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The 2021-2022 flood is one of the most serious flood events in Malaysian history, with approximately 70,000 victims evacuated daily, 54 killed and total losses were up to MYR 6.1 billion. From this devastating event, we realized the lack of extreme precipitation and flood inundation information, which is a common problem in tropical regions. Therefore, we have developed Flood-Tropical framework to provide a rapid extreme precipitation information and flood inundation mapping by utilizing (1) a cloud-computing platform, the Google Earth Engine (GEE); (2) open-sources satellite images such as Global Precipitation Mission (GPM), Sentinel-1 SAR and Sentinel-2 optical; and (3) flood victim information. The preliminary results on the 2021-2022 Malaysia flood were satisfactory, as the accuracy of inundated floods was up to 70%. Overall, two precipitation peaks resulted 60000 to 70000 people mostly in Selangor and Pahang evacuated on 21 – 24 December 2021, and 10000 to 15000 people from southern Peninsular evacuated on 2 – 6 Jan 2022. Extreme daily precipitation of up to 230 mm/day was observed and resulted in an inundated area of 77.43 km² in Peninsular Malaysia. This framework can act as a useful tool for local authorities to visualize extreme precipitation and floods for rescue planning and flood management.

Kajian ini bertujuan memahami klimatologi kitaran hujan diurnal dan mekanismanya di Semenanjung Malaysia berdasarkan analisis data cerapan. Analisis jumlah, kekerapan dan keamatan hujan diurnal memperlihatkan 4 peristiwa hujan diurnal yang utama, iaitu: kejadian hujan petang maksimum semasa musim peralihan monsun di kaki bukit Banjaran Titiwangsa adalah lebat dan sering berlaku; kejadian hujan sepanjang hari di pantai timur semenanjung (subrantauan PT) semasa monsun timur laut adalah lebat dan sering berlaku; kejadian hujan pada pagi di lembah-pedalaman semenanjung (sub-rantauan LP) semasa monsun timur laut adalah rendah walaupun hujan lebat sering berlaku pada petangnya; dan kejadian hujan pagi maksimum di pantai barat semenanjung (sub-rantauan PB) semasa Jun-Julai-OgosSeptember-Oktober-November (JJOSON) merupakan kejadian hujan yang melampau namun kekerapannya adalah rendah. Di sub-rantauan PB, kelajuan angin permukaan yang kuat berbanding lemah pada aras troposfera yang lebih tinggi semasa musim peralihan monsun menyebabkan ricih angin bergerak ke atas. Sebaliknya, kombinasi angin monsun dan bayu laut semasa monsun barat daya menyebabkan ricih angin bergerak ke troposfera bawah. Semasa monsun timur laut, luluran angin sejuk dan bayu laut menyebabkan kelajuan angin adalah kuat pada permukaan sehingga ke aras 2 km tinggi di timur semenanjung. Ini menyebabkan zon perolakan yang tertumpu di sub-rantauan PT pada pagi meluas sehingga ke sub-rantauan LP pada waktu petang.

Ocean–atmosphere modes of climate variability in the Pacific and Indian oceans, as well as monsoons, regulate the regional wet and dry episodes in tropical regions. However, how those modes of climate variability, and their interactions, lead to spatial differences in drought patterns over tropical Asia at seasonal to interannual time scales remains unclear. This study aims to analyse the hydroclimate processes for both short- and long-term spatial drought patterns (3-, 6, 12- and 24-months) over Peninsular Malaysia using the Standardized Precipitation Index, Standardized Precipitation Evapotranspiration Index, and Palmer Drought Severity Index. Besides that, a generalized least squares regression is used to explore underlying circulation mechanisms of these spatio-temporal drought patterns. The tested drought indices indicate a tendency towards wetter conditions over Peninsular Malaysia. Based on principal component analysis, distinct spatio-temporal drought patterns are revealed, suggesting North–South and East–West gradients in drought distribution. The Pacific El Nino Southern Oscillation (ENSO), the South Western Indian Ocean (SWIO) variability, and the quasi-biennial oscillation (QBO) are significant contributors to the observed spatio-temporal variability in drought. Both the ENSO and the SWIO modulate the North–South gradient in drought conditions over Peninsular Malaysia, while the QBO contributes more to the East–West gradient. Through modulating regional moisture fluxes, the warm phases of the ENSO and the SWIO, and the western phases of the QBO weaken the southwest and northeast monsoon, leading to precipitation deficits and droughts over Peninsular Malaysia. The East–West or North–South gradients in droughts are related to the middle mountains blocking southwest and northeast moisture fluxes towards Peninsular Malaysia. In addition, the ENSO and QBO variations are significantly leading to short-term droughts (less than a year), while the SWIO is significantly associated with longer-duration droughts (2 years or more). Overall, this work demonstrates how spatio-temporal drought patterns in tropical regions are related to monsoons and moisture transports affected by the oscillations over the Pacific and Indian oceans, which is important for national water risk management.

One of the efforts to control the forest and land fire disasters which affect on the biomass burning haze is fire hotspots monitoring. Biomass burning haze in Southeast Asia (SEA) has become a recurring annual issue. This study aims to determine the spatial and temporal distribution of fire hotspots along SEA, so that it can serve as guidance for efforts to control them. The hotspot data used is derived from NASA’s Fire Information for Resource Management System (FIRMS) MODIS sensors which is collected from 2001-2020. Spatial analysis of the re-gridded data shows the highest burning activities over SEA occurred in Feb-Apr, with >2000 fire events in the Indo-China area and >1000 fire events in Sumatra and Borneo. Empirical Orthogonal Function (EOF) was performed on monthly total hotspot data for 228 months for determining dominant patterns spatially and temporally. Based on the EOF analysis results, the three major modes have achieved a total variance of 71 %. The first mode (EOF1) explains 65 % of the total variance. The second (EOF2) and third (EOF3) modes account for 3.60 % and 2.97 % of the total variance respectively. The first and the third principal component identified high loadings over the Indo-China and Sumatra-Borneo regions respectively. Whereas the second principal component separates the fire areas into China and Indo-China region. Inter-annual pattern is dominant in the EOF1, while the inter-seasonal pattern is dominant in EOF2 and EOF3. ENSO, IOD, and MJO are factors that influence the pattern of the determined principal components. The result of this study provides general understanding on how the fire events varied over the past two decades in SEA.