Response of CO2 and H2O fluxes in a mountainous tropical rainforest in equatorial Indonesia to El Niño events

[摘要] The possible impact of El Niño–Southern Oscillation (ENSO) events on themain components of CO₂ and H₂O fluxes between the tropical rainforestand the atmosphere is investigated. The fluxes were continuously measured in anold-growth mountainous tropical rainforest in Central Sulawesi inIndonesia using the eddy covariance method for the period from January 2004to June 2008. During this period, two episodes of El Niño and oneepisode of La Niña were observed. All these ENSO episodes had moderateintensity and were of the central Pacific type. The temporal variabilityanalysis of the main meteorological parameters and components of CO₂and H₂O exchange showed a high sensitivity of evapotranspiration (ET)and gross primary production (GPP) of the tropical rainforest tometeorological variations caused by both El Niño and La Niñaepisodes. Incoming solar radiation is the main governing factor that isresponsible for ET and GPP variability. Ecosystem respiration (RE) dynamicsdepend mainly on the air temperature changes and are almost insensitive toENSO. Changes in precipitation due to moderate ENSO events did not have anynotable effect on ET and GPP, mainly because of sufficient soil moistureconditions even in periods of an anomalous reduction in precipitation in theregion.

[学科分类] 地球化学与岩石