Weather and Climate Notes

Difference between Weather and Climate

  • Weather:

    • Defined as short-term atmospheric conditions (natural variables such as sun, rain, snow, etc.).

    • Fluctuates from day to day; includes temperature, humidity, precipitation, and wind conditions.

  • Climate:

    • Refers to long-term average of weather patterns in a specific area.

    • Typically assessed over a period of 30 years or more.

Significance of Weather

  • Impact on Daily Life:

    • Changes in weather affect mood, activities, and perspectives.

  • Severe Weather Events:

    • Includes tornadoes, hurricanes, blizzards, etc.

    • These events can cause significant disruption to lives and communities due to destruction and damage.

  • Economic Activities:

    • Weather influences agriculture, tourism, and local economies, impacting livelihood and access to resources.

Measuring Weather Elements

Measuring Air Temperature

  • Importance of Accurate Measurement:

    • Essential for understanding immediate environmental conditions and for monitoring climate change.

  • Method of Measurement:

    • Thermometers must be isolated from outside influences to provide accurate readings.

  • Types of Thermometers:

    • Historically, thermometers utilize liquids (mercury and alcohol) that expand when heated.

    • Accuracy: Mercury thermometers are more precise but are hazardous due to mercury's toxicity.

  • Max/Min Thermometer (Six's Thermometer):

    • Records highest and lowest temperatures over a given period.

Structure of Six's Thermometer

  • Components:

    • U-shaped glass tube with two independent temperature scales.

    • Right tube indicates maximum temperature, left tube indicates minimum temperature.

    • Sealed glass bulbs at tube ends; left bulb contains alcohol, right bulb holds a vacuum.

Working Mechanism

  • Temperature Increases:

    • Alcohol in left tube expands, moving mercury toward the right tube, marking the maximum temperature.

  • Temperature Decreases:

    • Alcohol contracts, mercury shifts to the left tube, marking the minimum temperature.

Digital Thermometers

  • Advantages over Traditional Thermometers:

    1. Higher safety (no toxic materials like mercury).

    2. Greater accuracy (down to fractions of a degree).

    3. Continuous broadcasting of readings to meteorologist's office for real-time data.

Measuring Precipitation

  • Definition:

    • Any form of water (hail, mist, rain, sleet, snow) falling to the earth.

  • Measurement Unit:

    • Measured in millimeters (mm); where 1 mm equals 1 liter of water per 1 square meter.

  • Instrumentation:

    • A rain gauge is used to collect and measure precipitation.

Rain Gauge Operation

  • Collect water daily into a tapered measuring cylinder.

  • Read level at eye level with the lowest part of the meniscus of the water.

  • Record measurements accurately; if too small, record as 'trace'.

Key Components of Rain Gauge

  • Metal cylinder, tapered inside for measuring accuracy.

  • Top part of the rain gauge is positioned at 30 cm above ground for effective capture of precipitation without interference.

Key Terminology and Differences

Differences in Precipitation Types

  • Rain vs. Drizzle:

    • Rain is characterized by larger droplets than drizzle, which falls lightly.

  • Snow vs. Hail:

    • Snow is soft and fluffy, formed from ice crystals during freezing atmospheric conditions.

    • Hail consists of hard, rounded pellets produced in thunderstorms.

  • Mist vs. Rain:

    • Rain involves large, heavy droplets, while mist has smaller, lighter droplets.

  • Sleet vs. Hail:

    • Sleet refers to frozen raindrops, while hail is larger and forms during thunderstorms in strong updrafts.