METEOR 4100 - Introduction
METEOR 4100 Tropical Meteorology (Introduction) - Jophet D. Flores
Page 2: Outline
Key Topics:
What is tropical meteorology?
Energy and the global climate
Defining the tropics
Energy balance and the role of tropics
Surface Energy Budget
Meridional Energy Transport by Atmosphere and Ocean
Latent Heat and Deep Convective Cloud Distribution
Surface-Air Interactions
Atmospheric structure
Temperature Profiles
Trade Wind Inversion
Atmospheric Humidity
Pressure Ranges
Temperature
Seasonal and Geographic Distribution of Temperature
Major Influence of Annual Surface Temperature Distribution
Diurnal Temperature Variability in the Tropics
Moisture and precipitation
Role of tropics in the momentum balance
Spatial and Temporal Scales in the Tropics
Tropical air masses and climates
Page 4: What is Tropical Meteorology?
Energy Sources and Sinks:
Surplus radiation
Latent heat
Sensible heat
Evapotranspiration
Ocean heat storage
Page 5: Differences from Higher Latitudes
Characteristics:
Weak Coriolis force and pressure gradients (except in cyclones)
Minimal temperature contrasts leading to homogeneous air masses
Weather disturbances initiated by modest wind velocity gradients
Page 6: Cyclones vs. Hurricanes
Mid-latitude Cyclones:
Synoptic scale low-pressure systems (30° N - 55° N)
Size: 1500-5000 km in diameter
Hurricanes/Tropical Storms:
Size: 200-1000 km in diameter
Page 7: Energy and the Global Climate
Primary Energy Source: The sun
Energy Exchange: Through physical and bio-geochemical cycles
Page 8: Conservation of Energy
First Law of Thermodynamics: Energy is conserved
Energy Equation: ( dQ = dU + dW )
Page 9: Energy Transfer Mechanisms
Methods:
Radiation
Conduction
Convection
Page 10: Solar Radiation Distribution
Latitudinal Effects: Maximum at the equator, minimum at poles due to beam spreading and atmospheric attenuation
Page 11: Stefan-Boltzmann Law
Energy Emission: ( E = \sigma T^4 )
Page 12: Wien’s Law
Wavelength Relation: ( \lambda_{max} = \frac{2897.9}{T} )
Page 13: Solar vs. Terrestrial Radiation
Energy Comparison: Solar radiation peaks at ~0.5 µm (shortwave) vs. terrestrial radiation at ~10 µm (longwave)
Page 14: Net Radiation and Climate
Net Radiation Equation: ( F_{sw}(1 - \alpha_p) = \epsilon \sigma T_e^4 )
Page 15: Absorption of Solar Radiation
Atmospheric Absorption: 20% absorbed, 70% of solar radiation entering the atmosphere is absorbed
Page 16: Fluid Motions as Heat Engine
Role of Ocean and Atmosphere: Compensate for radiative imbalance
Page 17: Heat Engine of the Earth System
Tropical Influence: Surplus heating in tropics creates horizontal temperature gradients
Page 18: Energy Transport in the Atmosphere
Riehl and Malkus Hypothesis: Upward transport of energy concentrated in deep convective systems
Page 19: Defining the Tropics
Latitudinal Limits: ±23.5° latitude (Tropic of Cancer and Capricorn)
Page 20: Surplus Radiation Region
Defined Limits: ±35 to 40° latitude
Page 21: Hadley Cell Circulation
Circulation Dynamics: Upward motion in tropics leads to low pressure and subsidence at poles
Page 22: Trade Winds
Wind Patterns: Primarily easterly winds, convergence at the ITCZ
Page 23: Temperature Range
Annual vs. Daily Range: Annual range less than or equal to daily range
Page 24: Seasonal Variability
Rainfall Patterns: Wet and dry seasons rather than four seasons
Page 25: Riehl's Definition of Tropics
Atmospheric Processes: Justification for separate study of tropical weather and climate
Page 26: Energy Balance in Earth-Atmosphere System
Energy Transport: By ocean and atmosphere due to differential heating
Page 27: Oceanic Dynamics
Driving Forces: Wind stress, net radiation, salinity changes
Page 28: Surface Energy Budget
Net Radiation Equation: ( R_s = F_{sw}(1 - \alpha_s) - \epsilon \sigma T_s^4 + \epsilon \sigma T_a^4 )
Page 29: Energy Components
Energy Partitioning: Sensible, latent, potential, kinetic, storage, and advection
Page 30: Energy in Northern Hemisphere
Mean Energy Values: Latent, sensible, potential, and kinetic energy contributions
Page 31: Steady State Conditions
Simplified Equations: For ocean and land energy budgets
Page 32: Energy Transport Measurements
Data Sources: Satellite measurements and ocean circulation data
Page 33: Meridional Energy Transport
Transport Mechanisms: Mean meridional circulation (Hadley cell) and eddy motion
Page 34: Seasonal Variability of Hadley Cell
Strength Variation: Stronger in winter than summer
Page 35: Latent Heat Transfer
Importance: Dominant energy source for tropical circulation
Page 36: Deep Convective Clouds
Characteristics: Cold cloud tops, low outgoing longwave radiation
Page 37: Water Vapor Transport
Mechanism: Mean meridional circulation transports water vapor
Page 38: Energy Transfer Mechanism
Deep Convective Clouds: Primary conduit for transferring heat into the atmosphere
Page 39: Climate Change Influences
Convection Shifts: Impact on global climate, e.g., during El Niño
Page 40: Surface-Air Interactions
Energy Exchange: Ocean-atmosphere interactions dominate
Page 41: Tropical Cyclones
Energy Gain: From warm ocean waters through latent heat transfer
Page 42: Madden-Julian Oscillation (MJO)
Oscillation Characteristics: Influences tropical weather and oceanic conditions
Page 43: Climate Models
Interactions: Account for various scales of variability in tropical weather