Page 407 - Contributed Paper Session (CPS) - Volume 2

CPS1911 Nurkhairary A. M. et al.
The Von Mises distribution is said to be the most useful distribution on the
circle (Mardia and Jupp (2000)). Fisher (1987) noted that the Von Mises
distribution is a symmetric unimodal distribution and characterised by a mean
direction  and concentration parameter . The probability density function of
the distribution is
1 cos(−)
(; , ) = (1)
2 0 ()

where () is the modified Bessel function of the first kind and order zero,
0
which can be defined by
2
1
() = ∫ cos (2)
0
2
0

for 0   2 , 0    2 and   0 where  is the mean direction and  is the
concentration parameter. The concentration parameter  influences the Von
Mises distribution (, ) inversely as influences the normal distribution
2
( , ). Thus, a concentrated Von Mises distribution will have large
2
concentration parameter, and a dispersed Von Mises distribution will have a
small concentration parameter (Caires and Wyatt (2003)).
In this paper, we attempt to describe the relationship of wind direction for
three consecutive years using simultaneous linear functional relationship
model. The beauty of this model is that it allows the error term in the model.
We use the wind direction of Kota Kinabalu coastal station in Malaysia during
northeast monsoon for three consecutive years from 2015 to 2017.
Kota Kinabalu is located at the Borneo Island of Malaysia where it is the
capital of Sabah state with the latitude and longitude of 6.0367°N, 116.1186°E.
The climate in Kota Kinabalu is classified as equatorial climate with high
humidity, a considerable amount of sun, abundant rainfall, due to its
geographical location (Djamila et al., 2011). It is named after the highest
mount in Malaysia, Mount Kinabalu. The weather in Kota Kinabalu is influenced
by the northeast monsoons between November and March, the southwest
monsoon from May to September and two intermonsoons, which happen in
April and October (Mojiol, 2006). Figure 1 shows the location of Kota Kinabalu.

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