Increasing smog haze and its impact on oil palm evapotranspiration and gross primary production during the 2015 fire: special discussion on diffuse radiation

Abstract

In 2015, several regions in Indonesia experienced drought which coincided with the El Nino phenomenon. A drought in Indonesia followed by fires has resulted in oil palm plantations in Jambi being covered by smog. The fire phenomenon has a major impact on the weakening of the sun that enters the earth's surface due to the closure of the atmosphere by thick smog so that it affects gross primary production (GPP) and evapotranspiration of oil palm. This study aims to analyze the intensity of smog based on diffuse radiation and analyze the relationship and pattern of GPP and evapotranspiration to diffuse radiation during the occurrence of smog in 2015. PM10 concentration as a representation of aerosols in the atmosphere on atmospheric transmissivity is negatively correlated with r = -0.8 and p-value = 0.0016. The high diffuse radiation is directly proportional to the atmospheric conditions covered by smog. When the smog cover in the atmosphere was at its peak in October 2015, most of the incoming solar radiation was diffuse radiation. The diffuse fraction with GPP and evapotranspiration was also negatively or inversely correlated. Both have a significant relationship with p-value < 0.05 and r = -0.93 for GPP and r = -0.88 for evapotranspiration. Based on the magnitude of the correlation coefficient, diffuse radiation with GPP has a closer relationship than evapotranspiration.