IDENTIFIKASI PEMAHAMAN MAHASISWA TERHADAP BESARAN VEKTOR DAN BESARAN SKALAR PADA KONSEP MOMENTUM DAN ENERGI

Penelitian ini merupakan penelitian pendahuluan yang bertujuan untuk mengidentifikasi pengetahuan awal mahasiswa mengenai besaran vektor dan skalar pada konsep momentum dan energi. Bentuk penelitian adalah penelitian deskriptif menggunakan metode campuran. Populasinya adalah seluruh mahasiswa yang mengikuti Kompetisi Olimpiade Fisika tingkat Universitas Sriwijaya tahun 2021 pada bidang Fisika dengan jumlah sampel 30 orang mahasiswa. Teknik pengumpuan data yang digunakan adalah metode tes.  Pada tes ini juga disertakan tingkat keyakinan mahasiswa dalam menjawab soal dan alasan memberikan jawaban. Hasil peneltian menunjukkan bahwa sebanyak 60% mahasiswa menjawab pertanyaan dengan salah. Hal ini menunjukkan ketidakpahaman mahasiswa terhadap konsep, terutama pada operasi perkalian antara besaran vektor dan besaran skalar ataupun sesama besaran vektor. Kurangnya rasa kepercayaan diri akan kemampuan yang dimiliki oleh mahasiswa, juga menyebabkan kesalahan

TREND IN PRECIPITATION OVER SUMATERA UNDER THE WARMING EARTH

A long-term climate variations in the western Indonesian region (e.g. Sumatera) were evaluated using precipitation data as a proxy. The result showed that there was a long-term climate variation over Sumatera region indicated by a decreasing trend in precipitation (drying trend). Moreover, the long-term precipitation trend has a strong seasonality. Remarkable decreasing trend at a rate of 3.9 cm/year (the largest trend) was observed during the northwest monsoon (DJF) season, while the smallest decreasing trend of 1.5 cm/year occurred during the southeast monsoon (JJA) season. This result suggested that the Sumatera Island experienced a drying trend during the northwest monsoon season, and a dryer condition will be more frequently observed during the southeast monsoon season. The long-term precipitation over the Sumatera Island was linked to coupled air-sea interactions in the Indian and Pacific oceans. The connection between the seasonal climate trends and sea surface temperature (SST) in the Indian and Pacific oceans was demonstrated by the simultaneous correlations between the climate indices (e.g. Dipole Mode Index (DMI) and the Niño3.4 index) and the precipitation over the Sumatera Island. The results suggested that both the Indian Ocean Dipole (IOD) and the El Niño-Southern Oscillation Index (ENSO) have significant correlation with precipitation. However, remarkable correlations were observed during the fall transition of the IOD event. Keywords: Climate variations, Dry season, Precipitation, Sumatera and Kalimantan, Wet season

Equatorial Oceanic Waves and the Evolution of 2007 Positive Indian Ocean Dipole

The role of equatorial oceanic waves on the evolution of the 2007 positive Indian Ocean Dipole (pIOD) event was evaluated using available observations and output from a quasi-analytical linear wave model. It was found that the 2007 pIOD event was a weak and short-lived event: developed in the mid-summer (July), matured in the early-fall (September), and terminated in the mid-fall (October). The evolution of the 2007 pIOD event was linked to the equatorial wave dynamics. The event development was associated with the generation of upwelling equatorial Kelvin waves (westward current anomalies) generated by easterly wind anomalies. The event termination was associated with the occurrence of eastward zonal current anomalies resulting from a complex interplay between the wind-forced down welling Kelvin waves and the eastern-boundary-reflected Rossby waves. Results from a quasi-analytical linear wave model show that during the event development and maturation, the wind-forced Kelvin waves played a dominant role in generating zonal current anomalies along the equatorial Indian Ocean, while the eastern-boundary-reflected Rossby waves tended to weaken the wind-forced Kelvin wave signals. During the event termination our model shows that the initiation of anomalous eastward current resulted from the reflected Rossby waves at the eastern boundary. The wind-forced Kelvin waves associated with the seasonal reversal of the monsoon further strengthened the eastward zonal currents generated by the boundary-generated Rossby waves in late-October/early-November. This highlights the importance of the eastern-boundary-reflected Rossby waves on the IOD event termination

Trend in Precipitation Over Sumatera Under The Warming Earth

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