DINAMIKA LAPISAN STRATOSFER DI BELAHAN BUMI UTARA DAN DAMPAKNYA TERHADAP WILAYAH TROPIS: STUDI KASUS MUSIM DINGIN 2012-2013 (STRATOSPHERIC DYNAMICS IN THE NORTHERN HEMISPHERE AND ITS IMPACT TO THE TROPICS: A CASE STUDY OF 2012-2013 WINTER)

This research aims to investigate the dynamic of static stability (N2), potential energy of gravity waves (Ep), and vortex in the stratospheric northern hemisphere during 2012-2013 winter using temperature (T) and zonal wind (u) data from NCEP-DOE Reanalysis II. The results showed two occurrences of decreasing N2 ascociated with reversal of u in the first and third week of December 2012 were believed as a trigger of Sudden Stratospheric Warmings (SSW) on January 7, 2013. There was a flow from the polar to the tropics region during the SSW event. It caused the tropopause folding in the sub-tropic region indicated by the distribution of Ep on January 24, 2013. This tropopause folding triggered the convective activity over the Indonesian continents as shown by the negative OLR anomaly from 22 to 26 January 2013. The impact of SSW event in the northern hemisphere to the convective activity was 20%. This results showed the interaction between stratosphere and troposphere and also the teleconnection between the polar and the tropics.   ABSTRAKPenelitian ini bertujuan menyelidiki dinamika stabilitas statis (N2), energi potensial gelombang gravitas (Ep), dan pusaran angin di lapisan stratosfer Belahan Bumi Utara (BBU) selama musim dingin 2012-2013 menggunakan data temperatur (T) dan komponen angin zonal (u) dari NCEP-DOE Reanalysis II. Hasil riset menunjukkan bahwa dua kejadian penurunan N2 pada pekan awal dan ketiga bulan Desember 2012 diyakini sebagai pemicu kejadian Sudden Stratosphere Warmings (SSW) tanggal 7 Januari 2013. Pada saat terjadi SSW terdapat aliran dari kutub menuju tropis. Aliran ini mengakibatkan terjadinya pelipatan lapisan tropopause di wilayah sub-tropis yang terlihat pada distribusi Ep tanggal 24 Januari 2013. Pelipatan lapisan tropopause ini kemudian memicu aktivitas konvektif di atas wilayah Indonesia yang ditandai oleh anomali OLR negatif antara tanggal 22-26 Januari 2013. Dampak kejadian SSW di BBU terhadap aktivitas konvektif di atas wilayah kepulauan Indonesia sebesar 20%. Hasil ini membuktikan interaksi antara lapisan stratosfer dan troposfer serta telekoneksi wilayah kutub dan tropis