Figure 8: Corrected Annual Rainfall from year 1980 – 2069 in the Cameron Highlands
Trenberth (1998) stated that an increase in
heavy precipitation events should be a primary
sign of climate change caused by increasing
atmospheric greenhouse gases. Higher
concentrations of greenhouse gases increase
the downward current of infrared radiation which
causes global heating at the surface. This heat not
only increases temperatures but also promotes
evaporation which enhances the atmospheric
moisture content. As a result all weather systems
that depend on moisture availability are likely to
result in intensified precipitation rates.
Precipitation
Simulation outputs from the Regional Climate
Model are used to develop the annual rainfall
trends. Figure 5 shows the simulated annual
rainfall from year 1980–2069. The equation
y = 2.5245x – 2498.1 gives a positive gradient of
2.5245 with an increase in annual precipitation of
2.5mm per year (25.2mm in 10 years or 252.5mm
in 100 years).
The observed annual rainfall recorded from
MMD climatic monitoring stations in the Cameron
Highlands from 1984 to 2013 shows a positive
gradient of 13.868 as seen in Figure 6. The
equation was found to be y = 13.868x – 24872.
There is an increment of 13.9mm of rainfall per
year. This complies with the field observations
where local people commented on “increased
heavy rain events”. Rainfall is common all year
round in the Cameron Highlands although the
Northeast monsoon season, between November
and February, has the highest levels. The dry
season is between February and April. January
has the least rainfall of 117.53mm while October
is the wettest month with the most rainfall of
367.09mm, as shown in Figure 7.
The corrected annual precipitation in Figure 8
gives an equation of y = 2.3178x – 2293.6 with a
slope of 2.3178. This positive slope indicates a rise
in rainfall amount of 2.3mm per year (23.2mm per
10 years or 231.8mm per 100 years). Increased
temperature could lead to more intense water
cycles. The evaporation rates from soils and water
plus the evapotranspiration from plants could
increase. This may cause the increase amount of
precipitation in the study area.
Extraordinary levels of rainfall can cause
increased flooding in the Cameron Highlands.
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