ANALYSIS OF VARIATIONS IN TURBULENCE FLUX DUE TO CROSS EQUATORIAL NORTHERLY SURGE (CENS) IN JAKARTA

• Main Author: Ilmar Batuparan, Ahlil
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85169
• Institution: Institut Teknologi Bandung

Cross Equatorial Northerly Surge (CENS) causes the strengthening of monsoon winds from the north around the Karimata Strait and Java Sea. CENS was often associated with heavy rain in western Java, especially during the early morning. As a meso-scale process, CENS might influence micro-scale meteorological conditions such as turbulence fluxes. The micrometeorological observation campaign in two locations in Jakarta, namely KKP and LLH, gives the opportunity to study the effect of CENS on micrometeorological conditions. This study aims to examine how CENS change the micro-scale turbulence fluxes during wet season in Jakarta, Indonesia. This study focused on wet seasons, between December and January, during the period of 2017-2022. The CENS period is defined using ERA5 surface wind data over 105°E–115°E and 5°S. The turbulence fluxes were estimated using eddy covariance method (EC) from the micrometeorological observation data at KKP and LLH. The mean meteorological and turbulent fluxes condition then compared between CENS and non-CENS period. Although CENS causes stronger northerly winds, it does not have a significant influence on the turbulent momentum flux (Fm) in Jakarta. The turbulent sensible heat flux (QH) however, shows lower value during daytime, suggesting that CENS might suppress sensible heat transfer. The latent heat flux (QL) estimation at LLH also shows lower values during daytime under CENS occurrences. However, during early morning on CENS periods, the latent heat flux shows higher values. This result indicates that overland turbulence processes might induce early morning heavy rain that was observed during CENS period.