Tropical and Mid-latitude 45-Day Perturbations over the Western Pacific During the Northern Summer

Kawamura, Ryuichi; Murakami, Takio; Wang, Bin

doi:10.2151/jmsj1965.74.6_867

Cited by 88 publications

(79 citation statements)

References 44 publications

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“…Thus, the vertical structure of the PJ is characterized by the transition from a baroclinic structure in the vicinity of anomalous convective forcing to an equivalent barotropic structure along the mid-latitude westerlies over the North Pacific. Such a vertical structure is very similar to that of the MJO-related PJ pattern examined by Kawamura et al (1996). According to their study, the anomalous cyclonic circulation around the Aleutian Islands, initially originated by the PJ, can further develop due to the barotropic interaction between the mid-latitude westerlies and intraseasonal disturbances.…”

Section: Resultssupporting

confidence: 74%

“…To validate whether the typhoon-related PJ pattern is a stationary Rossby wave teleconnection, the wave activity flux, defined by Takaya and Nakamura (2001), is calculated for the anomalous stream function field at the 850-hPa level because the wavetrain pattern of the PJ is evident along a low-level westerly duct that is established by a combination of mid-latitude westerlies and monsoon westerlies (Kawamura et al 1996). Figure 3 reveals the composite maps of the 850-hPa stream function anomalies and wave activity flux from day 2 to day +3 along with 200-hPa stream function anomalies.…”

Section: Resultsmentioning

confidence: 99%

“…Previous studies have shown that the tropical Madden-Julian oscillation (MJO), which is of convective origin, systematically propagates northward or northwestward in the western North Pacific summer monsoon region (e.g., Wang and Rui 1990;Kawamura et al 1996;Tsou et al 2005). Kawamura et al (1996) postulated that while the MJO is migrating northward, MJO-related convective forcing excites a barotropic Rossby wave train extending to the central North Pacific approximately along the great circle. Fukutomi and Yasunari (1999) also showed an extratropical wave train with a 10 25 day scale emanating out of the South China Sea.…”

Section: Introductionmentioning

confidence: 99%

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On the Role of Typhoons in Generating PJ Teleconnection Patterns over the Western North Pacific in Late Summer

Kawamura

Ogasawara

2006

SOLA

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Section: Resultssupporting

confidence: 74%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Role of Typhoons in Generating PJ Teleconnection Patterns over the Western North Pacific in Late Summer

Kawamura

Ogasawara

2006

SOLA

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“…These researchers demonstrated that the observed precipitation and convective activity increase considerably in the wintertime East Asia region when the center of convection associated with the MJO is located over the tropical Indian Ocean, while they decrease when the center is located over the western Pacific. Kawamura et al (1996) showed that the MJO-related convective forcing excites a barotropic Rossby wave train extending to the central North Pacific that is approximately along the great circle. Jeong et al (2008) suggested that the relationship between the MJO phase and precipitation anomaly can be explained by the strong vertical motion anomalies that occur near the entrance region of the East Asian uppertropospheric jet and the moisture supply in the lower troposphere.…”

Section: Introductionmentioning

confidence: 99%

The Madden-Julian Oscillation and Extratropical Teleconnection over East Asia during the Northern Winter in IPCC AR4 Climate Models

Takahashi

Yoneyama

Sato

et al. 2012

Journal of the Meteorological Society of Japan

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The reproducibility of the extratropical teleconnection in East Asia associated with the Madden-Julian Oscillation (MJO) during the boreal winter is evaluated in the 20 th century experiment (20C3M) outputs from 16 global climate models participating in the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4). It is revealed that five of the models (BEST models) realistically simulate the MJOextratropical convection teleconnection. These models successfully represent the MJO convective signals better than the other models. Through analysis of the wave activity flux and Rossby wave source (RWS), the upper-level extratropical wave train induced by MJO convection is demonstrated to propagate northeastward along the Asian jet with its reinforcement, which eventually a¤ects the convective variability in East Asia. The BEST models pronouncedly reproduce the extratropical wave train and RWS. However, the other models produce unrealisCorresponding author: Chiharu Takahashi, Research Institute for Global Change, Japan Agency for MarineEarth Science and Technology, 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan. E-mail: takachi@jamstec.go.jp 6 2012, Meteorological Society of Japan tic or no extratropical wave trains due to unrealistically produced RWSs, although all models realistically exhibit the climatological absolute vorticity over the Asian jet as a waveguide. Furthermore, only the BEST models reproduce the low-level moisture transport with southerlies from the tropics into East Asia, which are associated with realistically reproduced anticyclonic circulation over the North Pacific, that is largely formed as a Rossbywave response to the cooling anomaly with meaningful suppressed convection over tropical western and central Pacific. In summary, correctly simulating the intensity of the MJO convection and its eastward propagation into the Pacific is necessary in order to predict the wintertime climate variability over East Asia.

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“…Guan and Yamagata (2003) postulated that this Rossby wave-train was mainly responsible for the occurrence of the extreme hot summer of 1994. The third pattern, which emanates out of the vicinity of the Philippine Sea, and propagates northeastward along the low-level monsoon westerlies and mid-latitude westerlies, is well known as the Pacific-Japan (PJ) pattern (e.g., Nitta 1987;Kurihara and Tsuyuki 1987;Kawamura et al 1996;Kosaka and Nakamura 2006). The PJ pattern also has potential to cause extraordinary summers in Korea and Japan (e.g., Kawamura et al 1998Kawamura et al , 2001).…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Teleconnection Patterns on Anomalous Summer Weather in Japan

Ogasawara

Kawamura

2007

Journal of the Meteorological Society of Japan

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Using ERA-40 and NCEP/NCAR reanalysis data, the characteristics of major teleconnection patterns were examined, particularly the West Asia-Japan (WJ) and Pacific-Japan (PJ) patterns, with a highfrequency (HF) component (from half a week to two or three weeks), and a low-frequency (LF) component (greater than about one month), and discussed the combined effects of the teleconnection patterns on the anomalous summer weather in Japan and the surrounding regions.Both patterns of the HF-WJ and LF-WJ, which propagate eastward along the upper-level Asian jet, induce an anomalous barotropic anticyclone centered on the Japan Sea. The HF-WJ pattern has no close link with the Asian summer monsoon activity, but, in contrast, the LF-WJ pattern is significantly correlated with anomalous monsoonal heating over the summer monsoon region. The HF-PJ and LF-PJ patterns, which can be identified with stationary waves stimulated by intense convection around the Philippine Sea, generate a nearly barotropic anticyclone anomaly to the east of Japan. A combination of the HF-WJ and HF-PJ patterns establishes a zonally elongated anticyclonic anomaly over northern Japan, resulting in anomalous high surface temperatures in northern Japan. Such a coupling was found to lead to a larger temperature increase in that region than a single teleconnection pattern alone.A typical case of the LF-WJ and LF-PJ combination also indicates a zonally elongated anticyclonic anomaly over northern Japan, which is similar to the combined pattern of HF-WJ and HF-PJ. The dynamic impact of LF-WJ on the surface temperature field around Japan differs significantly from that of LF-PJ. The dominance of the LF-WJ causes enhanced subsidence over Japan, which can bring about adiabatic heating and increased incoming solar radiation. On the other hand, PJ-induced anomalous anticyclone in the lower troposphere facilitates northward warm advection to the east of northern Japan, where the north-south temperature gradient is large. As for the extreme hot summer of 2004, no combined patterns of the LF-WJ and LF-PJ were found during the summer. Alternatively, a tripole structure appeared in the lower geopotential height field in mid-June. Such a tripole pattern may be established by a combination of the LF-PJ and a barotropic Rossby wave train propagating southeastward from high latitudes.

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Tropical and Mid-latitude 45-Day Perturbations over the Western Pacific During the Northern Summer

Cited by 88 publications

References 44 publications

On the Role of Typhoons in Generating PJ Teleconnection Patterns over the Western North Pacific in Late Summer

On the Role of Typhoons in Generating PJ Teleconnection Patterns over the Western North Pacific in Late Summer

The Madden-Julian Oscillation and Extratropical Teleconnection over East Asia during the Northern Winter in IPCC AR4 Climate Models

Combined Effects of Teleconnection Patterns on Anomalous Summer Weather in Japan

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