Natural Disasters Week 7

Relative Humidity

  • Ratio of water vapor in the air to the amount of water vapor air could contain at a given temp

  • The warmer it is, the more spread-out gas molecules, so the more water vapor molecules you can get into the air.

  • The more vapor in the air at a given temp, the harder it is to get more in

  • Cool air cannot hold much water vapor, so it is typically dry

  • Warm air can hold more water vapor, so is typically moist

  • If temps are equal, the rate of condensation/evaporation will depend on how much water vapor is in the air

Cloud Formation

  • Clouds form when water molecules in supersaturated air collect on aerosols to form tiny liquid droplets and ice particles

  • Raindrops are spheres of water > 0.5mm in dimeter that are too heavy to overcome air resistance and fall towards the ground

  • Droplets can’t get bigger than 4 mm

  • If there is enough aerosols, you get snow

  • If there is not enough aerosols, you get super cooled water

Wind

  • Three forces of air, pressure gradient, frictional force, Coriolis force

  • Air moves from high pressure to low pressure

  • Velocity depends on the size of the pressure difference over a given distance

  • Coriolis effect - the apparent east-west deflection of air currents observed in convective cells

  • Less dense, warmer air rises, creating vertical currents

FAVORITE FOOD: BROWNIES
FAVORITE WEATHER: THUNDERSTORMS

Fronts

  • A cold front occurs when cold air moves in and pushes under a warm air mass.

  • A warm front forms when warm air slowly slides over a retreating cold air mass.

  • A stationary front happens when two air masses meet but neither one moves much.

  • An occluded front forms when a cold front catches up to a warm front.

  • Polar front divides warm air originating in the tropics and polar air originating in the arctic or sub arctic

  • Polar vortex is the spin of air around the north pole