Lecture Notes: Weather and Climate - Gateway 1

Overview

• Focus: Weather and Climate Gateway 1.
• Key topics: Monsoon, Climograph, Study Tips, Typical Question Types.

Key Question

• Is variable weather and changing climate a continuous challenge?
• Understanding of weather and climate essentials.

Climograph

• Important Aspects:
  • Check the axis positions to avoid errors in data interpretation.
  • Common Points to Note:
    1. Mean Annual Temperature:
       • Calculate if not provided; descriptive terms (e.g., high if >30°C).
    2. Annual Temperature Range:
       • Difference between warmest and coolest months.
    3. Warmest and Coolest Months.
    4. Rainfall Trends:
       • General trend (e.g., constantly high in Singapore).
    5. Total Annual Rainfall:
       • Sum of monthly values; categorize as high/medium/low with units.
    6. Wettest and Driest Months:
       • Example: July (650 mm) vs. January/February (20 mm).

Factors Affecting Temperature

1. Latitude:

   • Higher latitudes = decreased temperatures.
   • Determines climatic zones (e.g., equatorial climates near the equator).

2. Altitude:

   • Higher altitudes = lower temperatures.
   • Temperature decreases by 6.5°C per 1000m increase.
   • Less dense air at high altitudes absorbs less heat.

3. Distance from the Sea:

   • Inland areas have larger annual temperature range.
   • Specific heat capacity: land heats/cools faster than sea.

4. Cloud Cover:

   • Increased cover = reduced temperature range.
   • Thick clouds reflect solar energy by day and trap heat by night.

Relative Humidity (RH)

• Inverse Relation:
  • Increased temperature = decreased RH.
  • Important for understanding rainfall formation.

Types of Rainfall

1. Convectional Rain:

   • Common in tropical regions; involves cumulonimbus clouds.
   • Short, intense rainfall bursts.

2. Relief Rain:

   • Requires large water body and mountain range.
   • Occurs on windward side, leeward side remains dry.

Air Pressure and Altitude

• Relation:
  • Higher altitudes = lower air pressure.
• Misconception Clarified:
  • Temperature affects pressure at sea level, not at varying altitudes.

Land and Sea Breeze

• Specific Heat Capacity:
  • Land heats/cools faster than sea.
• Diurnal Temperature Variation:
  • Affects localized wind movement.
• Pressure Gradient:
  • Monsoon winds faster due to steeper pressure gradient compared to localized breezes.

Monsoons

• Seasonal Differences:
  • Affected by hemisphere temperatures.
• Wind Direction:
  • Determined by air pressure variations and Coriolis effect.
• Rainfall and Flooding:
  • Monsoon rains cause seasonal flooding in certain regions.

Climatic Types

• Equatorial Climate:
  • High temperatures and rainfall.
• Monsoon Climate:
  • Distinct wet and dry seasons.
• Marine West Coast:
  • Higher latitudes; four seasons; larger temperature range.

Conclusion

• Understanding Gateway 1 is crucial for upcoming Gateways 2 and 3.
• Emphasis on study techniques and exam preparation strategies.