Four Stages of the Rainy Season in Early Summer over East Asia (Part II)

Yoshino, Masatoshi

doi:10.2151/jmsj1965.44.4_209

Cited by 39 publications

(30 citation statements)

References 4 publications

(4 reference statements)

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“…Yoshino (1965Yoshino ( , 1966 divided the Baiu season into four stages and described the circulation in each stage. Kato (1989) described the seasonal march of the Baiu season of 1979.…”

Section: Introductionmentioning

confidence: 99%

The Large-Scale Circulation Change at the End of the Baiu Season in Japan as Seen in ERA40 Data

Suzuki

Hoskins

2009

Journal of the Meteorological Society of Japan

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The time evolution of the circulation change at the end of the Baiu season is investigated using ERA40 data. An end-day is defined for each of the 23 years based on the 850 hPa y e value at 40 N in the 130-140 E sector exceeding 330 K. Daily time series of variables are composited with respect to this day. These composite timeseries exhibit a clearer and more rapid change in the precipitation and the large-scale circulation over the whole East Asia region than those performed using calendar days. The precipitation change includes the abrupt end of the Baiu rain, the northward shift of tropical convection perhaps starting a few days before this, and the start of the heavier rain at higher latitudes.The northward migration of lower tropospheric warm, moist tropical air, a general feature of the seasonal march in the region, is fast over the continent and slow over the ocean. By mid to late July the cooler air over the Sea of Japan is surrounded on 3 sides by the tropical air. It is suggestive that the large-scale stage has been set for a jump to the post-Baiu state, i.e., for the end of the Baiu season. Two likely triggers for the actual change emerge from the analysis. The first is the northward movement of tropical convection into the Philippine region. The second is an equivalent barotropic Rossby wave-train, that over a 10-day period develops downstream across Eurasia. It appears likely that in most years one or both mechanisms can be important in triggering the actual end of the Baiu season.

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“…Yoshino (1965Yoshino ( , 1966 divided the Baiu season into four stages and described the circulation in each stage. Kato (1989) described the seasonal march of the Baiu season of 1979.…”

Section: Introductionmentioning

confidence: 99%

The Large-Scale Circulation Change at the End of the Baiu Season in Japan as Seen in ERA40 Data

Suzuki

Hoskins

2009

Journal of the Meteorological Society of Japan

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“…During the rainy season in the Yangtze river basin (Mei-yu) and the Japan Islands (Baiu) in June and July, the EA-band corresponding to the Baiu frontal zone is located along the northern periphery of a very warm and moist air mass, and a large amount of rain falls along the EA-band (Yoshino, 1966;Akiyama, 1973;Ninomiya, 1984;Ninomiya and Muraki, 1986). In this period, a quasi-stationary front appears more frequently on daily weather maps than in other periods (Yamakawa, 1988), and the upperlevel cloud amount is the largest in the year, as is the middle-level cloud amount (Kodama and Asai, 1988).…”

Section: Introductionmentioning

confidence: 99%

“…A zone with large rainfall amount is established in late May over South China through the Nansei Islands in the 10-year averaged field (Yoshino, 1966), where heavy rain (>50mm/day) is frequently observed (Matsumoto,Recently, Matsumoto (1992) pointed out, based on the 12-year averaged fields, that a minimum OLR zone appears from South China through the south of Japan during the "onset period" (May 16-June 9) of the rainy season over the Indochina Peninsula. Tanaka (1992) also found, based on the 10-year averaged fields, that a zone with a large amount of high level clouds, above 400 mb level, is formed in the middle of May over the northern part of the South China Sea and extends south of Japan.…”

Section: Introductionmentioning

confidence: 99%

Abrupt Change in the Characteristics of the Cloud Zone in Subtropical East Asia around the Middle of May

Hirasawa

Kato

Takeda

1995

Journal of the Meteorological Society of Japan

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An abrupt seasonal change in cloud features around the East Asian cloud band (EA-band) was found in the middle of May or late May in all the years of 1982 to 1987 by using two indexes derived from GMS infrared data, middle-and high-level cloud amount (MHc-amount) and the appearance frequency of the high-level cloud region (Hc-frequency) for a 10-or 15-day period. The change occurred over a short period, less than 5 days (transition period: TP), nearly simultaneously with the onset of the "Southeast Asian summer monsoon" about one month before the onset of the Indian monsoon. The main results are as follows:1) The MHc-amount and Hc-frequency increase considerably in the coastal region of South China after the TP. The greater part of the Hc-frequency are associated with the deep convective clouds. This change is associated with the enhancement of the low-level southwesterly wind, an decrease in thickness of baroclinic layer below the 500 mb level and an increase in specific humidity there and in the region to the south of the EA-band.2) MHc-amount and Hc-frequency in the EA-band also increase to the east of 130E after the TP, accompanied by the enhancement of the southwesterly wind in its southern part and the southward shift of a subtropical high pressure area west of 150°E.3) As for the year-to-year variation, the distribution of the area with large MHc-amount in the EA-band before the TP seems to be greatly influenced by the amount of confluence between the southwesterly wind in the north of the subtropical high pressure area and westerly wind north of the EA-band.4) MHc-amount over Central China after the TP is about 60% in the year of stronger baroclinicity there, but is about 20% in the year of weaker baroclinicity. 5) Only in 1987, the EA-band and a subtropical high pressure area east of 130E shifted northward after the TP, which are the opposite characteristics to all the other years.

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“…As for application to frontal climatology, the shift and periodicity of the Bai-u (the rainy season in early summer) frontal clouds have been investigated only by EDAGAWA (1979), adding new information to the results of YOSHINO (1965YOSHINO ( , 1966.…”

Section: Introductionmentioning

confidence: 99%

Regional and Seasonal Features of Cold Fronts in Japan and Its Surroundings

Yamakawa

1984

Geogr. Rev. Jpn, Ser B

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Four Stages of the Rainy Season in Early Summer over East Asia (Part II)

Cited by 39 publications

References 4 publications

The Large-Scale Circulation Change at the End of the Baiu Season in Japan as Seen in ERA40 Data

The Large-Scale Circulation Change at the End of the Baiu Season in Japan as Seen in ERA40 Data

Abrupt Change in the Characteristics of the Cloud Zone in Subtropical East Asia around the Middle of May

Regional and Seasonal Features of Cold Fronts in Japan and Its Surroundings

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