Agriculture Reference
In-Depth Information
water vapour pressure under certain given
conditions, with respect to the saturation
water vapour pressure (
e
s
). RH = 100(
e
a
/
e
s
).
It changes with temperature.
4.
By the vapour pressure deficit (VPD) or
saturation deficit. This expresses the amount
of water that the air, at a certain temperature,
can still absorb before reaching saturation.
(a)
Almeria (Spain)
30
Jun
Jul
May
25
Apr
Aug
20
Mar
15
Sep
Feb
Oct
10
Jan
Nov
5
Dec
0
0
5
10
15
20
25
30
Tenerife (Spain)
Jul
30
Jun
May
Aug
25
Apr
Mar
20
Sep
15
Feb
Oct
10
Jan
Nov
Dec
5
0
0
5
10
15
20
25
30
30
De Bilt (The Netherlands)
25
Jun
20
May
Jul
Aug
15
Apr
Sep
Mar
10
Feb
5
Oct
Jan
Dec
Nov
0
0
5
10
15
20
25
30
Temperature (°C)
Fig. 2.15.
Global radiation and average outside air temperature for an average year in (a) Almeria and
Tenerife (Spain) and De Bilt (The Netherlands) (data from FAO; Kamp and Timmerman, 1996;
experimental Station 'Las Palmerillas', Almeria, Spain); (b) at Mexican locations of different altitudes:
Culiacán (84 m), ensenada (13 m) and Guanajuato (2050 m) (data from FAO).
