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OCEAN-ATMOSPHERE ANALYSIS OF SUPER TYPHOON SONGDA 2011 OVER WESTERN NORTH PACIFIC OCEAN Ilhamsyah, Yopi; Bey, Ahmad; Aldrian, Edvin; Affan, Junaidi M.
Proceedings of The Annual International Conference, Syiah Kuala University - Life Sciences & Engineering Chapter Vol 3, No 3 (2013): Addendum
Publisher : Syiah Kuala University

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Abstract

The purpose of the research is to understand the influences of ocean and atmosphere to the formation of Super Typhoon Songda 2011. Daily SST from NOAA AVHRR with spatial resolution of 0.5° in latitude and longitude was used to study upper oceanic response to the formation of Typhoon Songda. Meanwhile, 3-hourly meteorological data from ARP model with spatial coverage of 0.5° Latitude x 0.5° Longitude cover 201 x 101 points from 25° N - 20° S and 70.0° E ? 170.0° E as well as 13 levels of atmospheric columns was also used in the study. The study was also supported by  MT-SAT satellite images. The result showed that from early disturbances until reaching mature stage of Typhoon Songda, SST over WNP reached averages temperature of 30?C. Warm ocean waters continuously produce heat and moisture to the air that are necessary to fuel the genesis, development, formation and intensification of Typhoon Songda. The study also proved that light vertical wind shear (850 ? 200 hPa) at about 0 ? 5 knot was observed in the early development of Songda at 1800 UTC on May 19th. For the time being, weak vertical wind shear extended to the northwestern of Pacific Ocean. Thus, it made the system to moved toward northwest and reached category Super Typhoon few days later on May 26th. The study also showed the present of Monsoon trough. Monsoon trough occurred where easterly wind met the reversal southerly wind. The region was stretched from southeast to northwest part of WNP Ocean and designated by an extended low pressure area at the surface as well as extended bands of thunderstorms as observed by satellite imagery. On the other hand, potential vorticity shown in the present paper is useful to obtain an understanding of atmospheric motions and development of the upper-level disturbance. Potential vorticity maximum characterize strong vorticity and upward motion. Conversely, weak vorticity with downward motion is demonstrated by mininum potential vorticity.
COMPARISON OF TOTAL SUSPENDED PARTICULATE (TSP) MEASUREMENT IN URBAN AND SUBURBAN AREAS OF BALI DURING NYEPI DAY 2015 Nuraini, Tri Astuti; Permana, Donaldi Sukma; Satyaningsih, Ratna; Anggraeni, Rian; Aldrian, Edvin
Forum Geografi Vol 33, No 2 (2019): December 2019
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v33i2.8670

Abstract

Nyepi or the Balinese Day of Silence (DOS) is a day when people celebrate every New Year according to the Balinese calendar (Saka). On that day, all resident activities were very restricted, with no outdoor activities. This event, which only lasted for 24 hours, is a unique period to conduct air quality measurements such as Total Suspended Particulate (TSP) for assessing the influence of human activities. This study only focuses on TSP monitoring before, during and after the DOS and its comparison with the meteorological data. TSP concentration measurements were conducted in 2 urban areas (Badung and Ubung) and a sub-urban area (Singaraja) from March 17 to March 25, 2015. The results show that TSP concentrations are negatively correlated with temperature and wind speed at each location. Hourly TSP concentrations during DOS are lower than the averaged TSP concentrations before and after DOS. During DOS, TSP concentrations decreased significantly in urban areas by 73-78% relative to regular days, which is likely due to drastically decreasing of human activities. In suburban areas, the decrease of TSP concentration was about 59%. These results show that human activities highly influence the air quality.
VARIASI SPASIAL DAN TEMPORAL HUJAN KONVEKTIF DI PULAU JAWA BERDASARKAN CITRA SATELIT(SPATIAL AND TEMPORAL VARIATION OF CONVECTIVE RAIN IN JAVA ISLAND BASED ON CITRA IMAGES) Kusumawati, Yetti; Effendy, Sobri; Aldrian, Edvin
Agromet Vol. 22 No. 1 (2008): June 2008
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (643.723 KB) | DOI: 10.29244/j.agromet.22.1.%p

Abstract

Convective rain is one of precipitation types that usually occur in Indonesia, result by convective process. This convective rain brings heavy rainfall in short period and could reach a higher intensity than common monsoon rain. Convective process may have a variation with time and location. This research have determined spatial and temporal variation of convective rain in Java island by using the black body temperature (TBB) gradient method based on the GMS-6 (MTSAT-1R) images. As a result, the seasonal convective rain generally occurred in similar period i.e. in the morning from 07.00 to 11.00 LT (local time) and in the evening from 18.00 LT until 05.00 LT. The maximum event occurred from 18.00 LT until mid night. There were different locations between the seasonal convective event. In the seasonal convective rain, there were two spatial patterns. In wet season (DJF) and transitional season from wet to dry (MAM) convective rain spread from east to west Java. While in dry season (JJA) and transitional season from dry to wet (SON), convective rain mostly occurred only in west Java.
COMPARISON PERFORMANCE OF THE MULTI-REGIONAL CLIMATE MODEL (RCM) IN SIMULATING RAINFALL AND AIR TEMPERATURE IN BATANGHARI WATERSHED Handoko, Unggul; Boer, Rizaldi; Aldrian, Edvin; Latifah, Arnida L.; Dasanto, Bambang D.; Apip, Apip; Misnawati, Misnawati
Aceh International Journal of Science and Technology Vol 8, No 2 (2019): August 2019
Publisher : Graduate School of Syiah Kuala University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.13170/aijst.8.2.12340

Abstract

Many scientists assume that RCM output is directly used as input for climate change impact models, while it consists of systematic errors. Consequently, RCM still requires bias correction to be used as an input model. The purpose of this study was to analyze the RCM performance before and after bias correction, its best performance from several models, as well as to clarify the importance of bias correction before it is used to analyze climate change. As a result of this, the method used for bias correction was Distribution Mapping method (for rainfall) and Average Ratio-method (for air temperature). While the Generalized Extrem Valuedistribution (GEV) was used to analysis extreme rainfall. To determine the performance of the model before and after bias correction, statistical analysis was used namelyR2, NSE, and RMSE. Furthermore, ranking for every single model and Taylor Diagram was used to determine the best model. The results showed that the RCMs performance improved with bias correction. However, CSIRO-Mk3-6-0, CCSM4, GFDL-ESM2M, and MPI-ESM-MR models can be ignored as ensemble models, because they demonstrated poor performance in simulating rainfall. From this study, it was suggested that the best model in simulating daily and monthly rainfall was ACCESS1-0, while MIROC-ESM-CHEM (daily air temperature) and ACCESS1-0 (monthly air temperature) were best models used in simulating air temperature. Key words: RCM, bias correction, performance, rainfall, air temperature
AN INDICATION OF SEA-AIR INTERACTION THAT AFFECTS THE CLIMATE PATTERN OVER THE MOLUCCAN SEA Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 3, No 2 (2002): December 2002
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v3i2.2170

Abstract

Starting with the regional annual cycle of rainfall over Molucca, which follow the sun eclipse movement instead of the common Inter Tropical Convergence Zone (ITCZ) movement, a suspicion of the sea-air interaction driven climate pattern comes up. The empirical study on rainfall – sea surface temperature (SST) relationship clarifies a function of rainfall accumulation to SST. A strong evident on the interaction comes from the result of Ocean General Circulation Model (OGCM). The model shows a surface water intrusion that comes from west Pacific into the north Molucca Sea before it enter the mainstream of the Indonesian throughflow in the north end of the Makasar strait. Most of the throughflow, as shown by the model, come from north Pacific, enter the Makasar strait southward and go into the Indian ocean through the Lombok strait (mostly) and a strait between Flores and Timor island. The intrusion of surface water in north Molucca conserves the warm sea surface temperature and keep a high convective area.Diawali dengan pembagian region berdasarkan pola hujan tahunan di Maluku, yangmengikuti pergerakan tahunan matahari dan bukannya yang biasa yaitu Inter TropicalConvergence Zone (ITCZ), kecurigaan akan adanya interaksi laut udara yang mendorong pola iklim timbul. Studi empiris mengenai hubungan hujan dan suhu permukaan laut menjelaskan fungsi akumulasi hujan terhadap suhu laut. Indikasi kuat adanya interaksi berasal dari keluaran model global sirkulasi laut. Model menunjukkan adanya intrusi arus permukaan dari pasifik barat ke Maluku utara sebelum masuk ke alur utama dari arus lintas Indonesia di ujung utara selat makasar. Sebagian besar arus lintas, sebagaimana dituntukkan oleh model, berasal dari utara, memasuki selat Makasar ke selatan dan menuju ke samudra Indonesia kebanyakan melalui selat Lombok dan sebagian kecil melalui selat antara pulau Flores dan Timor. Intrusi arus permukaan di utara Maluku menjaga kehangatan suhu muka laut dan menjaga daerah konvektif aktif.
PEMBAGIAN IKLIM INDONESIA BERDASARKAN POLA CURAH HUJAN DENGAN METODA “DOUBLE CORRELATION” Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 2, No 1 (2001): June 2001
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v2i1.2142

Abstract

Pembagian wilayah atau region iklim Indonesia berdasarkan pola curah hujan tahunandibahas disini. Sebuah metoda yang dinamakan metoda “double correlation” diperkenalkan untuk tujuan di atas. Dengan metoda regionalisasi yang dipakai dihasilkan tiga region iklim berdasarkan pola curah hujan tahunan. Region pertama adalah region A yang terletak di wilayah selatan Indonesia yang disebut region monsun Australia karena region ini lebih banyak dipengaruhi oleh monsun Australia. Region kedua adalah region B di wilayah barat laut Indonesia, yang disebut sebagai region monsun passat tenggara karena dipengaruhi oleh monsun ini. Region terakhir adalah region C atau region arus lintas laut Indonesia (arlindo) karena terletak pada daerah aliran arlindo. Pola hasil dari regionalisasi ini dibandingkan dengan pola pada region yang sama pada keluaran model reanalisa ECMWF dan ECHAM.A regionalization of Indonesian climate based on its annual rainfall patterns has been done. A new method called the “double correlation method” was introduced and used for such purpose. With this regionalization method there are three climate regions based on their annual rainfall patterns. The first region or region A lies in south Indonesia and is called the Australian monsoon region because it is much affected by the Australian monsoon. The second region or region B lies in northwest Indonesia, which is called as the NE Passat region because it is much affected by that monsoon. The last region or region C lies over the Indonesian Throughflow and is called as the Indonesian Throughflow region. Patterns resulted from this regionalization method are compared to those of their corresponding regions from the output of ECMWF reanalysis and a Global Circulation Model ECHAM.
THE SIMULATION OF CO- AND CROSS-POLAR CHARACTERS OF RAINFALL DROPLETS AND CHAFF Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 3, No 2 (2002): December 2002
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v3i2.2166

Abstract

The error analyses and simulations of the co- and cross-polar characters of chaff andrainfall have been done. Error analyses include the ZDR distribution, numbers ofscaterers, the orientation and shape dependence, the system DC bias, the channel gainimbalance and the quantification errors. There is no effect of number of scatterers on the noise. The orientation and shape dependence study indicates wider frequency distribution of ZDR from chaff is because of the chaffs needle shape. The orientation of chaff contributes insignificantly to noises The noises has been reduced considerably after eliminating system DC bias and gaining more channel balance. Further possible source of error is the quantification error in data analyses. LDR is more useful than ZDR when both chaff and rain are present. The result suggests a possibility of using chaff’s LDR in tracing air movement.Analisa error dan simulasi sifat co- dan cross-polar dari chaff dan butir -butir hujan telahdilakukan. Analisa error termasuk penyebaran ZDR, jumlah chaff atau bidang pemantul(scatterers), orientasi dan bentuk dari chaff, factor kesalahan DC, keseimbangan keduakanal pada radar dan factor kesalahan kuantitatif unit. Tidak ada sumbangan kesalahandari jumlah scatterers pada noise. Penelitian orientasi dan bentuk menunjukkan lebarnya penyebaran ZDR pada chaff karena bentuknya. Orientasi dari chaff tidak menyumbang factor kesalahan yang berarti. Noise telah dapat dikurangi hingga minimal setelah menghilangkan factor kesalahan system DC dan menyeimbangkan kedua kanal. Faktor kesalahan lainnya yang mungkin adalah kesalahan kuantitatif unit pada analisis data. LDR lebih berguna dari ZDR ketika kedua duanya yaitu chaff dan butir hujan berada. Hasil tersebut menyarankan kegunaan chaff LDR untuk pemantauan pergerakan udara.
THE SPECTRUM THRESHOLD FILTER METHOD FOR CHAFF AND RAIN Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 3, No 1 (2002): June 2002
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v3i1.2157

Abstract

Polarization doppler radar observations of chaff and rain were conducted. At least in thevertical pointing case, the spectrum of chaff is much narrower than that of rain. In dataanalysis a new method of filtering chaff data from noise is used. This filter method, named the spectrum threshold filter method, was also applied for rain data for comparison. Instead of using the average power as in the conventional method this fil ter method utilizes the doppler spectral peak power. Consequently this filter method is able to detect a presence of even a single strong doppler velocity signals. Hence the performance of this filter is better with metallic strips, such as chaff, than raindrops. The variation of the filter’ s threshold will change significantly the filtered rainfall area but not the chaff one. The filter technique is also useful to detect a narrow but strong spectral data.Pengamatan hujan dan chaff dengan memakai radar dengan polarisasi doppler telahdilakukan. Paling tidak pada posisi tegak lurus, spektrum dari chaff lebih sempit daripada pada butir hujan. Dalam melakukan analisa data kita telah mengembangkan sebuah metoda filtering untuk memilah data chaff dari noise sekitarnya. Metoda filter ini, yang disebut metoda filter spectrum threshold, juga diterapkan pada data hujan sebagai perbandingan. Daripada memakai kekuatan rata-rata dengan metoda umumnya, metoda filter ini memakai puncak spektrum. Sehingga metoda filter ini dapat mendeteksi keberadaan dari hanya sebuah puncak kecepatan doppler dalam sinyal. Pada akhirnya kinerja metoda filter ini lebih baik untuk aplikasi pada pita-pita logam seperti chaff daripada butiran hujan. Variasi dari batas ambang (threshold) dari filter ini akan mengubah area hujan yang terfilter secara drastis tetapi tidak pada data chaff. Teknik filter ini juga berguna untuk mendeteksi spektrum doppler yang sempit tetapi kuat.
POLA HUJAN RATA-RATA BULANAN WILAYAH INDONESIA; TINJAUAN HASIL KONTUR DATA PENAKAR DENGAN RESOLUSI ECHAM T -42 Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 1, No 2 (2000): December 2000
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v1i2.2124

Abstract

Kajian temporal dari sifat iklim Indonesia berdasarkan pola curah hujan rata-rata bulanan telah dilakukan dengan mengacu pada beberapa parameter ECMWF seperti angin 850 mb, OLR dan suhu permukaan. Parameter ECMWF tersebut dapat menjelaskan hampir semua pola kecuali daerah yang terdapat pola gangguan lokal. Dengan kajian temporal ini, penulis menemukan ITCZ, daerah siklon di utara Australia dan aktivitas monsun yang dominan pada beberapa bulan. Hasil lainnya menunjukkan adanya perioda transisi pada bulan April dan Oktober yang dapat dimengerti dari pola angin 850 mb dan suhu permukaan. Juga dijelaskan bahwa puncak hujan tahunan di Bali ke Timor lebih banyak dipengaruhi oleh siklon tropis di utara Australia daripada monsun Asia.Temporal assesment of Indonesian climate characteristic based on monthly rainfall pattern was done with several ECMWF (European Center for Medium Range Weather Forecast) parameters; i.e. wind field of 850 mb, Outgoing Longwave Radiation (OLR) and surface temperature. Those ECMWF parameters could explain almost all rainfall pattern with some exceptional areas which are due to their local disturbances. With this temporal assesment, the author found Inter Tropical Continental Zone (ITCZ), cyclonic area in north of Australia and monsoon activities which are dominant in some specific months. One results of this research shows transitional period existence in April and October which are fully understood by analysis of 850 mb wind and surface temperature. It is also explained that peak of rainfall pattern in Bali - Timor area are much characterized by tropical cyclones in north of Australia rather than by Asian monsoon.
SPATIAL PATTERNS OF ENSO IMPACT ON INDONESIAN RAINFALL Aldrian, Edvin
Jurnal Sains & Teknologi Modifikasi Cuaca Vol 3, No 1 (2002): June 2002
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29122/jstmc.v3i1.2154

Abstract

A monthly temporal and spatial assesment on ENSO impact on Indonesian rainfall hasbeen done. The study uses monthly ensemble averages of El Nino and La Nina years from 1961 to 1993. There are 6 El Niño years and 5 La Niña years during that period. Indonesia experiences negative ENSO influences from April on both El Niño (warm phase) and La Niña (cold phase). The influences of ENSO reach their peaks in August and September by both types of events and decay afterward. The influences diminish totally by December. Since the influences occur in the dry season, El Niño contributes a negative impact, while La Niña a positive impact to the Indonesian climate. The maximum spatial extension of ENSO reaches almost all parts of Indonesia except north Sumatera and some parts of Kalimantan. There is an indication of a negative influence of ENSO to the onset of Asian monsoon in the Southeast Asian.Kajian bulanan secara temporal dan geografis tentang pengaruh ENSO terhadap curahhujan Indonesia telah dilakukan. Penelitian ini memakai nilai rata-rata gabungan bulanan dari tahun El Niño dan La Niña dari 1961 hingga 1993. Ada 6 tahun El Niño dan 5 tahun La Niña pada perioda tersebut. Indonesia menerima pengaruh negatif dari ENSO mulai April pada tahun ENSO. Pengaruh ENSO mencapai puncaknya pada bulan Agustus dan September pada keduanya dan menurun setelahnya. Pengaruhnya benar-benar hilang pada bulan Desember. Karena pengaruh ENSO terjadi pada musim kering, El Niño memberikan kontribusi negative terhadap iklim Indonesia, sementara La Niña memberikan kontribusi positive. Luasan daerah pengaruh ENSO yang maksimal terjadi di hampir seluruh wilayah Indonesia kecuali bagian utara Sumatera dan sebagian Kalimantan. Ada indikasi pengaruh negative dari ENSO terhadap kedatangan muson Asia ke wilayah Asia Tenggara.