Pendugaan hotspot sebagai indikator kebakaran hutan di Kalimantan berdasarkan faktor iklim

The occurance of forest fire indonesia especially in Kalimantan is a potential threat to sustainable development. The purpose of this research is a early warning system in forest fire in Kalimantan, by estimating the hotspot as indicators based on visibility and climate data. This research using F test, T test, Multiple Linear Regression analysis, Principle Component Analysis (PCA) and Principle Component Regression Analysis (PCR) Vvisibility, hotspot and temperature data have releated, meaning the very big effect with forest fire incident. Test result of T test and ANOVA P-Value less than 0.05, there is influence between independent variables in this visibility and climate factor against dependent variables in this is the number of hotspots. Relation of climate variables to 10 days forest fire in Central Kalimantan R2 adjusted is 0.4699 with F calculate larger from F table is 160.0940. Relation of climate variables to dasarian forest fire in central kalimantan as early warning system has R2 adjusted that is 0.4176 with f calculate larger from table F of 129.3551. Conclusion forest fires following monsoon character and being affected by el nino events, visibility has a closer and can be used as a indicator of forest fire and land intensity, hotspot in a relationship has a close connection with visibility and climate condition at the same decade period, used equations for early warning system for predicted fire genesis indicates with hotspot amount, compiled from climate condition 10 days

Studi Kejadian Cross Equatorial Northly Surges (CENS) di Pesisir Utara Jakarta: Event Study of Cross Equatorial Northly Surges (CENS) in The North Coast of Jakarta

Banjir rob yang terjadi di Pesisir Utara Jakarta disebabkan faktor astonomis, tetapi banjir rob juga seringkali diperkuat dengan adanya fenomena meteorologis. Curah hujan yang lebat akibat adanya Cross Equatorial Northly Surges (CENS) serta angin yang di timbulkan sering menjadi penyabab banjir rob di pesisir di Utara Jakarta. Dengan terjadinya curah hujan yang lebat akibat adanya Cross Equatorial Northly Surges (CENS) serta angin yang di timbulkan sering menjadi penyabab banjir rob di Pesisir di Utara Jakarta. Penelitian ini bertujuan mengetahui curah hujan yang terjadi karena adanya CENS, mengetahui besarnya energi kinetik angin saat kejadian rob di Pesisir Utara Jakarta. Data yang digunakan meliputi data angin diambil dari https: //cds.climate.copernicus.eu/cdsapp#!/dataset/, data curah hujan dari https: //sharaku.eorc.jaxa.jp/GSMaP/index. Waktu penelitian dimulai Januari 2021 dengan lokasi Pesisir Utara Jakarta. Hasil penelitian ini menunjukan bahwa pada umumnya kejadian banjir rob diiringi dengan hujan lebat baik sebelum maupun pada saat banjir rob terjadi. Nilai curah hujan 1,078 mm/jam sampai 7,836 mm/jam dengan Energi Kinetik sekitar 0,635 joule sampai 43,62 Joule

The Impact of Concave Coastline on Rainfall Offshore Distribution over Indonesian Maritime Continent

Indonesian Maritime Continent has the second longest coastline in the world, but the characteristics of offshore rainfall and its relation to coastline type are not clearly understood. As a region with eighty percent being an ocean, knowledge of offshore rainfall is important to support activity over oceans. This study investigates the climatology of offshore rainfall based on TRMM 3B42 composite during 1998-2015 and its dynamical atmosphere which induces high rainfall intensity using WRF-ARW. The result shows that concave coastline drives the increasing rainfall over ocean with Cenderawasih Bay (widest concave coastline) having the highest rainfall offshore intensity (16.5 mm per day) over Indonesian Maritime Continent. Monthly peak offshore rainfall over concave coastline is related to direction of concave coastline and peak of diurnal cycle influenced by the shifting of low level convergence. Concave coastline facing the north has peak during northwesterly monsoonal flow (March), while concave coastline facing the east has peak during easterly monsoonal flow (July). Low level convergence zone shifts from inland during daytime to ocean during nighttime. Due to shape of concave coastline, land breeze strengthens low level convergence and supports merging rainfall over ocean during nighttime. Rainfall propagating from the area around inland to ocean is approximately 5.4 m/s over Cenderawasih Bay and 4.1 m/s over Tolo Bay. Merger rainfall and low level convergence are playing role in increasing offshore rainfall over concave coastline

The Impact of the Interaction between Madden-Julian Oscillation and Cold Surge, on Rainfall over Western Indonesia

The Madden-Julian Oscillation and Cold Surge phenomena have been known to cause increased rainfall, with the capacity to trigger hydrometeorological disasters, in western Indonesia. However, further investigations are required regarding the interaction between these phenomena on rainfall pattern. Therefore, this study aims to analyze the interaction between MJO and CS over western Indonesia, particularly by using land-based rainfall observation data from multiple stations, as previous studies were dominated by the use of gridded data from remote observations. This study utilized in-situ observation data obtained from 4329 weather observations and rain stations between 1989 and 2018.  Subsequently, quality control performed based on data availability exceeding 70% over a 30-year period resulted in 303 selected stations to be used for further analysis. Meanwhile, the RMM index, as well as reanalysis data of mean sea level pressure and 925 hPa meridional wind, were also applied for MJO and CS identification. According to the composite analysis, the effect of CS on MJO phases tends to increase precipitation by about 50%, over western Indonesia, with maximum increase ranging from 200 to 400% over the northeastern coast of Sumatra, around Karimata Strait (Riau Islands and West Kalimantan), as well as the northern coast of Java. These areas are exposed to the sea and have direct access to the wind-terrain interaction. In addition, the highest rainfall anomaly due to the MJO-CS interaction occurs around Karimata Strait, followed by northern Sumatra and Java, with spatially averaged rainfall anomaly reaching 5 mm/day over the area

Reconstruction of Extreme Rainfall Event on September 19-20, 2017, Using a Weather Radar in Bengkulu of Sumatra Island

Extreme rainfall accompanied by strong winds hit the province of Bengkulu in the western coastal area of Sumatera Island during September 19-20, 2017, causing floods and landslides in Seluma and Central Bengkulu district. This extreme rainfall was recorded by Bengkulu Meteorological Station about 257.0 mm day−1 using rain-gauge observation. The spatial distribution of extreme rainfall cannot be seen if only using a rain-gauge observation in this location. The spatial distribution of extreme rainfall is needed to identify the impact of rainfall on landslides in large areas. The study aims to (1) develop the reconstruction of the spatial distribution of extreme rainfall using weather radar and (2) investigate the trigger that caused extreme rainfall by analyzing the synoptic-scale tropical waves. Each weather radar datum is saved in a Constant Altitude Plan Position Indicator (CAPPI). To get rainfall information, the CAPPI must be derived from Quantitative Precipitation Estimation (QPE) values. In this paper, we derived CAPPI using a Marshall-Palmer reflectivity-rain rate relationship. The result shows that rainfall formed on September 20, 2017, 21.00 UTC with total daily rainfall ranged between 176 and 247 mm in both districts and the mean of total daily rainfall has exceeded the average of monthly rainfall. The analysis of tropical waves suggests that only Kelvin waves were active and served as a possible trigger factor while the Madden-Julian Oscillation (MJO) and Equatorial Rossby (ER) waves were inactive during this extreme rainfall