Geoscience Reference
In-Depth Information
APPENDIX
A
UNITS, CONSTANTS,
AND CONVERSIONS
UNITS:
Temperature:
Celsius (˚C) Kelvin (K) 273.15
˚C (5/9) (˚F 32)
temperature interval ˚C ˚K 1.8˚F
Distance: meter (m) or kilometer (km)
1 mile 1.6 km
Wind speed: meters per second (m/s)
1 mi/hr 0.446 m/s
Angular velocity: radians per second (s
-1
)
Precipitation rate: mm/day or cm/day
Pressure: 1 millibar (mb) 10
2
Pa (pascals) 10
2
kg/(m s
2
) 1 hPa (hectapascal)
Energy: joules (J) (kg m
2
)/s
2
Heating rates: joules per second (J/s) Watts (W)
Radiation flux density: heating rate per unit area [W/m
2
J/(m
2
s)]
Atmospheric concentration: parts per million by volume (ppm)
parts per billion by volume (ppb)
parts per trillion by volume (ppt)
Salinity: practical salinity units (psu)
CONSTANTS, WITH THE SYMBOLS
USED IN THIS TOPIC:
Radiation constants:
Stefan-Boltzman constant (s) 5.67 10
−8
W/(m
2
K
4
)
Planck's constant (h) 6.626 10
−34
J s
Boltzmann constant (k) 1.38 10
−23
J/K
speed of light (c) 3.00 10
8
m/s
The Sun:
solar “constant” (S
0
) 1368 W/m
2
solar luminosity (L
S
) 3.9 10
26
J/s
solar radius 6.96 10
5
km
average Earth-sun distance 1.50 10
8
km
