ESTIMATION OF PAN EVAPORATION COEFFICIENTS - Management, Performance, and Applications of Micro Irrigation Systems - page 109

FIGURE 5 Average monthly pan evaporation with time at Corozal, Isabela and
Fortuna, Puerto Rico.

TABLE 1 Linear regression results for the pan evaporation data from the seven
substations.

Station Lati-

tude

Eleva-
tion
(m)

NOAA
Cli-
mate
Divi-
sion

Regres-
sion
Coefficient
(slope
of line)

r 2

Signif-
icant
at the
5%
level

Trend

Gurabo 18°15'N 48 5 0.029 0.55 Yes Increasing

Adjun-
tas

18°11'N 549 6 0.021 0.47 Yes Increasing

Corozal 18°20'N 195 6 0.010 0.11 No Increasing

Isabela 18°28'N 126 3 -0.008 0.08 No Decreasing

Fortuna 18°01'N 21 2 -0.015 0.10 No Decreasing

Río Pie-
dras

18°24'N 100 3 -0.019 0.28 Yes Decreasing

Lajas 18°03'N 27 2 -0.055 0.81 Yes Decreasing

Regression coeffi cients associated with the linear regression lines shown
in Fig. 5 were not statistically signifi cant. The linear regression results are
summarized in Table 1. Following noteworthy results can be summarized
from Figs. 3 to 5 and Table 1:
• Lajas had the greatest decrease in the average monthly pan evapora-
tion: 1.4 mm per month (average) per year. This amount is equivalent to