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Upwelling di Laut Banda dan Pesisir Selatan Jawa serta Hubungannya dengan ENSO dan IOD Herlina Ika Ratnawati; Rahmat Hidayat; Ahmad Bey; Tania June
Journal Omni-Akuatika Vol 12, No 3 (2016): Omni-Akuatika Special Issue Kripik SCiFiMaS
Publisher : Fisheries and Marine Science Faculty - Jenderal Soedirman University

Upwelling events analysis in southern coast of Java and Banda sea were conducted. The events were identified by using satellite data i.e. wind surface, Sea Surface Temperature (SST) and ocean color during period of 14 years (2002-2016) which calculated by Ekman pumping and Ekman transport. It’s found that Ekman pumping velocity in Banda Sea reached a maximum in June-July-August (JJA) by approximately 3,65x10 -6 . Comparing with Ekman transport, Ekman pumping makes an even greater contribution to the local upwelling in Banda Sea. Ekman pumping velocity in southern coast of Java reached a maximum in June-July-August (JJA) by approximately 4,9x10 -1 ms . Ekman pumping and Ekman transport makes an equal contribution to coastal upwelling in southern coast of Java. That’s related to highest clorophyll-a concentration apperars in JJA periode. Partial correlation analysis then was applied to identify a correlation between chlorophyll-a concentration and interannual climate variabilities such as ENSO and IOD. Partial Correlation between chlorophyll-a and Nino 3.4 and DMI-Dipole Mode Index (controlled) in Banda Sea is 0.18, and 0.05 in southercoast of Java. It’s represent ENSO (Elnino Southern Oscilation) has higher influences to Banda Sea than southern coast of Java. Partial correlation between chlorophyll-a and DMI and Nino 3.4 (controlled) is 0.55 in southern coast of Java, and 0.25 in Banda Sea. Its represent IOD (Indian Ocean Dipole) has higher influences to southern coast of Java than Banda Sea. Upwelling in Banda sea and along southern coast of Java dominantly occurs in southeast monsoon as a responds to regional wind driven motion associated with the monsoon climate. Various condition of chlorophyll-a booming also occured according to combination of ENSO and IOD events. -6 -1 msKeywords: upwelling, Banda sea, southern coast of Java, Ekman transport, Ekman pumping, IOD, ENSO

SIMULASI KESEIMBANGAN ENERGI PERMUKAAN DI JAKARTA DAN SEKITARNYA MENGGUNAKAN MODEL NUMERIK MM5 Yopi Ilhamsyah; Kurnia Endah Komalasari; Rima Novianti; Ahmad Bey; Rahmat Hidayat
Jurnal Meteorologi dan Geofisika Vol 16, No 2 (2015)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31172/jmg.v16i2.271

Studi simulasi keseimbangan energi permukaan di Jakarta dan daerah sekitarnya menggunakan model numerik Fifth-Generation Penn State/NCAR Mesoscale Model (MM5) telah dilakukan. Empat domain dengan resolusi spasial 9 km yang menggambarkan daerah Jakarta dan sekitarnya disimulasikan selama 5 hari pada tanggal 04-08 Agustus 2004 untuk memperoleh hubungan radiasi dan keseimbangan energi di wilayah tersebut. Hasil menunjukkan bahwa keseimbangan energi lebih tinggi pada siang hari terjadi di perkotaan dibandingkan daerah lainnya. Sementara itu, komponen energi seperti fluks bahang terindera dan laten di permukaan masing-masing menunjukkan bahwa wilayah laut dan perkotaan lebih tinggi daripada daerah lainnya. Sebaliknya, fluks bahang tanah menunjukkan daerah rural di bagian timur Jakarta lebih tinggi dibandingkan daerah lainnya. Secara umum, keseimbangan radiasi dan energi pada siang hari lebih tinggi daripada malam hari di seluruh daerah. Rasio Bowen di wilayah kota yang mencerminkan kawasan bangunan dan perkotaan lebih tinggi daripada di daerah rural yang didominasi oleh lahan pertanian beririgasi. Hal ini sesuai dengan perubahan sifat fisik tutupan lahan seperti albedo, kelembaban tanah dan karakteristik bahang. A study of surface energy balance simulation in Jakarta and surrounding areas by using Fifth-Generation Penn State/NCAR Mesoscale Model (MM5) numerical model was done. Four domains that presented the outermost and the innermost of Jakarta and surrounding areas were utilized. All domains have spatial resolutions of 9 km. The model was simulated for 5 days on August 4-8, 2004. The relation of radiation and energy balance at the surface was derived from the model output. The result showed that the energy balance was higher in the city during the daytime. Meanwhile, the energy component, i.e., surface sensible and latent heat flux showed that sea and city were higher than others, respectively. Moreover, ground flux showed the eastern rural area was higher than others. In general, radiation and energy balance was higher during daytime and lower in the nighttime for all areas. The calculation of the Bowen ratio was also higher in the city that reflected the urban and built-upland. Meanwhile, the Bowen ratio in the rural area dominated by irrigated cropland was lower than the city. It is consistent with changes in land cover properties, i.e., albedo, soil moisture, and thermal characteristics.

POLA SPASIAL DAN TEMPORAL PREDIKSI HUJAN INDONESIA BARAT MENGGUNAKAN WRF-EMS Sri Muslimah; Rahmat Hidayat; Wido Hanggoro
Jurnal Meteorologi dan Geofisika Vol 17, No 1 (2016)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31172/jmg.v17i1.371

Model numerik Weather Research and Forecasting Environmental Modelling System (WRF-EMS) digunakan pada studi ini dengan tujuan untuk mengkaji hasil keluaran prediksi hujan model WRF-EMS 1 dan 2 hari ke depan di 6 stasiun pengamatan cuaca terhadap data sinoptik dan TRMM, 8 initial and boundary conditions, serta mengkaji hasil keluaran prediksi hujan secara spasial model WRF-EMS. Konfigurasi skema standar dari model WRF-EMS dipertahankan dan hanya mengubah skema kumulus saja, yaitu menggunakan skema kumulus Betts-Miller-Janjic. Akurasi model ditunjukkan oleh rentang nilai threat score (TS) hasil prediksi hujan 1 dan 2 hari kedepan. Hasil prediksi hujan menunjukkan bahwa model WRF-EMS cukup baik untuk mensimulasikan kejadian tidak-hujan di Pulau Sumatera dan Kalimantan. Nilai TS di stasiun pengamatan cuaca Citeko dari model dengan resolusi horizontal 27 km untuk prediksi 1 dan 2 hari kedepan masing-masing berkisar antara 0 – 0.33 dan 0 – 0.30 sedangkan nilai TS dari model dengan resolusi horizontal 3 km untuk prediksi hujan 1 dan 2 hari kedepan masing-masing berkisar antara 0,17 – 0,75 dan 0.38 – 0.63. Peningkatan resolusi horizontal dari 27 km menjadi 3 km dapat meningkatkan nilai TS. Hal ini mengindikasikan bahwa model dengan resolusi horizontal 3 km lebih akurat untuk memprediksi hujan dibandingkan dengan model resolusi horizontal 27 km. Model WRF-EMS menghasilkan prediksi hujan yang over estimated secara spasial dan model ini lebih sensitif memprediksi hujan di Stasiun Citeko. WRF-EMS numerical models use to examine the output prediction of rain on 1 or two days ahead using the WRF-EMS model at 6 weather observations stations and the TRMM data, 8 initials and boundary conditions, and to examine the output prediction of rain spatially using the WRF-EMS. In this study, the configuration of the standard scheme using the WRF-EMS model is maintained; however, the cumulus scheme is the Betts-Miller-Janjic cumulus scheme. The accuracy shown by threat values score (TS) of rain predicted on the 1 and 2 days later. The result shows that the model predictions of rain using WRF-EMS is good enough to simulate a no-rain events on the island of Sumatra and Kalimantan. The TS value at Citeko, horizontal resolution of 27 km, for the prediction of 1 and 2 days in advance of each ranged from 0 – 0.33, and 0 – 0.30, while the TS value of the model with a horizontal resolution of 3 km for rainfall predictions 1 and 2 days in advance each ranged from 0.17 to 0.75 and 0.38 - 0.63. The increased of horizontal resolution from 27 km to 3 km can also increase the value of TS. This indicates that the model with a horizontal resolution of 3 km is more accurate for predicting rain compared to the model horizontal resolution of 27 km. The rainfall prediction was spatially over estimated when using the WRF-EMS Model, and this model is more sensitive in predicting rain at Citeko Station.

THE SEASONAL TREND OF UPPER-AIR AND VERTICAL TEMPERATURE PROFILE BASED ON RADIOSONDE OVER INDONESIA Eka Fibriantika; Rahmat Hidayat; Bambang Dwi Dasanto; Yunus Subagyo Swarinoto
Jurnal Sains & Teknologi Modifikasi Cuaca Vol. 23 No. 2 (2022): December 2022
Publisher : BPPT

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/jstmc.v23i2.5393

Radiosonde data is one of the data that can be used for upper-air climatological analysis. Pressure, air temperature (T), dew point temperature (Td), wind, and humidity (RH) are the types of data provided by radiosondes. Unfortunately, the utilization of radiosonde data in Indonesia has not been optimal, resulting in a lack of understanding of seasonal air parameter patterns and the vertical structure of the trend of changes in upper-air temperature in Indonesia. This study aims to analyze the seasonal upper-air parameters and analyze the vertical structure of the trend of changes in upper-air temperature in Indonesia. This study uses radiosonde data from 10 radiosonde observation stations in Indonesia. The analysis of seasonal air parameters was carried out by finding the average seasonal value, while the analysis of air temperature trends was carried out using the Mann-Kendall method. The results indicate that the dew point temperature is distinctly different seasonally than the seasonal air temperature. The seasonal dew point temperature difference ranges from 0.5 to 13 oC, while the seasonal air temperature difference ranges from -0.6 to 1.1 oC. The smaller T-Td value, the greater RH value. The trends in upper-air temperature show that most of the study area shows a trend of heating of the upper-air temperature in the troposphere (1000-250 mb), which is between 0.00005 to0.00058 oC/13 years, 0.00012 to 0.00031 oC/9 years, and 0.00009 to 0.00042 oC/10 years and cooling in the lower stratosphere(100 mb) is -0.00011 to -0.00067 oC/13 years.

SIMULASI KESEIMBANGAN ENERGI PERMUKAAN DI JAKARTA DAN SEKITARNYA MENGGUNAKAN MODEL NUMERIK MM5 Yopi Ilhamsyah; Kurnia Endah Komalasari; Rima Novianti; Ahmad Bey; Rahmat Hidayat
Jurnal Meteorologi dan Geofisika Vol. 16 No. 2 (2015)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31172/jmg.v16i2.271

Studi simulasi keseimbangan energi permukaan di Jakarta dan daerah sekitarnya menggunakan model numerik Fifth-Generation Penn State/NCAR Mesoscale Model (MM5) telah dilakukan. Empat domain dengan resolusi spasial 9 km yang menggambarkan daerah Jakarta dan sekitarnya disimulasikan selama 5 hari pada tanggal 04-08 Agustus 2004 untuk memperoleh hubungan radiasi dan keseimbangan energi di wilayah tersebut. Hasil menunjukkan bahwa keseimbangan energi lebih tinggi pada siang hari terjadi di perkotaan dibandingkan daerah lainnya. Sementara itu, komponen energi seperti fluks bahang terindera dan laten di permukaan masing-masing menunjukkan bahwa wilayah laut dan perkotaan lebih tinggi daripada daerah lainnya. Sebaliknya, fluks bahang tanah menunjukkan daerah rural di bagian timur Jakarta lebih tinggi dibandingkan daerah lainnya. Secara umum, keseimbangan radiasi dan energi pada siang hari lebih tinggi daripada malam hari di seluruh daerah. Rasio Bowen di wilayah kota yang mencerminkan kawasan bangunan dan perkotaan lebih tinggi daripada di daerah rural yang didominasi oleh lahan pertanian beririgasi. Hal ini sesuai dengan perubahan sifat fisik tutupan lahan seperti albedo, kelembaban tanah dan karakteristik bahang. A study of surface energy balance simulation in Jakarta and surrounding areas by using Fifth-Generation Penn State/NCAR Mesoscale Model (MM5) numerical model was done. Four domains that presented the outermost and the innermost of Jakarta and surrounding areas were utilized. All domains have spatial resolutions of 9 km. The model was simulated for 5 days on August 4-8, 2004. The relation of radiation and energy balance at the surface was derived from the model output. The result showed that the energy balance was higher in the city during the daytime. Meanwhile, the energy component, i.e., surface sensible and latent heat flux showed that sea and city were higher than others, respectively. Moreover, ground flux showed the eastern rural area was higher than others. In general, radiation and energy balance was higher during daytime and lower in the nighttime for all areas. The calculation of the Bowen ratio was also higher in the city that reflected the urban and built-upland. Meanwhile, the Bowen ratio in the rural area dominated by irrigated cropland was lower than the city. It is consistent with changes in land cover properties, i.e., albedo, soil moisture, and thermal characteristics.

POLA SPASIAL DAN TEMPORAL PREDIKSI HUJAN INDONESIA BARAT MENGGUNAKAN WRF-EMS Sri Muslimah; Rahmat Hidayat; Wido Hanggoro
Jurnal Meteorologi dan Geofisika Vol. 17 No. 1 (2016)
Publisher : Pusat Penelitian dan Pengembangan BMKG

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31172/jmg.v17i1.371

Model numerik Weather Research and Forecasting Environmental Modelling System (WRF-EMS) digunakan pada studi ini dengan tujuan untuk mengkaji hasil keluaran prediksi hujan model WRF-EMS 1 dan 2 hari ke depan di 6 stasiun pengamatan cuaca terhadap data sinoptik dan TRMM, 8 initial and boundary conditions, serta mengkaji hasil keluaran prediksi hujan secara spasial model WRF-EMS. Konfigurasi skema standar dari model WRF-EMS dipertahankan dan hanya mengubah skema kumulus saja, yaitu menggunakan skema kumulus Betts-Miller-Janjic. Akurasi model ditunjukkan oleh rentang nilai threat score (TS) hasil prediksi hujan 1 dan 2 hari kedepan. Hasil prediksi hujan menunjukkan bahwa model WRF-EMS cukup baik untuk mensimulasikan kejadian tidak-hujan di Pulau Sumatera dan Kalimantan. Nilai TS di stasiun pengamatan cuaca Citeko dari model dengan resolusi horizontal 27 km untuk prediksi 1 dan 2 hari kedepan masing-masing berkisar antara 0 – 0.33 dan 0 – 0.30 sedangkan nilai TS dari model dengan resolusi horizontal 3 km untuk prediksi hujan 1 dan 2 hari kedepan masing-masing berkisar antara 0,17 – 0,75 dan 0.38 – 0.63. Peningkatan resolusi horizontal dari 27 km menjadi 3 km dapat meningkatkan nilai TS. Hal ini mengindikasikan bahwa model dengan resolusi horizontal 3 km lebih akurat untuk memprediksi hujan dibandingkan dengan model resolusi horizontal 27 km. Model WRF-EMS menghasilkan prediksi hujan yang over estimated secara spasial dan model ini lebih sensitif memprediksi hujan di Stasiun Citeko. WRF-EMS numerical models use to examine the output prediction of rain on 1 or two days ahead using the WRF-EMS model at 6 weather observations stations and the TRMM data, 8 initials and boundary conditions, and to examine the output prediction of rain spatially using the WRF-EMS. In this study, the configuration of the standard scheme using the WRF-EMS model is maintained; however, the cumulus scheme is the Betts-Miller-Janjic cumulus scheme. The accuracy shown by threat values score (TS) of rain predicted on the 1 and 2 days later. The result shows that the model predictions of rain using WRF-EMS is good enough to simulate a no-rain events on the island of Sumatra and Kalimantan. The TS value at Citeko, horizontal resolution of 27 km, for the prediction of 1 and 2 days in advance of each ranged from 0 – 0.33, and 0 – 0.30, while the TS value of the model with a horizontal resolution of 3 km for rainfall predictions 1 and 2 days in advance each ranged from 0.17 to 0.75 and 0.38 - 0.63. The increased of horizontal resolution from 27 km to 3 km can also increase the value of TS. This indicates that the model with a horizontal resolution of 3 km is more accurate for predicting rain compared to the model horizontal resolution of 27 km. The rainfall prediction was spatially over estimated when using the WRF-EMS Model, and this model is more sensitive in predicting rain at Citeko Station.

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