Beta drift refers to the southwestward motion in the Southern Hemisphere and the northwestward motion in the Northern Hemisphere of a tropical cyclone caused by the variation in the Coriolis parameter. Also referred to as beta gyres or the beta effect. The drift results in a propagation speed of about 1–2 meters per second (3.6–7.2 kilometers per hour, 2.2–4.4 miles per hour, 2–4 knots).[1]
For a mesoscale system like a tropical cyclone, there is a significant difference between the value of the Coriolis parameter at the northern edge and the southern edge. As a result of the circulation of winds around the storm, the relative vorticity is changed because the absolute vorticity is advected around the storm.[2]
References
edit- ^ Todd S. Glickman, ed. (June 2000). "Beta drift". AMS Glossary Second Edition. Retrieved 08 July 2010.
{{cite web}}: Check date values in:|accessdate=(help) - ^ The COMET Program (2010). "Tropical Cyclone Motion". Introduction to Tropical Meteorology 1st Edition. University Corporation for Atmospheric Research. Retrieved 08 July 2010.
{{cite web}}: Check date values in:|accessdate=(help) Requires free registration. - ^ The COMET Program (2010). "The "β-Effect"". Introduction to Tropical Meteorology 1st Edition. University Corporation for Atmospheric Research. Retrieved 08 July 2010.
{{cite web}}: Check date values in:|accessdate=(help) - ^ The COMET Program (2010). "Environmental "β" Effects". Introduction to Tropical Meteorology 1st Edition. University Corporation for Atmospheric Research. Retrieved 08 July 2010.
{{cite web}}: Check date values in:|accessdate=(help) - ^ Chan, Johnny C. L.; Williams, R. T. (1987). "Analytical and Numerical Studies of the Beta-Effect in Tropical Cyclone Motion. Part I: Zero Mean Flow". Journal of the Atmospheric Sciences. 44 (9): 1257–1265.
- ^ Smith, Ronald B. (1993). "A Hurricane Beta-Drift Law". Journal of the Atmospheric Sciences. 50 (18): 3213–3215.
- ^ Liang, Xudong; Chan, Johnny C. L. (2005). "The Effects of the Full Coriolis Force on the Structure and Motion of a Tropical Cyclone. Part I: Effects due to Vertical Motion". Journal of the Atmospheric Sciences. 62 (10): 3825–3830.
- ^ Li, Xiaofan; Wang, Bin (1994). "Barotropic Dynamics of the Beta Gyres and Beta Drift". Journal of the Atmospheric Sciences. 51 (5): 746–756. doi:10.1175/1520-0469(1994)051<0746:BDOTBG>2.0.CO;2.
- ^ Wang, Yuqing; Holland, Greg J. "The Beta Drift of Baroclinic Vortices. Part II: Diabatic Vortices". Journal of the Atmospheric Sciences. 53 (24): 3737–3756.
{{cite journal}}: Unknown parameter|years=ignored (help) - ^ Sutyrin, Georgi (2001). "Effects of topography on the beta-drift of a baroclinic vortex". Journal of Marine Research. 59: 977–989. doi:10.1357/00222400160497733.
- ^ Ritchie, Elizabeth A.; Frank, William M. (2007). "Interactions between Simulated Tropical Cyclones and an Environment with a Variable Coriolis Parameter". Monthly Weather Review. 135 (5): 1889–1905. doi:10.1175/MWR3359.1.