PhD Thesis, 2007 - University College Cork

Chapter 6
Water and energy budgets
The latent heat flux related well with net radiation (R n ) (Figure 6.11). Between 71
and 80 % of the variation in LE during the growing season was explained by R n .
The amount of R n used for LE was between 0.24 and 0.30, being highest in the
growing season in 2004/05 and lowest in 2005/06. We consider the offset in the
equations of Figure 6.11 to be due to the advective component of ET.
daytime 30-min good LE
[W m -2 ]
350
300
250
200
150
100
50
0
April-September 2003
LE=0.28*R n
+20.56; r 2 =0.75 300 LE=0.25*R n
+22.45; r 2 =0.75
250
200
150
100
50
0
0 200 400 600
0 200 400 600
350
April-September 2004
daytime 30-min good LE
[W m -2 ]
350
300
250
200
150
100
50
0
April-September 2005
LE=0.30*R n
+20.89; r 2 =0.71 300 LE=0.24*R n
+19.60; r 2 =0.80
250
200
150
100
50
0
0 200 400 600
0 200 400 600
daytime 30-min R n
[W m -2 ]
daytime 30-min R n
[W m -2 ]
350
April-September 2006
Figure 6.11. Relationship between 30-minute good LE and R n in the four studied
growing seasons. We considered the offset in each of these four figures to be due to
the advection component of ET.
100