Symbols and acronyms

$α$	Albedo
$α_{p}$	Planetary albedo
$δ$	Solar declination
$δ$ ¹³C	Delta value for the relative abundance of ¹³C in a sample
$δ$ ¹⁸O	Delta value for the relative abundance of ¹⁸O in a sample
$Δ Q$	Radiative forcing at the tropopause
$ε$	Emissivity of an object
$ε_{o b l}$	Obliquity
$φ$	Latitude (on Earth)
$ρ$	Density
$θ_{s}$	Solar zenith distance
$λ$	Longitude (on Earth)
$λ_{f}$	Feedback parameter
$λ_{t}$	True longitude
$η$	Sea-surface elevation
$σ$	Stefan-Boltzman constant (= 5.67 10^-8 W m^-2 K^-4)
$\tilde{ω}$	Infrared transmissivity of the atmosphere
$τ_{a}$	Longitude of the perihelion measured from the vernal equinox
$\vec{Ω}$	Angular velocity vector of the Earth

AABW	Antarctic Bottom Water
AAIW	Antarctic Intermediate Water
ACC	Antarctic Circumpolar Current
AD	Anno Domini, yr AD is the number of years since the beginning of the Christian (or Common) era
AGCM	Atmospheric General Circulation Model
$A l k$	Alkalinity
AOGCM	Atmosphere Ocean General Circulation Model
BC	Before Christ, yr BC is the number of years before 1AD
BP	Before Present, i.e. before 1950 AD
C	Condensation
CDW	Circumpolar Deep Water
CGCM	Coupled General Circulation Model
$c_{p}$	Specific heat (J kg^-1 K^-1)
CRF	Cloud Radiative Forcing
DGVM	Dynamic Global Vegetation Model
DIC	Dissolved Inorganic Carbon
DJF	December, January and February
E	Evaporation
EBM	Energy Balance Model
ecc	Eccentricity
EMIC	Earth Model of Intermediate Complexity
ENSO	El Niño Southern Oscillation
$e_{s}$	Saturation vapour pressure (Pa)
$f_{f}$	Feedback factor
F_fric	Force due to friction
$F_{I R ↓}$	Downward longwave radiation at the surface (W m^-2)
$F_{I R ↑}$	Upward longwave radiation at the surface (W m^-2)
F_LH	Latent heat flux at the surface (W m^-2)
F_SH	Sensible heat flux at the surface (W m^-2)
F_SOL	Incoming solar radiation at the surface (W m^-2)
g	Acceleration due to gravity at the Earth's surface (= 9.8 m s^-2)
GCM	General Circulation Model
GtC	Gigaton of carbon (10¹⁵ grams of carbon)
HA	Hour Angle
IPCC	Intergovernmental Panel on Climate Change (`http://www.ipcc.ch/`)
ITCZ	Intertropical Convergence Zone
J	Joule
JJA	June, July and August
K	Kelvin
ka	1000 years
K_H	Solubility (of CO₂)
kyr	1000 years
L_f	Latent heat of fusion of water (= 334 kJ kg^-1 at 0^oC)
LGM	Last Glacial Maximum (around 21 kyr BP)
L_v	Latent heat of vaporisation of water (= 2250 kJ kg^-1 at 100^oC, 2500 kJ kg^-1 at 0^oC)
m	Metre
NADW	North Atlantic Deep Water
NAM	Northern Annular Mode
NAO	North Atlantic Oscillation
nm	Nanometre (10^-9 m)
NPP	Net Primary Production
OGCM	Ocean General Circulation Model
p	Pressure (Pa)
p_s	Surface pressure (Pa)
P	Precipitation
Pa	Pascal
PDE	Partial Differential Equations
PERH	Longitude of the perihelion measured from the autumn equinox
PETM	Paleocene Eocene Thermal Maximum
PFT	Plant Functional Type
PgC	Petagrams of carbon (10¹⁵ grams of carbon)
ppb	Parts per billion
ppm	Parts per million
psu	Practical salinity unit
PW	10¹⁵ W
q	Specific humidity (kg/kg)
R	Earth's radius (= 6371 km)
R_g	Perfect gas constant
RF_TOA	Net radiative flux at the top of the atmosphere (W m^-2)
RH	Relative Humidity
r_m	Mean distance between the Earth and the Sun
RMS	Root Mean Square
R_riv	River runoff
R_v	Gas constant for water vapour (= 461.39 J kg^-1 K^-1)
S	Ocean salinity
S₀	Solar constant (~ 1368 W m^-2)
SAM	Southern Annular Mode
SLP	Sea Level Pressure
SOI	Southern Oscillation Index
SST	Sea Surface Temperature
Sv	Sverdrup (= 10⁶ m³ s^-1)
TCR	Transient Climate Response
T_e	Effective emission temperature of the Earth
T_s	Surface temperature
$\vec{v}$	Velocity vector
W	Watt
WMO	World Meteorological Organisation
yr	Year
z	Altitude depth, measured from the bottom upwards