Forced and Internal Variability of Tropical Cyclone Track Density in the Western North Pacific*

Abstract

Forced interannual-to-decadal variability of annual tropical cyclone (TC) track density in the western North Pacific between 1979 and 2008 is studied using TC tracks from observations and simulations by a 25-km-resolution version of the GFDL High-Resolution Atmospheric Model (HiRAM) that is forced by observed sea surface temperatures (SSTs). Two modes dominate the decadal variability: a nearly basinwide mode, and a dipole mode between the subtropics and lower latitudes. The former mode links to variations in TC number and is forced by SST variations over the off-equatorial tropical central North Pacific, whereas the latter might be associated with the Atlantic multidecadal oscillation. The interannual variability is also controlled by two modes: a basinwide mode driven by SST anomalies of opposite signs located in the tropical central Pacific and eastern Indian Ocean, and a southeast-northwest dipole mode connected to the conventional eastern Pacific ENSO. The seasonal evolution of the ENSO effect on TC activity is further explored via a joint empirical orthogonal function analysis using TC track density of consecutive seasons, and the analysis reveals that two types of ENSO are at work. Internal variability in TC track density is then examined using ensemble simulations from both HiRAM and a regional atmospheric model. It exhibits prominent spatial and seasonal patterns, and it is particularly strong in the South China Sea and along the coast of East Asia. This makes an accurate prediction and projection of TC landfall extremely challenging in these regions. In contrast, basin-integrated metrics (e.g., total TC counts and TC days) are more predictable.

Indo-western Pacific ocean capacitor and coherent climate anomalies in post-ENSO summer: A review

“…Extra predictability might be achieved by improving the simulation of the Mei-yu rain band in light of the im- portance of midlatitude latent heating for the PJ pattern (Lu and Lin, 2009). Prediction systems with a high-resolution (50 km or finer grid spacing) atmospheric model component hold the promise of predicting TC track density and even landfall probability at seasonal leads Mei et al, 2015).…”

“…5d; Wang et al, 2013). These TC anomalies are captured in highresolution AGCM simulations, pointing to the importance of SST boundary conditions (Mei et al, 2015). Using a regional atmospheric model, Zhan et al (2011) showed that eastern IO SST anomalies affect TC genesis over the TNW Pacific by modulating the western Pacific summer monsoon via the equatorial Kelvin wave.…”

Climatological analysis of passage-type tropical cyclones from the Western North Pacific into the South China Sea

“…TC activity characteristics are generally examined in terms of three aspects: count, formation location, and track (e.g., Mei et al 2015). These three aspects of passage-type TCs are examined for the major TC season.…”

Climatological Relationship between Warm Season Atmospheric Rivers and Heavy Rainfall over East Asia

“…Moreover, the rainbearing East Asian summer monsoon (e.g., Ninomiya and Murakami 1987;Tao and Chen 1987;Ninomiya and Akiyama 1992;Sampe and Xie 2010) exhibits substantial seasonal-interannual variability because of the influence of both tropical forcing (e.g., the El Niño Southern Oscillation; ENSO) and extratropical atmospheric circulation (e.g., mid-latitude atmospheric teleconnections; Wu and Wang 2002;Ding et al 2011;Kosaka et al 2012;He et al 2017;and references therein). In addition to typhoons from the northwestern Pacific (e.g., Mei et al 2015;Mei and Xie 2016), a quasi-stationary Meiyu-Baiu rainband that extends from southeast China to Japan from June to mid-July is critically important for water resources and natural disasters in the regions.…”

“…Moreover, the rainbearing East Asian summer monsoon (e.g., Ninomiya and Murakami 1987; Tao and Chen 1987;Ninomiya and Akiyama 1992; Sampe and Xie 2010) exhibits substantial seasonal-interannual variability because of the influence of both tropical forcing (e.g., the El Niño Southern Oscillation; ENSO) and extratropical atmospheric circulation (e.g., mid-latitude atmospheric teleconnections; Wu and Wang 2002;Ding et al 2011;Kosaka et al 2012; He et al 2017; and references therein). In addition to typhoons from the northwestern Pacific (e.g., Mei et al 2015;Mei and Xie 2016), a quasi-stationary Meiyu-Baiu rainband that extends from southeast China to Japan from June to mid-July is critically important for water resources and natural disasters in the regions.Tropical climate variability, such as ENSO, strongly affects the interannual variability of the East Asian summer monsoon through the tropical western North Pacific (TWNP) anticyclone and references therein). K17 found that the interannual variability of summertime AR occurrence over the northwestern Pacific is largely controlled by the preceding-winter ENSO through the Indo-western Pacific ocean capacitor (IPOC) effect (e.g., Xie et al 2009Xie et al , 2016.…”