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Nonlinear carbon flux response
to
aridity
and water storage deficit
during
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2015
-
2016 El Niño
compromise
d
recovery of the tropical South America
2
carbon balance
3
4
5
Junjie Liu
1,2*
, Kevin Bowman
1,6
, Paul I. Palmer
3,1
, Joanna Joiner
4
,
Paul
Levine
1
,
A.
Anthony
6
Bloom
1
, Liang Feng
3
,7
, Sassan Saatchi
1
, Michael Keller
5,1
, Marcos Longo
1,†
, David Schimel
1
, Paul
7
O. Wennberg
2
8
9
1.
NASA
Jet Propulsion Laboratory, Caltech, Pasadena, CA, USA.
10
2.
Caltech, Pasadena, CA, USA.
11
3.
National Centre for Earth Observation, University of Edinburgh, UK.
12
4.
Goddard Space Flight Center, Greenbelt, MD, USA.
13
5.
USDA Forest Service, International Institute of Tropical Forestry.
14
6.
Joint Institute for Regional Earth System Science and Engineering, University of
15
California, Los Angeles, CA, USA.
16
17
18
Present Address:
Climate and Ecosystem Sciences Division, Lawrence Berkeley National
19
Laboratory, Berkeley, CA, USA.
20
21
22
*
Correspondence to:
junjie.liu@jpl.nasa.gov
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©Copyright,
202
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Abstract:
49
During
the
20
15
-
2016 El Ni
ñ
o
,
t
he Amazon
basin
released almost
one
gigato
n
of
carbon
(
Gt
C)
into
50
the atmosphere due to
extreme
temperatures
and drought
.
T
he link
between the drought impact and
51
recovery of the total carbon pools and its biogeochemical drivers
is still unknown
.
With satellite
-
52
constrained net carbon
exchange
and its component fluxes including gross primary production and
53
fire emissions, w
e show that the total carbon loss caused by the 2015
-
2016 El Niño had not
54
recovered by
the end of
2018.
Forest
ecosystems over
North
e
astern
(NE)
Amazon
suffered
a
55
cumulative
total carbon
loss of ~0.6
Gt
C
through December 2018
,
driven primarily by
a
suppression
56
of photosynthesis
whereas
southeastern
savanna
h
carbon
loss was driven in part
due to fire.
We
57
attribute the slow recovery
to
the unexpected large carbon loss caused by
the
severe
atmospheric
58
aridity coupled
and a water storage deficit
during drought
.
We show
the attenuation of carbon
59
uptake is three times
higher
than expected
from the pre
-
drought sensitivity to
atmospheric aridity
60
and ground water supply
.
Our study fills an important knowledge gap in our understanding of the
61
unexpected
ly
nonlinear response of carbon fluxes to atmospheric aridity and its impact on regional
62
post
-
drought recovery as a function of the vegetation type and climate perturbations.
Our
results
63
suggest that
the disproportionate impact of
water supply and
demand could compromise resiliency
64
of the Amazonian carbon balance
to
future
increase
s
in
extreme events
.
65
66