Indra Gustari
Badan Meteorologi Klimatologi Dan Geofisika (BMKG)

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ANALISIS CURAH HUJAN PANTAI BARAT SUMATERA BAGIAN UTARA PERIODE 1994-2007 Indra Gustari
Jurnal Meteorologi dan Geofisika Vol 10, No 1 (2009)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (682.146 KB) | DOI: 10.31172/jmg.v10i1.31

Abstract

Dari data curah hujan di pantai barat Sumatera bagian utara dilakukan analisis spektrum daya untuk mengetahui pola curah hujan di daerah tersebut, selanjut dilihat hubungannya dengan intensitas monsun,  Indian Ocean Dipole Mode (IODM) dan El-Nino Southern Oscillation (ENSO). Hasil analisis menunjukkan bahwa pola curah hujan di pantai barat Sumatera bagian utara memiliki dua puncak dan sangat dipengaruhi oleh faktor cuaca dengan dengan osilasi satu tahunan (annual oscillation), dan setengah tahunan (semi-annual oscillation) dan ditemukan hubungan yang kuat antara variabilitas monsun dan IODM. Pola hujan didaerah ini tidak memperlihatkan pengaruh ENSO. The data of Rainfall in the west coast of northern Sumatera were analyzed through power spectrum analyzer to find out the rainfall pattern in that area and to look at the relationship between rainfall pattern and monsoon intensity, Indian Ocean Dipole Mode (IODM) and El-Nino Southern Oscillation (ENSO). The result of this analysis shows that the main rainfall pattern in the west coast of northern Sumatera has two peaks and is very much influenced by the factor of weather with annual oscillation and semi-annual oscillation, there is a strong relationship between monsoon variability and IODM, and the influence of ENSO on the rainfall in this region is not significant.
AKURASI PREDIKSI CURAH HUJAN HARIAN OPERASIONAL DI JABODETABEK : PERBANDINGAN DENGAN MODEL WRF Indra Gustari; Tri Wahyu Hadi; Safwan Hadi; Findy Renggono
Jurnal Meteorologi dan Geofisika Vol 13, No 2 (2012)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31172/jmg.v13i2.126

Abstract

Akurasi prakiraan curah hujan harian operasional yang dibuat oleh Badan Meteorologi Klimatologi dan Geofisika (BMKG) dikaji dengan cara diverifikasi berdasarkan kategori hujan dikotomi, lebat dan sangat lebat terhadap data dari 25 titik pengamatan di Jakarta. Prosedur yang sama juga diterapkan pada prakiraan curah hujan model Weather Research and Forecasting (WRF) dengan teknik multi-nesting yang di-downscale dari keluaran Global Forecast System (GFS). Hasilnya memperlihatkan bahwa kedua metode prediksi tersebut memiliki akurasi yang baik untuk prediksi dikotomi tetapi hampir gagal dalam memprediksi curah hujan lebat dan sangat lebat. Khususnya, kegagalan prediksi operasional dalam mendeteksi tiga kejadian hujan sangat lebat dalam periode kajian. Dalam hal ini, model WRF yang cenderung menghasilkan false alarm memperlihatkan prospek yang bagus untuk pengembangan sistem prediksi cuaca skala lokal/regional yang lebih akurat di Indonesia. The accuracy of daily rainfall forecasts produced operationally by the Meteorological, Climatological, and Geophysical Agency (BMKG) has been assessed by verifying the prediction of dichotomous, heavy, and very heavy rain events against observed data at 25 stations in Jakarta. Similar procedure was applied to raw hindcasts performed  using the Weather Research and Forecasting (WRF) model with multi-nesting technique up to 3 km resolution downscaled from NOAA global forecast system (GFS) outputs.  The results show that both forecasts have quite favorable accuracy for dichotomous rain events but almost no meaningful score for the predictions of heavy and very heavy rain events was obtained. Particularly, none of as many as three observed very heavy rain events was predicted by the operational forecast. In this case, WRF tend produce false alarms indicating a better prospect for future development of more accurate local/regional weather forecasting system in Indonesia.