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International Conference on Mathematics and Natural Sciences (ICMNS) November 29-30, 2006, Bandung-Indonesia

Case Analysis of Relationship between Rainfall Convection and Flood Phenomena on January 2002 in DKI-Jakarta Area Rahmat Gernowo 1 ; Bayong Tj. H.K.2; The H.L.3; Tri Wahyu Hadi 4 ; Ina Juaeni 5 1 Faculty of Mathematics and Natural Sciences, Diponegoro University, Semarang Jl. Prof. Sudarto, Tembalang Semarang. 2,4 Expertise of Atmosphere Science Group, Bandung Institute of Technology 3 Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology 5 Faculty of Earth Science and Mineral Technology, Bandung Institute of Technology Jl. Ganesha No. 10 Bandung 40132 *Email: [email protected]

Abstract The dynamics of cloud rain especially in area of Jakarta represent to important matter in seeking of step solution, to prevention of floods especially in Jakarta. The research of convection pattern above area of DKI-Jakarta based on to existing perception data, especially high resolution satellite image which is expected will give the understanding of growth of convection cloud yield torrential rains and deliver floods in DKI-Jakarta.The result of research into whereas in this research is obtained by the rain study of extreme in DKI-Jakarta. As rainfall data result of average from some stations is residing in DKI-Jakarta. The rainfall data taken end 2001- early 2002 year, where happened the floods with pond more than 10 day source data of Kimpraswil-Cilsi. The result of research is obtained by analysis whereas, that cloud dynamics in DKI-Jakarta caused by local atmospheric circulation’s factor.

Keywords : Flood, cloud dynamics and satellite image. during range of time the year 1990-2006, the biggest rainfall term as extremely rain happened for once in the period. a.

b.

120 Curah Hujan

Curah Hujan (mm)

The floods of natural disaster (see Fig, 1), what knocks over approximate 70 % of all region in DKI-Jakarta takes place from date 29 January 2002 to 10 February 2002 with pond height ranges from 10-250 cm 1). The nature phenomenon because of taking place torrential rains for hours for area that is wide enough and added with consignment floods which in bringing by river passing DKI especially river of Ciliwung, Pasanggrahan and Sunter 2).

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I. Introduction.

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Fig. 2(a). Rainfall graph the year 2001-2002. (b). Rainfall histogram during range of time the year 19902006 of DKI-Jakarta

In this paper will be studied mechanism the happening of extremely rain floods DKI Jakarta the year 2002.The diurnal cycle of rainfall and its regional variations are important in the tropics, where the synoptic-scale cyclones that cause rainfall in extratropical regions don’t exist. Because tropical rainfall involves the up take and release of significant amounts of latent heat of vaporization 3). The extremely rainfall phenomenon evaluated from effect synoptic which is change of atmosphere regional, can be in the form of factor change of condition of MJO (Madden Julian Oscillation) and streamline of wind (vortex) of area DKI-Jakarta. The periodicity of MJO for the year 1996, however for the year 2002 in stable condition as Fig. 3a. Figure 3b shows the amplitude variability of MJO by the end

Fig.1. The floods of natural disaster, DKI-Jakarta 2002.

The floods of disaster knocking over area of Jakarta and its surroundings is because of big and the duration close rainfall as case of atmosphere change anomaly. The change anomaly of atmosphere from rainfall, as in Fig. 2a and b graph and rainfall histogram of Jakarta, with maximum of rainfall time periodicity happened on 30 January 2002. As for from rainfall histogram

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International Conference on Mathematics and Natural Sciences (ICMNS) November 29-30, 2006, Bandung-Indonesia

of January 2002, stays at phase 3-6 in normal condition. a.

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3.5

II. Research Methodologies. As initial step in this research, be study to convection pattern above area DKI Jakarta based on the observation data, especially high resolution satellite image which will give understanding about growth pattern of convection cloud yielding torrential rains and delivers floods in region DKIJakarta. The Cloud dynamics analysis with determination of extreme rainfall of floods cause is region in DKI Jakarta, cloud types analysis based on data visible satellite obtained from data center in University of Wisconsin-Madison Space Science and Engineering Center (SSEC) (http://www.ssec.wisc.edu/datacenter/). Then as step of hereinafter, analyses change pattern of amplitude MJO (Madden Julian Oscillation) and OLR (Out going Long wave Radiation), this thing done to see domination of effect regional (effect synoptic) or local effect to case of floods DKI Jakarta the year 2002.

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Fig. 3(a). The periodicity of MJO for the year 19952005. (b). Amplitude variability of MJO by the end of January 2002 of DKI-Jakarta

The case streamline of wind (vortex) is from date 23 ending 26 January 2002 as in Fig. 4a. The result of analysis is explains case of tropical cyclone in region of Indonesia south happened in one years average of seven cases with monthly rainfall stays to average value with anomaly 12,6 mm 4). a.

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Fig. 4 (a). The streamline of wind (vortex) is from date 26-1-2002. (b). The rainfall of Bandung at January 2002.

III. Results and Analysis. The extremely rain phenomenon is analyzed based on cloud dynamics pattern (IR1 Temperature data) in DKI-Jakarta. The growth pattern of cloud is started on 27 January 2002, but growth of maximum cloud happened on 29 January 2002 started when 00-03 UTC (07-09 WIB) and finished on 30 January 2002 (Fig. 5a).

It is concluded that tropical cyclone winds are convectively unstable. A review of past measurements provides overwhelming evidence of higher turbulence intensities, guest factor, and turbulence integral length scales in the tropical cyclone boundary layer as compared with those obtained under neutral conditions. This is a direct consequence of convective instability and the additional influence of convective activity above the boundary layer. Instability in the tropical cyclone also causes the mean and gust wind profiles to be flatter than the neutral boundary layer profiles 5). Which if effect synoptic predominating hence rainfall there will be across the board as impact of the effect 6), as seen from case of rainfall Bandung area at January 2002 (Fig. 4b) doesn't show extreme of rainfall variability. Based on the thing, hence extremely rainfall that caused floods in DKI-Jakarta is dominated by local factor. In this handing out study is continued with analyzing cloud dynamics at case period of extremely rain.

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Fig.5(a). Change pattern of IR1 Temperature 29January 2002, at 00 UTC in DKI-Jakarta. (b). Graph of Time Series IR1 Temperature (diurnal variation) 29Januari-2002, at 00 UTC in DKI-Jakarta.

The study in this research will be analyzed from data AVN for date on 28 to 30 January 2002 in DKI-Jakarta. Data of contour pattern AVN for example covering divergence by streamline of wind, absolute vorticity, pressure vertical velocity and atmosphere column precipitable water obtained from data NCEP/NCAR (see fig. 6 and 7). Data of every 6 hours from the NCEP/NCAR reanalysis data was used to know that extremely rain influence was predominated by local factor. Fig. 6a, b and c

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International Conference on Mathematics and Natural Sciences (ICMNS) November 29-30, 2006, Bandung-Indonesia

show convergent pattern above sea around area of DKI-Jakarta and Indian Ocean. The Change of pattern was started on 28 January 2002 and became maximal above Java’s island on 29 January 2002 and finished on 30 January 2002. As according to 7) in its the research telling that any three aspect of see breeze circulation over tropical site if DKI-Jakarta, Indonesia, have been investigated. With regard to the horizontal extent, satellite image obtained during the dry season clearly show that see breeze front develops well along the northern coastal plain of west Java. A propagates inland until its structure is modified over more complex topography at a distance of about 60 – 80 km from the coastline. a.

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d. Fig. 7a, b, c) Pressure Vertical Velocity [Pa/s] of DKI-Jakarta Date of 28-29-30 January 2002. d, e, f) Atmos. column Precipitable water [kg/m^2] of DKI-Jakarta Date of 28-29-30 January 2002 from NCEP/NCAR data.

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Figure 7a, 7b and 7c show a speed of vertical pressure to reach maximum on 29 January 2002 and a speed anomaly of vertical minimum pressure on 28 January 2002, between area of Java Sea and Indian Ocean in DKI-Jakarta. The precipitate level in figure 7d, e, and f was started on 28 January 2002 and finished on 30 January 2002. The growth pattern of cloud in DKI Jakarta was caused by circulation factor of local atmosphere. This thing proves that change of climate anomaly on January 2002 is affected by the growth of convection.

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Fig. 6 a, b, c) Wind divergence of DKI-Jakarta Date of 28-29-30 January 2002. d, e, f) Absolute Vorticity [ /s] of DKIJakarta Date of 28-29-30 January 2002 from data NCEP/NCAR.

III. Conclusion. The extremely rain phenomenon in region of DKI-Jakarta was analyzed based on change pattern of phase and amplitude MJO and tropical cyclone phenomenon. However, this analysis doesn’t show extremely change of pattern. This thing proves that synoptic scale is not predominant of extremely rain in DKI-Jakarta. Based on AVN data analysis, the floods in DKI-Jakarta on 29 January 2002 are dominated by circulation factor of local atmosphere. The dynamics of rain cloud caused torrential rain or extremely rain is caused by the growth of convection cloud in DKI-Jakarta.

Figure 5d, 5e and 5f show a negative absolute vorticity for on 28 January 2002 between Java’s sea and Indian Ocean, around of Jakarta area. Then on 29 January 2002, the negative vorticity anomaly was happened above part of Java’s island and finished on 30 January 2002. This thing proves that the activity of tropic convection above ocean is more actively with large variations 8).

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International Conference on Mathematics and Natural Sciences (ICMNS) November 29-30, 2006, Bandung-Indonesia

IV. References. 1.

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Denny Z., 2005, ‘Pengembangan Kawasan Banjir Kanal Timur, Sisitim Manajemen Air Untuk Menata Kehidupan’, ITB Press. The H.L., Bayong Tj HK, Martuani P.S., Gernowo R., Bramantyo B., dan H. Widodo, 2005, Proceeding National Conference of Indonesia Hydrology Expert, BPPT Jakarta. Mori S., Jun-Ichi H., Yudi Iman T., Yamanaka M.D., Okamoto N., Murata F., Sakurai N., Hashiguchi H., and Sribimawati T., 2004. , American Meteorological Society, PP 2021-2039. Nasrul I., 2004,’ Studi Siklon Tropis Diselatan Indonesia dan Pengaruhnya Terhadap Curah Hujan Jakarta’, FIKTM ITB Bandung. Sharma R.N., and Richard P.J., 1999, Journal of Wind Engineering and Industrial Aerodynamics 83 pp. 21-33. Roxana C., and Wajsowicz, 2005, Journal Dynamics of Atmospheres and Ocean pp.115. Hadi Tri W., Horinouchi T., Tsuda T., Hashiguchi H., and Fukao S., 2002, Monthly Weather Review, vol. 130, pp. 2153-2165. Chaudhry F.H., Filho A.G.A., and Calheiros R.V., 1996, Atmospheric Research 42, pp.217-227.

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