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

• Main Authors: Daria Gushchina, Florian Heimsch, Alexander Osipov, Tania June, Abdul Rauf, Heiner Kreilein, Oleg Panferov, Alexander Olchev, Alexander Knohl
• Format: Article
• Language: English
• Published: Lomonosov Moscow State University 2019-07-01
• Series: Geography, Environment, Sustainability
• Subjects: el niño southern oscillation; niño4; tropical rainforest; eddy covariance flux measurements; energy and co2 fluxes
• Online Access: https://ges.rgo.ru/jour/article/view/746
• ISSN: 2071-9388; 2542-1565

The influence  of the very strong 2015–16 El Niño event on local and regional meteorological   conditions,  as  well as  on  energy and CO2   fluxes in  a  mountainous primary  tropical  rainforest  was investigated  using ERA-Interim  reanalysis  data as well as meteorological  and eddy covariance  flux measurements   from  Central Sulawesi  in Indonesia. The El Niño event led to a strong increase of incoming monthly solar radiation and air temperature, simultaneously with the increasing Niño4 index. Monthly precipitation first strongly decreased  and then increased  reaching  a maximum  in 3–4 months after El  Niño culmination.  Ecosystem  respiration  increased  while gross  primary  production showed only a weak response  to the El  Niño event resulting  in a positive  anomaly  of net ecosystem CO2 exchange (reduced CO2 uptake). The changes of key meteorological parameters and fluxes caused  by the strong  El Niño event of 2015–16  differed from the effects  of moderate  El Niño events  observed  during  the period  2003-2008,  where net ecosystem CO2 exchange  remained largely unaffected. In contrast to earlier moderate  El Niño events, the strong El Niño 2015–16 affected mostly the air temperature  resulting  in a weakening of the net carbon  sink at the rainforest site in Central Sulawesi, Indonesia.