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30 April 2009



by Bayong Tjasyono HK.*, The Houw liong**, P. A. Winarso***, Kartika L.*, Zadrach L. D.*, Plato M. S.*
*) Department of Geophysics and Meteorology, ITB
**) Department of Physics, ITB
***) Meteorological and Geophysical Agency, Jakarta

Drought periods in the Indonesian maritime continent are affected by ENSO (El Niño – Southern Oscillation) events at the equatorial Pacific and the west coast of South America. During June to September 1997, many areas of Indonesia located mainly south of the equator and near Australian Continent suffered lack of sufficient water to meet requirement i. e. less than 60 mm per month. ENSO affects the activity of rainfall mainly in the eastern part rather than in the western part of the Indonesian maritime continen. The amount of rainfall in the ENSO event of 1997 is less, on the contrary the number of drought area is greater then that in the pre and post – ENSO events. Average dry pentad probability knowing the preceding two dry pentads increases from 15th pentad up to 50th pentad.

Keywords : Drought, ENSO, rainfall

29 April 2009

Metoda Web Komputasi Untuk Perhitungan Intensitas Bencana Kekeringan di Wilayah Indonesia

Indonesian Journal of Physics, Vol 13, No 2 (2002)

Metoda Web Komputasi Untuk Perhitungan Intensitas Bencana Kekeringan di Wilayah Indonesia
Plato Martuani Siregar, Bayong Tjasyono HK, The Houw Liong


Komputasi meteorologi dituntut menggunakan sistem jaringan database untuk kepentingan analisa sinoptik,komputasi menggunakan komputer tunggal diperluas ke jaringan mengingat perlu informasi untuk pemrosesan data yang simultan,cepat,dan akurat untuk memprakirakan kondisi cuaca. Komputasi melalui jaringan internet diapplikasikan dalam bahasa CGI dan manajemen database oleh MySQL. Semua persamaan dinamika atmosfer dimplimentasikan dengan CGI (pemograman php atau perl)

Perhitungan intensitas kekeringan menggunakan faktor hujan atau indeks kekeringan dibentuk oleh elemen iklim misalnya curah hujan dan suhu. Batas kering adalah 5.0,jika curah hujan (mm) dan suhu (Kelvin). Setiap kejadian El Niño,daerah wilayah Indonesia bagian timur dan selatan menjadi lebih kering dibanding tahun non-El Niño. El Niño menyebabkan kekeringan dibeberapa daerah Indonesia,tetapi kekeringan tidak selalu akibat peristiwa El Niño, ada faktor lain yang menyebabkanya misalnya monsun timur.

27 April 2009

Weather Monitoring and Nowcasting System Using Satellite Imagery and GPS/Meteorology Data

Weather Monitoring and Nowcasting System Using Satellite Imagery and GPS/Meteorology Data
Accession number;06A0392338
Weather Monitoring and Nowcasting System Using Satellite Imagery and GPS/Meteorology Data
HADI TRI W.(Inst. Teknologi Bandung, Idn)
SETYADJI B.(Inst. Teknologi Bandung, Idn)
HOUW LIONG THE (Inst. Teknologi Bandung, Idn)
Journal Title : Asahigarasu Zaidan Jyosei Kenkyu Seika Hokoku (Web)
Journal Code:U0002A
VOL.2005;NO.;PAGE.WEB ONLY 05F-2-7(2005)
Pub. Country :Japan
Language : English

This research is mainly concern with the development of a weather monitoring and prediction system using satellite data downloaded freely from the internet. This document summarizes the important results of several investigations that have been conducted during the years of 2003-2005 which can be divided into four parts. First, an automatic system for downloading and pre-processing the satellite data has been established on a linux personal computer. A process study on short-range weather variability over Java Island has then been conducted using the satellite and other auxilliary data. A technique to predict future changes of 2-D spatial variation in the infra-red temperature has also been developed based on principle component analysis and adaptive neuro-fuzzy inference system. Finally, the potential use of GPS/Meteorology data for weather monitoring and prediction is discussed. All of the results suggest that satellite data can be used for an objective short-range weather forcasting with the help of a suitable empirical prediction method. Such a weather monitoring and prediction system will be useful in anticipating a plausible immediate occurrence of medium to large-scale convective system that can produce exessive amount of rainfall.

24 April 2009



V. Archontis et al 2009 ApJ 691 1276-1291 doi: 10.1088/0004-637X/691/2/1276

V. Archontis1, A. W. Hood1, A. Savcheva2, L. Golub2 and E. Deluca2
1 School of Mathematics and Statistics, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, UK
2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02139, USA

ABSTRACT. Sigmoids are structures with a forward or inverse S-shape, generally observed in the solar corona in soft X-ray emission. It is believed that the appearance of a sigmoid in an active region is an important factor in eruptive activity. The association of sigmoids with dynamic phenomena such as flares and coronal mass ejections (CMEs) make the study of sigmoids important. Recent observations of a coronal sigmoid, obtained with the X-Ray Telescope (XRT) on board Hinode, showed the formation and eruption phase with high spatial resolution. These observations revealed that the topological structure of the sigmoid is complex: it consists of many differently oriented loops that all together form two opposite J-like bundles or an overall S-shaped structure. A series of theoretical and numerical models have been proposed, over the past years, to explain the nature of sigmoids but there is no explanation on how the aforementioned complexity in sigmoids is built up. In this paper, we present a flux emergence model that leads to the formation of a sigmoid, whose structure and evolution of complexity are in good qualitative agreement with the recent observations. For the initial state of the experiment a twisted flux tube is placed below the photosphere. A density deficit along the axis of the tube makes the system buoyant in the middle and it adopts an Ω-shape as it rises toward the outer atmosphere. During the evolution of the system, expanding field lines that touch the photosphere at bald-patches (BPs) form two seperatrix surfaces where dissipation is enhanced and current sheets are formed. Originally, each of the BP seperatrix surfaces has a J-like shape. Each one of the J's consist of reconnected field lines with different shapes and different relative orientation. The further dynamical evolution of the emerging flux tube results in the occurrence of many sites that resemble rotational discontinuities. Thus, additional current layers are formed inside the rising magnetized volume increasing the complexity of the system. The reconnected field lines along these layers form an overall S-shaped structure. The reconnection process continues to occur leading to the formation of another current concentration in the middle of the sigmoid where a flaring episode occurs. This central brightening is accompanied by the eruption of a flux rope from the central area of the sigmoid and the appearance of "post-flare" loops underneath the current structure.

Key words: MHD; Sun: activity; Sun: corona; Sun: magnetic fields

Print publication: Issue 2 (2009 February 1)
Received 2008 August 13, accepted for publication 2008 October 1
Published 2009 February 2
The Astrophysical Journal, 691:1276–1291, 2009 February 1 doi:10.1088/0004-637X/691/2/1276
American Astronomical Society. All rights reserved. Printed in the U.S.A.

23 April 2009

Regional TEC Modeling from GPS Data

Pemodelan TEC Regional dari data GPS stasiun tetap di Indonesia dan Sekitarnya

Buldan Muslim 1), Hasanuddin Z. Abidin 2), The Houw Liong 3), Wedyanto Kuntjoro 2), Cecep Subarya 4), Heri Andreas 2) & M. Gama 2)

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.

ULF geomagnetic anomalous changes possibly associated with 2004–2005 Sumatra earthquakes

ULF geomagnetic anomalous changes possibly associated with 2004–2005 Sumatra earthquakes

S. Saroso (a), K. Hattori(b), H. Ishikawa (b), Y. Idac, R. Shirogane (c), M. Hayakawa (c), K. Yumoto (d), K. Shiokawa (e) and M. Nishihashi(f)

(a)National Institute of Aeronautics and Space (LAPAN), Bandung, Indonesia
(b)Graduate School of Science, Chiba University, Yayoi 1-33, Inage, Chiba 263-8522, Japan
(c)Department of Electronic Engineering and Research Station on Seismo Electromagnetics, The University of Electro-Communications, Chofu, Japan
(d)Space Environment Research Center, Kyushu University, Fukuoka, Japan
(e)Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan
(f)Graduate School of Science and Technology, Chiba University, Chiba, Japan

Received 12 June 2008;
revised 8 October 2008;
accepted 14 October 2008.
Available online 1 November 2008.


Anomalous ULF geomagnetic field change is considered to be one of the most convincing and promising phenomena among earthquake-related electromagnetic effects, because we expect emissions from the crust of the source region. There has been a great deal of accumulated and convincing evidence of ULF magnetic signatures before large earthquakes as reported in the previous studies. In order to verify these phenomena preceding large earthquakes and to clarify the relationship between electromagnetic phenomena and possible physical mechanism, we have investigated the data of ULF geomagnetic observations at Kototabang and Biak stations associated with the 2004/2005 Sumatra earthquakes. A case study is carried out in this work to investigate the pre-earthquake ULF geomagnetic anomalies during the Sumatra–Andaman earthquake on December 26, 2004 (magnitude Mw = 9.0 and depth = 30 km from USGS catalog), and Sumatra–Nias earthquake on March 28, 2005 (Mw = 8.7 and depth = 30 km). For the aim of finding any precursors, we have adopted the spectral density ratio analysis and transfer functions analysis based on wavelet transform method. Results of the spectral density analysis indicate similar variations to those of amplitude for the induction arrow in transfer function analysis. Both of these variations at Kototabang exhibit strange or anomalous changes from a few weeks before the Sumatra–Andaman earthquake to July 2005, while there are no apparent changes at remote station of Biak. To make these results more convincing, the fractal analysis based on a Higuchi method has been applied to the same observed data, which also show a significant change (or decrease) in mono-fractal dimension a few weeks before the earthquakes. This result would lend a further support to those by the spectral density ratio and transfer function analyses. So, we can conclude that the anomalous change as observed simultaneously by the three methods, might be a possible signature related with the earthquake preparation phase of Sumatra earthquakes.

Keywords: ULF geomagnetic field; Pre-earthquake anomaly; Spectral density ratio analysis; Transfer functions analysis; Fractal analysis; The 2004/2005 Sumatra earthquakes

Some results of seismo-electromagnetic research at LAPAN

International Conference on Mathematics and Natural Sciences, 2008 , ITB

Some results of seismo-electromagnetic research at LAPAN, Indonesia
Sarmoko Saroso,
National Institute of Aeronautics and Space (LAPAN), Indonesia

Indonesia is recognized as one of the most tectonically active regions in the world. This is evident in the number of earthquakes experienced by the country annually. Every year, Indonesia suffers extensive damage and loss of human life from earthquakes. To mitigate death and destruction on the islands of Indonesia, it is necessary that a way of making a “forecast” for earthquakes be developed. Recently, seismo-electromagnetic phenomena have been considered a promising tool for monitoring seismic activity. The presence of such precursory signature related to strong earthquakes has been identified in the ionospheric perturbations and anomalous ULF geomagnetic field change. There has been a good deal of accumulated and convincing evidence of ionospheric perturbations and ULF magnetic signatures before strong earthquakes as reported in the previous studies. Studies related with ionospheric precursors of the earthquakes in Indonesia using the TEC (Total Electron Content) data and the pre-earthquake ULF geomagnetic anomalies are carried out at LAPAN in collaboration with Chiba University, The University of Electro-Communications, Nagoya University, Kyushu University, NCU Taiwan, LIPI, BMG, and Bakosurtanal. Case studies are carried out in this work to investigate the ionospheric precursors of the earthquakes and the pre-earthquake ULF geomagnetic anomalies during the Aceh earthquake on December 26, 2004 (magnitude Mw= 9.0 and depth = 30 km from USGS catalog), and Nias earthquake of March 28, 2005 (Mw= 8.7 and depth = 30 km). It has been found that the ionospheric anomalies appear a few days prior to earthquakes and seismic activity is possible source of the ionospheric anomalies. To investigate the pre-earthquake ULF geomagnetic anomalies, the polarization analysis and transfer functions analysis based on wavelet transform method have been applied to the observed data. Results of polarization analysis show similar variation of those of amplitude for induction arrow in transfer function analysis. These variations at Kototabang exhibit an anomalous changes a few weeks before the strong earthquakes with M>6.5, while there are no apparent changes in Biak data. This suggests that the anomalous change might be a possible signal related with the earthquake preparation phase of Sumatra earthquakes. Applying various methods with multiple independent instruments for the same event or at the same time as a hopeful way to make results more convincing and to increase robustness of anomalous changes associated with earthquakes.

Ionospheric Perturbations, Anomalous ULF Geomagnetic Field

20 April 2009



Buldan Muslim
NIM : 35104002
Promotor : Prof. Dr. Ir. Hasanuddin Zaenal Abidin MSc.
Co-Promotor : Prof. The Houw Liong Ph.D.
Co-Promotor : Dr. Ir. Wedyanto Kuntjoro MSc.

Ionospheric total electron content (TEC) determination and low geomagnetic latitude ionospheric modeling over Indonesian region (from -2,77° to -20,65° geomagnetic latitude) are needed for ionospheric correction in high precision point positioning by using single frequency Global Positioning System (GPS) receiver. The data and TEC model are also important for analyze of earthquake precursors in ionosphere several days before earthquakes in effort to understanding coupling mechanisms of lithosphere-atmosphere-ionosphere. In this research, ionospheric TEC determination from GPS data, ionospheric TEC modeling over Indonesian region and revealing method of earthquake precursors from ionospheric TEC data and model have been developed from dual frequency GPS data. Conceptual model of lithosphere-atmosphere-ionosphere has been also developed by involved local earth gravity effect that has not been considered, to describe ionospheric TEC variation several days before earthquakes.

Dual frequency GPS signal observations data in Indonesian region and it’s around have been used to derive ionospheric total electron content (TEC) by using phase leveling method. The algorithm of TEC determination has been implemented by using matlab software that can be used to download GPS data through file transfer protocol (ftp) and then to compute TEC value.

Low geomagnetic latitude ionospheric models over Indonesian region have been developed based on the ionospheric TEC data. Temporally the TEC model can be grouped into daily model that has been developed from daily TEC data and monthly model that has been developed from monthly average of daily TEC data. Spatially the TEC model can be classified into local model based on single GPS reference station and regional model based on multiple GPS reference stations. Daily TEC model formulation is combination of polynomial function that is used to represent spatial variation of ionosphere and harmonic function that is used to represent diurnal variation of polynomial coefficients of spatial model of ionosphere. Order of polynomial and harmonic functions are optimized by minimizing of model errors from observations. In this way the optimum local daily TEC model over West Java from BAKO station obtained is P(12,2,2) where the first number is order of harmonic function, the second number is order of polynomial function to represent ionospheric variation to geographic latitude and the last number is order of polynomial function to represent ionospheric variation to geographic longitude. With same way the optimum regional daily model over Indonesian region obtained is P(12,7,3). The regional monthly TEC model over Indonesia is made by using polynomial function to represent ionospheric variation to geographic latitude, harmonic function to represent diurnal variation of ionosphere and linear function to represent ionospheric response to solar activity. Regional monthly TEC model over Indonesia obtained is P(6,5,0,1), where 6 is order of harmonic function to represent diurnal variation of ionosphere in local time frame, 5 is the order polynomial function to represent latitudinal variation of ionosphere, 0 is order of polynomial function to represent longitudinal variation of ionosphere at same local time and latitude, which means that longitudinal dependence of ionosphere is ignored, and 1 is order of polynomial function to represent ionospheric response to solar activity, which means that ionospheric response to solar activity during increasing and decreasing of solar cycle is linear. The regional monthly TEC model obtained is a simplified low latitude TEC regional model (SLTECRM). The SLTECRM which is based on monthly average of TEC data at certain hour can be used as a reference value of TEC in quite days for a particular month over the Indonesian region so the model can be used for ionospheric correction in positioning by using single frequency GPS receiver during quite days and for revealing of ionospheric anomaly related to solar storm as well as earthquake precursor.

The regional monthly TEC model and TEC data can be combined to derive ionospheric activity index (S index), which can be used as a weather space parameter over Indonesia. Ionospheric diurnal tide activity index (A index) was also derived from daily TEC data. Spatial analysis of A index few days before large earthquakes show that the A index can be used to identify earthquake precursors by using exponential function, to predict large earthquakes by using earthquake preparation zone radius model and to approximate earthquake epicenter by using resection method adopted from GPS point positioning.

Decreasing of day time ionospheic TEC few days before large earthquakes can be described by using coupling model of lithosphere-atmosphere-ionosphere caused by decreasing of local earth gravity that can modify E region dynamo electric field through modification of atmospheric diurnal tide amplitude, can accelerate atmospheric vertical drift, and can reduce diffusion drift of ionosphere. Ionospheric anomaly caused by earth gravity anomaly is a hypothetical alternative. Various theoretical and experimental efforts are necessary to examine the hypothesis.

Key words: GPS, ionosphere, low latitude, Indonesia, model, ionospheric index, anomaly, earthquake precursor.

Drought in Indonesia

Journal from #PUBLISHER# / 2004-02-10 14:07:38
by The Houw Liong,

Jurnal Matematika & Sains vol.8 no.2 Juni 2003 - FMIPA - ITB

Keyword : fuzzy clustering; fuzzy set; fuzzy relations; ENSO; IOD; drought; monsoon; maritime continent.
Url : http://

In general drought in Indonesia can be predicted from intensities of El Nino that can be defined by using time series of sea surface anomaly on Pacific Ocean (SSTA 3.4). It can be shown that when El Nino with strong intensities occur then more than 65% regions in Indonesia the precipitations are below normal (drought in Indonesia). The correlation between strong El Nino intensities and percentages of regions in Indonesia with precipitations below normal are high, but when the intensities are weak the correlations are low. In this case other phenomena such as on Indian Ocean Dipole Mode (IOD) can contribute to drought in Indonesia. Clustering of climatic regions in Indonesia based on monthly rainfall pattern using fuzzy set, fuzzy relations or Kohonen's neural network will help to clarify drought on these regions. It can be shown that climatic regions in Indonesia can be clustered based on monthly rainfall patterns that are strongly influence by Australian monsoon which is known as North Australia Indonesian Monsoon (MAIM) and Maritime Continent (MC) which has equatorial precipitation characteristic. The
climatic clustering is based on the ground that ENSO and IOD are regional atmospheric dynamic so the clustering should be based on average monthly pattern or geopotential height. The east MC and NAIM will be influence strongly by ENSO and the western MC especially south Sumatra and west Java is influence also by IOD.

Mgnetic Properties of Stalagmite in Java , PSV and Paleoclimate

PhD Theses from #PUBLISHER# / 2006-03-01 12:36:39
by Siti Zulaikah, S3 - Mathematics and Natural Sciences

Promotor : Prof. Dr. The Houw Liong
Co-Promotor : Dr. Satria Bijaksana
Co-Promotor : Dr. rer.nat. Umar Fauzi

Keyword : Magnetic properties, stalagmite, paleosecular variation, paleoclimate

Nomor Panggil (DDC) :
T 538. 727 ZUL
Sumber pengambilan dokumen : 20051515

Absract :
Research on rock magnetism has been performed for many purposes. In this study, rock magnetic properties especially those observed in stalagmite are used to determine the past geomagnetic field secular variation or paleosecular variation (PSV). Furthermore, magnetic properties of stalagmites in this study are also used as proxy data indicator of past climate change or paleoclimate.

The global paleosecular variation can not be determined in great detail as the PSV data are available mostly high latitude regions but lacking those from low latitude regions such as Indonesia. In this study, PSV for low latitude is constructed from stalagmites. Compared to ordinary sediments, stalagmites and other cave deposits have an advantage that they show no sign of inclination error as sediments generally do. Cave deposits and stalagmites are abundant in Indonesia encompassing wide range of age and rate of sedimentation that is faster that those from temperate climate. These allow for greater number of data and higher resolution.

The wide range age (up to teens of thousand years) is also beneficial for paleoclimatic study. Its unique and chaotic climate change makes Indonesia a key area in regional and global changes. This is one of the main reasons for this research. Although still limited in quantity, proxy paleoclimatic data are already available for Indonesia, for example O 8 variation in corals, tree ring in teak as well as pollen and charcoal abundance in lake sediments. Every proxy data provides a specific range of age and resolution. These proxy data are still insufficient to build a reliable climatic record. Stalagmites have been shown to act as multi proxy recorders. In this research, magnetic properties are studied as potential proxy data for pelaoclimate. The magnetic data of the stalagmit in this study, can records the climate change of Java and generally Indonesia at least in the last of thousand years.

Measurements were carried out on several magnetic parameters notably magnetic susceptibility and magnetic remanence in various forms, such as NRM (natural remanent magnetization), ARM (anhysteretic remanent magnetization) and IRM (isothermal remanent magnetization). Other supporting analyses to characterize the magnetic minerals were also performed, such as visual observation using SEM (scanning electron microscope) equipped with EDX, compositional analysis using X-ray diffraction (XRD) and absolute age determination using radiocarbon method.

In this study, sample collection includes 6 stalagmites from Trenggalek, East Java (one of the region that is sensitive to ENSO or El-Nino Southern Oscillation), 2 stalagmites from Purworejo and Bantul and 1 stalagmite from the Island of Muna in Sutheast Sulawesi. Two stalagmites from Trenggalek yield absolute ages of 3320+100 years old (STG-NDL) and 6300+470 years old (STG-NJL). It is known that the deposition rate of stalagmite is lower for the younger part. From mineralogical point of view, these stalagmites are dominated by calcite (CaCO3) and low magnetic mineral content. Grain size of magnetic mineral, predominantly multi-domain magnetite (Fe304), varies from 10-2 to 102 gm. Variation of magnetic parameter in stalagmite is controlled by the concentration of magnetic minerals. The grains appear to be interacting but no compositional variation along the stalagmites.

Magnetic susceptibility observed in stalagmites show no special pattern. Magnetic susceptibility of each sample varies averaging between -3.0 x 10-6 to 5.0 x 10-m3fkg. Meanwhile, two stalagmites that grew in flooding free enclosure show similar pattern of susceptibility variation. Anisotropy of magnetic susceptibility (AMS) analysis shows that the degree of anisotropy varies from 2 to 16% although most samples have degree of anisotropy that are less than 10%. The maximum axes of susceptibility tend to be parallel with bedding plane, even though some samples show the opposite.

NRM intensities generally show no specific pattern along these stalagmites. The initial NRM intensity varies from 10-6 to 104 Am2/kg. while the median destructive field (MDF) varies from 5 to 25 mT, although some have MDF of up to 40 mT. Some of samples show unstable record of remanence as indicated by C C95
more than 10°. PSV record nevertheless show local consistency especially in inclination with coefficient of similarity (r) of up to 0.97. PSV data obtained in this study is similar to that of Xingwen, China with r value varied from 0.6 up to 0.98.

Based on susceptibility pattern found in stalagmites that grew in flooding-free enclosure, magnetic mineral abundance is related to wet condition. This agrees with sunspot data as well as the CO2 abundance, which is an indicator of greenhouse effect. Comparison of the above parameters shows that there has been an increase in global warming for the last ± 150 years. Comparison between magnetic and delta C14 data shows similar pattern are found for the years of 1175, 1400, 1600 and 1675. These findings prove that magnetic data can be used as a proxy data for climate change, where high susceptibility value indicates wet condition and low susceptibility value indicates dry condition.



# by Ruminta* The Houw Liong** Bayong Tjasyono***
# * Laboratorium Klimatologi Fakultas Pertanian UNPAD. ** Program Studi Fisika - FMIPA - ITB. *** Program Studi Meteorologi – FIKTM - ITB.

# Abstract

An investigations on the fractal and cyclic the hydrometeorology had been carried out in the Citarum river basin. The investigations used monthly observations data there are rainfall, evapotranspiration, humidity, and runoff (1968 to 2000). In this investigations indicated that hydrometeorological processes in the Citarum river basin was low-dimension chaos ( correlation dimension, ν<4). The ν-values of the rainfall, evapotranspiration, humidity, and runoff are 1.83, 1.68, 1.23, and 2.05 respectively that showed a minimum numbers of the main variables in the dynamic model of the hidrometeorological processes are 2, 2, 2, and 3 respectively. The rainfall and runoff are chaotic mono-fractal (qD<2) that showed deterministic processes but the evapotranspiration and humidity are chaotic multi-fractal (qD>2) that showed stochastic processes. The extreme values of the rainfall, evapotranspiration, humidity, and run off had return periods more than 170, 50, 30, and 80 months respectively. The rainfall and runoff had the same two main cyclic there are 6 and 12 monthly but the evapotranspiration and humidity had one main cyclic there are 12 and 16 monthly respectively. The hydrometeorological processes in the Citarum river basin was the results of the unbounded cascade processes because that had the value of exponent spectrum less than one.

Keywords : hydrometeorology, fractal, correlation dimension, return period, cyclic, exponent spectrum

19 April 2009

Russian scientist says Earth could soon face new Ice Age

Russian scientist says Earth could soon face new Ice Age
14:31 | 22/ 01/ 2008

ST. PETERSBURG, January 22 (RIA Novosti) - Temperatures on Earth have stabilized in the past decade, and the planet should brace itself for a new Ice Age rather than global warming, a Russian scientist said in an interview with RIA Novosti Tuesday.

"Russian and foreign research data confirm that global temperatures in 2007 were practically similar to those in 2006, and, in general, identical to 1998-2006 temperatures, which, basically, means that the Earth passed the peak of global warming in 1998-2005," said Khabibullo Abdusamatov, head of a space research lab at the Pulkovo observatory in St. Petersburg.

According to the scientist, the concentration of carbon dioxide in the Earth's atmosphere has risen more than 4% in the past decade, but global warming has practically stopped. It confirms the theory of "solar" impact on changes in the Earth's climate, because the amount of solar energy reaching the planet has drastically decreased during the same period, the scientist said.

Had global temperatures directly responded to concentrations of "greenhouse" gases in the atmosphere, they would have risen by at least 0.1 Celsius in the past ten years, however, it never happened, he said.

"A year ago, many meteorologists predicted that higher levels of carbon dioxide in the atmosphere would make the year 2007 the hottest in the last decade, but, fortunately, these predictions did not become reality," Abdusamatov said.

He also said that in 2008, global temperatures would drop slightly, rather than rise, due to unprecedentedly low solar radiation in the past 30 years, and would continue decreasing even if industrial emissions of carbon dioxide reach record levels.

By 2041, solar activity will reach its minimum according to a 200-year cycle, and a deep cooling period will hit the Earth approximately in 2055-2060. It will last for about 45-65 years, the scientist added.

"By the mid-21st century the planet will face another Little Ice Age, similar to the Maunder Minimum, because the amount of solar radiation hitting the Earth has been constantly decreasing since the 1990s and will reach its minimum approximately in 2041," he said.

The Maunder Minimum occurred between 1645 and 1715, when only about 50 spots appeared on the Sun, as opposed to the typical 40,000-50,000 spots.

It coincided with the middle and coldest part of the so called Little Ice Age, during which Europe and North America were subjected to bitterly cold winters.

"However, the thermal inertia of the world's oceans and seas will delay a 'deep cooling' of the planet, and the new Ice Age will begin sometime during 2055-2060, probably lasting for several decades," Abdusamatov said.

Therefore, the Earth must brace itself for a growing ice cap, rather than rising waters in global oceans caused by ice melting.

Mankind will face serious economic, social, and demographic consequences of the coming Ice Age because it will directly affect more than 80% of the earth's population, the scientist concluded.

17 April 2009

Pengaruh Aktivitas Matahari pada Cuaca/Iklim Wilayah Indonesia

Pengaruh Aktivitas Matahari pada Cuaca/Iklim Wilayah Indonesia
The Houw Liong1)
1)Departemen Fisika, ITB
2)Departemen GM , ITB

Abstrak yang diperluas
Kedudukan relatif matahari terhadap wilayah Indonesia dan berbagai aktivitas matahari akan mempengaruhi cuaca/iklim di wilayah itu. Ketika matahari aktif meningkatnya iradiansi matahari mempengaruhi jumlah energi matahari yang sampai ke bumi, demikian juga medan magnetik sekitar bumi dan jumlah partikel bermuatan yang dipancarkan matahari sehingga mengubah inensitas sinar kosmik yang sampai ke bumi. Hal itu mempengaruhi dinamika atmosfer dan lautan, serta proses pembentukan awan dan hujan .
Berdasarkan berbagai laporan ilmiah dapat diperlihatkan korelasi yang kuat antara aktivitas matahari dengan suhu rata-rata bumi, dengan tutupan awan, dengan suhu permukaan laut di suatu wilayah , dengan curah hujan suatu wilayah , dll.
Penelitian awal yang dilakukan di ITB juga menunjukkan korelasi erat antara cuaca/iklim di benua maritim Indonesia dengan aktivitas matahari.

Sejumlah ilmuwan berkeyakinan bahwa aktivitas matahari merupakan faktor dominan dalam dinamika iklim.1,2) Dinamika atmosfer, penguapan, pembentukan awan semuanya dipengaruhi oleh energi surya yang masuk ke bumi. Aktivitas matahari juga mempengaruhi medan magnetik sekitar bumi sehingga mengubah intensitas sinar kosmik yang datang ke bumi. Ketika matahari tenang intensitas sinar kosmik bertambah besar dan sebaliknya ketika matahari aktif intensitas sinar kosmik berkurang. Korelasi antara tutupan awan dan intensitas sinar kosmik ternyata besar.3)
Kedua hal tsb. sangat mempengaruhi iklim, hal ini dapat terlihat pada sekitar tahun 1645 – 1715 ketika aktivitas matahari sangat rendah yang dikenal sebagai minimum Maunder suhu bumi menjadi sangat rendah, sehingga dikenal sebagai zaman es.
Aktivitas matahari yang diwakili oleh ledakan maksimum (eruption maximum) EM, bintik surya minimum ( sunspot minimum) SM dan siklus torka (torque cycles) TCg dapat dipakai untuk memprediksi ENSO.4)

Sinar kosmik berinteraksi dengan lapisan atmosfer atas menghasilkan partikel sekunder dan pada umumnya partikel bermuatan hasil interaksi tsb tidak dapat menembus sampai atmosfer bawah, tetapi neutron dan muon hasil interaksi tsb. dapat menembus sampai ke atmosfer bawah ( di bawah ketinggian 6 km) dan ketika neutron atau muon berinteraksi dengan molekul udara atau molekul air maka molekul menjadi ion bermuatan yang merupakan inti kondensasi. Sinar kosmik merupakan sumber ion di udara selain radiasi radioisotop dari bumi seperti radon.
Ketika aktivitas matahari rendah atau bintik surya minimum SM, intensitas sinar kosmik maksimum sehingga tutupan awan menjadi maksimum. Ini berarti radiasi energi surya yang sampai ke bumi menjadi minimum. Sebaliknya ketika aktivitas matahari maksimum EM intensitas sinar kosmik yang sampai ke atmosfer bawah menjadi minimum, tutupan awan menjadi minimum, ditambah lagi dengan energi tambahan dari flare ketika terjadi EM , maka radiasi energi surya yang sampai ke permukaan bumi menjadi maksimum.
Tutupan awan secara global menimbulkan efek pemanasan (efek rumah kaca) sebesar 13% tetapi juga menimbulkan efek pendinginan sebesar 20% karena memantulkan radiasi energi yang langsung dari matahari1) .
Jumlah energi surya yang diterima bumi sangat besar yaitu rata-rata 6,3 . 10^20 joule/jam setara dengan energi 40 siklon tropis atau 60 energi yang dilepas pada gempa yang besar.
Dalam siklus surya 21 iradiansi surya yang sampai ke permukaan bumi berkisar antara 1367,0 W/m2 dan 1368,5 W/m2 , variasinya sekitar 0,15 % saja5), tetapi mengingat jumlah energi surya yang diterima bumi sangat besar, dan diperkuat dengan dinamika atmosfer dan lautan bumi maka variasi iradiansi surya itu dapat mempunyai pengaruh besar terhadap cuaca/iklim wilayah Indonesia.

Daftar Pustaka
1.E. Bryant, Climate Process and Change, Cambridge University Press, 1977.
2.T. Landscheidt, Solar Activity : A Dominant Factor in Climate Dynamics, Schroeter Institute for Research in Cycles of Solar Activity,, 1988.
3.K.S. Carlslaw, R.G. Harrison, J. Kirkby, Cosmic Rays, Clouds, and Climate, Science’s Compass, Vol. 298, 2002.
4.T. Landscheidt, New ENSO Forcast Based on Solar Model, Schroeter Institute for Research in Cycles of Solar Activity, 2003.
5.P. Foucal and J. Lean, An Empirical Model of Total Solar Irradiance Variation between 1874 and 1988, Science,247,556-558,1990.

Solar Effects on Weather and Climate in the Indonesian Archipelago

Solar Effects on Weather and Climate in the Indonesian Archipelago

The Houw Liong1)
Plato Martuani Siregar2)
Iratius Radiman3)

1) Department of Physics, ITB
2) Department of Geophysics and Meteorology, ITB
3) Department of Astronomy, ITB

International Seminar APRIM, Bali, 2005

From various stations at Geographic Latitudes from 60N to 100S throughout the Indonesian Archipelago, anomalies of rainfall and irradiance were collected and plotted to those of the Monthly Sunspot Number between 1948 and 2003. It is shown that there is a tight correlation between solar activity and the various geophysical variables, such as the mean temperature of Earth, the cloud cover, the sea surface temperature and the rainfall throughout the region. It is also found that there is a weak correlation between the coefficients of correlation obtained from various plots of the number of sunspot to irradiance, the irradiance to rainfall and the number of sunspot to rainfall from each station against the geomagnetic latitude of the stations. The coefficients of correlations increases as we go to higher geomagnetic latitudes.
This is the initial study at ITB to embark and promote research on Solar Effects on Weather and Climate in the Indonesian Archipelago.

Keywords: Solar Cycle, Geomagnetic Effects.



Badan Pengkajian dan Penerapan Teknologi (BPPT) menyatakan, percepatan hujan dengan mengandalkan teknologi modifikasi cuaca (TMC) dapat mengurangi curah hujan diatas normal. “TMC atau hujan buatan dapat merangsang hujan maksimal untuk turun sebelum waktunya. Tentunya sedikit demi sedikit, sehingga curah hujannya tetap normal,” jelas Asep Karsidi Kepala UPT Hujan Buatan BPPT di Jakarta, Kamis (19/1). Dia menjelaskan, pihaknya dapat mempercepat hujan tersebut dengan melakukan penyemaian di dasar awan pada ketinggian 10.000 feet. Penyemaian menggunakan pesawat terbang jenis CASA 121-200. Jika sebelumnya menggunakan bahan dasar garam dengan metode penyemprotan, kini penyemaian memanfaatkan flare dengan metode pembakaran. Pemanfaatan flare merupakan teknologi terbaru. Kapasitasnya lebih besar dibanding penyemaian dengan bubuk garam. Satu kilogram flare setara dengan satu ton bubuk garam.

Satu pesawat mampu mengangkut 24 flare atau setara 24 ton padahal berat eksisting hanya 12 kilogram. Kalau metode lama paling banyak mengangkut satu ton saja. Jadi, flare mampu mengurangi debit uap air di awan lebih banyak dibanding metode bubuk garam. “Operasional akan lebih efesien,” kata Asep. Upaya percepatan hujan tersebut perlu dilakukan mengingat hasil kajian Tim Prediksi Banjir BPPT, BMG dan ITB yang memperkirakan bahwa banjir di Jakarta akan terjadi pada pertengahan Februari 2006. Metode yang digunakan adalah Anfis. Risetnya selama tiga tahun terakhir.

Menurut pakar cuaca dari Departemen Fisika ITB The Houw Liong, pada pertengahan bulan itu akan terjadi hujan yang maksimal. Namun, kata dia, banjir tersebut tidak terlalu besar seperti tahun 2002 dan 1996. Genangan airnya paling lama hanya satu atau dua hari. Pada tahun 2002 dan tahun 1996 bisa mencapai enam hingga tujuh hari. Liong berharap, pemerintah segera mengeluarkan peringatan dini. “Saat ini, sudah harus berhati-hati, terutama bagi warga yang tinggal di bantaran kali,” tegas dia. Pimpinan Proyek Pengembangan Wilayah Sungai Ciliwung Cisadane (Pimpro PWSCC) Pitoyo Subandrio mengaku sudah memperingatkan kawasan warga di bantaran sungai di Jakarta. Namun warga kurang peduli. “Biasanya, banjir kiriman dari Katulampa ke Jakarta membutuhkan waktu 16 jam,” ujar dia. (c81)

Sumber : Investor Daily (20/1/06)

Komentar :
Artikel ini ditulis berdasarkan wawancara pada 19 Januari 2006.
Gagasan seperti ini dipakai oleh China untuk mencegah hujan lebat di Beijing ketika Olimpiade tahun 2008.


A Couple Model of Droplet Growth Above Bandung

By: Plato Martuani Siregar
S2 - Oceanography and Atmospheric Sciences
Supervisors :
Prof. Dr. The Houw Liong
Dr. Bayong Tj H K

Convection process, cloud droplet

A couple model of droplet growth is developed by three kinds of processes, which are dynamic, thermodynamic, and cloud physics that assume water vapor is present between ground surface and tropopause layer. Updraft in boundary condition is zero. Factor of convergence, lateral advection, turbulent motion, updraft vorticity, and ice phase are neglected, then developed numerical modeling in one dimension of the formation, of droplet growth. This model is very sensitive to initial conditions.

The formation of droplet growth requires high supersaturated vapor to oppose curvature term. For the saturation ratio at relative humidities less than 100 %, droplet growth will be blocked by curvature term, so it needs addition of ammonium sulfate solution to an air parcel until droplet radius 0.13 micrometer, after critical saturation ratio is formed, droplet will grow although relative humidities approach one. On the other hand,solution effect growth is increased by heat conduction and vapor diffusion becomes droplet of radius around 10 micrometer.
A major part of solar radiation have absorbed by the surface of the earth. The atmosphere then becomes unstable due to the heating around ground,and thus convection is generated in the troposphere. The temperature of an air parcel moving upward decreases because of the adiabatic expansion,while water vapor in the air is warmed when it condenses. The temperature lapse rate in the troposphere is thus determined by balance of water vapor in the atmosphere. Using radiosonde data at LAPAN Bandung period in the 1992-1996 to optimize model trend and do verification, after that modeling can be used to estimate updraft rate, parcel temperature, rain mixing ratio, and mixing ratio of the condensed water in the atmosphere.

Convection process is determined in cloud droplet growth. The formation of cloud causes give temperature variations and mixing ratio in atmosphere. It can be seen that temperature variations in the level of 1500m above Bandung is larger than near ground. In this level, the cloud will be formed to absorb solar radiation, current air in cloud and separation of electrical dipole of water molecules which will give temperature variation of air parcel.

Copyright © 2005 ITB Central Library,
Jl. Ganesha 10 Bandung, 40132, Indonesia.
Verbatim copying and distribution of this entire article is permitted by author to ITB Central Library in any medium, provided this notice is preserved

15 April 2009

City counts on bigger budget for flood canal in Jakarta

Wednesday, April 15, 2009 3:23 PM

City counts on bigger budget for flood canal
The Jakarta Post , Jakarta | Thu, 02/01/2007 4:29 PM | Jakarta

Adianto P. Simamora, The Jakarta Post, Jakarta

The city administration hopes to get a higher budgetary allocation for the East Flood Canal project when the Home Ministry reviews the 2007 budget, after the City Council slashed budget support for the project.

Governor Sutiyoso said Wednesday the administration needed Rp 1 trillion to get the project off the ground as soon as possible, in order to prevent water from streaming into the city from upland areas and causing floods.

""The East Flood Canal is the only way to protect the city against floods,"" he said.

""It should be constructed immediately. Otherwise, the area will always be inundated in the rainy season.""

The construction of the 23.5-kilometer canal is expected to be completed by 2010.

The central government has allocated Rp 2.5 trillion for the construction work, while the Jakarta administration spent Rp 2.4 trillion on land acquisition.

To date, only a 7.6-km stretch of the canal has been completed.

The canal, which has an upstream depth of three meters and a downstream depth of seven m, is projected to accommodate more than 390 cubic meters of water per second.

The Public Works Ministry, which is supervising the project, said it was aimed at preventing water from the Cipinang, Sunter, Buaran, Jati Kramat and Cakung rivers flooding areas of East and North Jakarta during the rainy season, when the river levels rise.

It would also protect more than 13 flood-prone areas, including in Cipinang Besar, Cipinang Muara, Cakung Timur, Pondok Kelapa and Duren Sawit.

The Jakarta administration has identified 78 flood-prone areas in the city.

During the budget assessment process earlier this month, the City Council cut the budget allocation to acquire land for the project.

As a result, the administration will only get Rp 600 billion (US$64.5 million) of the proposed Rp 1 trillion to resume the project this year.

The decision was made due to the prolonged dispute between the administration and land owners over land prices.

The council claimed the administration's failure to solve the dispute had caused the low rate of budget usage in the last two years.

It urged the administration to spend the money on disaster preparedness and flood prevention in the first quarter of the year, rather than keeping it for an unclear land acquisition process.

The administration will have the chance to argue its case during the Home Ministry review and mid-year budget revision.

City secretary Ritola Tasmaya said Wednesday the budget files would be sent to the Home Ministry for review this week.

However, experts have said building the canal is no solution.

The Houw Liong of the Bandung Institute of Technology's (ITB) School of Physics said the project developers were shortsighted.

""It's no solution because it will only channel all the water into the sea. Jakarta will then experience serious water shortages in the dry season.""

It is better to choose cheaper solutions i.e. to rebuild and preserve the rainfall catchment areas on the upstream of the rivers that cross Jakarta and to build ponds/rainfall absorbing areas.


11 April 2009

NASA Admits that 1934, Not 1998, was the Warmest Year on Record

August 14, 2007 by B. McLaughlin

In one more devastating blow against the global warming or "climate Apocalypse" supporters such as former Vice President Al Gore, NASA stated today that it was wrong when it release a report that 1998 was the warmest year ever recorded in modern history.

NASA has now corrected that error, and 1934 is now known as the warmest year on record, with 1921 the third warmest year instead of 2006 as was also previously claimed.
NASA has been forced to correct calculations for temperatures of the last 120 years taken from ground-based measuring facilities. Critics of the man-made global warming theory have long been vocal that these measurements are distorted because the ground, and even more the urban ground where most of these measurements took place, is warmed considerably by human activities and cannot accurately represent atmospheric conditions.

"Much of the current global warming fear has been driven by Hansen's pronouncements, and he routinely claims to have been censored by the Bush administration for his views on warming. Now that NASA, without fanfare, has cleaned up his mess, Hansen has been silent -- I guess we can chalk this up to self-censorship," said Burnett.

09 April 2009

Using ANFIS and Fuzzy Clustering to Predict Extreme Climate in Indonesian Regions

Using ANFIS and Fuzzy Clustering to Predict Extreme Climate in Indonesian Regions

The Houw Liong2) and Plato M.Siregar1)

ICICI 2007 proceedings
Jl. Ganesha 10
Bandung, 40132 INA

1) Faculty of Earth Science and Mineral Technology, ITB
2) Faculty of Mathematics and Natural Sciences, ITB


Extreme climate in Indonesia 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 so that 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.
This study explores the physical of climate predictions and classifications of Indonesian regions and its physical interpretations.

Keywords: ANFIS, fuzzy clustering, climate, solar activity

01 April 2009

Dyson : "Global Warming Isn't as Big a Problem as Disease or Poverty"

One of the Planet's Great Scientists: "Global Warming Isn't as Big a Problem as Disease or Poverty"

Famous physicist, author, and visionary Freeman Dyson has been making enemies with his critical stance on global warming. It's important to note that even he, an outspoken opponent, doesn't deny that it's happening - he just doesn't think it's that big a deal.

How does on octogenarian author get people so upset? Well, calling Al Gore a preacher and comparing the climate control movement to a religious cult is a fantastic way to start. If you ever want to piss off a scientist, call them a religion. Disagreeing with them is one thing - accusing them of doctrine is another.
We should welcome smart people who oppose popular conclusions. We might disagree, but we should enter into debate to do so.

Posted by Luke McKinney

Dyson agrees with the prevailing view that there are rapidly rising carbon-dioxide levels in the atmosphere caused by human activity. To the planet, he suggests, the rising carbon may well be a MacGuffin, a striking yet ultimately benign occurrence in what Dyson says is still “a relatively cool period in the earth’s history.” The warming, he says, is not global but local, “making cold places warmer rather than making hot places hotter.” Far from expecting any drastic harmful consequences from these increased temperatures, he says the carbon may well be salubrious — a sign that “the climate is actually improving rather than getting worse,” because carbon acts as an ideal fertilizer promoting forest growth and crop yields. “Most of the evolution of life occurred on a planet substantially warmer than it is now,” he contends, “and substantially richer in carbon dioxide.” Dyson calls ocean acidification, which many scientists say is destroying the saltwater food chain, a genuine but probably exaggerated problem. Sea levels, he says, are rising steadily, but why this is and what dangers it might portend “cannot be predicted until we know much more about its causes.”