Tropical Storms and Low Pressure Hazards

Atmospheric Pressure and the Equator

• The sun's energy is concentrated on a smaller area at the Equator, leading to higher temperatures.

• Hot, less dense air rises at the Equator, creating a low-pressure band known as the Intertropical Convergence Zone (ITCZ).

• As this air rises, it cools, becomes denser, and descends around 30 degrees north and south of the Equator, resulting in high-pressure bands.

Formation and Characteristics of Tropical Storms

• Ocean temperatures reach above $26^{\circ}C$$$26^{\circ}C$$ at different times of the year, leading to tropical storm seasons.

• Tropical storms develop over oceans between $5^{\circ}$$$5^{\circ}$$ and $30^{\circ}$$$30^{\circ}$$ north and south of the Equator, but never directly on the Equator.

• They weaken rapidly upon making landfall or moving over cooler waters.

• Tropical storms are fueled by warm ocean waters (above $26^{\circ}C$$$26^{\circ}C$$).

• Significant water vapor evaporates and rises, creating very low-pressure systems.

• As the air rises, it cools, condenses, and forms large cumulonimbus clouds, producing substantial rainfall.

• Air rushes in to fill the low pressure, leading to strong winds.

• The Coriolis effect deflects these winds, causing them to spin around the eye, which is the calm center of the storm.

• The eyewall, surrounding the eye, experiences the highest wind speeds and rainfall.

Impact of Global Warming on Tropical Storms

• Global warming is expected to:

  • Increase the power of tropical storms due to higher evaporation rates from warmer temperatures.

  • Increase the frequency of tropical storms as oceans remain above $26^{\circ}C$$$26^{\circ}C$$ for longer periods, extending storm seasons.

  • Expand the geographical range of tropical storms as larger ocean areas exceed $26^{\circ}C$$$26^{\circ}C$$.

Secondary Effects: Storm Surges

• Storm surges are secondary effects of tropical storms, causing sea levels to rise.

• Strong winds push water towards the shore, and low pressure causes a bulge of water to rise in the storm center.

Saffir-Simpson Hurricane Intensity Scale

• Used to classify the intensity of tropical storms, specifically hurricanes.

Seasons and Movements of Tropical Storms

• Cyclones occur from October to May.

• Typhoons occur from April to January.

• Hurricanes occur from May to November, and June to November.

Key Components of a Tropical Storm

• Eye: The calm center of the storm.

• Spiral Bands: Bands of thunderstorms rotating around the eye.

• Ocean: The source of warm, moist air that fuels the storm.

• Diverging Airflow: Occurs in the upper atmosphere.

• Convergence of Moist Warm Air: Near the surface.

Linking Impacts and Consequences

• Impacts and consequences should be linked together in sentences using connectives such as:

  • …this caused…

  • …as a result of…

  • …this meant…

  • …due to…

  • …consequently…

  • …therefore…

  • …so…

  • …because…

Pressure Systems

• Air sinks at $60^{\circ}N$$$60^{\circ}N$$ and $30^{\circ}N$$$30^{\circ}N$$ resulting in high pressure.

• Air rises at the Equator resulting in low pressure.