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29 January 2009

Mechanisms of Extreme Climate in Pontianak and Jayapura Regions

Mechanisms of Extreme Climate in Pontianak and Jayapura Regions

Plato M.Siregar1) and The Houw Liong2)

1) Science Atmosphere Division, Faculty of Earth Science and Mineral Technology, ITB
2) Physics of Complex System Division, Faculty of Mathematics and Natural Sciences, ITB

Abstract

Base on our study extreme climate in Pontianak mainly influenced by Sunspot numbers cycles and Jayapura regions are influenced by El Nino Southern Oscillation (ENSO) cycles.
In the middle of Indonesian archipelago (Pontianak Regions) heavy rainfalls are mainly local convection process, on the other hand in the eastern of Indonesian archipelago(Jayapura regions) heavy rainfalls by local convection, Walker cycles and warm pools oscillation.
The detail mechanisms are shown by Navier Stokes equation, energy conservation of mass, Clasius Clyperon, equation of state and cloud microphysics.
In this study we intend to explain the mechanism phenomenologicaly using assimilation data of precipitation, wind surface, and precipitable water.

Keyword: Solar activity, ENSO, mechanism, Navier Stokes, and extreme climate.

Background

When solar activity is low or sunspot minimum SMin, the intensity of the cosmic ray becomes maximized so that coverage of clouds grows. This means that solar radiation coming to earth will be minimized. Reversely, when solar activity is maximum ME the intensity of cosmic ray reaching lower levels of the atmosphere is minimum, the cloud covers decreases, additionally extra energy received from flares during prominent eruptions, maximized the amount of solar energy received on earth.
The global cloud cover produced global warming (the greenhouse effect) which amounts to 13%, but it also caused a cooling effect as much as 20% due to reflections against direct solar radiation1). The total energy derived from the sun is thus the solar constant averaging to 6.3 10^20 joules/hour which is equal to the energy of 40 tropical cyclones or 60 times the energy released by a major earthquake in Indonesia.
From the 21st solar cycle the irradiance received on earth shifted between 1367.0 W/m2 and 1368,5 W/m2 , it varies as much as 0,15 % or only 5%), however considering the large quantity of energy derived from the sun and due to the forcing of atmospheric dynamics and oceans the variation of the irradiance contribute considerably to the weather and climate.
Landscheidt4) has shown that between years 1950 to 1975 very strong correlations exist between the events of El Nino to sunspot minimum SMin and its harmonics to SM/2 or SMax. The occurrences of La Nina correspond to maximum eruption ME and its harmonics ME/2. Then around year 1975 a phase reversal occurred, and this happens from year 1976 up to the present, there the ME and its harmonics correlated well to El Nino, while SM and its harmonics correspond to La Nina.

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