PENGARUH MADDEN JULIAN OSCILLATION (MJO) TERHADAP VARIABILITAS SUHU PERMUKAAN LAUT DAN KLOROFIL-A DI LAUT NATUNA

ABSTRAKMJO dapat mempengaruhi variabilitas suhu permukaan laut dan klorofil-a. Penelitian ini dilakukan untuk mengetahui secara spasial pengaruh fenomena MJO terhadap variabilitas suhu permukaan laut dan klorofil-a saat periode Monsun Asia. Data yang digunakan pada penelitian ini adalah data angin dari ECMWF, data monitoring MJO dari BOM, data suhu permukaan laut dan klorofil-a dari Satelit Aqua MODIS NOAA. Metode yang digunakan pada penelitian ini yaitu dengan mengelompokkan kejadian MJO aktif fase 4 kemudian membuat rata-rata bulanan SPL, dan klorofil-a. Selanjutnya menentukan anomali bulanan SPL dan klorofil-a kemudian dianalisis. Hasil penelitian menunjukkan bahwa pada saat MJO aktif fase 4 terjadi peningkatan SPL dan penurunan jumlah klorofil-a.Kata kunci:  MJO,SPL, Klorofil-aABSTRACTMJO can affect the variability of sea surface temperature and chlorophyll-a. This research was conducted to determine spatially the effect of the MJO phenomenon on the variability of sea surface temperature and chlorophyll-a during the Asian Monsoon period. The data used in this study are wind data from ECMWF, MJO monitoring data from BOM, sea surface temperature data and chlorophyll-a from NOAA's Aqua MODIS Satellite. The method used in this study is to classify the incidence of active MJO phase 4 then make a monthly average of SST, and chlorophyll-a. Then determine the monthly anomaly of SST and chlorophyll-a and then analyzed. The results showed that when the MJO was active in phase 4 there was an increase in SPL and a decrease in the amount of chlorophyll-a.Keywords: MJO, SPL, Chlorophyll-

Kajian Dinamika Atmosfer saat Terjadinya Cold Surge, Southerly Surge, dan Borneo Vortex dengan Memanfaatkan Model WRF

Fenomena cuaca seperti cold surge, southerly surge, dan Borneo vortex dapat menjadi penyebab anomali musim hujan di Indonesia. Penelitian ini mengkaji dinamika atmosfer saat terjadinya cold surge, southerly surge, dan Borneo vortex di benua maritim Indonesia (BMI) bagian barat pada tanggal 9 – 15 Desember 2012 dengan memanfaatkan model weather research and forecasting (WRF). Penelitian ini menggunakan final global data. Untuk verifikasi digunakan data angin, kelembapan relatif, curah hujan hasil observasi, serta data curah hujan global satellite mapping of precipitation (GSMaP). Metode yang digunakan adalah metode statistik dan deskriptif. Hasilnya didapatkan bahwa model WRF mampu merespon kehadiran cold surge, southerly surge dan Borneo vortex dengan baik. Hal ini dibuktikan dengan nilai  mean absolute error (MAE) pada kelembapan relatif, kecepatan angin, dan curah hujan yang secara umum masih di bawah nilai toleransi kesalahan. Nilai korelasi yang sangat kuat juga didapatkan pada unsur curah hujan. Namun, model WRF belum mampu mengikuti pola spasial curah hujan GSMaP. Hasil kajian menggunakan keluaran model WRF didapatkan bahwa kehadiran southerly surge mengurangi intensitas cold surge dan Borneo vortex serta menyebabkan penurunan curah hujan di BMI bagian barat. Sementara itu, meningkatnya intensitas cold surge dan Borneo vortex menyebabkan peningkatan curah hujan di BMI bagian barat

Pengaruh ENSO Terhadap Curah Hujan dan Kelembapan Relatif serta Suhu Permukaan Laut di Sulawesi

El Niño – Southern Oscillation (ENSO) is a climate variability phenomenon characterized by anomaly of changes in sea surface temperature in the tropical Pacific Ocean. Positive anomaly of sea surface temperature (El Niño) can cause extreme dryness, while negative anomaly of sea surface temperature (La Nia) can cause a prolonged rainy season in most parts of Indonesia. In this case, Sulawesi is included in the area affected by the ENSO phenomenon. This study aims to examine the effect of the ENSO phenomenon on weather parameters (rainfall, relative humidity, and sea surface temperature (SST)) in the Sulawesi Island region. ENSO is identified based on the Southern Oscillation Index (SOI). The main data used in this study came from observations from the Meteorology, Climatology and Geophysics Agency (BMKG) stations in Kendari, Makassar, Palu, Luwuk, Gorontalo, and Manado. The data was processed over a period of 30 years (1988 – 2017) which was then analyzed using descriptive statistical methods. The results of this study reveal that ENSO has a quite strong relationship with relative humidity, but has a weak relationship with rainfall in most of the BMKG station data in Sulawesi.. The relationship between ENSO and rainfall was strongest in Gorontalo (r = 0.537), while the weakest relationship was in Manado (r = 0.242). The relationship between ENSO and relative humidity was strongest in Makassar (r = 0.479), while the weakest relationship was in Palu (r = –0.057). The correlation value of SST anomalies in Sulawesi with SOI is 0.5067. It can be interpreted that there is a quite strong and directly proportional relationship between SST in Sulawesi and ENSO.El Niño – Southern Oscillation (ENSO) merupakan fenomena variabilitas iklim yang dicirikan dengan anomali perubahan suhu permukaan laut di Samudra Pasifik wilayah tropis. Anomali positif suhu muka laut (El Niño) dapat menyebabkan kemarau ekstrem sedangkan anomali negatif suhu muka laut (La Niña) dapat menyebabkan musim hujan berkepanjangan di sebagian besar wilayah Indonesia. Dalam hal ini, Sulawesi termasuk kedalam wilayah yang terdampak oleh fenomena ENSO. Penelitian ini bertujuan untuk mengkaji pengaruh dari fenomena ENSO terhadap parameter cuaca seperti curah hujan, kelembapan relatif, dan suhu permukaan laut (SPL) di wilayah Pulau Sulawesi. ENSO diidentifikasi berdasarkan indeks Southern Oscillation Indeks (SOI). Data utama yang dipakai dalam penelitian ini berasal dari pengamatan stasiun Badan Meteorologi Klimatologi dan Geofisika (BMKG) Kota Kendari, Makassar, Palu, Luwuk, Gorontalo, dan Manado. Data diolah dalam periode waktu 30 tahun (1988 – 2017) yang kemudian dianalisis menggunakan metode statistika deskriptif. Hasil dari penelitian ini mengungkapkan bahwa ENSO memiliki hubungan yang cukup kuat dengan kelembapan relatif, namun memiliki hubungan yang lemah dengan curah hujan di sebagian besar data stasiun BMKG di Sulawesi. Hubungan ENSO dengan curah hujan terkuat terdapat di Gorontalo (r = 0.537), sedangkan hubungan terlemah terdapat di Manado (r = 0.242). Hubungan ENSO dengan kelembapan relatif terkuat terdapat di Makassar (r = 0.479), sedangkan hubungan terlemah terdapat di Palu (r = –0.057). Nilai korelasi anomali SPL di wilayah Perairan Sulawesi dengan SOI adalah sebesar 0.5067. Hal ini dapat diinterpretasikan bahwa terdapat hubungan yang cukup kuat dan berbanding lurus antara SPL di Sulawesi dan ENSO

The role of tropical waves in the genesis of Tropical Cyclone Seroja in the Maritime Continent

Tropical cyclone Seroja was one of the first tropical cyclones to significantly impact Indonesian land, and the strongest one in such close proximity to Timor Island. In April 2021 Seroja brought historic flooding to near-equatorial regions of Indonesia and East Timor, as well as impacting Western Australia. Here we show that the unusual near-equatorial cyclogenesis in close proximity to a land mass was due to “perfect storm” conditions associated with multiple wave interactions. Specifically, this was associated with enhanced equatorial convection on the leading edge of a Madden–Julian Oscillation (MJO) event. Within the MJO, the interaction between a convectively coupled equatorial Rossby wave and two convectively coupled Kelvin waves span up the initial vortex and accelerated cyclogenesis. On average, such favorable atmospheric conditions can occur once per year. These results indicate the potential for increased predictability of tropical cyclones over the Maritime Continent

Detecting change in the Indonesian Seas

© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Sprintall, J., Gordon, A. L., Wijffels, S. E., Feng, M., Hu, S., Koch-Larrouy, A., Phillips, H., Nugroho, D., Napitu, A., Pujiana, K., Susanto, R. D., Sloyan, B., Yuan, D., Riama, N. F., Siswanto, S., Kuswardani, A., Arifin, Z., Wahyudi, A. J., Zhou, H., Nagai, T., Ansong, J. K., Bourdalle-Badie, R., Chanuts, J., Lyard, F., Arbic, B. K., Ramdhani, A., & Setiawan, A. Detecting change in the Indonesian Seas. Frontiers in Marine Science, 6, (2019):257, doi:10.3389/fmars.2019.00257.The Indonesian seas play a fundamental role in the coupled ocean and climate system with the Indonesian Throughflow (ITF) providing the only tropical pathway connecting the global oceans. Pacific warm pool waters passing through the Indonesian seas are cooled and freshened by strong air-sea fluxes and mixing from internal tides to form a unique water mass that can be tracked across the Indian Ocean basin and beyond. The Indonesian seas lie at the climatological center of the atmospheric deep convection associated with the ascending branch of the Walker Circulation. Regional SST variations cause changes in the surface winds that can shift the center of atmospheric deep convection, subsequently altering the precipitation and ocean circulation patterns within the entire Indo-Pacific region. Recent multi-decadal changes in the wind and buoyancy forcing over the tropical Indo-Pacific have directly affected the vertical profile, strength, and the heat and freshwater transports of the ITF. These changes influence the large-scale sea level, SST, precipitation and wind patterns. Observing long-term changes in mass, heat and freshwater within the Indonesian seas is central to understanding the variability and predictability of the global coupled climate system. Although substantial progress has been made over the past decade in measuring and modeling the physical and biogeochemical variability within the Indonesian seas, large uncertainties remain. A comprehensive strategy is needed for measuring the temporal and spatial scales of variability that govern the various water mass transport streams of the ITF, its connection with the circulation and heat and freshwater inventories and associated air-sea fluxes of the regional and global oceans. This white paper puts forward the design of an observational array using multi-platforms combined with high-resolution models aimed at increasing our quantitative understanding of water mass transformation rates and advection within the Indonesian seas and their impacts on the air-sea climate system. IntroductionJS acknowledges funding to support her effort by the National Science Foundation under Grant Number OCE-1736285 and NOAA’s Climate Program Office, Climate Variability and Predictability Program under Award Number NA17OAR4310257. SH was supported by the National Natural Science Foundation of China (Grant 41776018) and the Key Research Program of Frontier Sciences, CAS (QYZDB-SSW-SYS023). HP acknowledges support from the Australian Government’s National Environmental Science Programme. HZ acknowledges support from National Science Foundation under Grant No. 41876009. RS was supported by National Science Foundation Grant No. OCE-07-25935; Office of Naval Research Grant No. N00014-08-01-0618 and National Aeronautics and Space Administration Grant No. 80NSSC18K0777. SW, MF, and BS were supported by Center for Southern Hemisphere Oceans Research (CSHOR), which is a joint initiative between the Qingdao National Laboratory for Marine Science and Technology (QNLM), CSIRO, University of New South Wales and University of Tasmania

Assessment on the Use of Meteorological and Social Media Information for Forest Fire Detection and Prediction in Riau, Indonesia

In this study, tweets related to fires in Riau, Sumatra, were identified using carefully selected keywords for the 2014–2019 timeframe. The TAGGS algorithm was applied, which allows for geoparsing based on the user’s nationality and hometown and on direct referrals to specific locations such as name of province or name of city in the message itself. Online newspapers covering Riau were analyzed for the year 2019 to provide additional information about the reasons why fires occurred and other factors, such as impact on people’s health, animal mortality related to ecosystem disruption, visibility, decrease in air quality and limitations in the government firefighting response. Correlation analysis between meteorological information, Twitter activity and satellite-derived hotspots was conducted. The existing approaches that BMKG and other Indonesian agencies use to detect fire activity are reviewed and a novel approach for early fire detection is proposed based on the crowdsourcing of tweets. The policy implications of these results suggest that crowdsourced data can be included in the fire management system in Indonesia to support early fire detection and fire disaster mitigation efforts

The Effect of the Difference in Intensity and Track of Tropical Cyclone on Significant Wave Height and Wave Direction in the Southeast Indian Ocean

This study aims to analyze the effect of the differences in intensity and track of tropical cyclones upon significant wave heights and direction of ocean waves in the southeast Indian Ocean. We used the tropical cyclone data from Japan Aerospace Exploration Agency (JAXA) starting from December 1997 to November 2017. The significant wave height and wave direction data are reanalysis data from Copernicus Marine Environment Monitoring Service (CMEMS), and the mean sea level pressure, surface wind speed, and wind direction data are reanalysis data from European Center for Medium-Range Weather Forecasts (ECMWF) from December 1997 to November 2017. The results show that the significant wave height increases with the increasing intensity of tropical cyclones. Meanwhile, the direction of the waves is influenced by the presence of tropical cyclones when tropical cyclones enter the categories of 3, 4, and 5. Tropical cyclones that move far from land tend to have higher significant wave height and wider affected areas compared to tropical cyclones that move near the mainland following the coastlin

The Level of Public Acceptance to the Development of a Coastal Flooding Early Warning System in Jakarta

Coastal flooding is a natural disaster that often occurs in coastal areas. Jakarta is an example of a location that is highly vulnerable to coastal flooding. Coastal flooding can result in economic and human life losses. Thus, there is a need for a coastal flooding early warning system in vulnerable locations to reduce the threat to the community and strengthen its resilience to coastal flooding disasters. This study aimed to measure the level of public acceptance toward the development of a coastal flooding early warning system of people who live in a coastal region in Jakarta. This knowledge is essential to ensure that the early warning system can be implemented successfully. A survey was conducted by distributing questionnaires to people in the coastal areas of Jakarta. The questionnaire results were analyzed using cross-tabulation and path analysis based on the variables of knowledge, perceptions, and community attitudes towards the development of a coastal flooding early warning system. The survey result shows that the level of public acceptance is excellent, as proven by the average score of the respondents’ attitude by 4.15 in agreeing with the establishment of an early warning system to manage coastal flooding. Thus, path analysis shows that knowledge and perception have a weak relationship with community attitudes when responding to the coastal flooding early warning model. The results show that only 23% of the community’s responses toward the coastal flooding early warning model can be explained by the community’s knowledge and perceptions. This research is expected to be useful in implementing a coastal flooding early warning system by considering the level of public acceptance