author = "Adedoyin, Akintayo",
          affiliation = "Physics Department, University of Botswana, P.O. Box 70121, 
                         Gaborone, Botswana",
                title = "On the parameterisation of mesoscale convective systems in 
                         regional climate models over Southern Africa",
            booktitle = "Proceedings...",
                 year = "2006",
               editor = "Vera, Carolina and Nobre, Carlos",
                pages = "691--692",
         organization = "International Conference on Southern Hemisphere Meteorology and 
                         Oceanography, 8. (ICSHMO).",
            publisher = "American Meteorological Society (AMS)",
              address = "45 Beacon Hill Road, Boston, MA, USA",
             keywords = "Mesoscale Convectyive Systems, Climate Models, Classification of 
             abstract = "Mesoscale Convective Systems (MCS) are organized groups of 
                         thunderstorms that range in horizontal dimension from 5-500 km and 
                         typically possess lifetimes of 6-24 hours. Vertical motions within 
                         MCSs could be as significant as horizontal motions. These 
                         updraughts and downdraughts impact heavily on local rainfall, 
                         wind, lightning and other forms of severe weather. However, their 
                         limited lateral extent and timescale do not often make them 
                         evident on synoptic charts. These also keep them at sub-grid 
                         levels in most climate models. It seems therefore that a realistic 
                         understanding of MCSs lies in the correct formulation of the 
                         physics and dynamics associated with them. This is more so in 
                         tropical Africa where more than seventy per cent of precipitation 
                         is associated with MCSs. These dynamics are examined with a 
                         linearised inviscid form of the hydrodynamical equations, solved 
                         in shear with the aid of a two-layer model of the atmosphere, 
                         which is consistent with the synoptic situation over tropical 
                         Africa. Results over tropical Africa confirm the existence, among 
                         others, of: a westward-propagating perturbation of wavelength 100 
                         km, phase speed of 7.7 m s-1, period of 3.6 and an amplification 
                         of 1.8 per hour (which has been shown by Adedoyin(1989) to trigger 
                         the dominant MCS in tropical Africa namely, line squalls) and a 
                         wave-like disturbance which has a phase speed of 6.0 ms-1 in the 
                         East-West direction, a wavelength of 2000 km, a period of 3.49 
                         days and growth rate of 3.6 per hour at 500 hPa, which axis 
                         Mphale(1999) has shown to be influenced by the Indian Ocean sea 
                         surface temperature (a study of the ECMWF analyses of vertical 
                         velocity at 400 hPa during a period of convective activities over 
                         Botswana, Southern Africa, (15-21 February 1995) confirmed the 
                         existence of this wave pattern. These perturbations have direct 
                         bearing on tropical Africa MCSs, and the development of mesoscale 
                         models based on them, as done by Abiodun(2003), is envisaged to 
                         improve current parameterisation schemes in regional climate 
                         models. Classification of precipitation as either stratiform or 
                         convective in climate models is examined against the backdrop of 
                         the model. In the case of convective classification, the model is 
                         shown to be useful in informing the choice of its representation 
                         in any of the following approaches: traditional, explicit or 
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "24-28 Apr. 2006",
             language = "en",
         organisation = "American Meteorological Society (AMS)",
                  ibi = "cptec.inpe.br/adm_conf/2005/",
                  url = "http://urlib.net/rep/cptec.inpe.br/adm_conf/2005/",
           targetfile = "691-692.pdf",
                 type = "Hydrological variability and modeling",
        urlaccessdate = "27 jan. 2021"