Abstract:
In this thesis, we aimed to simulate papaya pollen distribution under various conditions using
CALPUFF modeling system. The input information for this model includes (a) Upper air data
obtained from Thai Meteorological Department at Bang-Na meteorological station (b) On-site
data obtained from an on-site weather device located at the actual plantation area, Kasetsart
University, Kamphaeng Saen Campus (c) Average mass of a papaya pollen and its diameter
measured in a laboratory (d) Emission rate of papaya pollens in a worst case obtained from
field experiments. It was found that the average mass and diameter of a papaya pollen are
11.755+1.468 ng. and 25.11 +1.05 J.lm, respectively. The estimated emission rate of papaya
pollens in a worst case is about 8 pollen/m2s. With these given information, CALPUFF can
simulate the distribution of papaya pollens under various conditions. Comparing the simulated
pollen distribution to the actual pollen distribution on dates 9 April 2008 for day time and 23-
24 June 2008 for night time suggests that the papaya pollens emitted might depend on the time
during the day. In term of quantity , the model can predict the amount of pollen distribution
reasonably well, providing the pollen amount in the same order of magnitude as in field experiments
of papaya female fruits. In addition we employed the model to study the influence of wind speed,
height of pollen source and area of plantation on the pollen distribution. We found that if the
papaya height is below 2 meters, most pollens will fall near the plantation. But if it grows up to
4 meters the pollen will have good distribution by wind. Besides, if the area of plantation is large,
the pollen will transverse farther from the source. We also found that a furthest distance at which
at least 1 pollen/m2 is found is directly proportional to the wind speed, when the emission source
is set above 2 meters in height.