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Abstract This study investigated the diurnal cycle of convection over Sumatra Island in an active phase of the Madden-Julian Oscillation (MJO) during the Pre-Years of the Maritime Continent (YMC) observation campaign in December 2015 based on in-situ and satellite observations and a convection-permitting numerical model. Observations suggest that before the active phase of the MJO in early December, convection occurred frequently over the island during the afternoon and at midnight. By contrast, during the active phase of the MJO in mid-December, afternoon convection over the island was delayed and suppressed, and midnight convection was suppressed. Numerical experiments also successfully replicated the main features of the observed modulations. In general, during the active phase of the MJO, the troposphere became drier in the Sumatra region. While the clouds reduced the solar radiation over the land, the sea breeze was also found to be delayed and weakened. As a result, the afternoon convection initiation was delayed and weakened. Further analyses suggested that the sea breeze was weakened mainly due to the orographic stagnation effect rather than the slightly reduced land-sea temperature contrast. On the other hand, the increased stratiform-anvil clouds induced the anomalous evaporative cooling in the mid-troposphere and generated island-scale subsidence during the nighttime, which finally led to the suppression of inland convection. Overall, our study reveals the modulation of diurnal convection over Sumatra Island by an active phase of the MJO and also shows the potential role of land-sea interaction in convection initiation and maintenance.


2022 ◽  
Vol 8 (1) ◽  
pp. 163-170
Author(s):  
Ravidho Ramadhan ◽  
Marzuki Marzuki ◽  
Helmi Yusnaini ◽  
Ayu Putri Ningsih ◽  
Hiroyuki Hashiguchi ◽  
...  

Accurate satellite precipitation estimates over areas of complex topography are still challenging, while such accuracy is of importance to the adoption of satellite data for hydrological applications. This study evaluated the ability of Integrated Multi-satellitE Retrievals for GPM -Final (IMERG) V06 product to observe the extreme rainfall over a mountainous area of Sumatra Island. Fifteen years of optical rain gauge (ORG) observation at Kototabang, West Sumatra, Indonesia (100.32°E, 0.20°S, 865 m above sea level), were used as reference surface measurement. The performance of IMERG-F was evaluated using 13 extreme rain indexes formulated by the Expert Team on Climate Change Detection and Indices (ETCCDI). The IMERG-F overestimated the values of all precipitation amount-based indices (PRCPTOT, R85P, R95P, and R99P), three precipitation frequency-based indices (R1mm, R10mm, R20mm), one precipitation duration-based indices (CWD), and one precipitation intensity-based indices (RX5day). Furthermore, the IMERG-F underestimated the values of precipitation frequency-based indices (R50mm), one precipitation duration-based indices (CDD), one precipitation intensity-based indices (SDII). In terms of correlation, only five indexes have a correlation coefficient (R) > 0.5, consistent with Kling–Gupta Efficiency (KGE) value. These results confirm the need to improve the accuracy of the IMERG-F data in mountainous areas.


2022 ◽  
Vol 4 (2) ◽  
pp. 728-732
Author(s):  
Yustini Ardillah ◽  
Anggun Budiastuti ◽  
Dian Safriantini ◽  
Rendi Sabana

Covid-19 continues to increase the number of patients who are positive for Covid-19. Indonesia is a risky country to visit, while the National Data for South Sumatra is the number one province on Sumatra Island with the highest number of Covid-19 patients. Government policy allows regions or regions with yellow zones to open schools offline. Banyuasin Regency is included in the yellow zone of Covid patients, so teaching and learning has been carried out offline with strict implementation of health protocols. To support offline teaching and learning activities, it is necessary to educate students about the 3M movement (maintaining distance, using masks, washing hands with soap). This activity aims to train students to apply the 3M health protocol correctly. The results of the service show that there is an increase in knowledge and changes in student behaviour after receiving training and counselling about health protocols at school. Optimization of health protocols needs to be carried out on an ongoing basis to prevent the transmission of COVID-19 in elementary schools.


Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 63
Author(s):  
Marzuki Marzuki ◽  
Helmi Yusnaini ◽  
Ravidho Ramadhan ◽  
Fredolin Tangang ◽  
Abdul Azim Bin Amirudin ◽  
...  

In this study we investigate the characteristics of the diurnal precipitation cycle including the Madden–Julian oscillation (MJO) and seasonal influences over a mountainous area in Sumatra Island based on the in situ measurement of precipitation using the optical rain gauge (ORG). For comparison with ORG data, the characteristics based on the Global Precipitation Measurement (GPM) mission (IMERG) and Weather Research and Forecasting (WRF) simulations were also investigated. Fifteen years of ORG data over a mountainous area of Sumatra, namely, at Kototabang (100.32° E, 0.20° S), were analyzed to obtain the characteristics of the diurnal cycle of precipitation in this region. The diurnal cycle of precipitation presented a single peak in the late afternoon, and the peak time difference was closely related to the rain event duration. The MJO acts to modulate the diurnal amplitude but not the diurnal phase. A high precipitation amount (PA) and frequency (PF) were observed during phases 2, 3, and 4, along with an increase in the number of longer-duration rain events, but the diurnal phase was similar in all MJO phases. In terms of season, the highest PA and PF values were observed during pre-southwest and pre-northeast monsoon seasons. WRF simulation reproduced the diurnal phase correctly and more realistically than the IMERG products. However, it largely overestimated the amplitude of the diurnal cycle in comparison with ORG. These disagreements could be related to the resolution and quality of IMERG and WRF data.


2021 ◽  
Vol 1 (11) ◽  
Author(s):  
Boy Piter Nizu Kekry ◽  
Muhammad Fahmi

Background: The formulation of this scientific research problem is what are the scientific facts that can be obtained, for 10 years on the island of Sumatra and Kalimantan. Research purposes: The purpose of this study is identifying scientific facts the direction and pattern of economic growth that occurs on the islands of Sumatra and Kalimantan. Research methods: The researcher applied quantitative approach, along with descriptive quantitative techniques. Research results: The results of this research are, there are 2 patterns of economic growth on the islands of Sumatra and Kalimantan during these 10 years. The trend towards growth on these two islands is, has a fluctuating tendency and has indications of a downward trend over the past 10 years. Some special findings are: (1) Aceh Province is quite risky, because over the past 10 years has historical economic growth movements that form the depth of the valley (can be indicated recession), (2) East Kalimantan as many as 4 times over the last 10 years, experiencing negative economic growth, (3) The plantation sector, through CPO exports is able to have its own impact, on the economy of South Kalimantan in 2020. Specifically for economic growth in 2020, it is a special record because of the overall economic growth of 10 provinces on the island of Sumatra and 5 provinces on the island of Kalimantan with negative growth performance.  Conclusion: For Sumatra Island there are 2 different forms of patterns between provinces, pattern 1: Aceh, Riau and Riau Islands. For the case of Aceh province is quite risky because for the past 10 years, it has historical economic growth movements that can indicate recession


2021 ◽  
Vol 893 (1) ◽  
pp. 012015
Author(s):  
P Wu ◽  
Y Fukutomi ◽  
K Kikuchi

Abstract This study examined the cause of a record torrential rain event over the western coast of Sumatra Island in March 2016. The influence of atmospheric equatorial waves (EWs) and the characteristics of the EWs were investigated. Analysis of the Japanese 55-year Reanalysis data (JRA-55) and precipitation data from the Global Precipitation Measurement (GPM) satellite showed that the event was caused by the combined effects of Kelvin waves, equatorial Rossby waves, and westward inertio-gravity (WIG) waves. An examination of the characteristics of the EWs revealed that the Kelvin waves had longitudinal scales of ~6,000 km, with a period of ~6 days and phase speed of ~12 m s-1, which was typical of the convectively coupled Kelvin waves in this region. The WIG waves had a scale of ~2,500 km, with a period of 2.5 days and a relatively fast phase speed of 12~13 m s-1. Heavy precipitation occurred when an eastward Kelvin wave from the Indian Ocean encountered a westward inertio-gravity (WIG) over Sumatra Island. It was concluded that along with the Kelvin and equatorial Rossby waves, the WIG waves might have played a major role in the formation of the extreme precipitation event.


2021 ◽  
Vol 934 (1) ◽  
pp. 012030
Author(s):  
D Hidayati ◽  
W Widayatun

Abstract Indonesia is known as a ‘Paradise under the Sea,’ with the richness and beauty of its coral reefs. This ecosystem is an important asset that has high economic value and a potential source of community income. However, this wealth has not been utilized optimally by coastal communities, especially fishermen. This is backed by their poor economic conditions. This paper discusses the dynamic of fishermen’s income and the influencing factors on the West and East Coasts of Sumatra Island. The fishermen’s income on both coasts is dominated by income from capture fisheries, which fluctuates throughout the year. The income of east coast fishermen is higher and more varied than west coast fishermen. This paper identifies three factors that influence the differences: 1) technological capacity of the fishermen’s fleet and fishing gear, 2) fish marketing and seasonal variations throughout the year, along with the degradation of coastal resources, and 3) policies and programs for fishermen’s empowerment and development in coastal areas. This paper uses quantitative and qualitative methods from the assessment of social aspects of coral reefs conducted by the COREMAP LIPI team. The authors also utilize secondary data from related documents, research results, papers and books.


2021 ◽  
Vol 918 (1) ◽  
pp. 012039
Author(s):  
S K Himmi ◽  
A Fajar ◽  
B Wikantyoso ◽  
B Tjahyono ◽  
N Nurjanah ◽  
...  

Abstract The domestic drywood termite, Cryptotermes domesticus (Haviland), has been referred to in past literature as a native species originating in the Southeast Asia region. The species come to prominence due to its destructive damage to a dried wood log by creating passages and nests inside the wood. Its economic importance makes the species one of the monitored species in inter-island transport as part of a biosecurity initiative by the Indonesian Government. In the present study, we collected drywood termites’ specimens from four locations in Riau Province, Sumatra Island, and conducted morphological identification. In the end, we verify the presence of C. domesticus in all four sites studied. This finding establishes the continued presence of the species in Sumatra, one of the areas reported as the native distribution of the species other than Java and Kalimantan following the Holmgren reports in 1913. We believe this report can be an addition to the current status of C. domesticus in Sumatra and also be an addition to the biosecurity initiative list of monitored species regarding the C. domesticus native range in Indonesia.


2021 ◽  
Vol 2117 (1) ◽  
pp. 012014
Author(s):  
Idarwati ◽  
H S Purwanto ◽  
E Sutriyono ◽  
C Prasetyadi

Abstract The lithological and earth structures which compose the geologic process space are terribly fascinating to study. elaborated investigation of pre-tertiary rock subduction at the Woyla web site is rarely carried out. the variability of rocks derived from the Woyla oceanic plate, that folded on the West Sumatra continental plate within the Age of Reptiles era, illustrates the magnitude of the subduction impact mirrored in the structures that are still reflected in the abandoned rocks. The ways want to discover this subduction event are elaborated field observations, skinny section, XRD, and earth science structure measurements, supported by drones and satellite imagery. The lithology of basalt, flint, serpentine, marble, and arenaceous rock is vital to the presence of the Intraoceanic Arch of Woyla within the Saka phase. elaborated structural calculation show that the Saka segment went through several tectonic stages from the Mesozoic to Recent, that is mirrored in the Saka fault and therefore the Penanggungan fault.


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