Satellite Image Basics  Visible: Senses reflected solar (lunar) radiation Visible –Cloud thickness, texture; not useful at night  Infrared (IR): Senses IR radiation emitted by earth and atmosphere Infrared –Cloud-top temperature and thus height  Water Vapor: Senses radiation emitted by water vapor (6.7 micron wavelength) Water Vapor Water Vapor –Tracks atmospheric motion even when no clouds

Atmospheric Absorption  High-energy (U-V) radiation High-energy  Lower-energy (IR) radiation Lower-energy –Greenhouse gases –Keep planet 60F warmer than without –ENHANCED GREENHOUSE EFFECT  Total Atmosphere Total Atmosphere Total Atmosphere –Visible radiation poorly absorbed

Distribution of Solar Radiation  Total entering top of atmosphere 100% –< one billionth of the sun’s energy  Reflected = 30% (Albedo of earth = 0.3)  Absorbed by atmosphere = 19%  Absorbed at earth’s surface = 51%

THE SUN WARMS THE GROUND AND THE GROUND WARMS THE AIR!!!  Conduction  Convection (hot air rises)  Vertical temperature structure  Elevation Elevation

Temperature Variation  Seasonal (tilt of earth’s axis) Seasonal (tilt of earth’s axis) Seasonal (tilt of earth’s axis)  Diurnal  Effect of clouds on diurnal cycle Effect of clouds on diurnal cycle Effect of clouds on diurnal cycle –Decrease daytime temperature –Increase nighttime temperature  all else being equal!

Seasonal Temperature Lag  Delay between maximum (minimum) solar input and maximum (min) temperature Delay between maximum (minimum) solar input and maximum (min) temperature Delay between maximum (minimum) solar input and maximum (min) temperature –Just like pizza in the oven  Heat Capacity of water is 3 times that of land –Sunlight penetrates water –Constant mixing (waves, currents) –Maritime locations generally have larger lag time

Key Figures  2.9, 2.10, 2.13, 2.19, 2.20, 3.2, 5.8, 5.14, 5.20