Significant Influences of Global Mean Temperature and ENSO on Extreme Rainfall in Southeast Asia

Abstract

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,...

Maritime continent coastlines controlling Earth’s climate

“…These results are essentially consistent with independent similar studies by Qian (2008) and Qian et al (2013). Decadal or longer-scale rainfall trends (e.g., Endo et al 2009;Villafuerte and Matsumoto 2015) should also appear through amplitude modulations of the diurnal cycles associated with variations of SST and moisture transport.…”

Simulation of Present Climate over Southeast Asia Using the Non-Hydrostatic Regional Climate Model

“…For example, the model evaluation is done relative to APHRODITE, which has its own limitations, especially for areas with high terrain and in the equatorial region (Yatagai et al 2012;Kieu-Thi et al 2016). However, this dataset shows comparable rainfall characteristics as indicated in station data in Southeast Asia, e.g., in the extreme rainfall trends (Villafuerte and Matsumoto 2015). While drivers of the seasonal rainfall in the region have been identified in the discussion, further study is required to determine which of these processes may not have been adequately represented in the model that contributes to the model biases.…”

Potential impact of sea surface temperature on rainfall over the western Philippines

“…Large-scale oceanic impacts, including El Niño-Southern Oscillation (ENSO, Lyon and Camargo 2009;Villafuerte and Matsumoto 2015), have been examined in many studies. However, the impact of local sea surface temperature (SST) on the country is not well understood.…”