Effects Of The 2015–2016 El Ni?o Event On Energy And CO2 Fluxes Of A Tropical Rainforest In Central Sulawesi, Indonesia

摘要

The influence of the very strong 2015–16 El Ni?o event on local and regionalmeteorological conditions, as well as on energy and CO2 fluxes in a mountainousprimary tropical rainforest was investigated using ERA-Interim reanalysis data as wellas meteorological and eddy covariance flux measurements from Central Sulawesi inIndonesia. The El Ni?o event led to a strong increase of incoming monthly solar radiationand air temperature, simultaneously with the increasing Ni?o4 index. Monthly precipitationfirst strongly decreased and then increased reaching a maximum in 3–4 months afterEl Ni?o culmination. Ecosystem respiration increased while gross primary productionshowed only a weak response to the El Ni?o event resulting in a positive anomaly ofnet ecosystem CO2 exchange (reduced CO2 uptake). The changes of key meteorologicalparameters and fluxes caused by the strong El Ni?o event of 2015–16 differed from theeffects of moderate El Ni?o events observed during the period 2003-2008, where netecosystem CO2 exchange remained largely unaffected. In contrast to earlier moderate ElNi?o events, the strong El Ni?o 2015–16 affected mostly the air temperature resulting ina weakening of the net carbon sink at the rainforest site in Central Sulawesi, Indonesia.