Pallav K' Ray

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Study of the Tropical Atmosphere
Introduction of a New Tool

• Pallav K. Ray
• MPO, RSMAS, University of Miami
• 6th May, 2004

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Outline

• Background and Motivations
• Model set up and Data
• Results
• Conclusions and Future Work

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Background
Mesoscale Model
GCM
1. Small area coverage 1. Global coverage 2.
Finer resolution
2. Coarse
resolution 3. Synoptic scale
3. Seasonal to Climate 4.
Prescribed boundary condition 4. No lateral
boundaries
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Motivation

• To fill the gap between mesoscale model and
  global model in terms of area coverage and
  resolution for the application in the tropics.

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Tropical MM5
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Is such a model applicable for tropics ?
Scientific Problem

• Equatorial Waves
• MJO (Slingo et al., 1996 Gustafson and Weare,
  2004)
• Double ITCZ (Mechoso et al., 1995).
• Monsoonal Circulation
• Atmospheric Teleconnection
• Shallow meridional circulation in the eastern
  Pacific (Zhang et al., 2004).

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Model Domains
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Model Physics and Data

• Goddard moisture scheme (Lin et al., 1983) .
• Grell et al. (1991) convective parameterization.
• Mellor Yamada PBL scheme (Janjic, 1990, 1994).
• 28 vertical levels (unevenly spaced)
• 240 sec integration time step
• NCEP-NCAR Reanalysis data for initialization and
  boundary conditions.
• TMI wind and precipitable water

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Wind at 200 mb (m/s)
D2
D1
D1D3
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Surface wind (m/s)
D2
D1
D1D3
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Atmospheric Water Vapor (Kg/m2)
D2
D1
D1D3
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Shallow Meridional Circulation in the Eastern
Pacific (Zhang et al., 2004)
V wind and RH at 95 W
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Wind at 200 mb and 850 mb
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Vertical-meridional cross-section of V wind (m/s)
and RH ()
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Conclusions

• Tropical MM5 has the potential to fill the gap
  between conventional mesoscale model and GCM.
• The model is able to capture the large-scale
  features of the tropics, and can be used for a
  variety of studies.

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Future Work
Scientific Problem
On the model

• Equatorial Waves
• MJO (Slingo et al., 1996)
• Double ITCZ (Mechoso et al., 1995).
• Monsoonal Circulation
• Atmospheric Teleconnection
• Shallow meridional circulation in the eastern
  Pacific (Zhang et al., 2004).
• .

• We plan to use different data for initialization
  (e.g., ECMWF data).
• Model output was taken every 12 hours. Diurnal
  variation could be important (Chen and Houze,
  1997).
• To run the model with finer resolution (e.g.,
  Colle et al. 1999)

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Acknowledgement

• To my advisor Prof. Chidong Zhang.
• Joe Tenerelli for help with the model.

Thank you
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Shallow Meridional Circulation in the Eastern
Pacific
V wind at 95 W
Zhang et al. (2004)