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Natalia Restrepo-Coupe, Brad Christoffersen, Daniel F. Amaral, Plínio B. de Camargo; Scott R. Saleska Carbon loss on the other side of drought: excess.

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Presentation on theme: "Natalia Restrepo-Coupe, Brad Christoffersen, Daniel F. Amaral, Plínio B. de Camargo; Scott R. Saleska Carbon loss on the other side of drought: excess."— Presentation transcript:

1 Natalia Restrepo-Coupe, Brad Christoffersen, Daniel F. Amaral, Plínio B. de Camargo; Scott R. Saleska Carbon loss on the other side of drought: excess wet season precipitation during La Niña suppresses Amazon forest photosynthesis

2 Motivation: will Amazon forest die- back with future climate change? Adapted from: Cox et al., 2003, Amazon Dieback under Climate-Carbon Cycle Projections for the 21st Century Mean daily temperature change(K) Precipitation change (mm day -1 ) Change in Vegetation Carbon (kg C m -2 ) W 0 90 N 45 N 0 45 S 90S Differences relative to mean W 0

3 Motivation: August 2008 – June 2008 La Niña Event El Niño La Niña neutral La Ni ñ a ONI value for ASO 2007 – AMJ 2008 is -1.4 o C The most recent ONI value (July – September 2009) is +0.8 o C. Source: Oceanic Nino Index, ONI (ERSST.v3b ONI) Upper ocean heat anomalies ( ) Sea Surface Temperature Anomlies (C)

4 Motivation: 2008 – June 2008 La Niña Event La Niña neutral Source: Oceanic Nino Index, ONI (ERSST.v3b ONI) Upper ocean heat anomalies ( ) Sea Surface Temperature Anomlies (C) NOV JAN MAR MAY JUL Sea Surface Temperature Anomlies (C)

5 Tropical Rainfall Measuring Mission (TRMM) data, at 0.25 spatial resolution 1998 – 2009 [NASA, 2006] Motivation: South America precipitation 2008 – 2009 Normilized anomaly Lon K67 Lon K67 Apr-May

6 … on the other side of drought …

7 Tapajós K67 tropical forest

8 Tapajós K67 tropical forest: Climate Hydrological year: Dry season – Wet season HY2002: Aug 1, 2002 – Jul 31, 2003HY2003: Aug 1, 2003 – Jul 31, 2004 HY2004: Aug 1, 2004 – Jul 31, 2005HY2005: Aug 1, 2005 – Jan 6, 2006 HY2008: Aug 1, 2008 – Jul 31, 2009 Aug 2008 – Jul 2009 dry season wet season

9 Result 1: La Niña Event corresponds to C Forest Loss Net ecosystem exchange Forest C losses Forest C uptake dry season wet season Aug 2008 – Jul 2009

10 dry season wet season Result 1: La Niña Event corresponds to C Forest Loss dry season wet season Aug 2008 – Jul 2009 Instantaneous C-flux Cumulative C-flux and Precipitation

11 What is the cause of C-loss? (split into photosynthesis & respiration) NEE: Net Ecosystem Exchange R: Ecosystem Respiration GEE: Gross Ecosystem Productivity ~ Photosynthetic activity Higher C uptake Higher C losses NEE = R + GEE dry season wet season

12 Result 2: Forest C Loss is due to reduced photosynthesis NEE: Net Ecosystem Exchange R: Ecosystem Respiration GEE: Gross Ecosystem Productivity ~ Photosynthetic activity Higher C uptake Higher C losses dry season wet season Reduced photosynthesis (less negative) NEE = R + GEE

13 Higher C uptake Higher C losses dry season wet season What is the cause of reduced photosynthesis?

14 Higher C uptake Higher C losses dry season wet season What is the cause of reduced photosynthesis? Lower PAR and…

15 Higher C uptake Higher C losses dry season wet season Result 3: decreased photosynthetic response Decreased photosynthetic response Jan Feb GEP = -GEE

16 What is the cause of reduced photosynthetic response? Earlier onset of the wet season? High soil moisture? ….

17 Summary: at Tapajós K67 tropical forest Result 1: La Niña Event (wet wet season and earlier onset of the wet season, corresponds to C Forest Loss. Result 2: Forest C Loss is due to reduced photosynthesis. Result 3: decreased photosynthetic response. Future work: Investigaion on the cause of reduced photosynthetic response?

18 Acknowledgments This research was funded by the National Science Foundations Partnerships for International Research and Education (PIRE) and the National Aeronautics and Space Administration (NASA) LBA investigation CD-32. Thank you

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