Thermal Response II Current News and Weather Surface Energy Balance Controls of Air Temperature Tropics vs. Middle and High Latitudes For Next Class: Read Chapter 6 Exam 1 on Wednesday (2/7)! (Review sheet is posted)

Discussion 1. Why do maritime locations typically exhibit more moderate climates (cooler in summertime, warmer in winter) than continental locations at the same latitude?

Land–Water Heating Differences Figure 5.7

Thermal Response and Specific Heat Maritime and Continental Climates Maritime climates: immediately downwind of the ocean, and experience much less contrast between average winter and summer temperature Continental Climates: well inland, experience a much greater contrast between winter and summer temperature © AMS

Latitude and Temperature Figure 5.4

Discussion 2. What is the Bowen Ratio? Which locations are characterized by high Bowen Ratios and which have low ones?

Heat Imbalance: Atmosphere vs. Earth’s Surface Sensible Heating The Bowen Ratio compares how heat at the Earth’s surface is divided between sensible heating and latent heating Varies from one place to another Depends on amount of surface moisture Surface energy budget through the course of a year © AMS

Bowen Ratio Bowen ratio = (sensible heating)/(latent heating) High Bowen ratio implies more sensible heating than latent heating (i.e., deserts) Low Bowen ratio implies more latent heating than sensible heating (i.e., oceans or water bodies)

Heat Imbalance: Atmosphere vs. Earth’s Surface © AMS

Surface Energy Balance Figure 4.15

Albedo (Reflectivity of a Surface) Figure 4.5

Simplified Surface Energy Balance NET R = +SW (insolation) –SW (reflection) +LW (infrared) –LW (infrared) Figure 4.16

Daily Radiation Curves Figure 4.14

Temperature Where is the coldest location in the world likely to be in January? Why? In July? Why? Which location has the greatest annual temperature range? Why?

January Temperatures Figure 5.14

July Temperatures Figure 5.17

Global Temperature Ranges Figure 5.19

What is Wind?

What is Wind? Horizontal movement of air Moves from areas of high pressure to areas of low pressure Above the surface, winds are geostrophic (parallel to isobars) and result from a combination of two forces: Pressure Gradient Force (High to Low) Coriolis Effect (Right in NH, Left in SH)

Pressure Gradient Figure 6.7

Coriolis Force Figure 6.9

Upper Level Winds What are the two forces that influence wind direction in the upper levels of the troposphere (i.e., above 12,000 ft or ~600 mb)?

Surface Winds What are the three forces that influence wind direction at the surface?