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The final published version of this manuscript will replace the preliminary version at the above DOI once it is available.If you would like to cite this EOR in a separate work, please use the following full citation:Villafuerte II, M., and J. Matsumoto, 2014: Significant influences of global mean temperature and ENSO on extreme rainfall in Southeast Asia. J. Climate.ABSTRACT 1 This study investigates the changes in annual and seasonal maximum daily rainfall 2 (RX1day) in Southeast Asia, obtained from gauge-based gridded precipitation data, to 3 address the increasing concerns about climate change in the region. First, the nonparametric 4 Mann-Kendall test was employed to detect significant trends in RX1day. Then, maximum 5 likelihood modeling, which allows the incorporation of covariates in the location parameter 6 of the generalized extreme value (GEV) distribution, was conducted to determine whether the 7 rising global mean temperature, as well as the El Niño-Southern Oscillation (ENSO), are 8 influencing extreme rainfall over the region. The findings revealed that annual and seasonal 9 RX1day is significantly increasing in the Indochina Peninsula and east-central Philippines 10 while decreasing in most parts of the Maritime Continent during the past 57 years (1951-11 2007). The trends in RX1day were further linked to the rising global mean temperature. It 12 was shown that the location parameter of the GEV, and hence the RX1day on average, has 13 significantly co-varied with the annually averaged near-surface global mean temperature 14 anomaly. Such co-variation is pronouncedly observed over the regions where significant 15 trends in RX1day were detected. Furthermore, the results demonstrated that as ENSO 16 develops in July-September, negative co-variations between the location parameter of the 17 GEV and the ENSO index, implying more (less) likelihood of extreme rainfall during La 18 Niña (El Niño), were observed over the Maritime Continent. Such conditions progress 19 northward to the regions of Indochina Peninsula and the Philippines as the ENSO approaches 20 its maturity in October-December, and then retreat southward as the ENSO weakens in the 21 ensuing seasons.22 23 25 19 latitudinal variations, where the greatest rate of change (exceeding 15% K -1 ) that occurred at 20 the latitudinal band between 6°S and 3°N. 21 While the global mean temperature has been proven to influence extreme precipitation, a 22 number of studies have also demonstrated the considerable influence of large-scale 23 circulation patterns on precipitation extremes. For instance, Zhang et al. (2010) found that the 24 El Niño-Southern Oscillation (ENSO) significantly influences the winter season maximum 25 3 daily precipitation over North America. They showed that El Niño conditions are associated 1 with an increased (decreased) likelihood of extreme precipitation over southern (northern) 2 North America. Separate studies have also shown that the influence of ENSO on extreme 3 precipitation extends to several regions across the globe,...

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Climatological seasonal changes of rainfall and lower tropospheric circulation in and around the Philippines are analysed by utilizing the TRMM 3B42 to obtain the 5‐day mean rainfall and ERA‐Interim wind data for the period 1998–2013. In particular, climatological onset and withdrawal processes of the southwest (SW) and northeast (NE) monsoon are investigated. It is found that the onset of the SW monsoon occurs abruptly in mid‐May almost simultaneously over the Philippines except in the southern region. The start of the SW monsoon in the Philippines occurs earlier in the north than in the south. In addition, a climatological increase in rainfall on the west coast precedes the SW monsoon arrival by approximately two pentads, due to tropical cyclone influences in some years. After the SW monsoon onset, the monsoon trough is located over the southern Philippines. In mid‐June, the monsoon trough begins to deepen, and migrates northward to the central Philippines, and easterly winds intrude shortly to the northern Philippines. Then, the entire Philippines is covered by the summer monsoon westerly in early July, which is followed by the rainfall peak over the west coast region occurring in early August. The SW monsoon begins to retreat from the north in mid‐September, and fully retreats from the Philippines rather suddenly in late September. In general, the rainfall amount in the west coastal region remains high for approximately 2 months after this wind reversal, showing relatively larger post monsoon rainfall due mainly to tropical cyclone effects. During the NE monsoon season, the rainfall centre in the east coast is located in the northern and central region until mid‐December. Afterwards it is anchored in the southern region from late December to mid‐March, indicating the fully established NE monsoon season.

Southeast Asia is a major rice-producing region with a high level of internal consumption and accounting for 40% of global rice exports. Limited land resources, climate change and yield stagnation during recent years have once again raised concerns about the capacity of the region to remain as a large net exporter. Here we use a modelling approach to map rice yield gaps and assess production potential and net exports by 2040. We find that the average yield gap represents 48% of the yield potential estimate for the region, but there are substantial differences among countries. Exploitable yield gaps are relatively large in Cambodia, Myanmar, Philippines and Thailand but comparably smaller in Indonesia and Vietnam. Continuation of current yield trends will not allow Indonesia and Philippines to meet their domestic rice demand. In contrast, closing the exploitable yield gap by half would drastically reduce the need for rice imports with an aggregated annual rice surplus of 54 million tons available for export. Our study provides insights for increasing regional production on existing cropland by narrowing existing yield gaps.