El Niño Impacts on Precipitation in the Western North Pacific–East Asian Sector

Abstract

In this study, the western North Pacific–East Asian (WNP–EA) rainfall anomaly induced by the strong El Niño in 1982–83, 1991–92, and 1997–98, and its association with the mean state, are examined. Over the northern part of the WNP–EA region (north of 20°N), which is dominated by southwest–northeast tilting frontal systems, positive rainfall anomalies from the fall before the El Niño peak phase (year 0) to the first wet period after the peak phase (year 1) are affected by low- and midlevel horizontal moisture convergence anomalies induced by low-level anticyclonic circulation anomalies over the WNP region that are associated with El Niño. Over the southern part of the WNP–EA region (south of 20°N), which is dominated by tropical convection, positive precipitation anomalies in the first and second wet periods of year 0 and negative precipitation anomalies from the fall of year 0 to the second wet period of year 1 are associated with the variation of the net energy into the atmosphere, which is mainly contributed to by local evaporation anomalies. The mechanisms for inducing the precipitation anomalies over both northern and southern parts of the WNP–EA region are similar to the mechanisms of the mean precipitation in each rainy period, but the detailed processes for the southern WNP–EA precipitation anomalies are more complicated, particularly in summer. In the first wet periods of years 0 and 1 and the fall of year 0, the precipitation anomalies are induced by evaporation anomalies that are contributed to by similar effects of sea surface temperature (SST) and wind speed anomalies. In the second wet period of years 0 and 1, on the other hand, near-surface wind speed anomalies affect precipitation via the process of evaporation. These wind speed anomalies are associated with the concurrence of the low-level circulation anomalies over the WNP region and the Asian summer monsoon trough. The SST anomalies are merely a response to evaporation and downward solar radiation anomalies. The dependence of the rainfall anomalies on the mean state, that is, similar causes for the rainfall mean and anomalies in each rainy period, implies that the mean state plays a key role in simulating the interannual variation over the WNP–EA region.

The Climate of the MIS-13 Interglacial according to HadCM3

“…This result is an increase in precipitation over the whole EASM region in this model experiment. Circulation anomalies in the Philippine Sea tend to appear in conjunction with changes to the Pacific SSTs, affecting precipitation rates in East Asia (e.g., Wang et al 2000;Watanabe and Jin 2002;Chou et al 2009). The Philippine Sea anticyclonic anomaly (Fig.…”

Occurrence and biological characteristics of glass eels of the Japanese eel Anguilla japonica at the Cagayan River of Luzon Island, Philippines in 2009

“…It can therefore be proposed that the recent climatic change might have caused the spawning sites of A. japonica to be frequently shifted southward, and subsequently, the glass eel recruitment along the Kuroshio decreased, while the numbers entering southern areas such as northern Luzon Island may have increased. Global atmospheric changes that have caused frequent El Niño events reduced precipitation in the tropical region (Chou et al 2009). The salinity front that is a landmark to determine the spawning site of Japanese eels in the North Equatorial Current (Aoyama et al 2014) then moved southward due to a reduction of the low-salinity water supply by rainfall to the ocean surface.…”

Seasonal to Interannual Variability of Satellite-Based Precipitation Estimates in the Pacific Ocean Associated with ENSO from 1998 to 2014

“…Advances in remote sensing have provided us with long-term and globally complete satellite-gauge-merged precipitation products and satellite-based estimates, such as the Global Precipitation Climatology Project (GPCP) [8], the Climate Prediction Center Merged Analysis of Precipitation (CMAP) [9], and the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) [10]. Many studies have investigated the impacts of ENSO on precipitation using these satellite-based precipitation datasets [11][12][13][14][15][16]. For example, Dai and Wigley [11] and Haddad et al [14] derived the global climatology and variability of ENSO-induced precipitation using the CMAP and TRMM datasets, respectively, and found that ENSO is the major driver of the interannual variability of global rainfall.…”

“…For example, SST anomalies, which are the expression of ENSO events and the response to evaporation and downward solar radiation, are generally observed positively correlated with precipitation in the tropics [15,23,24]. Precipitation variability is also generally proportional to wind speed variability associated with ENSO; high wind speeds are associated with higher evaporation and latent heat flux from the ocean to the atmosphere [15,25].…”

“…For example, SST anomalies, which are the expression of ENSO events and the response to evaporation and downward solar radiation, are generally observed positively correlated with precipitation in the tropics [15,23,24]. Precipitation variability is also generally proportional to wind speed variability associated with ENSO; high wind speeds are associated with higher evaporation and latent heat flux from the ocean to the atmosphere [15,25]. Recent studies have also reported that El Niño events can be divided into two types based on the area where the largest September-February SST anomaly occurs: central Pacific (CP) El Niño (i.e., El Niño Modoki), and eastern Pacific (EP) El Niño (i.e., traditional El Niño) [26][27][28].…”