T
Time-dimensional parameter; absolute temperature
T Ã
Friction temperature
T a
Air temperature
T c
Canopy temperature
T
Ã
E
Apparent equivalent temperature
T f
Effective temperature
T n
Temperature at cloud bottom
T o
Regression constant (−46.03 ºC)
T ref
Reference temperature
T S
Sonic temperature (K)
T v
Virtual temperature
TKE
Turbulent kinetic energy
t
Apparent local solar time; period where Sun is above horizon;
Eulerian time scale
t j
Julian day
U
Mean velocity
UCL
Uptake of CO 2 by land
UCO
Uptake of CO 2 by the oceans
UNEP
United Nations Environment Programme
UNFCCC United Nations Framework Convention on Climate Change
U D
Air velocity along linear space between transducers in sonic
anemometer
U ai
Unidirectional airflow after contact with transducers
U i
Unidirectional airflow before contact with transducers
U N
Air velocity component in normal direction to space over space
between transducers in sonic anemometer
UPE
Variable power flow resistance
u c
Wind velocity constant
u Ã
Friction velocity
u hc
Mean air velocity at canopy height
W
Space between buildings
WMO
World Meteorological Organization
WPL
Webb–Pearman–Leuning coefficient
Z Ã
Total height of rough sublayer
z Ã
Height of roughness sublayer above level d
z 0H
Roughness length for sensible heat
z 0T
Roughness length for sensible heat
z 0V
Roughness length for latent heat
z 0M
Roughness length for linear momentum
z 01 , z 02
Upwind and downwind aerodynamic roughness length from contact
point
z h
Atmospheric boundary layer height
z i
Day time atmospheric mixed boundary layer height
Acronyms
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