Weather Basics Temperature Pressure Moisture

Temperature

Diurnal Temperature: Why?

Lag time varies, Phoenix Zoo

Global Pattern Warm Lower Latitudes Cold Mtns Cold Higher Latitudes Cold Currents

Classroom Resource Global pattern shows warmer in lower latitudes; colder in higher latitudes

Why Latitude Temp Differences?

Seasonal Changes: more with higher latitudes and warmth follows the sun

Temperature Differences Create Climate Zones

Why San Diego “even” climate and Phoenix more “extreme”?

Cold and Warm currents influence temperature THINK San Diego vs Phoenix

Classroom Resources Can see continentality in these movies (bigger changes in temperature between winter and summer in the middle of North America

East Coasts: Warm Water

Pressure

Classroom Resource: Sea Breeze as example of pressure gradient

Cold Air Drainage

Most intense closest to poles because greatest difference in speed of rotation

Classroom Resources

Online Resource Atmospheric Pressure and Wind Animations visualization/collections/atmospheric_pres sure.html

Coriolis Effect impacts more than atmosphere and oceans

Geostrophic Wind

Combination of all 3

Effect of Friction: cross the isobars

Classroom Resource

Divergence at surface generates uplift and cloud formation

Opposite in So. Hemisphere

Global Patterns of Pressure Drive Earth’s Climates: Example of Asian Monsoon Winter High Pressure Siberia. Air flow from Siberia (dry air) outward

Winter Dry Summer Wet

Then, in summer, winds reverse

Monsoon (singular) is a seasonal wind shift

Indus Floods Before After

Before

Arizona (Mexican) Monsoon: Wind shift from westerly winds

To easterly winds

Season shift in wind brings trpoical moisture from east and south

Mexican Monsoon, as reflected by percentage of rain in summer

Moisture at mid-levels generates weaker storms

Lower-level moisture often comes from the gulf, giving sudden surge of moisture

Combination of mid and low level moisture generates stronger storms

July – mid September (storms not Monsoons)

Classroom Resource: Movie showing global patterns in water vapor Dark – little water vapor Bright: lots of water vapor

Example of Condensation by Adding Moisture: Lake Effect Snows

Example of Condensation by Cooling: Advection Fog

Advection Fog Common over Cold Currents

California Cold Current produces fog

Example of Condensation by Cooling: Air Goes Up & Cools

Can go up by convergence

Cloud Types

Vertical Development: Cumulus

More horizontal flow: Stratus

Online Resource

Need to get large enough to drop out

Classroom Resource: Precipitation in the U.S. throughout the year Watch Arizona in monsoon months (wetter) Watch Pacific Northwest in winter (wetter)

Global Pattern of Precipitation More around equator Less in subtropics More around latitude 50 Seasonal shifts (summer monsoon in low laittudes; winter storms in higher latitudes)

Another way of thinking about moisture: Air Masses

Classroom Resources Can see outbreaks of Continental Polar air in movie Can see Arizona develop Continental Tropical Air mass in June

Global Air Masses

Online Resources Atmosphere Animations ctions/atmosphere.html Atmospheric Heating Animations ctions/atmospheric_heating.html Moisture Animations ctions/moisture.html

Imagery seen in this presentation is courtesy of Ron Dorn and other ASU colleagues, students and colleagues in other academic departments, individual illustrations in scholarly journals such as Science and Nature, scholarly societies such as the Association of American Geographers, city, state governments, other countries government websites and U.S. government agencies such as NASA, USGS, NRCS, Library of Congress, U.S. Fish and Wildlife Service USAID and NOAA.