Clouds & Precipitation Sections 2.3 & 2.4 1/2/2019 8:25 AM Clouds & Precipitation Sections 2.3 & 2.4 By: Dr. Abdulaziz Taqi PhD Ali Al Osaimi Musaed Al Hazeem Hadi Dahbour © 2007 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Please save all questions for the end of the lecture Please save all questions for the end of the lecture. If you behave, there will be two bonus questions on your quiz!

Vocab 2.3 Evaporation, the process by which a liquid changes into a gas Condensation, the process by which a gas changes into liquid. Occurs when moist air cools

Precipitation, any type of liquid or solid water that falls to Earth’s surface Humidity, the amount of water vapor in the air. Saturation, the conditions when condensation and evaporation are equal

Relative humidity, compares the amount of water vapor in air with the maximum amount of water vapor that can be present at that temperature Dew point, the temperature at which air with a given amount of water vapor will reach saturation

Types of Clouds

Cirrus Form in very cold air High altitudes Have a feathery appearance Can be a sign that a storm is coming

Cumulus Puffy-looking cotton ball like Appear in fair weather, usually at daytime Cooler sinks along the sides, keeping them separated from each other The cumulonimbus cloud is the biggest and can be up to 18 kilometers high

Stratus Form in layers when air cools over a large area without rising Grey and dark looking If formed at high altitudes, much thinner

Fog A cloud that rests on the ground or a body of water Forms when a surface is colder than the air above Cleared when the ground is heated by sunlight

Vocab 2.4 Freezing rain, raindrops that freeze when they hit the ground or other surfaces. Sleet, when rain passes through a layer of cold air and freezes before hitting the ground

Hail, lumps of ice that fall from cumulonimbus clouds Acid rain, rain that is more acidic than normal because of pollution

Precipitation All comes from clouds There are two ways that precipitation forms Cloud droplets collide with each other to form raindrops Growth of ice crystals When a cloud is freezing, cloud droplets become ice crystals

Types of Precipitation There are 6 types of precipitation Rain, freezing rain, acid rain, sleet, snow, hail

Rain Most common type of precipitation Form from both cloud droplets and ice crystals that melt before as they fall Light rain with very small drops is called drizzle

Freezing Rain Rain that freezes when it hits the ground or other surfaces The weight of the ice can bring down trees and power lines

Sleet When rain passes through a layer of cold air and freezes before hitting the ground The small pellets of ice are called sleet NOT TO BE CONFUSED WITH HAIL!!!!!!!!

Snow Form as ice crystals grow and merge in clouds When falling through moist air, snowflakes join together When it falls through dry air, they don’t join and the snow is powdery

Hail Lumps of ice that fall from cumulonimbus clouds Water grows on frozen ice pellets again, and again until it eventually falls as hail The biggest hailstone ever found weighed 1.7 pounds

Acid Rain Rain that is more acidic than normal because of pollution Factories, automobiles, and power plants release sulfur dioxide into the air which is combined with the water vapor

Cats & Dogs By far the most dangerous form of precipitation Falls after tornadoes or report card day