In consideration of the distinct behavior of machine learning (ML) algorithms, six well-defined ML used were carried out in this study for predicting sea level on a day-to-day basis. Data compiled from 1985 to 2018 was utilized for training and testing the developed models. An assessment of the multiple statistics-driven regression algorithms resulted such that each tested location was associated with a particular preferred model. The following were the developed best models for their respective study areas: In Peninsular Malaysia, the interactions linear regression model was the best at Pulau Langkawi (RMSE = 19.066), the Matern 5/2 gaussian process regression model at Geting (RMSE = 49.891), and the trilayered artificial neural network at Pulau Pinang (RMSE = 20.026), while the linear regression model was the best at Sandakan in Sabah, East Malaysia (RMSE = 14.054). Other metrics, such as MAE and R-square, were also at their best values, each providing its best values, further substantiating the RMSE respectively, at each of the study areas. These empirical statistics (or metrics) also revealed that despite employing sea level as the sole parameter, results obtained were exceptional better when utilizing a 7-day lag, regardless of the model used. Notably, lag variables with less than a 7-day lag could degrade the model's accuracy in representing ground reality. The study emphasizes the importance of thorough training and testing of ML to aid decision-makers in developing mitigation actions for the climate change phenomena of sea level rise through reliable ML.

Climate change is a complex and multi-layer issue with global and local entanglement. In this study, Langat River Basin is chosen. Secondary data was used including the historical flood and drought event reports, Standardized Precipitation Index-1 data and Canadian Earth System Model (CanESM2) along with Australian Community Climate and Earth System Simulator Coupled Model (ACCESS CM-2). These data were used to determine the monthly flood and drought precipitation risk based on five regions of Langat River Basin. The CanESM2 and ACCESS CM-2 based on RCP 4.5 and RCP 8.5 scenarios were downscaled and bias corrected for this study. The reliability of these models was then analyzed with Pearson correlation and probability density function (PDF). The future flood and drought risks from year 2020 to 2100 were predicted using the most reliable local climate model local climate hazard thresholds. The CanESM2 RCP 4.5 scenario was identified to have moderate relationship with the historical precipitation trend in Langat River Basin. The Pearson correlation outcomes were then verified by analyzing the PDF curve between models and historical precipitation. The result shows that the downscaled CanESM2 RCP 4.5 was determined to have moderate correlation r = 0.30, whereas highest similarity with the historical precipitation trend 98.63 % based on 2006 to 2018 period. The scenario is consistent with medium emission coupled with increasing mitigation efforts in Malaysia. Furthermore, the flood and drought risk assessment outcomes show that the occurrence rate for Central, Northern, Southern, Western, and Eastern region in Langat River Basin were determined as 41.97 %, 60.19 %, 40.23 %, 20.16 %, and 34.98% respectively. The Central region was predicted having two drought incidences (February 2069 and February 2099) due to extreme dry season predicted based on 2020 to 2100 period.

Kit Fai FUNG, Yuk Feng HUANG, Chai Hoon KOO & Kok Weng TAN - STANDARDIZED PRECIPITATION INDEX (SPI) AND STANDARDIZED PRECIPITATION EVAPOTRANSPIRATION INDEX (SPEI) DROUGHT CHARACTERISTIC AND TREND ANALYSIS USING THE SECOND GENERATION CANADIAN EARTH SYSTEM MODEL (CanESM2) OUTPUTS UNDER REPRESENTATIVE CONCENTRATION PATHWAY (RCP) 8.5, Carpathian Journal of Earth and Environmental Sciences, August 2019, Vol. 14, No. 2, p. 399 - 408; DOI:10.26471/cjees/2019/014/089

Climate change is unambiguous as there is much evidence from around the world showing that changes have already occurred. This phenomenon is in response to an array of human activities, notably the release of greenhouse gases; an understanding of the rate, mode and scale of this change is now of literally vital importance to society. Researchers utilize climate models to study the dynamics of our changing climate and also to make future projections. Climate models are basic representation of many interactions within the Earth’s climate which includes the atmosphere, land surface, oceans and ice. These models are typically quantitative in nature and range from simple depictions of the climate to very complex ones. In this present study, downscaled PRECIS regional climate models (RCMs) were used to project the average minimum and average maximum temperatures and average precipitation for Penang, Selangor and Johor in Peninsular Malaysia. The RCM projections for these three states were developed based on ECHAM4 A2 and ECHAM5 A1B scenarios for the years 1980 to 2069 and ECHAM4 B2 scenario for the years 2010 to 2069. Bias correction will be applied to the simulated historical data to remove common systematic model errors. Historical observation data of monthly average minimum and maximum temperatures and monthly average rainfall from the Malaysian Meteorological Department (MMD) will be used in the bias correction. Finally, a RCM scenario which matches with the historical observation data of the three states for future projections will be recommended.