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Appendix VI - Units
SI (Systeme Internationale) Units:
 |
| Physical Quantity |
Name of Unit |
Symbol |
|
| length |
metre |
m |
| mass |
kilogram |
kg |
| time |
second |
s |
| thermodynamic temperature |
kelvin |
K |
| amount of substance |
mole |
mol |
|
|
|
Fraction
|
Prefix
|
Symbol
|
Multiple
|
Prefix
|
Symbol
|
|
|
10-1
|
deci
|
d
|
10
|
deca
|
da
|
|
10-2
|
centi
|
c
|
102
|
hecto
|
h
|
|
10-3
|
milli
|
m
|
103
|
kilo
|
k
|
|
10-6
|
micro
|
µ
|
106
|
mega
|
M
|
|
10-9
|
nano
|
n
|
109
|
giga
|
G
|
|
10-12
|
pico
|
p
|
1012
|
tera
|
T
|
|
10-15
|
femto
|
f
|
1015
|
peta
|
P
|
|
Special Names and Symbols for Certain SI-Derived Units:
|
| Physical Quantity |
Name of SI Unit |
Symbol for SI Unit |
Definition of Unit |
|
| force |
newton |
N |
kg m s-2 |
| pressure |
pascal |
Pa |
kg m-1 s-2 (=N m-2) |
| energy |
joule |
J |
kg m2 s-2 |
| power |
watt |
W |
kg m2 s-3 (=J s-1) |
| frequency |
hertz |
Hz |
s-1 (cycles per second) |
|
Decimal Fractions and Multiples of SI Units Having Special Names:
|
| Physical Quantity |
Name of Unit |
Symbol for Unit |
Definition of Unit |
|
| length |
Ångstrom |
Å |
10-10 m = 10-8 cm |
| length |
micron |
µm |
10-6 m |
| area |
hectare |
ha |
104 m2 |
| force |
dyne |
dyn |
10-5 N |
| pressure |
bar |
bar |
105 N m-2 = 105 Pa |
| pressure |
millibar |
mb |
102 N m-2 = 1 hPa |
| mass |
tonne |
t |
103 kg |
| mass |
gram |
g |
10-3 kg |
| column density |
Dobson units |
DU |
2.687x1016 molecules cm-2 |
| streamfunction |
Sverdrup |
Sv |
106 m3 s-1 |
|
|
| Non-SI Units: |
|
| °C |
degree Celsius (0 °C = 273 K approximately)
Temperature differences are also given in °C (=K) rather than the more
correct form of “Celsius degrees”. |
| ppmv |
parts per million (106) by volume |
| ppbv |
parts per billion (109) by volume |
| pptv |
parts per trillion (1012) by volume |
| yr |
year |
| ky |
thousands of years |
| bp |
before present |
|
|
| The units of mass adopted in this report are generally
those which have come into common usage and have deliberately not been harmonised,
e.g., |
|
| GtC |
gigatonnes of carbon (1 GtC = 3.7 Gt carbon dioxide) |
| PgC |
petagrams of carbon (1 PgC = 1 GtC) |
| MtN |
megatonnes of nitrogen |
| TgC |
teragrams of carbon (1 TgC = 1 MtC) |
| Tg(CH4) |
teragrams of methane |
| TgN |
teragrams of nitrogen |
| TgS |
teragrams of sulphur |
|
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