaysia(Springer, 2023) Mohamad Rajab Houmsi; Zulhilmi Ismail; llya Khairanis Othman; Daeng Siti Maimunah Ishak; Mohammed Magdy Hamed; Zafar Iqbal; Deprizon Syamsunur; Shamsuddin ShahidGlobal warming causes a temperature rise and alteration of other meteorological variables that directly or indirectly affect human comfort. The wet bulb globe temperature (WBGT) incorporates the effects of multiple meteorological variables to provide a reliable measure of human thermal stress. Despite the large significance of WBGT on public health, studies related to characterization and trends assessment of WBGT are limited in the tropical humid region like Peninsular Malaysia due to the unavailability of all meteorological variables required for such analysis. This study employed reanalysis meteorological data of ERA5 to assess the characteristics and changes in hourly, daily, monthly, seasonal and annual outdoor WBGT over peninsular Malaysia for the period 1959–2021 using the Liljegren method.Item Open Access Trends analysis of rainfall and rainfall extremes in Sarawak, Malaysia using modified Mann-Kendall test(Springer, 2017) Zulfaqar Sa adi; Shamsuddin Shahid; Tarmizi Ismail; Eun-Sung Chung; Xiao-Jun WangThis study assesses the spatial pattern of changes in rainfall extremes of Sarawak in recent years (1980-2014). The Mann-Kendall (MK) test along with modified Mann-Kendall (m-MK) test, which can discriminate multi-scale variability of unidirectional trend, was used to analyze the changes at 31 stations.