Pengaruh Convective Available Potential Energy (CAPE) Terhadap Variasi Spasial Temporal Curah Hujan Ekstrem Indonesia

Abstract

Distribusi curah hujan berkaitan erat dengan dinamika dan termodinamika atmosfer. Umumnya, kondisi stabilitas atmosfer dapat merepresentasi proses pembentukan curah hujan di permukaan. Convective Available Potential Energy (CAPE) merupakan salah satu parameter atmosfer yang dapat menjelaskan kondisi ketidakstabilan atmosfer. Fluktuasi peningkatan CAPE berpotensi pembentukan awan konvektif, sehingga mengakibatkan terbentuknya curah hujan ekstrem suatu wilayah. Tujuan dari penelitian ini adalah menjelaskan berbagai kondisi spasial dan temporal dari variasi Convective Available Potential Energy (CAPE) dan curah hujan ekstrem di Indonesia, serta menganalisis hubungan korelasi nilai CAPE terhadap curah hujan dan beberapa indeks curah hujan ekstrem di Indonesia. Cropping dan subsetting merupakan tahapan awal dalam ekstraksi data curah hujan APHRODITE dan CAPE dalam analisis kondisi wilayah Indonesia. Perhitungan indeks curah hujan ekstrem telah dikembangkan oleh Expert Team for Climate Change Detection Monitoring and Indices (ETCCDMI), diantaranya indeks R95p (very wet days), CDD (consecutive dry days), CWD (consecutive wet days), R10mm (heavy rain), R20mm (very heavy rain), dan SDII (simply daily intensity index). Tahun 1983 – 2007 secara umum, wilayah Indonesia mengalami trend kejadian ekstrem dengan kategori ekstrem kering yang terlihat pada indeks CDD yang meningkat secara signifikan (p-value < 0,05), terutama pada wilayah Papua, berdasarkan uji statistik Mann-Kendall. Kontribusi CAPE terhadap curah hujan di Indonesia signifikan terjadi saat musim MAM, dan SON, dan rendahnya nilai CAPE saat musim JJA berkorelasi positif signifikan terhadap kondisi curah hujan rendah pada periode tersebut. Sedangkan, besarnya nilai CAPE menyebabkan meningkatnya indeks CWD dan R10mm, dengan koefisien korelasi positif yang signifikan, sedangkan pada indeks CDD mengalami penurunan kejadian yang signifikan, dengan koefisien korelasi negatif.

Precipitation distribution is closely related to atmospheric dynamics and thermodynamics. In most cases, instability atmospheres describe the process of precipitation formation on the surface. Convective Available Potential Energy (CAPE) is one measure that takes into account instability. An increase in the CAPE parameter has the potential to cause the convective cloud effect, which causes the region's extreme rainfall. The aim of this study is to better understand the spatial and temporal variations in conditions caused by varying convection energy or Convective Available Potential Energy (CAPE) and rainfall extreme events in Indonesia, as well as the relationship between CAPE value and some rainfall extremes index. Cropping and subsetting were carried out using rainfall data from APHRODITE and CAPE from ECMWF. Based on the Expert Team for Climate Change Detection Monitoring and Indices(ETCCDMI), rainfall data was converted into the extreme rainfall index R95p (very wet days), CDD (consecutive dry days), CWD (consecutive wet days), R10mm (heavy rain), R20mm (very heavy rain), and SDII (simply daily intensity index). According to Mann-Kendall statistics, Indonesia experienced an extreme trend from 1983 to 2007, with a higher extreme category reflected in a rising CDD index (p-value<0,05), particularly in Papua. In Indonesia, the CAPE contribution to rainfall is significant during the MAM and SON seasons, and a low CAPE value during the JJA season has a significant positive correlation with low rainfall conditions during that period. Meanwhile, with a p-value of <0,05, the magnitude of the CAPE value showed a significant positive correlation to the CWD and R10mm indices and a negative correlation to the CDD indices.