### Measures & Units

Temperature
oC | degree Celcius
Energy
cal | calorie (1 cal = 4.184 J)
J | joule (1 J = 0.239 cal)
W | watt (J s-1)
Concentration
ppmv | parts per million by volume
ppbv | parts per billion by volume
pptv | parts per trillion by volume
DU | dobson unit
Distance
m | meter
Area
m2 | square meter
ha | hectare (104 m2; 10-2 km2)
Mass
g | gram
Tonne | metric tonne (106 g; 1000 kg)
Numbers
thousand | 103
million | 106
billion | 109
Time
s | second
d | day
yr | year
Prefixes
c | centi (10-2)
k | kilo (103)
M | mega (106)
G | giga (109)
T | tera (1012)
P | peta (1015)
E | exa (1018)