ATOC 4720: class 5 1. The fair weather atmospheric electric field 1. The fair weather atmospheric electric field The atmospheric temperature distribution The atmospheric temperature distribution

1. The fair weather electric field 10-50km

Most electrons: >60km 80km

Magnitude near the earth’s surface 120V/m: global mean 120V/m: global mean 130V/m over ocean 130V/m over ocean 360V/m industrial region 360V/m industrial region >100km, conductivity of air increases with height--the fair weather electric field decreases with height >100km, conductivity of air increases with height--the fair weather electric field decreases with height

Electrosphere carries a net positive charge; Electrosphere carries a net positive charge; The erath’s surface a net negative charge; The erath’s surface a net negative charge; Average electric current: 2-4 Average electric current: 2-4

Question: The electric field in the atmosphere is nearly constant with time although there is electric current that would be large enough to discharge the capacitor. What does this mean? The electric field in the atmosphere is nearly constant with time although there is electric current that would be large enough to discharge the capacitor. What does this mean?

Answer: There must be an electric generator in the atmosphere/earth system. There must be an electric generator in the atmosphere/earth system. Thunderstorms: widely accepted idea Thunderstorms: widely accepted idea

10-50km

Elecrical Budget for the earth: 90 units gained from fair weather conductivity (positive charges); 90 units gained from fair weather conductivity (positive charges); 30 units from precipitation (positive charges); 30 units from precipitation (positive charges); 100 units lost by point charges; 100 units lost by point charges; 20 units lost due to transfer of negative charges by lightning. (C/km2/yr) 20 units lost due to transfer of negative charges by lightning. (C/km2/yr)

2. The temperatuer distribution andits meansurement Early exploration: manned balloon flights-- provided first conclusive evidence that within 10km, temperature decreases with height at a rate of about 7C, which is called lapse rate (troposphere). Early exploration: manned balloon flights-- provided first conclusive evidence that within 10km, temperature decreases with height at a rate of about 7C, which is called lapse rate (troposphere). >10km, T constant or increases with Z: (stratosphere) (1902) >10km, T constant or increases with Z: (stratosphere) (1902) 1920’s: radiosonde: unmanned balloon; modern--up to 40km; (born aloft by rockets: km). 1920’s: radiosonde: unmanned balloon; modern--up to 40km; (born aloft by rockets: km).

2. The temperature distribution and its measurement 80% mass All water (homo or heter?) Sharp drop In water