Weather and Climate

Structure & Bonding

SECTION ONE - WEATHER AND CLIMATE

A. Atmosphere, Weather, Climate

  • Atmosphere: The envelope/layer of gases surrounding the Earth.

  • Weather: The state of the atmosphere at a particular place and time regarding heat, cloudiness, humidity, sunshine, wind, rain, etc.

  • Climate: The average weather conditions prevailing in an area in general or over a long period.

Starter Activity: Mind Map on Earth's Atmosphere

  • Encourage participants to brainstorm knowledge about the atmosphere.

  • Relevant aspects include: greenhouse gases, pollutants like methane, and structural layers of the atmosphere.

2. Significance of Weather

  • Influences of Weather: Day-to-day variations impact mood and perception; severe weather can cause significant disruption (e.g., tornadoes, hurricanes, blizzards).

  • Economic Activities Affected by Weather:

    • Farming: Weather's unpredictability can lead to droughts, affecting crop yield/productivity.

    • Fishing: Fish populations and behaviors can be influenced by weather patterns.

    • Hunting: Hunting success can be dependent on weather conditions (e.g., animal movements, visibility).

Questions & Answers

  • Q1: List THREE economic activities dependent on weather:

    • Farming

    • Fishing

    • Hunting

  • Q2: Example of how weather affects farming:

    • Unpredictable weather leads to droughts affecting crop viability.

  • Q3: Examples of school activities influenced by weather:

    • Outdoor recess

    • School sports events

    • Field trips

1. Key Terms

  • Atmosphere: Layer of gases surrounding Earth.

  • Weather: State of the atmosphere at a specific time, including factors like heat and humidity.

  • Climate: Refers to average atmospheric conditions over time in a given area.

Question: Difference Between Weather and Climate

  • Weather is immediate, subject to rapid changes; climate represents long-term conditions.

4. Weather Elements

  • Elements of Weather: Clouds, humidity, precipitation, air pressure, temperature, wind (6 total).

    • Prioritize: Temperature and Wind.

    • Impact of Temperature: Influences indoor climate, heating requirements, and active outdoor conditions.

    • Impact of Wind: Can lead to energy generation (wind turbines) and weather broadcasts.

B. Measuring Weather Elements

1. Measuring Air Temperature

  • Key Instruments: Thermometers (historically mercury and alcohol thermometers).

  • Mercury Thermometer:

    • Accurate within ±1-2 degrees but hazardous.

  • Alcohol Thermometer:

    • Safer and usable in colder climates but less accurate.

  • Maximum Thermometer:

    • Records highest temperature, uses expansion principle of mercury or alcohol.

1b. Digital Thermometers

  • Attributes:

    • Measure resistance changes, accurate to decimal degrees, constant data transmission to meteorologist's office.

Advantages of Digital Thermometers:

  1. Detect changes in resistance precisely.

  2. Provide continuous readings.

  3. Accuracy is high to fractions of a degree.

2. Measuring Air Humidity

  • Humidity: Amount of water vapor within a specific volume of air.

  • Relative Humidity: Indicates how much moisture air can hold; comparably higher in warm air.

Instrument: Hygrometer

  • Composition: Two thermometers - one dry and one wet-bulb.

  • Functionality: Uses evaporation to derive humidity from the temperature differential between wet and dry thermometers.

3. Measuring Precipitation

  • Definition: Any form of water (rain, hail, mist, sleet, snow) that falls to Earth. 1 mm equals 1 liter on 1 m².

  • Instrument: Rain Gauge,

    • Procedure: Collect water daily in a cylinder; readings taken from the meniscus level.

Water Measurement Procedure:

  • Ensure the gauge is level for accuracy and check at a consistent time daily.

4. Measuring Air Pressure

  • Air Pressure Definition: The weight of the air per unit area exerting pressure at a given altitude.

  • Sea Level Pressure: Approximately 1013.25 hPa (hectopascals).

  • Instrument: Barometer.

5. Measuring Wind Features

  • Wind Definition: Natural air movement from regions of high pressure to low pressure.

  • Wind Direction Measurement: Using a wind vane; includes cardinal directions (N, S, E, W).

  • Wind Speed Measurement: Anemometer.

6. Measuring Sunshine Hours

  • Definition: Measures the total amount of direct sunshine received over time.

  • Instrument: Campbell-Stokes sunshine recorder; sunlight burns a card, indicating hours of sunshine based on the length of the burn.

7. Stevenson Screen

  • Function: Shelters thermometers and hygrometers from ground heat and direct sunlight.

  • Design Specifications: Painted white to reflect sunlight, placed on legs to avoid heat from the ground, and structured for air circulation.

C. Presenting Weather and Climate Elements

1. Isoline Maps

  • Definition: Maps using lines connecting points of equal value.

  • Types:

    • Isohyets: Equal rainfall.

    • Isotherms: Equal temperature.

    • Isobars: Equal pressure.

2. Synoptic Maps

  • Usage: Pictorial weather summaries including wind speed, direction, pressure systems, cloud cover, and temperature.

  • Reading Techniques:

    • Pressure patterns indicate weather changes.

    • Wind speed characterized by the spacing between isobars.

    • Wind direction shows movement based on pressure systems.

3. Climate Graphs

  • Purpose: Visualizing average monthly temperature and precipitation over long periods.

  • Graph Interpretation: Identify seasonal patterns, calculate averages and extremes, assess overall climate trends.

Conclusion

  • Relevance of Understanding Weather: Crucial for forecasting and responding to atmospheric phenomena affecting daily life and economic activities. Further learning about weather measuring instruments and their impacts assists in comprehension of larger climatic patterns.