Claim Missing Document
Check
Articles

Found 4 Documents
Search

Determination of Air Stability Parameter Threshold Value for Cumulonimbus and Thunderstorm Cloud Events at Kualanamu Meteorological Station Prima, Rajab; Arifianto, Fendy; Donni H, Yosafat; Avrionesti, Avrionesti
Journal of Technomaterial Physics Vol. 5 No. 2 (2023): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v5i2.12487

Abstract

Many studies have carried out calculations related to atmospheric lability as a reference in weather forecasts, especially cumulonimbus clouds, and thunderstorms. However, many air lability index values are found to be inappropriate in each region because conditions in each region are different from each other in the region. So it is necessary to use precise index thresholds to determine weather conditions. In the study, observational data and data from Showalter Index (SI), Lifted Index (LI), K Index (KI), Severe Weather Threat Index (SWEAT), and Convective data were used. Available Potential Energy (CAPE) for ten years (2013-2022), then statistical calculations and verification for one year (2022) are carried out. The results obtained are the atmospheric stability index with the best accuracy in predicting the presence of cumulonimbus clouds and thunderstorms at the Kualanamu Meteorological Station, Deli Serdang is the best LI index to predict TS 00 and TS 12, and the best KI index to predict CB 00 and CB 12.
PLANKTON CONCENTRATION MODELING IN THE SOUTHERN WATERS OF NUSA TENGGARA DURING THE TROPICAL CYCLONE SEROJA Avrionesti, Avrionesti
Majalah Ilmiah METHODA Vol. 13 No. 1 (2023): Majalah Ilmiah METHODA
Publisher : Universitas Methodist Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.46880/methoda.Vol13No1.pp1-5

Abstract

Tropical Cyclone Seroja is one of the unique cyclone phenomena that occured in Indonesian waters. To determine its effect to the plankton concentration in East Nusa Tenggara Waters, 1-D Nutrient, Phytoplankton, Zooplankton, and Detritus (NPZD) ecosystem modeling was carried out. The temperature changes caused by the cyclone has a direct impact on the phytoplankton concentration and indirectly on zooplankton. The simulation shows that the peak concentration of phytoplankton due to TC Seroja occurred on 8-10 April 2021 (3.49 mmolC/m3), while for zooplankton it occurred on 20-22 April 2021 (8.55 mmolC/m3).
SEA-LEVEL VARIABILITY IN THE JAVA SEA LINKED TO MONSOON FORCING AND CLIMATE TELECONNECTIONS (2009–2024) Nugraheni, Imma Redha; Lestari, Tri Anggun; Kristianto, Aries; Avrionesti, Avrionesti; Rejeki, Hasti Amrih; Wijaya, Yusuf Jati
Indonesian Physical Review Vol. 8 No. 3 (2025)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v8i3.571

Abstract

The Java Sea is a shallow, strait-connected shelf where seasonal monsoon forcing and climate modes can strongly modulate sea level, yet their sectoral expressions remain under-resolved. Altimetric observations from 2009–2024 (DUACS) are analyzed and validated against a network of Indonesian tide gauges and partition the basin into western (W-JS), central (C-JS), and eastern (E-JS) sectors. After detrending, the seasonal cycle is diagnosed via amplitude and phase metrics and quantifies interannual teleconnections using lead–lag cross-correlations (−12 to +12 months) between sea-level anomaly (SLA) and the Dipole Mode Index (DMI) and Southern Oscillation Index (SOI), with confidence intervals. DUACS reproduces tide-gauge variability with high skill (median correlation ≈ 0.82; RMSE 5–11 cm; small negative biases), supporting its use as a basin proxy. Seasonally, SLA peaks in DJF, weakens in MAM, reaches a pronounced minimum in JJA, and recovers in SON, with marked zonal heterogeneity: E-JS exhibits the strongest annual range (~18 cm) versus W-/C-JS (~12–13 cm). The seasonal phase is non-synchronous (W-JS maxima in May–June; E-JS in December–January), while C-JS behaves as a transition zone. Interannually, IOD impacts are near-synchronous and negative (lag-0, r ~ −0.41 to −0.47 across sectors), whereas ENSO peaks at short positive lags (SOI leads by ~1 month; r ~ 0.45–0.53), implying higher sea level during La Niña and lower during El Niño. These sign-and-lag relationships, combined with tide and surge information, have the potential to inform seasonal outlooks for ports and low-lying coastal areas of Java.
Analysis of Upwelling Parameters when the El Nino Southern Oscillation (ENSO) Occurred in the Halmahera Sea Marthinus, Libertinus; Avrionesti, Avrionesti; Haryanto, Yosafat Donni; Qomariyatuzzamzami, Latifah Nurul
Tropical Marine Environmental Sciences Vol. 2 No. 2 (2024)
Publisher : Department of Marine Science, Faculty of Fisheries and Marine Universitas Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/tromes.2.02.36-41

Abstract

Upwelling events that occur in the Halmahera Sea are influenced by the El Nino Southern Oscillation (ENSO). Upwelling can cause sea surface temperatures to be lower than normal, affecting the potential of fishery resources in the region. The purpose of this study was to determine the conditions of sea surface temperature, chlorophyll-a content, salinity, and upwelling conditions when viewed from the parameters of chlorophyll-α content and sea surface temperature when El Nino was strong, El Nino was weak, La Nina was strong, and La Nina weak and in normal conditions in the Halmahera Sea region. The data used in this study include the Oceanic Nino Index, sea surface temperature, salinity, and chlorophyll-α content during the 2010–2019 period. A quantitative descriptive research type is used by filtering ENSO data to determine when ENSO occurred, then visualizing the data in each parameter and analyzing it. The results of this study show that upwelling is known to occur in the northern to western parts of the Halmahera Sea. When the El Nino phase is vital, the upwelling parameter changes, the sea surface temperature decreases to 27.1⁰C, the chlorophyll-α content increases to 0.70 mg/m3 compared to the normal phase, and the upwelling intensity changes.