Page
1
of
38
Nonlinear carbon flux response
to
aridity
and water storage deficit
during
1
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
23
24
25
26
27
©Copyright,
202
4
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
Page
2
of
38
48
Abstract:
49
During
the
20
15
-
2016 El Ni
ñ
o
,
t
he Amazon
basin
released almost
one
gigato
n
of
carbon
(
Gt
C)
50
into the atmosphere due to
extreme
temperatures
and drought
.
T
he link between the drought
51
impact and recovery of the total carbon pools and its biogeochemical drivers
is still unknown
.
52
With satellite
-
constrained net carbon
exchange
and its component fluxes including gross primary
53
production and fire emissions, w
e show that the total carbon loss
caused by the 2015
-
2016 El
54
Niño had not recovered by
the end of
2018.
Forest
ecosystems over
the
North
e
astern
(NE)
55
Amazon
suffered
a cumulative
total carbon
loss of ~0.6
Gt
C
through December 2018
,
driven
56
primarily by
a
suppression of photosynthesis
wherea
s
southeastern
savanna
h
carbon
loss was
57
driven in part
by
fire.
We attribute the slow recovery
to
the unexpected large carbon loss caused
58
by
the
severe
atmospheric aridity coupled
with
a water storage deficit
during drought
.
We show
59
the attenuation of carbon uptake is three times
higher
than expected
from the pre
-
drought
60
sensitivity to
atmospheric aridity
and ground water supply
.
Our study fills an important
61
knowledge gap in our understanding of the
unexpected
ly
nonlinear response of
carbon fluxes to
62
atmospheric aridity
and water storage
and its impact on regional post
-
drought recovery as a
63
function of the vegetation type
s
and climate perturbations.
Our
results suggest that
the
64
disproportionate impact of
water supply and
demand could
compromise resiliency of the
65
Amazonian carbon balance
to
future
increase
s
in
extreme events
.
66
67