Relationship between Sea Surface Temperature and Rainfall in the Philippines during the Asian Summer Monsoon

Abstract

We offer a new perspective on a relationship between sea surface temperature (SST) over the windward region of the Philippines and rainfall in the western Philippines during the Asian summer monsoon season, which has been known as the negative correlation, using observational daily SST, rainfall, and atmospheric circulation datasets. This study focuses on the local SST effect rather than the remote effect. A warmer local SST results in greater rainfall over the western Philippines under similar monsoon westerlies conditions, particularly during moderate and relatively stronger monsoon regimes. This result is obtained after selecting only the moderate or relatively stronger monsoon days, because the positive effect of SST on rainfall is masked by the apparent negative correlation between SST and rainfall. The warmer SSTs being associated with less rainfall correspond to weaker cooling by weaker monsoon westerlies and the cooler SSTs being associated with more rainfall correspond to stronger cooling by stronger monsoon westerlies. The cooler SSTs are the result of stronger monsoon cooling and are not the cause of the greater rainfall, which is the apparent statistical relationship. This also implies that the monsoon westerly is the primary driver of the variation in rainfall in this region. We conclude that the local SST makes a positive contribution toward rainfall, although it does not primarily control rainfall. This conclusion can be applicable to coastal regions where, climatologically, rainfall is controlled by winds from the ocean.

Variability in vertical structure of precipitation with sea surface temperature over the Arabian Sea and the Bay of Bengal as inferred by Tropical Rainfall Measuring Mission precipitation radar measurements

“…Recent studies (Wang et al, 2005;Rajeevan et al, 2012;Chaudhari et al, 2013Chaudhari et al, , 2016Weller et al, 2016;Feng et al, 2018) have shown that the simulation of the ISM can be improved with the exact representation of the SST-precipitation relationship. SST modulates the meteorological factors that influence the formation and evolution of different kinds of precipitating systems over tropical oceans (Gadgil et al, 1984;Schumacher and Houze, 2003;Takayabu et al, 2010;Oueslati and Bellon, 2015).…”

Potential influence of sea surface temperature representation in climate model simulations over CORDEX‐SEA domain

“…However, during JJA, climate variables with low correlation with SST have better correlation with observation. This implies that SST has a more direct statistical relationship with rainfall, for example, during DJF than JJA where the Asian summer monsoon has a direct effect (Ueda, 2005; Dado and Takahashi, 2017; Takahashi and Dado, 2018). Also, temperature, rainfall, and wind speed are adequately simulated by models over regions of SWM influence (i.e., WEST‐basin) where SST seasonal variability is captured well.…”

“…During JJA (Figure 9), the weak negative correlation between model SST and RegCM precipitation is different from the weak positive correlation found between model SST and GCMs. This implies that weak correlation and difference in sign are associated with other factors, such as SWM, the dominant climate driver during this season (Ueda, 2005; Dado and Takahashi, 2017; Takahashi and Dado, 2018). While downscaled simulations give better simulation of monsoon‐related seasonal contrasts, RegCM simulations are still affected by poor representation from GCM simulations, which provide the boundary conditions to RegCM.…”

“…Conversely, SSTs and precipitation are connected through monsoonal activity. Monsoons act as dominant driver over the region, causing heavy rainfall and ocean surface cooling (Meehl, 1994; Chang et al ., 2000; Wang et al ., 2004; Johnson and Xie, 2010; Xie et al ., 2010; Roxy and Tanimoto, 2012; Roxy, 2014; Nguyen‐Le et al ., 2015; Dado and Takahashi, 2017; Ngo‐Thanh et al ., 2018; Takahashi and Dado, 2018). Furthermore, land‐sea contrasts related with SST changes are known to affect climate (Meehl, 1994; Li and Yanai, 1996; Joshi et al ., 2008; Tyrrell et al ., 2015; Wallace and Joshi, 2018).…”

Long‐term trends in snowfall characteristics and extremes in Japan from 1961 to 2012

“…In turn, the SAT warming induces an increase in precipitation and a decrease in R ( s / p ) when the environmental SAT condition is close to the threshold value between snowfall and rainfall. Although monthly and seasonal observational data analyses indicated that SST had a weak impact on precipitation, some studies have suggested a positive contribution of SST to precipitation on intra‐seasonal time‐scales even under vigorous air‐sea interaction environments (Takahashi and Idenaga, 2013; Takahashi and Dado, 2018). Nevertheless, quantitative evaluations are ongoing.…”