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ANALISIS STRUKTUR VERTIKAL MJO TERKAIT DENGAN AKTIVITAS SUPER CLOUD CLUSTERS (SCCs) DI KAWASAN BARAT INDONESIA Eddy Hermawan
Jurnal Sains Dirgantara Vol 8, No 1 (2010)
Publisher : Lembaga Penerbangan dan Antariksa Nasional

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One important aspect when its Coupling Processes Equatorial Atmosphere (CPEA) Campaign 2004 in Kototabang which lasted for approximately one month of observation (April 10 to May 10, 2004) was an analysis of the vertical structure of the phenomenon of the Madden-Julian Oscillation (MJO) related to the activity of the Super Cloud Clusters (SCCs) as one of the main parameters in assessing the behavior of rainfall occurred in the western region of Indonesia. The data used are data of Equatorial Atmosphere Radar (EAR), Boundary Layer Radar (BLR), Mini Automatic Weather Station (MAWS), and Optical Rain Gauge (ORG) at Kototabang, LAPAN Ground Station. While the supporting data used are long-wave radiation anomaly data (Outgoing Longwave Radiation, OLR) and surface rainfall data. The analysis using spectral techniques, particularly the Fast Fourier Transform (FFT) on data anomalies daily average five (pentad) OLR oscillation 2001-2005 period shows that the dominant than the data is approximately 30 daily. These oscillations typically occurred in the lower troposphere layer with the direction of propagation toward the east. Besides that, the existence of convergence and divergence processes in the layer 3 and 10 km above mean sea level (msl) is also found, particularly on the date April 23, 2004 of EAR data analysis. Finally, we try to link these events by analyzing the relationship between OLR with the rainfall in Kototabang and the surrounding region, particularly ORG measurement results with the correlation coefficient of about 0.71. Keywords : CPEA Campaign, MJO, OLR, EAR, and ORG

ANALISIS PERILAKU ANGIN DI LAPISAN 850 hPa HASIL OBSERVASI DATA WPR DIKAITKAN DENGAN PERILAKU DATA INDEKS MONSUN GLOBAL DI INDONESIA Noviyanti Erfien Kaparang; Eddy Hermawan
Jurnal Sains Dirgantara Vol 8, No 1 (2010)
Publisher : Lembaga Penerbangan dan Antariksa Nasional

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This study analyzed the behavior of winds in the lower layers of the troposphere, or rather at "approximately" 850 hPa layer, which is equivalent to an altitude of "about" 1.5 km above the sea level (asl) and observed the data at Wind Profiling Radar (WPR) in Pontianak, Biak, Manado, Serpong and Kototabang, particularly in the wet months (BB) and dry months (BK) for a few months. The results show that the WPR data used to identify the Monsoon on the Indonesian Maritime Continent region (BMI) is quite refresentative. The results further show that the cities which are located relatively close to the equatorial line, such as Pontianak and Biak are relatively strongly influenced by wind zonal (East-West). While the city which is relatively far from the equatorial line (like Manado), is relatively strongly affected by the meridional wind (North-South). There is further analysis of why this is happening. However, this is allegedly due to the influence of Coriolis force (Coriolis Force), particularly at the lower layers of the troposphere in the region that is located relatively far from the equatorial than in the precise area at the equatorial considering that the Coriolis force itself is close to zero (very small) for the equatorial region. Another interesting point is that the zonal winds are stronger influence on the data AUSMI (Australian Monsoon Index), while the meridional winds are the stronger influence on the data WNPMI (Western North Pacific Monsoon Index) with correlation values respectively around 0.76 and 0.45. Keywords: Monsoon Signal, WPR, and Global Monsoon Index

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 Eddy Hermawan; Sri Hartati Soeparno; Filla Aulifin Kemirah
Jurnal Sains Dirgantara Vol 3, No.2 Juni (2006)
Publisher : Lembaga Penerbangan dan Antariksa Nasional

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This 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 (0.2˚S;100.32˚E) 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.

PENGGUNAAN METODE ASPECT SENSITIVITY DALAM PENENTUAN TINGGI LAPISAN TROPOPAUSE DI SAAT MJO AKTIF MELINTAS KAWASAN KOTOTABANG DAN SEKITARNYA Eddy Hermawan; Irma Nurlela; Tri Wahyu Hadi
Jurnal Sains Dirgantara Vol 5, No.1 Desember (2007)
Publisher : Lembaga Penerbangan dan Antariksa Nasional

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This paper is mainly concerned to the utilization of aspect sensitivity (Pv/Po) method to define the tropopause height variation over the equatorial Indonesia, nearby Kototabang (0,2˚S; 100,32˚E), Bukittinggi, West Sumatera using the Equatorial Atmosphere Radar (EAR), especially during the Coupling Processes Equatorial Atmosphere (CPEA) Campign I in 2004 is already done. It is very important to be done since the tropopause is the buffer layer between troposphere and stratosphere (and also contrary) that usually called as the Stratosphere-Troposphere Exchanged (STE) (Holton, 1996). Validation's results with the radiosonde data shows that (Pv/Po relatively higher that radiosonde data. They are about 712 meter and 961 meter for Cold Point Tropopause (CPT) and Lapse Rate Tropopause (LRT) version, respectively. The mean difference between CPT and LRT itself is about 248 meter. This is enough valid considering to the maximum difference between of them not more 500 meter ( Haynes and Shepherd, 2001). This result then be applied in determining of tropopause height variation over Kototabang especially when the Madden-Julian Oscillation (MJO) passed over this region from November to December 2001. It shown that there are no significant differences between MJO active and no active on the tropopause height determination about 17.98 km and 17.73 km, respectively. The most interest is the tropopause height variation is larger during the MJO active than non active.To get the better understanding of tropopause height variation, especially with good time and spatial height resolution, the utilization of ERA and other instruments Kototabang are very needed.

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