2.3. Weather measurements
Rainfall, global radiation, and air temperature were measured
hourly by a weather station (ENERCO 411, Cimel Electronique,
France) located 500 m from the plot. Daily global radiation (Rg
d
,
MJ m
2
) was used to calculate the daily reference evapotranspira-tion (ETPr
d
, mm) by applying the equation proposed by Bastergue
(1988) for the local conditions of Guadeloupe:
ETPr
d
¼ Rg
d
0 :24: (1)
For modelling purposes we estimated a moisture index for each
regrowth period of the grass (Im
p
, mm day
1
):
Im
p ¼ R p ETPr
p
(2)
where R p
(mm day
1
) and ETPr
p
(mm day
1
) are the daily mean
rainfall and reference evapotranspiration of the regrowth period p,
respectively. Weather conditions for the four regrowth periods of
the grass are presented in Table 2.