Temperature

a measure of the average speed at which molecules are moving or vibrating.

Temperature scales Freeze Boil Celsius 100 Fahrenheit 32 212 Kelvin 100 Fahrenheit 32 212 Kelvin 273 373

Conversions oF = (1.8 x oC) + 32 oC = 0.56 (oF – 32) K = oC + 273

What Controls temperature? 1. Insolation differences (latitudinal , seasonal, daily) 2. Proximity to water bodies (land/water distribution) 3. Elevation 4. Ocean currents 5. Cloud Cover

1. Insolation a. Latitudinal High latitudes receive less insolation than low latitudes because… sun’s rays are more oblique Day length is variable Net energy surplus in tropics; net energy deficit in polar regions demonstrate

b. Seasonal Changing angle of sun throughout the year changes temperature on a seasonal basis.

c. Daily (diurnally) Changing angle of sun throughout the day changes temperature on a daily basis.

Diurnal temperature pattern Temperature increases as long as net all wave incoming exceeds net all wave outgoing. Min: end of deficit Max: end of surplus

2. Proximity to water bodies Water bodies have a moderating effect on temperature. Maritime locations (coastal, island) have smaller daily and annual ranges in temp than continental locations demonstration

Small effect from Lake Superior on Duluth temperatures Warmer winters, cooler summers near lake vs inland Top of the hill vs. harbor Harbor warmer in fall; cooler in spring Extreme example (May 2009)

3. Elevation Temperature decreases as elevation increases. less mass, less pressure, less absorption

4. Ocean Currents Ocean exchanges heat with atmosphere and therefore influences air temperature.

Gulf Stream

5. Cloud Cover Exert influence on shortwave and longwave exchanges: Very efficient absorbers and emitters of longwave Reduce incoming shortwave High albedo

Net Result: Dampen diurnal temp range Cloudy: uniform temps, small diurnal range Clear: daytime high insolation and nighttime loss of longwave; large diurnal range About cloud measurement

Factors affecting the air temperature of a place: Review: Factors affecting the air temperature of a place: Insolation differences at various latitudes, during seasons, during the course of a day Proximity to big water bodies Elevation Ocean currents Cloud cover