Journal of Geophysical Research Biogeosciences,
Год журнала:
2024,
Номер
129(5)
Опубликована: Май 1, 2024
Abstract
Gross
primary
productivity
(GPP)
is
an
important
component
of
the
terrestrial
carbon
cycle
in
climate
change
research.
The
global
GPP
product
derived
using
Moderate
Resolution
Imaging
Spectroradiometer
(MODIS)
data
perhaps
most
widely
used.
Unfortunately,
many
studies
have
indicated
evident
error
patterns
MODIS
product.
One
main
reasons
for
this
that
applied
big‐leaf
(BL)
MOD17
model
cannot
properly
handle
variable
relative
contribution
sunlit
and
shaded
leaves
to
total
canopy‐level
GPP.
In
study,
we
developed
a
correcting
errors
by
bridging
BL
two‐leaf
(TL)
light
use
efficiency
(LUE)
models
(CTL‐MOD17).
With
available
product,
which
considers
environmental
stress
factors,
CTL‐MOD17
only
needs
reuse
two
inputs
leaf
area
index
(LAI)
incoming
radiation.
was
calibrated
validated
at
153
FLUXNET
eddy
covariance
(EC)
sites.
results
indicate
modeled
obtained
with
correction
matches
better
EC
than
original
different
time
scales,
improvement
0.07
R
2
reduction
root‐mean‐square
(RMSE)
117.08
g
C
m
−2
year
−1
.
improvements
are
more
significant
green
season
when
larger.
terms
spatial
pattern,
obvious
underestimation
regions
high
LAI
overestimation
low
effectively
corrected
model.
This
paper
not
bridges
TL
LUE
models,
but
also
provides
new
simple
method
obtain
accurate
through
reusing
used
producing
Global Change Biology,
Год журнала:
2024,
Номер
30(1)
Опубликована: Янв. 1, 2024
Abstract
Droughts
have
been
implicated
as
the
main
driver
behind
recent
vegetation
die‐off
and
are
projected
to
drive
greater
mortality
under
future
climate
change.
Understanding
coupling
relationship
between
drought
has
of
great
global
interest.
Currently,
is
mainly
evaluated
by
correlation
coefficients
or
regression
slopes.
However,
optimal
timescale
response
drought,
a
key
indicator
reflecting
sensitivity
largely
ignored.
Here,
we
apply
identification
method
examine
change
in
over
past
three
decades
(1982–2015)
with
long‐term
satellite‐derived
Normalized
Difference
Vegetation
Index
Standardized
Precipitation‐Evapotranspiration
data.
We
find
substantial
increasing
timescales
globally,
coefficient
overall
declines
1982
2015.
This
decrease
vegetation–drought
observed
regions
water
deficit,
although
its
initial
relatively
high.
water‐surplus
regions,
low
earlier
stages,
prone
show
an
trend.
The
changes
may
be
driven
trend
atmospheric
CO
2
.
Our
findings
highlight
more
pressing
risk
than
water‐deficit
which
advances
our
understanding
provides
essential
insights
for
mapping
changing
conditions.
Ecological Indicators,
Год журнала:
2024,
Номер
158, С. 111511 - 111511
Опубликована: Янв. 1, 2024
Arid
and
humid
ecosystems
are
undergoing
significant
changes
over
the
past
decades
due
to
warming
temperature
frequent
occurrence
of
climate
extremes.
Quantifying
climatic
vegetation
sensitivity
in
regions
with
different
classifications
is
crucial
for
understanding
interaction
mechanisms
between
ongoing
change.
However,
such
knowledge
about
spatiotemporal
variations
its
driving
factors
arid
still
unclear.
Based
on
this
consideration,
a
moving-window-based
Vegetation
Sensitivity
Index
(VSI)
scheme
was
applied
Enhanced
(EVI),
Leaf
Area
(LAI),
Solar-induced
Chlorophyll
Fluorescence
(GOSIF)
data
evaluate
terrestrial
ecosystem
response
explore
from
2003
2020.
Results
indicated
that
high
VSI
(>60)
observed
tropical
rainforests
central
Eurasia
semi-arid
regions.
By
contrast,
low
(<40)
typically
Spatially,
we
found
exhibited
nonlinear
parabolic
variation
along
gradient
aridity
index
but
generally
presented
linear
an
upward
trend
Temporally,
showed
declining
two
displayed
significantly
increasing
areas.
Temperature
dominant
factor
explain
spatial
globally,
while
precipitation
mainly
dominated
temporal
VSI.
The
varied
across
as
were
main
drive
classifications,
respectively.
Our
results
provide
unique
insights
into
future
change
classifications.
Ecological Indicators,
Год журнала:
2024,
Номер
164, С. 112141 - 112141
Опубликована: Май 21, 2024
Meteorological
droughts
triggered
by
relative
precipitation
deficits
would
propagate
through
ecohydrological
processes
and
result
in
comprehensive
drought
events
terrestrial
ecosystems.
Drought
indices
indicating
integrated
information
from
perspective
are
essential
for
monitoring
assessment.
Considering
processes,
Copula
modeling
was
utilized
to
develop
an
ecological
index
(ECDI)
that
included
key
elements
as
precipitation,
actual
evapotranspiration,
soil
moisture,
gross
primary
production.
Spatial
temporal
variations
risk
were
assessed
mainland
China
2001
2022
based
on
the
ECDI.
The
results
showed
(1)
method
suitable
ECDI
establishment.
Over
90%
of
grids
had
RMSE
values
between
estimated
empirical
joint
distributions
less
than
0.1.
(2)
a
reliable
value
98.51%,
96.51%,
59.21%
significant
positive
correlations
with
other
respectively
(standardized
solar-induced
chlorophyll
fluorescence
index,
self-calibrated
Palmer
severity
vegetation
condition
index).
also
satisfactory
relevance
consistency
univariate
each
subregion
(the
correlation
coefficients
ranged
0.4
0.77,
rates
47%
81%).
(3)
mitigation
observed
77.94%
(unused
land
excluded)
last
two
decades,
while
intensification
compound
mainly
located
Qinghai–Tibet
Plateau
Southwest
China.
(4)
composite
assessment
Northeast
China,
middle
reach
Yellow
River
Basin,
Yangtze
Basin
hot
spot
areas
high
drought.
It
is
expected
could
be
indicator
systems.
Ecological Indicators,
Год журнала:
2024,
Номер
163, С. 112140 - 112140
Опубликована: Май 16, 2024
Climate
change
is
one
of
dominators
driving
the
greening
vegetation
worldwide,
which
expected
to
enhance
land
carbon
sink
and
mitigate
global
warming.
The
sensitivity
greenness
climate
fluctuant
regulated
by
other
environmental
factors.
However,
drivers
mechanisms
behind
remain
unclear
so
far.
Here,
we
hired
long-term
satellite-based
index
(NDVI),
climatic
variables,
nitrogen
deposition,
atmospheric
CO2
records
investigate
variations
its
across
Eurasia.
To
obtain
timeseries
temperature
(γNDVITEM)
precipitation
(γNDVIPRE),
applied
multi-regression
models
regressed
on
NDVI
in
each
9-year
moving
windows.
results
showed
that
area
limited
low
temperatures
substantially
shrunk,
while
deficit
increased
during
1982–2015.
Specifically,
significantly
decreasing
γNDVITEM
γNDVIPRE
accounted
for
29.8%
20.1%,
respectively,
remarkably
increasing
about
18.2%
24.5%,
vegetated
lands
Declining
was
widely
observed
most
biomes,
including
tropical
subtropical
moist
broadleaf
forests,
temperate
mixed
coniferous
croplands,
deserts
xeric
shrublands.
Substantially
merely
found
montane
grasslands
shrublands,
dry
nonlinear
regimes
proved
biome
types.
Spatially,
rather
than
elevated
factors
(temperature,
precipitation,
radiation)
jointly
dominated
nearly
45%
48%
Eurasia
respectively.
Our
uncovered
apparent
pattern
changes
highlighted
necessity
unfold
underlying
based
plant
physiology
traits.
Abstract
Multiple
lines
of
evidence
confirm
a
widespread
increase
in
vegetation
growth
across
China
over
the
past
few
decades.
The
relationship
between
and
water
availability
is
thought
to
be
becoming
stronger
under
climate
change,
that
is,
constraints
on
have
been
increasing.
However,
our
understanding
how
influenced
these
greening
trends,
especially
those
change‐driven
ones,
remains
limited.
Here,
we
conduct
comprehensive
evaluation
recent
their
implications
for
1982
2015.
By
analyzing
spatiotemporal
patterns
availability,
reveal
changes
hidden
within
an
overall
trend
China.
Further
analysis
demonstrates
two
change‐related
categories,
defined
broadly
as
“climate”
(e.g.,
air
temperature,
precipitation,
so
on)
“CO
2
”
(i.e.,
atmospheric
carbon
dioxide),
exerted
varying
levels
importance
regulating
different
constraints.
With
increasing
constraints,
proportion
climate‐dominated
area
has
significantly
risen,
while
CO
‐dominated
sharply
declined.
Our
findings
highlight
can
mediate
dominance
growth.
This
great
potential
exacerbate
uncertainty
surrounding
current
future
sustainable
trends.
