Abstract
There exist typically two kinds of low-level col fields over the middle and lower reaches of the Yangtze River of China during summer. One is associated with the mesoscale vortex embedded in the Meiyu front; the other is related to tropical cyclones making landfall over eastern or southern China. The first one is the focus of this study. The meso-β scale vortex (MβV) causing heavy rainfall usually forms in a col field or within a shear line associated with the mesoscale low-level jet (mLLJ). The MβV, triggered by mesoscale wind perturbation in a col field, is simulated by using a three-dimensional η-coordinate mesoscale model. This col field represents the circumstance of the “98.7” heavy rainfall event over eastern Hubei Province. The results show that the MβV triggered by wind perturbation was weak and maintained only several hours if the latent heat feedback was switched off. The wind perturbation also weakened rapidly. However, when the latent heat feedback was included, precipitation became more intense and the mLLJ and MβV quickly developed. The MβV maintained quasi-stationary during its life cycle under the stable col field.
The MβV triggered by the southwesterly perturbation was located closely to that by the northeasterly perturbation. They were both located in the weak wind region near the col point. The stronger the perturbation was, the more intense and longer the dynamic MβV lived. The 24-h accumulated precipitation in different experiments showed a similar pattern, which indicates that the relatively stable intensity and range of precipitation were the intrinsic characters of the stable col field. Furthermore, it is found that mesoscale perturbations had some impacts on the location and intensity of the rainfall. The fluctuation of large-scale LLJ to the south of the col field might produce a perturbation, causing instable stratification and rainfall within the low-level col field or shear line. The mLLJ near the rainfall was enhanced due to the latent heat feedback and then caused formation of the MβV. The stable col field provided favorable thermodynamic conditions for the formation and development of the MβV. Therefore, it is an “incubator” for MβVs and the associated consecutive heavy rainfall.
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References
Akiyama, T., 1973a: The large-scale aspects of the characteristic features of the Baiu front. Paper Meteor. Geophys., 24, 157–188.
—, 1973b: Frequent occurrence of heavy rainfall along the north side to the low-level jet stream in the Baiu season. Paper Meteor. Geophys., 24, 379–388.
—, 1973c: Ageostrophic low-level jet stream in the Baiu season associated with heavy rainfalls over the sea area. J. Meteor. Soc. Japan, 51, 205–208.
Bei, N. F., S. X. Zhao, and S. T. Gao, 2002: Numerical simulation of a heavy rainfall event in China during July 1998. Meteor. Atmos. Phys., 80, 153–164.
Betts, A. K., 1986: A new convective adjustment scheme. Part I: Observational and theoretical basis. Quart. J. Roy. Meteor. Soc., 112, 677–691.
Brown, R. A., 1991: Fluid Mechanics of the Atmosphere. Academic Press, INC., San Diego, California, 489 pp.
Chen George Tai-jen and Chi Shui-Shang, 1978: On the mesoscale structure of Meiyu front in Taiwan. Atmos. Sci., 5(1), 35–47. (in Chinese)
Chen, G. T. J., 1983: Observational aspects of the Meiyu phenomena in subtropical China. J. Meteor. Soc. Japan, 61, 306–312.
—, and C. C. Yu, 1988: Study of low-level jet and extremely heavy rainfall over northern Taiwan in the Meiyu season. Mon. Wea. Rev., 116, 884–891.
—, C. C. Wang, and D. T. W. Lin, 2005: Characteristics of low-level jets over northern Taiwan in Meiyu season and their relationship to heavy rain events. Mon. Wea. Rev., 133, 20–43.
—, —, and L. F. Lin, 2006: A diagnostic study of a retreating Meiyu front and the accompanying lowlevel jet formation and intensification. Mon. Wea. Rev., 134, 874–896.
Chen, Q. S., 1982: The instability of the gravity-inertia wave and its relation to low-level jet and heavy rain. J. Meteor. Soc. Japan, 60, 1041–1057.
Chen, S. J., Y. H. Kuo, W. Wang, et al., 1998: A modeling case study of heavy rainstorms along the Meiyu front. Mon. Wea. Rev., 126, 2330–2351.
—, W. Wang, K. H. Lau, et al., 2000: Mesoscale convective systems along the Meiyu front in a numerical model. Meteor. Atmos. Phys., 75, 149–160.
Chou, L. C., C. P. Chang, and R. T. Williams, 1990: A numerical simulation of the Meiyu front and the associated low level jet. Mon. Wea. Rev., 118, 1408–1428.
Cuxart, J., 2008: Nocturnal basin low-level jets: An integrated study. Acta Geophysica, 56, 100–113.
Ding, Y. H., 1992: Summer monsoon rainfalls in China. J. Meteor. Soc. Japan, 70, 373–396.
Eliassen, A., 1962: On the vertical circulation in frontal zones. Geofys. Publ., 24, 147–160.
Fu, G., H. Niino, R. Kimura, et al., 2004: Multiple polar mesocyclones over the Japan Sea on 11 February 1997. Mon. Wea. Rev., 132, 793–814.
Hamming, R. W., 1989: Digital Filters. 3rd Edition. Englewood Cliffs, New Jersey, Prentice-Hall, 284 pp.
Hu Bowei, Cui Chunguang, and Fang Chunhua, 2001: Causes of a two-day successively extremely heavy rain along the Changjiang valley in the eastern Hubei Province during 21–22 July 1998. Chinese J. Atmos. Sci., 25(4), 479–491. (in Chinese)
Jiang Yongqiang, Zhang Weihuan, Zhou Zugang, et al., 2002: Mesoscale rainstorm model MRM1 and its impact test. Journal of PLA University of Science and Technology (Natural Science Edition), 3(1), 1–7. (in Chinese)
—, Wang Cangyu, Zhang Weihuan, et al., 2004: Numerical simulation of extremely heavy rain and meso-β scale low vortex in inverted typhoon trough. Acta Meteor. Sinica. 18(2), 195–210.
— and Song Jinjie, 2010: Sensitivity experiments of a severe storm in Jiangxi Province. Journal of Nanjing University (Natural Sciences), 46(3), 261–276. (in Chinese)
— and Wang Yuan, 2010: Effects of terrain on saddle pattern during the course of “98.7” extremely heavy rainstorm in the east of Hubei Province. Plateau Meteor., 29(2), 298–308. (in Chinese)
Long Xiao, Chen Linsheng, and Wen Lijuan, 2006: A numerical study of the structure and evolution of meso-β scale system during the “02.6” Meiyu rainfall. Chinese J. Atmos. Sci., 30(2), 327–340. (in Chinese)
Lynch, P., and X. Y. Huang, 1992: Initialization of the HIRLAM model using a digital filter. Mon. Wea. Rev., 120, 1019–1034.
Maddox, R. A., C. F. Chappell, and L. R. Hoxit, 1979: Synoptic and mesoscale aspects of flash flood events. Bull. Amer. Meteor. Soc., 60, 115–123.
Matsumoto, S., 1973: Lower tropospheric wind speed and precipitation activity. J. Meteor. Soc. Japan, 51, 101–107.
Muñoz, E., J. B. Antonio, S. Nigam, et al., 2008: Winter and summer structure of the Caribbean low-level jet. J. Climate, 21, 1260–1276.
Ninomiya, K., and T. Akiyama, 1974: Band structure of mesoscale echo clusters associated with low-level jet stream. J. Meteor. Soc. Japan, 52, 300–313.
Parish, T. R., 2010: Forcing of the summertime low-level jet along the California coast. J. Appl. Meteor., 39, 2421–2433.
Petterssen, S., 1936: Contribution to the theory of frontogenesis. Geofys. Publ., 11, 1–27.
Sawyer, J. S., 1956: The vertical circulation at meteorological fronts and its relation to frontogenesis. Proc. Roy. Soc. London, A234, 346–362.
Shapiro, A., and E. Fedorovich, 2009: Nocturnal lowlevel jet over a shallow slope. Acta Geophysica, 57, 950–980.
Sun Shuqing and Zhai Guoqing, 1980: On the instability of the low level jet and its trigger function for the occurrence of heavy rain-storms. Chinese J. Atmos. Sci., 4(4), 327–337. (in Chinese)
Tao Shiyan, 1980: The Torrential Rain in China. Science Press, Beijing, 225 pp. (in Chinese)
—, Ni Yunqi, Zhao Sixiong, et al., 2001: Study on the Formative Mechanism and the Forecast of the Heavy Rainfall in Summer 1998 in China. China Meteorological Press, Beijing, 184 pp. (in Chinese)
Wallace, J. M., S. Tibaldi, and A. J. Simmons, 1983: Reduction of systematic forecast errors in ECMWF model through the introduction of an envelope orography. Quart. J. Roy. Meteor. Soc., 109, 638–717.
Whyte, F. S., M. A. Taylor, T. S. Stephenson, et al., 2008: Features of the Caribbean low level jet. Int. J. Climatol., 28, 119–128.
Xu Xiaofeng and Sun Zhaobo, 2003: Dynamic study on influence of gravity wave induced by unbalanced flow on Meiyu front heavy rain. Acta Meteor. Sinica, 61(6), 655–660. (in Chinese)
Xu Yamei and Gao Kun, 2002: Simulation and analysis of meso-β vortex over middle reaches of the Yangtze River on 22 July 1998. Acta Meteor. Sinica, 60(1), 85–95. (in Chinese)
Yu Rucong, Zeng Qingcun, Peng Guikang, et al., 1994: Research on “Ya-An-Tian-Lou”. Part II: Numerical trial forecasting. Sci. Atmos. Sinica, 18(5), 535–551. (in Chinese)
Zeng Qingcun and Zhang Xuehong, 1981: A temporalspatial difference scheme with complete energy conservation for compressible fluid and a harmonious splitting method. Scientia Sinica, 11, 1355–1366. (in Chinese)
Zhai Guoqing, Wang Zhi, and He Bing, 2003: Formation and evolution analysis of the mesoscale vortex group in the middle and lower reaches during Meiyu of the Yangtze River. Acta Meteor. Sinica, 61(6), 661–672. (in Chinese)
Zhang, D. L., and R. A. Anthes, 1982: A high-resolution model of planetary boundary layer-sensitivity tests and comparisons with SESAME-79 data. J. Appl. Meteor., 21, 1594–1609.
—, and J. M. Fritsch, 1988: A numerical investigation of a convectively generated, inertially stable, extratropical warm-core mesovortex over land. Part I: Structure and evolution. Mon. Wea. Rev., 116, 2660–2687.
Zhang Xiaoling, Tao Shiyan, and Zhang Shunli, 2004: Three types of heavy rainstorms associated with the Meiyu front. Chinese J. Atmos. Sci., 28(2), 187–205. (in Chinese)
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Supported by the China Meteorological Administration Special Public Welfare Research Fund (GYHY200906011) and the National Natural Science Foundation of China (40921160382 and 40905021).
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Jiang, Y., Wang, Y. Numerical simulation on the formation of mesoscale vortex in col field. Acta Meteorol Sin 26, 112–128 (2012). https://doi.org/10.1007/s13351-012-0111-6
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DOI: https://doi.org/10.1007/s13351-012-0111-6