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29 July 2009


Seminar Nasional Proyeksi Iklim Dan Kualitas Udara 2010-2014(Juli 2009)


The Houw Liong2), Plato M.Siregar1), R.Gernowo1), Heru Widodo3)
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
3) UPT Hujan Buatan (Weather Modification Unit), BPPT

According to researchers in LAPAN (Indonesian Space and Aeronautics Institute) Global Circulation Model (GCM) and Limited Area Climate Model (DARLAM) can be used to predict climate in Indonesian regions. With a scenario that the concentration of CO2 will be doubled in 100 years, the temperature anomaly can be calculated. In 50 years from 1990 most Indonesian regions the very likely will raise by 0.5 to 1.0 degrees Celsius. Some regions the temperature very likely will raise by 1.0 to 1.5 degrees Celsius. This climate model cannot predict the precipitations in Indonesian regions well. It needs some modification before it can be use to predict the precipitations well.
We know that climate model can be classified as weak causality therefore the accuracy of prediction is good only for short range prediction.
WRF (weather research and forecasting), a regional numerical weather model developed by Pennsylvania State University/ National Center for Atmospheric Research (PSU/NCAR), with a horizontal grid resolution of 5 km can be used for short range prediction.
The second approach to predict climate in Indonesia is based on soft computing by knowing that the climate in Indonesian regions is influenced by four main quasi periodic cycles: Solar Activity Cycle (Sunspot Numbers Cycle), Galactic Cosmic Ray Cycle, El Nino Southern Oscillation (ENSO) Cycle, and Indian Ocean Dipole Mode (IOD) Cycle. It can be shown that solar activity cycle can be considered as primary cycle that influence other cycles.
In practice eastern Indonesian region is dominantly influenced by ENSO. When the heat pools moves to eastern Indonesian region, then rainfall in this region will be above normal. On the other hand when the heat pool leaves eastern Indonesian region and moves to Pacific Ocean then the rainfall in this region will be below normal.
During a typical Indian Ocean Dipole Mode (IOD) event the weakening and reversal of winds in the central equatorial Indian Ocean lead to the development of unusually warm sea surface temperatures in the western Indian Ocean. IOD negative means wet condition or the rainfall will be above normal along the western Indonesian region.
Precipitation in Pontianak region which represent middle Indonesian region correlated strongly with sunspot numbers cycle (solar activity cycle). Using ANFIS (Adaptive Neuro Fuzzy Inference System) we are able to predict sunspot numbers cycles about 10 years from now so that climate and extreme weather in Indonesian regions can be predicted.
Fuzzy c-means is used to classify regions that are influenced strongly by sunspot numbers (solar activity), IOD, and ENSO cycles. This method is based on fuzzy set as fuzzy c-partition of three cycles above and as cluster center. Fuzzy c-partition matrix for grouping a collection of n data set into c classes.

Keywords: climate model, ANFIS, fuzzy clustering, climate, solar activity, soft computing

22 July 2009

Modeling of Regional Total Electron Content (TEC) from Continuous GPS Station in Indonesia

PROC. ITB Sains & Tek. Vol. 38 A, No. 2, 2006, 163-180

Buldan Muslim, Hasanuddin Z. Abidin2), The Houw Liong3), Wedyanto Kuntjoro2), Cecep Subarya4)2) , Heri Andreas& M. Gamal2)
1)Kelompok Dinamika Atmosfer Atas, Bidang Ionosfer dan Telekomunikasi
Pusat Pemanfaatan Sains Antariksa, LAPAN, Jl. Dr. Junjunan 133 Bandung 40173
2)Kelompok Keahlian Geodesi dan Geomatika, Program Studi Teknik Geodesi
Fakultas Teknik dan Linkungan, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung
3)Program Studi Fisika, Fakultas Matematika dan Ilmi Pengetahuan Alam
Institut Teknologi Bandung, Jl. Ganesha 10 Bandung
4) Bidang Geodinamika, Pusat Geodesi dan Geodinamika, Badan Koordinasi Survei dan Pemetaan Nasional, Jl. Raya Jakarta - Bogor Km 46, Cibinong 16911

Ionosphere affect propagation of electromagnetic waves through it by adding a transmission delay time. In GPS positioning and navigation, ionospheric delay is largest source of error after error from Selective Availability (SA) was turned off. For GPS positioning precisely ionospheric effect must be estimated so ionospheric correction can be determinated to eliminate ionospheric effect on GPS observation. In positioning by using GPS single frequency, ionospheric correction can be obtained from GPS dual frequency receiver at reference station or model. This paper describes method of determination and modeling of regional total electron content (TEC) from continuous GPS station in Indonesia and it’s around. Spatial model of TEC at certain time is estimated by using polynomial function. Diurnal variation of polynomial model coefficient at certain hour from 00.00 – 23.00 UT is estimated with Fourier expansion.

Keywords: Regional; model; calibration; total electron content; code and phase combination; ionospheric bias and GPS.

21 July 2009

Solar Activity Effects on Cloud Cover over Indonesia

Proceedings of The 9th Asian-Pacific Regional IAU Meeting 2005, 52–53 (2005)

Solar Activity Effects on Cloud Cover over Indonesia
J. T. Nugroho and T. Djamaluddin
National Institute of Aeronautics and Space (LAPAN) Bandung, Indonesia

It is known the relationship between global cloud cover and solar activity. It is interesting to study the solar signal on cloud cover over Indonesia, where the atmospheric convection is very active. We divide the analysed region in Indonesia based on their climate patterns, i.e. monsoon, equatorial, and local patterns. We also analysed the data based on the position on the sun, related to the season, i.e. June-August (JJA,dry season in monsoon pattern), September-November (SON, transition dry to wet),December-February (DJF, wet seasons in monsoon pattern), and March-May (MAM,transition wet to dry). Using the Weighted Wavelet Z-transform (WWZ), we analysed the dominant periodicity of about 11 year, indicating the solar signal. It is found that solar signal does not appear on all regions with different climate pattern or seasonal time ranges. The stronger solar signal appears over region with monsoon pattern and during dry seasons, when local or regional effects is least.
Key words: solar activity – cloud cover – ENSO signal

Prediction of Solar Cycle 24 Based on Wavelet Analysis of Asymmetric Hemispheric Sunspot Number

Proceedings of The 9th Asian-Pacific Regional IAU Meeting 2005, 28–29 (2005)

Prediction of Solar Cycle 24 Based on Wavelet Analysis of Asymmetric Hemispheric Sunspot Number
T. Djamaluddin
National Institute of Aeronautics and Space (LAPAN), Bandung, Indonesia

Djamaluddin (2003, Proc. ISCS 2003, ESA SP-535, p. 83) proposed a new method of solar activity prediction from reconstruction of wavelet analysis. That method still used precursor analysis to predict the peak of cycle. Recently it is found that separate wavelet analysis of asymmetric hemispheric sunspot number gives a better result in predicting the shape of the next cycle, even more than one cycle ahead. The improved method does not use the precursor analysis to predict the peak of cycle, instead purely from wavelet analysis, i.e. the relationship between length-of-cycle and the maximum amplitude. Reconstruction of the cycle 21 is used to predict cycle 22 and 23 with good results, especially for the current cycle 23. The prediction is prolonged to cycle 24.
The cycle 24 is also predicted from the reconstruction of cycle 22. Comparison of those predictions of cycle 24 will be discussed.

Key words: prediction – solar cycle – wavelet – sunspot number

Long Term Variations in Solar Magnetic Field, Geomagnetic Field and Climate

Proceedings of The 9th Asian-Pacific Regional IAU Meeting 2005, 18–23 (2005)

Long Term Variations in Solar Magnetic Field,
Geomagnetic Field and Climate
S. Duhau
Department of Physics, Buenos Aires University, Buenos Aires, Argentina

MHD losses from the Sun by coronal mass ejection (CMEs) have a strong impact on climate. In the long-term, the strength of this and other sources of climate variability depends on long-term solar activity variability which in turn is determined by solar dynamo magnetic field strength evolution. The prediction of this evolution on which CMEs events play an important role is discussed in the light of present empirical and theoretical knowledge of solar dynamo system. The mechanisms by which CMEs influence climate are summarized. In particular geomagnetic field strength and morphology determine the strength of the CMEs shock waves- magnetosphere interaction and so of its impact on climate. The possible causes of ice ages are discussed on this framework.

Key words: climate changes – ozone – solar activity prediction – ice ages – geomagnetic field – solar magnetic field – solar Coronal mass ejections

Solar Effects on Weather and Climate in the Indonesian Archipelago

Proceedings of The 9th Asian-Pacific Regional IAU Meeting 2005, 79–80 (2005)

Solar Effects on Weather and Climate
in the Indonesian Archipelago

H. L. The1, P. M. Siregar2, and I. Radiman.3
1Department of Physics, Institut Teknologi Bandung, Indonesia
2Department of Geophysics and Meteorology, Institut Teknologi Bandung, Indonesia
3Department of Astronomy and Bosscha Observatory, Institut Teknologi Bandung, Indonesia

From various stations at Geographic Latitudes from 60N to 100S throughout the Indonesian Archipelago, anomalies of yearly rainfall were collected and plotted to those of the yearly Sunspot Number between 1948 and 2003. It is shown that there is a tight correlation between solar activity and the various geophysical variables, such the cloud cover, the sea surface temperature and the rainfall throughout the region. The Number of Sunspot to Rainfall from each station against the Geomagnetic Latitude of the stations is also studied. The coefficients of correlations increase as we go to higher Geomagnetic Latitudes. This research shows that the knowledge of solar activities can be used to predict extreme weather in Indonesia.

Key words: solar cycles – geomagnetic effects – solar activity – extreme weather

17 July 2009



Peneliti :Sinta Berliana Sipayung
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Recently, the temperature changed has become one of the most serious problem over the world, especially over Indonesia. The increasing of sea surface temperature (SST) has already reached over Indonesia.

The increasing of green house gases also has already investigated. This study is mainly concerned to analyze the temperature changed over several cities over Indonesia, such as Aceh, Kupang and Pontianak, respectively for one hundred years observations based on several climate models (1900-2000) analyses. The result shows that for Aceh, the surface temperature increases of about 1.90C or 8% (CGCM), and 2.10C or 2% (CSIRO), respectively. While for Pontianak and Kupang, their temperature decreases of about -0.30C or 0.5% (CGCM) -0.30C or 1.1% (CSIRO), and - 0.10C or 0.2% (CGCM), -0.20C or 0.6% (CSIRO), respectively. Based on the increasing of CO2 globally, we can mention here that Aceh city relatively is more affected by the global warming than Kupang and Pontianak cities, especially from 1800 to 2000. We need more locations to get better understanding effects of global warming over Indonesian Maritime Continent in next future. The other is, not only the annual temperature changed information is needed, the daily of temperature changed information is also important to be investigated.

Keywords : temperature changed, CGCM, and CSIRO model

12 July 2009

Fractal Dimension and Analysis of Chaotic System Predictions

By: Acep Purqon
Advisor: Prof. Dr. The Houw Liong
Departemen Fisika - ITB
: Jl. Ganesa 10, Bandung
Created: 2005-01-27 , with 1 file(s).
Master Theses from JBPTITBFI / 2005-02-08 14:16:05

In 1963 Edward Lorenz successfully formulated chaotic behavior in weather. Lorenz simplified model of 2D thermal convection known as Rayleigh-Benard convection into three simultaneous ordinary differential equations called Lorenz equations. Lorenz noticed that, in his simplified mathematical model of Rayleigh-Benard convection, very small differences in the initial conditions blew up and quickly led to enormous differences in the final behavior. He reasoned that if this type of behavior could occur in such a simple dynamical system, then it may also be possible in a much more complex physical system involving convection i.e. the weather system. Almost one decade for scientists to understand the paper. Nowadays chaos becomes interesting subject to be studied in all area. The irregularities are usually measured by Lyapunov exponent, fractal dimension etc. The sentence that states the impossible prediction has challenged scientists to develop prediction methods. Many prediction methods have been developed and improved and one of it is ANFIS (Adaptive Neuro-Fuzzy Inference Systems). In this time ANFIS will be tested to analyze prediction of chaotic behavior in the Lorenz equations. The prediction results for short time are very good which coefficient of correlation for the prediction is 0.99. We also want to test how long the prediction still has good result. So we will analyze based on analysis of r-value, degree of freedom analysis, analysis of increasing amount of training data and superposition between periodic and chaotic.

10 July 2009

The occurrence of equatorial spread F (ESF) at Biak (01deg S.Lat ,135 deg E.Long)

Kontribusi Fisika Indonesia
Vol. 12, No.3, Juli 2001

Buldan Muslim1), Sarmoko Saroso1) dan The Houw Liong2)
1)Pusat Pemanfaatan Sains Antariksa LAPAN
Jl. Dr. Junjunan 133 Bandung 40173
2) Departemen Fisika FMIPA Insitut Teknologi Bandung

The occurrence of equatorial spread F (ESF) at Biak (01deg S.Lat.,135deg E.Long.) , during March and April has been investigated on daily basis in sunspot medium years 1992 in terms of the growth rate of irregularities by the gravitational Rayleigh-Taylor (GRT) instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of ESF at Biak are examined in relation to maximum of h’F after sunset, rate of h’F and fluctuation of rise as well as with solar and magnetic activity conditions. It is found that the day-to-day variation of ESF occurrence at Biak can be accounted generally for on the basis of the GRT mechanism. On the basis of March data from 1992 – 1995 occurrence of ESF decrease with decreasing solar activity.

Keywords: Ionosphere, Instability, Spread F

04 July 2009


Bionatura,Vol. 9, No. 1, March 2007

Ruminta, Bayong Tjasyono, The Houw Liong, dan Indratmo Soekarno

A study on trends of the hydrometeorology had been carried out in the Upper Citarum River Basin, West Java. The investigations based on monthly observations data of the rainfall, evapotranspiration, humidity, and runoff from January 1968 to December 2000. The results indicated that odds ratio of the rainfall, evapotranspiration, humidity, and runoff are -3.64, 3.88, 4.21, and -1.11 respectively. The rainfall and runoff had been decreased by about -3.64% and -1.11% respectively. The decreasing trend in the rainfall and runoff had controlled mainly by the decreasing of the clouds and rains formation as a consequence of the global climate change. On the other hand, the evapotranspiration and air humidity had been increased by about 3.88% and 4.21% respectively. The increasing trend in the evapotranspiration and air humidity had influenced by the increasing of the water vapour removal from vegetation lands surface to the atmosphere by both evaporation and transpiration.

03 July 2009


Proceeding National Seminar on Space Science III, Lapan, Bandung, 2007


Bambang Setiahadi1, Takashi Sakurai2, Hideaki Miyazaki2 and Eijiro Hiei2
1Indonesian National Institute of Aeronautics and Space (LAPAN)
Watukosek, Gempol P.O. Box 04, Pasuruan 67155, Indonesia
2National Astronomical Observatory of Japan (NAOJ)
Mitaka-shi, Osawa, Tokyo 181-8588, Japan

Physical interactions in solar-terrestrial space are mostly magnetohydrodynamics (MHD) transport phenomena. The phenomena have been much well understood by utilizing theories derived from fundamental interactions in MHD plasma state. Furthermore, the over-all physical processes and propagation in space can be described as the MHD transport phenomena. There are many advances in solar magnetohydrodynamo (MHDo) research during the last decade. These include research on solar convective layers, the dynamics of active regions at solar surface, the super-active solar corona, the interplanetary magnetic-plasma field propagations, as well as the planetary-magnetospheric plasma dynamics. Our research is intended to initiate the efforts in developing an aeronautics and space early warning at LAPAN Watukosek.
Key words: MHD interactions, transport phenomena, solar-terrestrial space, aeronautics and space early warning


Proceeding National Seminar on Space Science III, Lapan, Bandung 2007


Katsumi Hattori1*, Masashi Hayakawa2, Nobuhiro Isezaki1,
Kiyohumi Yumoto3, Toshiyasu Nagao4, and Seiya Uyeda4
1 Dept. of Earth Sciences, Fac. of Science, Chiba University Japan,
2 The University of Electro-Communications, Japan,
3 Kyushu University, Japan.
4 Earthquake Prediction Research Center, Tokai University, Japan

Despite its extreme importance and years of effort, practical short-term earthquake prediction still remains to be achieved in future. However, earthquake- related electromagnetic phenomena are recently considered as a promising candidate for short-term earthquake prediction. There have been accumulated a lot of evidences of precursory signatures in a wide frequency range (DC-VHF). The ULF geomagnetic change is one of the most promising phenomena and it suggests that the short-term prediction is expected to realize. The recent progress and the state of the art in Japan will be present in the talk. Especially, the methodologies to detect abnormal changes in ULF electromagnetic approach are described in this paper.
Key words: earthquake- related electromagnetic phenomena, short-term earthquake prediction, precursory signatures, ULF geomagnetic change, ULF short-term