Jurnal Sains Dirgantara
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KETERKAITAN AKTIVITAS MATAHARI DENGAN SUHU PERMUKAAN LAUT ( SEA SURFACE TEMPERATURE/SST) DAN ENSO DI ATAS INDONESIA
Get PDFThis paper present the relationships between long-term solar activities and sea surface temperature (SST) anomalies over Indonesian regions. Analysis on the relatioships between these parameters is carried out by using wavelet-base analysis techniques and correlation analysis. The wavalet Transform-base analysis (WWZ) for SST anomaly time series are gouped for overall Indonesian SST (SSTI), Western Indonesia SST (SST KIB), Middel Indonesian (SST KITeng) and Eastern Indonesian SST (SST KIT). And also grouped by season, dry season (JJA) and wet season (DJF) during the period of 1860-2005. The WWZ result for SST anomaly time series over Indonesia show some long period main signals with periods of 83 year, (50, 33, 25) year, (9-13) year which are suspected to be associated with solar activity sycles of 80-110 year (Gleissberg cycle), 50 year (interdecadal cycle), 22 year (cycle Hale) and 11-year of solar activity. There are also appear some signals with shorter periods of (3-7) year, (1.5-2.7) year, and (0.5-1) year which are suspected to be associated with ENSO, QBO, and seasonal / annual effects, respectively. From the result of long-term correlation analysis between solar activities with solar cycle length indicator and the 11 and 22 year running moving average Indonesian SST anomalies show good correlation for all data group. While the SST over KIT shows a negative correlation, but during of 1950-2005 shows s positive correlation
KARAKTERISTIK SUDDEN COMMENCEMENT DAN SUDDEN IMPULSE DI SPD BIAK PERIODE 1992-2001
Get PDFKenaikan mendadak intensitas medan geomagnet dapat dibedakan menjadi 2 tipe yaitu tipe Sudden Comencement (SC) dan tipe Sudden Impulse (SI). Tipe SC berupa kenaikan mendadak intensitas medan geomagnet yang diikuti kejadian badai geomagnet dan umumnya berkaitan dengan arah selatan medan magnet antar planet (Interplanetary Magnetic Field/IMF), sedangkan tipe SI berupa kenaikan mendadak medan geomagnet yang tidak diikuti kejadian badai geomagnet dan umumnya berkaitan dengan arah utara IMF. Untuk mengetahui karakteristik SC dan SI, dilakukan identifikasi dan analisis statistik terhadap ketiga parameter SC dan SI, yaitu amplitudo, periode dan gradien dari data komponen horizontal (H) geomagnet di Stasiun Pengamat Dirgantara (SPD) Biak tahun 1992-2001. Hasil yang diperoleh menunjukkan bahwa karakteristik SC(H) mempunyai kriteria seperti amplitudonya yang lebih besar dari 10 nT, periodenya kurang dari 10 menit dan gradiennya lebih besar dari 2.48 nT/menit. Sedangkan karakteristik Karakteristik Sudden Commencement .... (Anwar Santoso et al.) 61 SI(H) mempunyai kriteria seperti amplitudonya lebih besar dari 6.1 nT, periodenya kurang dari 10 menit dan gradiennya lebih besar dari 1.63 nT/menit. Selanjutnya dihitung korelasi antara ketiga parameter SC(H) terhadap H minimum (Hmin) dan durasi Hmin. Hasil korelasi tersebut menunjukkan bahwa amplitudo SC(H) dan periode SC(H) merupakan indikator yang baik yang dapat digunakan untuk memprediksi intensitas dan durasi badai geomagnet. Kata Kunci : SC, SI, Badai geomagnet
IDENTIFIKASI MODEL FLUKTUASI INDEKS K HARIAN MENGGUNAKAN MODEL ARIMA (2.0.1)
Get PDFThe geomagnetic level called geomagnetic index. Based on the latitude, geomagnetic index for high to intermediate latitude is Kp index and for equator area is Dst index. For a certain location it is called local geomagnetic index, K index. Flunctuation of geomagnetic index is one of information that describes condition of space weather. Based on the above condition, this paper discusses identification of daily K index flunctuation model using Auto Regression Integrated Moving Average-ARIMA (2.0.1), 2, 0, and 1 order. Using observation data 1 order. Using observation data and reconstruction of four days data, it is found ARIMA (2.0.1) model 2, 0, and 1 order. Both model are validated, calculating errors and pattern correlation. Model validation result using observational data, showed the error of 2.18 and the pattern correlation of 0,99940. Model validation using reconstruction data, showed the error of 0.3582 and the pattern corelation of 0.9988
DAMPAK CUACA ANTARRIKSA PADA VARIABILITAS IKLIM DI INDONESIA
Get PDFSince a long time ago the Sun as the main source of energy of the Earth is considered to give influence the Earth's climate. It is seen from the analysis of solar activity influence on surface air temparature in various cities in Indonesian area using available data. The result Weighted Wavelet Z-transform (WWZ) analysis of surface air temperature which shows siilarity between periodicity of that of solar activity, especially about 11 yaer, is the first indications of the influence of space weather to the Indonesian climate variability. Additionally, from statistical analyzes by using 11 years-running moving averages, it is seen that the pattern of surface air temperature changes follows the pattern of solar activity variability, although they are sometimes out of phase and move ahead in about 5-15 years. Furthermore, although time series data of surface air temperature is limited, the result shows a good correction between the changes of surface air temperature and solar cycle length/SCL with an applied smoothing with the coefficients 1-2-2-2-1 (from now on we call SCL 12221). We therefore find that this agreement supports (although it does not prove) the sugestion of a direct solar activity influence on surface air temperature in Indonesia
LAPISAN F3 DI IONOSFER LINTANG RENDAH
Get PDFCalculation using the Sheffield University plasmasphere ionosphere model (SUMIP) have shown that under certain conditions an additional layer (F3 layer) can form in the equatorial ionosphere. The F3 layer forms during the morning-noon period in the equatorial region where the combined effect of the upward ExB drift and neutral wind provides vertically upward plasma drift velocity at altitude near and above the F2 peak. The observation results over Biak and Parepare are shown that F3 layer may form in low latitude ionosphere. The observations result over Biak (1.20ËšS, 136.04ËšE, magnetic latitude 12.18ËšS) on January 2005 shown the occurence of the F3 layer 75% of the days from 09:00 to 18:00 local time. The critical frequency of the F3 layer (foF3) exceeds foF2 by about 1 to 3 MHz, and the virtual height h'F3 ranges from 400 to 600 km. Generally, observation result indicate that the formation of F3 layer at low latitude is different with the equatorial region. Where, in addition to the fountain effects, the dynamical processes of the formation of this layer is influenced by the station location relative to the geographic equator
MODEL TEMPORAL CURAH HUJAN DAN DEBIT SUNGAI CITARUM BERBASIS ANFIS
Get PDFPenelitian terhadap model temporal curah hujan dan debit sungai berbasis ANFIS telah dilakukan di daerah aliran sungai Citarum, Jawa Barat. Penelitian tersebut menggunakan data bulanan hasil observasi curah hujan, evapotranspirasi, dan debit sungai dari Januari 1968 hingga Desember 2000 dan data bulanan Global Temperature (GT) dan Central Indian Precipitation (CIP) yang diperoleh dari National Centers for Environmental Prediction (NCEP). Identifikasi model temporal curah hujan dan debit sungai didasarkan pada Adaptive Neuro-Fuzzy Inference System (ANFIS). Hasil penelitian menunjukkan bahwa model temporal curah hujan dan debit sungai berbasis ANFIS dapat mensimulasi data observasi secara akurat. Model tersebut mampu meminimalisasi bias (RMSE) dan memaksimalisasi presisi (E). Model tersebut sangat potensial untuk memprediksi curah hujan dan debit sungai di masa Model Temporal Curah Hujan dan Debit ......... (Ruminta) 23 datang. Prediksi curah hujan dan debit sungai dari model temporal tahunan lebih akurat dibanding model temporal bulanan. Koefisien limpasan (C) sungai Citarum sangat besar (lebih dari 53%) dan cenderung naik secara signifikan. Hal ini menunjukkan bahwa tutupan lahan oleh hutan cenderung makin berkurang. Nilai rasio debit sungai maksimum-minimum (Qmax /Qmin ratio) relatif tinggi yaitu berkisar antara 2.17 – 15.48, menunjukkan bahwa sumber daya air di daerah aliran sungai Citarum telah mengalami kerusakan. Cadangan air (ï„S) adalah defisit dan cenderung berkurang secara signifikan. Fakta ini menunjukkan bahwa kekeringan di daerah aliran sungai Citarum akan terjadi sangat rawan. Kata kunci: Curah hujan, Debit sungai, ANFIS, Koefisien limpasan, Rasio Qmax /Qmin
ANALISIS STABILITAS ATMOSFER PADA LAPISAN TROPOSFER ATAS DAN STRATOSFER BAWAH DI ATAS KOTOTABANG MENGGUNAKAN DATA EQUATORIAL ATMOSPHERE RADAR (EAR), BOUNDARY LAYER RADAR (BLR) DAN RADIOSONDE
Get PDFThis paper is mainly concerned to the analysis of atmospheric stability especialy near the tropopause layer as well as the variation on wet and dry seasons over Kototabang area, West Sumatera (0.2ËšS;100.32ËšE) using Equatorial Atmosphere Radar (EAR), Boundary Layer Radar (BLR) and radiosonde data. The Observation of atmosphere stability nearby the tropopauselayer is very important, condering its function as a buffer of an air masses exchanges from troposphere to stratosphere layer and so the contrary, which is usually called as Statosphere - Troposphere Exchange (STE). Data analysis divide in two stages, firstly is the short periode data analysis from Aptil, 10th until May, 9th of 2004 with the main pupose of validation between vertical echo power (VEP) from EAR and Brunt-Vailsala Frequency Squared (N2) from radiosondes. The result shows that the average of correlation coeffisient from 9 observations is 0.81. This point shows that EAR's ability to replace radiosondes data to inform atmosphere stability. The second stage, contain the long periode data analysis from June and November in the years of 2001 until 2004. Both month representing dry and wet seasons based on monthly Global Precipitation Climatology Project (GPCP) data over 25 years (1979-2004) observations in Sumatera Inland area, specifically for Kototabang. Final result shows that the tropopause height variation in dry season (November) is easier to identify. In the other side, zonal wind dominant in November compare to vertical wind on July. This situation probably because the strong monsual affect in wet seasons. The tropopause height is also estimate have no significant effevt to rain intensity
AEROSOL BACKGROUND LAPISAN STRATOSFER DI ATAS BANDUNG (6Ëš54'LS 107Ëš35'BT) BERDASARKAN PENELITIAN TAHUN 1997-2000 MENGGUNAKAN RAMAN LIDAR
Get PDFAerosol background observation over Bandung (6Ëš54'S 107Ëš35'E) using LIDAR has being done since 1997 as a part of global LIDAR network coordinated by Japan. The 5 years dta shows that the Integrated Backscattering Coefficient at altitude 18-35 km is very small, in the order of 10-6 sr-1. It is 1/100 times compared to IBC over Japan 4 years after Pinatubo eruption. The altitude of IBC weight is relatively stable, in the range of 20-25 km
HUBUNGAN AIR TERKANDUNG DENGAN REFLEKTIFITAS RADAR
Get PDFThis paper is mainly concentrated to the correlation between Total Precipitable Water (TPW) on one single column of the vertical air mass and radar reflectivity (Z) over Kototabang (0.2ËšS; 100.32ËšE), Bukittinggi, West Sumatera based on to the analysis of Radio Acoustic Sounding System (RASS) and Boundary Layer Radar (BLR) data during the Coupling Processes of Equatorial Atmosphere (CPEA) Campaign I from April 10 to May 9, 2004 was going on. wWe firstly reviewed yhe basic concept of TPW using the Weisner method ti estimate the TPW value from the radiosonde data. We reviewed the basic concpt of RASS and BLR system also, especially on the Z data analysis. By arranging the mean value of RASS data every 10 minutes and 150 meter in height, respectively, we estimated the TPW values from the RASS data. By analysing the Cross Cirrelation Function (CCF) of both values taken from SPSS software version 13, we found a good agreement between TPW and Z parameter, especially on 5 May 2004. The correlation values are 0.05, and 0.61 at around 2.7 and 2.25 km, repectively. Although, the maximum correlation value in only 0.61, but this is still good enough to describe the correlation between TPW and Z
IDENTIFIKASI FLUKS MAGNETIK DARI GERAK PASANGAN BINTIK BIPOLAR
Get PDFProper motion of a pair of bipolar spots is analyzed using TRACE white light data to find their relation with the emerging flux. These spots were located under flaring region of NOAA 0424, which ejected an M1.7/S N flare on August 5, 2003. As the result, it is found that the preceding moved westward of the following. We interpret this as the indicator of emerging magnetic flux triggering flare