Impact Analysis of Tropical Cyclone Cempaka-Dahlia on Wave Heights in Indonesian Waters from Numerical Model and Altimetry Satellite

Indonesia is located side by side with the Pacific Ocean and the Indian Ocean where there are often tropical cyclones in these two oceans. As was the case some time ago in the Indian Ocean a tropical cyclone of Cempaka and Dahlia occurred which had a significant impact on Indonesian areas. Another impact felt is the disruption of economic activity in the area of tourism, ports, and power plants. Numerical modeling is carried out to simulate the phenomena of Cempaka and Dahlia tropical cyclones to determine the impacts caused especially in Lampung to Lombok areas. Numerical modeling is done using SWAN version 41.20. SWAN was chosen because it has good modeling calculations in coastal areas and is very suitable for wave analysis in coastal areas. The results of the modeling are verified by the significant wave height correlation coefficient from altimetry satellites that cross the tropical cyclones of Cempaka and Dahlia. The results showed a significant increase in wave height in the study area with an increase of up to 1028.31% at the observation point in Pelabuhan Ratu, West Java Province

The Study of Position Accuracy Using Precise Point Positioning (PPP) In Perspective of Indonesian National Standard of Horizontal Reference Network

Precise point positioning is a GNSS based positioning method that is known to regaining more precise information about major systematical errors in its functional model. This method is seen as an advanced version of the conventional absolute positioning method that is able to offer higher accuracy of the estimate parameter. Contrarily, the relative positioning method is able to achieve high precise of the estimated parameters by using two or more receiver. Consequently, it utilizes more resources in performing observation. Hence, this contribution attempts to explore some considerable aspects that can make the PPP method has a comparable precision of the National Standard of Horizontal Reference Network (SNI JKH). Based on the experiments, with data rate of 0.03 Hz for GPS and GLONASS observation shown that result of the PPP method is comparable to the relative method, whenever the observation is performed in minimum duration of six hours. Moreover, the 3th order of accuracy can be achieved after a demanding observation period, depends on processing strategy

The Effect of TLS Radome on GNSS Precise Positioning

This article presents the results of a test carried out to check the usability of spherical TLS targets as GNSS antenna radomes (herein called TLS radomes). On different days, the survey was conducted using two GNSS antennas, one of them with a TLS radome. Measurements were made using 2 roof pillars on the rooftop as base-rover pillars with little obstruction. The measurements were carried out for approximately 1 hour in every scenario. The software used for data processing is MATLAB-based software and the raw data were processed using the double difference (DD) strategy to obtain optimal results. The results of the data processing indicated that the TLS radome has no significant influence on availability and accuracy of estimated position. The signals are slightly attenuated by the radome (1-2 dBHz) and the noise level is slightly increased but both effects are negligible for practical purposes. However, we found that the antenna should be calibrated with the TLS radome to clarify apparent minor phase center eccentricities (1-2 mm) and to reduce systematic effects with long periods (few minutes) and amplitudes up to about 5 mm which are likely due to phase center variations

Komparasi Komponen Pasut Utama Hasil Pengolahan Data Satelit Altimetri Dengan Data Stasiun Pasang Surut (Studi Kasus Perairan Serang Banten)

Pasang surut adalah proses naik turunnya permukaan air laut secara hampir periodik karena gaya tarik menarik bumi dengan benda-benda angkasa, terutama bulan dan matahari. Pasang surut tidak hanya mempengaruhi lapisan di bagian permukaan saja, melainkan seluruh massa air dengan energi yang sangat besar. Data pengamatan pada bulan Agustus 2016 yang diolah menggunakan Least Square dan mendapatkan konstata pasut M2, S2, N2, K2, K1, O1, P1, M4 ,MS4 data tersebut dibandingkan dengan data Konstanta pasut yang sama dan dimodelkan dari Satelit Altimetri oleh Oregon State University, Model Kontanta Pasut tersebut bernama Tidal Model Driver (TMD) yang menghasilkan konstanta pasang surut  M2, S2, N2, K2, K1, O1, P1, M4 ,MS4 dan dari tiap tiap konstanta pasang surut menghasilkan Amplitudo dan Fase. Penelitian ini bertujuan untuk mengetahui tingkat kemiripan dan selisih data yang dihasikan dan, kemudian digambarkan menggunakan Software Ocean Data View (ODV) menjadi 2D Horizontal di perairan utara Serang Banten

Ionospheric Disturbances after the 2022 Hunga Tonga-Hunga Ha’apai Eruption above Indonesia from GNSS-TEC Observations

On 15 January 2022, a VEI 5 eruption occurred at the submarine Hunga Tonga-Hunga Ha’apai (HTHH) Volcano in the Southwest Pacific, causing an ash plume reaching a height of 50–55 km. The eruption generated strong acoustic-gravity waves in the near-field and stations all over the world recorded Lamb waves (LW) that travelled around the earth multiple times at a speed of ~0.3 km/s. Here we report ionospheric anomalies due to the LW over Indonesian islands, 5000–10,000 km away from the volcano, in terms of changes in total electron contents (TEC) using the nationwide network of GNSS stations. We detected ionospheric anomalies travelling above Indonesia several times both westward and eastward. The first passage of LW over Java caused strong TEC increases of >12 TECU. The wave circled the earth and returned to Java on subsequent days. The second passage was recorded early 1/17, the anomaly decayed to 6 TECU. We also detected the passage of long-path waves propagating from west to east. In addition to such anomalies, we examined the existence of ionospheric disturbances apparently propagating from the geomagnetic conjugate point of the volcano that could possibly emerge in Indonesia. However, their signatures in Indonesia were not clear

The Study of Position Accuracy Using Precise Point Positioning (PPP) In Perspective of Indonesian National Standard of Horizontal Reference Network

Precise point positioning is a GNSS based positioning method that is known to regaining more precise information about major systematical errors in its functional model. This method is seen as an advanced version of the conventional absolute positioning method that is able to offer higher accuracy of the estimate parameter. Contrarily, the relative positioning method is able to achieve high precise of the estimated parameters by using two or more receiver. Consequently, it utilizes more resources in performing observation. Hence, this contribution attempts to explore some considerable aspects that can make the PPP method has a comparable precision of the National Standard of Horizontal Reference Network (SNI JKH). Based on the experiments, with data rate of 0.03 Hz for GPS and GLONASS observation shown that result of the PPP method is comparable to the relative method, whenever the observation is performed in minimum duration of six hours. Moreover, the 3th order of accuracy can be achieved after a demanding observation period, depends on processing strategy

Determination of ZNHD based on GPS Data, Radiosonde, and Numerical Weather Model

Abstract. Water vapor is a principal element in the thermodynamics of the atmosphere and plays an important role in clouds condensation, which eventually can affect the radiative energy balance. Water vapor cobservation is essential for monitoring global/regional scale of weather and climate changes. However, high variation of water vapor concentrations makes it difficult to observe accurately using the conventional meteorogical observation technique (radiosonde), which is limited in both space and time. Nowadays, accurate observation of water vapor can be accomplished by the Global Positioning System (GPS). In this research, we use 14 continuous GPS stations from Bakosurtanal to observe temporal characteristic of water vapor concentration over West Java region.Keywords: GPS, NCEP, radiosonde, topographic, ZNH

The Effect of TLS Radome on GNSS Precise Positioning

This article presents the results of a test carried out to check the usability of spherical TLS targets as GNSS antenna radomes (herein called TLS radomes). On different days, the survey was conducted using two GNSS antennas, one of them with a TLS radome. Measurements were made using 2 roof pillars on the rooftop as base-rover pillars with little obstruction. The measurements were carried out for approximately 1 hour in every scenario. The software used for data processing is MATLAB-based software and the raw data were processed using the double difference (DD) strategy to obtain optimal results. The results of the data processing indicated that the TLS radome has no significant influence on availability and accuracy of estimated position. The signals are slightly attenuated by the radome (1-2 dBHz) and the noise level is slightly increased but both effects are negligible for practical purposes. However, we found that the antenna should be calibrated with the TLS radome to clarify apparent minor phase center eccentricities (1-2 mm) and to reduce systematic effects with long periods (few minutes) and amplitudes up to about 5 mm which are likely due to phase center variations