Enhanced
Carbon
Flux
Response
to
Atmospheric
Aridity
and
Water
Storage
Deficit
During
the
2015–2016
El
Niño
Compromised
Carbon
Balance
Recovery
in
Tropical
South
America
Junjie
Liu
1,2
,
Kevin
Bowman
1,3
,
Paul
I.
Palmer
1,4
,
Joanna
Joiner
5
,
Paul
Levine
1
,
A.
Anthony
Bloom
1
,
Liang
Feng
4,6
,
Sassan
Saatchi
1
,
Michael
Keller
1,7
,
Marcos
Longo
1,8
,
David
Schimel
1
,
and
Paul
O.
Wennberg
2
1
NASA
Jet
Propulsion
Laboratory,
California
Institute
of
Technology,
Pasadena,
CA,
USA,
2
California
Institute
of
Technology,
Pasadena,
CA,
USA,
3
Joint
Institute
for
Regional
Earth
System
Science
and
Engineering,
University
of
California
Los
Angeles,
Los
Angeles,
CA,
USA,
4
National
Centre
for
Earth
Observation,
University
of
Edinburgh,
Edinburgh,
UK,
5
Goddard
Space
Flight
Center,
Greenbelt,
MD,
USA,
6
School
of
GeoSciences,
University
of
Edinburgh,
Edinburgh,
UK,
7
USDA
Forest
Service,
International
Institute
of
Tropical
Forestry,
San
Juan,
PR,
USA,
8
Now
at
Climate
and
Ecosystem
Sciences
Division,
Lawrence
Berkeley
National
Laboratory,
Berkeley,
CA,
USA
Abstract
During
the
2015–2016
El
Niño,
the
Amazon
basin
released
almost
one
gigaton
of
carbon
(GtC)
into
the
atmosphere
due
to
extreme
temperatures
and
drought.
The
link
between
the
drought
impact
and
recovery
of
the
total
carbon
pools
and
its
biogeochemical
drivers
is
still
unknown.
With
satellite‐constrained
net
carbon
exchange
and
its
component
fluxes
including
gross
primary
production
and
fire
emissions,
we
show
that
the
total
carbon
loss
caused
by
the
2015–2016
El
Niño
had
not
recovered
by
the
end
of
2018.
Forest
ecosystems
over
the
Northeastern
(NE)
Amazon
suffered
a
cumulative
total
carbon
loss
of
∼
0.6
GtC
through
December
2018,
driven
primarily
by
a
suppression
of
photosynthesis
whereas
southeastern
savannah
carbon
loss
was
driven
in
part
by
fire.
We
attribute
the
slow
recovery
to
the
unexpected
large
carbon
loss
caused
by
the
severe
atmospheric
aridity
coupled
with
a
water
storage
deficit
during
drought.
We
show
the
attenuation
of
carbon
uptake
is
three
times
higher
than
expected
from
the
pre‐drought
sensitivity
to
atmospheric
aridity
and
ground
water
supply.
Our
study
fills
an
important
knowledge
gap
in
our
understanding
of
the
unexpectedly
enhanced
response
of
carbon
fluxes
to
atmospheric
aridity
and
water
storage
deficit
and
its
impact
on
regional
post‐
drought
recovery
as
a
function
of
the
vegetation
types
and
climate
perturbations.
Our
results
suggest
that
the
disproportionate
impact
of
water
supply
and
demand
could
compromise
resiliency
of
the
Amazonian
carbon
balance
to
future
increases
in
extreme
events.
Plain
Language
Summary
The
carbon
storage
in
tropical
South
America
(SA,
15°S