Weather and Climate Notes

WEATHER AND CLIMATE

  • Definition of Weather and Climate

    • Weather: Refers to the atmospheric conditions observed over a short period (usually up to 30 days). It can change rapidly, even within minutes or hours.
    • Climate: Refers to the long-term average of weather conditions in a specific area, typically measured over 30 years or more.

  • Local Weather vs. Global Climate

    • Local weather is specific to a region at any given time (e.g., daily weather forecasts).
    • Global climate refers to long-term patterns and average conditions across the earth.

CONSTITUENTS OF WEATHER

  • Temperature:

    • Determined by the amount of sunlight a location receives.
    • Measured using a thermometer.
    • Influenced by the angle at which the sun’s rays hit the Earth. Lower angles result in greater heating.

  • Rainfall:

    • The total amount of rain that falls in a specific area over a defined period.

  • Wind Direction:

    • Refers to the originating direction of the wind.

  • Cloud Cover:

    • The fraction of the sky obscured by clouds, formed from condensation of water vapor as it rises.

INSTRUMENTS FOR MEASURING WEATHER

  • Thermometer:

    • Best kept in a shaded area for accurate readings.

  • Rain Gauge:

    • Should be situated in an open area, shielded from wind, and away from buildings.

  • Wind Vane:

    • Positioned on the highest point of a roof, indicates wind direction.

  • Anemometer:

    • Needs to be installed in an open area, at least 10 meters above the ground, to measure wind speed accurately.

  • Barometer:

    • Measures atmospheric pressure; can be placed both indoors and outdoors.

FACTORS AFFECTING CLIMATE

  • Latitude and Sun Angle:

    • Latitude is measured in degrees relative to the equator and affects the amount of sunlight a location receives.There is a direct correlation between latitude, sun exposure duration, and temperature.

  • Distance from Sea:

    • Water has a high heat capacity and retains heat longer, resulting in milder climates near the coast. Coastal regions experience moderated temperatures compared to inland areas, which have greater temperature fluctuations.

  • Altitude:

    • As altitude increases, temperature typically decreases at an average rate of 1ext°C1 ^ ext{°C} for every 100100 meters.

  • Prevailing Winds:

    • Winds that consistently blow from a particular direction, impacting local weather patterns (e.g., warm winds bringing warm weather and vice versa).

MALTESE CLIMATE AND WINDS

  • Predominantly influenced by the Majjistral wind from the northwest.
  • The Westerlies are associated with winter conditions.
  • The Sirocco wind from the south can bring warmer temperatures often laden with dust.

RAINFALL PROCESSES

  • Relief Rainfall:

    • Occurs when moist air is lifted over mountains, cools, and condenses into rain.

  • Frontal Rainfall:

    • Happens when cold dry air meets warm moist air causing the warm air to rise, leading to condensation and precipitation.

  • Convectional Rainfall:

    • Initiated by ground heating; warm air rises, cools, and condenses, often resulting in thunderstorms.

VEGETATION IN CLIMATE REGIONS

  • Mediterranean Climate:

    • Characterized by scrublands and moderate-sized trees, adapted to withstand hot, dry summers.
    • Vegetation often enters a dormant state during summer droughts and resumes during wetter winter months.
    • Adaptations include waxy, hairy, or prickly leaves to minimize moisture loss.

  • Equatorial Climate:

    • Defined by consistent high temperatures and abundant rainfall year-round, with convectional rainfall as a prevalent weather pattern.
    • Rich biodiversity includes dense, broadleaf, evergreen rainforests. Limited underbrush due to insufficient sunlight penetrating the canopy.