Moisture transport in mid-latitude cyclones
To link to this article DOI: 10.1002/qj.783
We discuss how synoptic-scale variability controls the transport of atmospheric water vapour by mid-latitude cyclones. Idealised simulations are used to investigate quantitatively what factors determine the magnitude of cyclone moisture transport. It is demonstrated that large-scale ascent on the warmconveyor belt and shallow cumulus convection are equally important for ventilating moisture from the boundary layer into the free troposphere, and that ventilated moisture can be transported large distances eastwards and polewards by the cyclone, before being returned to the surface as precipitation. The initial relative humidity is shown to have little affect on the ability of the cyclone to transport moisture, whilst the absolute temperature and meridional temperature gradient provide much stronger controls. Scaling arguments are presented to quantify the dependence of moisture transport on large-scale and boundary-layer parameters. It is shown that ventilation by shallow convection and warm-conveyor belt advection vary in the same way with changes to large-scale parameters. However, shallow convective ventilation has a much stronger dependence on boundary-layer parameters than warm-conveyor belt ventilation.
Ahmadi-Givi F, Craig GC, Plant RS. 2004. The dynamics of a midlatitude cyclone with very strong latent-heat release. Q. J. R. Meteorol. Soc. 130: 295–323. Allen M, Ingram W. 2002. Constraints on future changes in climate and the hydrologic cycle. Nature 419: 224–232. Balasubramanian G, Garner ST. 1997. The Role of Momentum Fluxes in Shaping the Life Cycle of a Baroclinic Wave. J. Atmos. Sci. 54: 510– 533. Bengtsson L, Hodges KI, Roeckner E. 2006. Storm tracks and climate change. J. Climate 19: 3518–3543. Bolton D. 1980. The computation of equivalent potential temperature. Mon. Weather Rev. 108: 1046–1053. Boutle IA, Beare RJ, Belcher SE, Brown AR, Plant RS. 2010. The moist boundary layer under a mid-latitude weather system. Boundary-Layer Meteorol. 134: 367–386. Dacre HF, Gray SL, Belcher SE. 2007. A case study of boundary layer ventilation by convection and coastal processes. J. Geophys. Res. 112: D17 106. Eady ET. 1949. Long waves and cyclone waves. Tellus 1: 33–52. Eckhardt S, Stohl A, Wernli H, James P, Forster C, Spichtinger N. 2004. A 15-year climatology of warm conveyor belts. J. Climate 17: 218–237. Emanuel K, Fantini M, Thorpe A. 1987. Baroclinic instability in an environment of small stability to slantwise moist convection. Part I: Two-dimensional models. J. Atmos. Sci. 44: 1559–1573. Field PR, Gettelman A, Neale RB, Wood R, Rasch PJ, Morrison H. 2008. Midlatitude cyclone compositing to constrain climate model behaviour using satellite observations. J. Climate 21: 5887–5903. Field PR, Wood R. 2007. Precipitation and Cloud Structure in Midlatitude Cyclones. J. Climate 20: 233–254. Frierson DMW. 2006. Robust increases in midlatitude static stability in simulations of global warming. Geophys. Res. Lett. 33: L24 816. Gutowski WJ, Jiang W. 1998. Surface-flux regulation of the coupling between cumulus convection and baroclinic waves. J. Atmos. Sci. 55: 940–953. Held IM, Soden BJ. 2006. Robust responses of the hydrological cycle to global warming. J. Climate 19: 5686–5699. Martin GM, Ringer MA, Pope V, Jones A, Dearden C, Hinton T. 2006. The Physical Properties of the Atmosphere in the New Hadley Centre Global Environment Model (HadGEM1). Part I: Model Description and Global Climatology. J. Climate 19: 1274–1301. Meehl GA, Stocker TF, Collins WD, Friedlingstein P, Gaye AT, Gregory JM, Kitoh A, Knutti R, Murphy JM, Noda A, Raper SCB, Watterson IG,Weaver AJ, Zhao ZC. 2007. Global climate projections. In: Climate Change 2007: The Physical Science Basis, Cambridge University Press: Cambridge, United Kingdom and New York, NY, USA. Paciorek CJ, Risbey JS, Ventura V, Rosen RD. 2002. Multiple indices of Northern Hemisphere cyclone activity, winters 1949-99. J. Climate 15: 1573–1590. Pavan V, Hall N, Valdes P, Blackburn M. 1999. The importance of moisture distribution for the growth and energetics of mid-latitude systems. Ann. Geophys. 17: 242–256. Polvani LM, Esler JG. 2007. Transport and mixing of chemical airmasses in idealized baroclinic life cycles. J. Geophys. Res. 112: D23 102. Ruprecht E, Schr¨oder S, Ubl S. 2002. On the relation between NAO and water vapour transport towards Europe. Meteor. Z. 11: 395–401. Schneider T, Smith KL, O’Gorman PA, Walker CC. 2006. A climatology of tropospheric zonal-mean water vapor fields and fluxes in isentropic coordinates. J. Climate 19: 5918–5933. Shapiro MA, Keyser D. 1990. Fronts, jet streams and the tropopause. In: Extratropical Cyclones: The Erik Palm´en Memorial Volume, Amer. Meteorol. Soc.: Boston, pp. 167–191. Sinclair VA, Gray SL, Belcher SE. 2008. Boundary-layer ventilation by baroclinic life cycles. Q. J. R. Meteorol. Soc. 134: 1409–1424. Sinclair VA, Gray SL, Belcher SE. 2010. Controls on boundary-layer ventilation: Boundary-layer processes and large-scale dynamics. J. Geophys. Res. 115: D11 107. Stohl A, Forster C, Sodemann H. 2008. Remote sources of water vapour forming precipitation on the Norwegian west coast at 60±N - a tale of hurricanes and an atmospheric river. J. Geophys. Res. 113: D05 102. Thorncroft CD, Hoskins BJ, McIntyre ME. 1993. Two paradigms of baroclinic-wave life-cycle behaviour. Q. J. R. Meteorol. Soc. 119: 17– 55. Trenberth KE, Stepaniak DP. 2003. Covariability of components of poleward atmospheric energy transports on seasonal and interannual timescales. J. Climate 16: 3691–3705. Wernli H. 1997. A Lagrangian-based analysis of extratropical cyclones. II: A detailed case-study. Q. J. R. Meteorol. Soc. 123: 1677–1706. Wernli H, Fehlmann R, L¨uthi D. 1998. The effect of barotropic shear on upper-level induced cyclogenesis: Semigeostrophic and primitive equation numerical simulations. J. Atmos. Sci. 55: 2080–2094. Yin JH. 2005. A consistent poleward shift of the storm tracks in simulations of 21st century climate. Geophys. Res. Lett. 32: L18 701.
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