Abstract
In this paper, it is elucidated that the total deformation (TD), defined as the square root of the sum of squared stretching deformation and squared shearing deformation, is an invariant independent of the coordinate system used. An idealized flow field is then constructed to demonstrate the confluence effect of a non-divergent and irrotational deformation field on moisture transport. To explore the characteristics and role of TD, one heavy rainfall case that occurred in the middle and lower reaches of the Yangtze River (MRYR) over China, associated with a front with shear line, is analyzed using the Weather Research and Forecasting (WRF) model output data. It is found that right before the occurrence of precipitation, the effect of the confluence induced by deformation on moisture transport provides a favorable condition for precipitation.
During the precipitation, both location and orientation of the zone of large TD coincide with the confluent shear line. The rainbands are nearly parallel with, and located lightly to the south of the zones of large TD and the confluent shear line. The TD in the lower troposphere increases in value as precipitation persists. When TD approaches its maximal value, the next 6-hour precipitation reaches its peak correspondingly.
A tendency equation for TD is derived. The analysis of linear correlation and RMS difference between individual terms in the total deformation equation and the sum of the terms shows that the pressure gradient plays a major role in determining the local change of total deformation.
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References
Bluestein, H. B., 1977: Synoptic-scale deformation and tropical bands. J. Atmos. Sci., 34, 891–900.
Caracena, F., R. A. Maddox, L. R. Hoxit, and C. F. Chappell, 1979: Mesoanalysis of the big Thompson storm. Mon. Wea. Rev., 107, 1–17.
David, J. S., and J. L. Anderson, 2001: Is midlatitude convection an active or passive player in producing global circulation patterns? J. Climate, 14, 2222–2237.
Davidson, N. E., K. Kurihara, T. Kato, G. Mills, and K. Puri, 1998: Dynamics and prediction of a mesoscale extreme rain event in the Baiu front over Kyushu, Japan. Mon. Wea. Rev., 121, 2005–2029.
Davies-Jones, R. P., 1984: The origin of updraft rotation in supercell storms. J. Atmos. Sci., 41, 2991–3006.
Droegemeier, K. K., S. M. Lazarus, and R. P. Davies-Jones, 1993: The influence of helicity on numerically simulated convective storms. Mon. Wea. Rev., 121, 2005–2029.
Dudhia, J., 1989: Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J. Atmos. Sci., 46, 3077–3107.
Etling, D., 1985: Some aspects of helicity in atmosphere flows. Beitr. Phys. Atmos., 58, 88–100.
Harasti, P. R., and R. List, 2005: Principal component analysis of Doppler radar data. Part I: Geometric connections between eigenvectors and the core region of atmosphere vorticies. J. Atmos. Sci., 62, 4027–4042.
Herbert, R., 1954: Rainfall and vorticity advection. J. Atmos. Sci., 5, 425–425.
Hong, S. Y., and H. L. Pan, 1996: Non-local boundary layer vertical diffusion in a medium-range forecast model. Mon. Wea. Rev., 124, 2322–2339.
Hoxit, L. R., J. M. Fritsch, and C. F. Chappell, 1978: Reply. Mon. Wea. Rev., 106, 1034–1034.
Kain, J. S., and J. M. Fritsch, 1990: A one-dimensional entraining/detraining plume model and its application in convective parameterization. J. Atmos. Sci., 47, 2784–2802.
Keyser, D., M. J. Pecnick, and M. A. Shapiro, 1986: Diagnosis of the role of vertical deformation in a two-dimensional primitive equation model of upper-level frontogenesis. J. Atmos. Sci., 43, 839–850.
Keyser, D., J. M. Reeder, and J. R. Reed, 1988: A generalization of Petterssen’s frontogenesis function and its relation to the forcing of vertical motion. Mon. Wea. Rev., 116, 762–780.
Liebmann, B., J. A. Marengo, J. D. Glick, V. E. Kousky, I. C. Wainer, and O. Massamban, 1998: A comparison of rainfall, outgoing longwave radiation, and divergence over the Amazon Basin. J. Climate, 11, 2892–2909.
Lilly, D. K., 1986a: The structure, energetics and propagation of rotation convective storms. Part I: Energy exchange with the mean flow. J. Atmos. Sci., 43, 113–125.
Lilly, D. K., 1986b: The structure, energetics and propagation of rotation convective storms. Part II: Helicity and storm stability. J. Atmos. Sci., 43, 126–140.
Lu, H., and S. Gao, 2003: On the helicity and the helicity equation. Acta Ameteorologica Sinica, 61, 684–691. (in Chinese)
Maddox, R. A., L. R. Hoxit, C. F. Chappell, and F. Caracena, 1978: Comparison of meteorological aspects of the big Thompson and rapid city flash floods. Mon. Wea. Rev., 106, 375–389.
Maddox, R. A., F. Canova, and L. R. Hoxit, 1980a: Meteorological characteristics of flash flood events over the western United States. Mon. Wea. Rev., 108, 1866–1877.
Maddox, R. A., L. R. Hoxit, and C. F. Chappell, 1980b: A study of tornadic thunderstorm interactions with thermal boundaries. Mon. Wea. Rev., 108, 322–336.
Mlawer, E. J., S. J. Taubman, and P. D. Brown, 1997: Radiative transfer for inhomogeneous atmosphere: RRTM, a validated correlated-k model for the long-wave. J. Geophys. Res., 102, 633–682.
Norbury, J., 2002: Large-Scale Atmosphere-Ocean Dynamics. Vol. I, Cambridge University Press, United Kingdom, 370pp.
Petterssen, S., 1956: Weather Analysis and Forecasting. Vol. I, 2nd ed., McGraw-Hill, New York, 428pp.
Rossby, C. G., 1937: On the mutual adjustment of pressure and velocity distribution in certain simple current systems, I. J. Mar. Res., 1, 15–28.
Rossby, C. G., 1938: On the mutual adjustment of pressure and velocity distribution in certain simple current systems, II. J. Mar. Res., 2, 239–263.
Stanley, L. U., and G. Michael, 1978a: The role of surface divergence and vorticity in the life cycle of convective rainfall. Part I: Observation and analysis. J. Atmos. Sci., 35, 1047–1062.
Stanley, L. U., and G. Michael, 1978b: The role of surface divergence and vorticity in the life cycle of convective rainfall. Part II: Descriptive model. J. Atmos. Sci., 35, 1063–1069.
Walter, F., and A. J. Thorpe, 1979: An evaluation of theories of storm motion using observations of tropical convective systems. Mon. Wea. Rev., 107, 1306–1319.
Weisman, M. L., and J. B. Klemp, 1982: The dependence of numerically simulated convective storms on vertical wind shear and buoyancy. Mon. Wea. Rev., 110, 504–520.
Wicker, L. J., and J. S. William, 2002: Time-splitting methods for elastic models using forward time schemes. Mon. Wea. Rev., 130, 2088–2097.
Wiin-Nielsen, A., 1973: Compendium of Meteorology. Vol. I, WMO, 364pp.
Wu, R., and Z. Tan, 1989: Generalized vorticity and potential vorticity conversation law and application. Acta Meteorologica Sinica, 47, 436–442. (in Chinese)
Yeh, T. C., 1957: On the formation of quasi-geostrohpic motion in the atmosphere. J. Meteor. Soc. Japan (75th anniversary volume), 130–137.
Yeh, T. C., and M. Li, 1982: On the characteristics of scales of the atmospheric motions. J. Meteor. Soc. Japan, 60, 16–23.
Zeng, Q., 1963a: The effect of original disturbance structure on adaptation and the application of observed wind field. Acta Meteorologica Sinica, 33, 37–50. (in Chinese)
Zeng, Q., 1963b: The adaptation and development in atmosphere. I. Acta Meteorologica Sinica, 35, 163–174. (in Chinese)
Zeng, Q., 1963c: The adaptation and development in atmosphere. II. Acta Meteorologica Sinica, 35, 281–189. (in Chinese)
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Gao, S., Yang, S., Xue, M. et al. Total deformation and its role in heavy precipitation events associated with deformation-dominant flow patterns. Adv. Atmos. Sci. 25, 11–23 (2008). https://doi.org/10.1007/s00376-008-0011-y
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DOI: https://doi.org/10.1007/s00376-008-0011-y