Abstract.
This
paper
presents
the
tran-SAS
package,
which
includes
a
set
of
codes
to
model
solute
transport
and
water
residence
times
through
hydrological
system.
The
is
based
on
catchment-scale
approach
that
aims
at
reproducing
integrated
response
system
one
its
outlets.
are
implemented
in
MATLAB
meant
be
easy
edit,
so
users
with
minimal
programming
knowledge
can
adapt
them
desired
application.
problem
large-scale
has
both
theoretical
practical
implications.
On
side,
ability
represent
ensemble
flow
trajectories
heterogeneous
helps
unraveling
streamflow
generation
processes
allows
making
inferences
plant-water
interactions.
other
models
tool
used
estimate
persistence
solutes
environment.
core
package
implementation
an
age
Master
Equation
(ME),
solved
using
general
StorAge
Selection
(SAS)
functions.
ME
first
converted
into
ordinary
differential
equations,
each
addressing
individual
precipitation
input
catchment,
then
it
discretized
explicit
numerical
scheme.
Results
show
efficient
run
short
times.
accuracy
critically
evaluated
shown
satisfactory
most
cases
hydrologic
interest.
Additionally,
higher-order
provided
within
evaluate
and,
if
necessary,
improve
results.
concentration,
but
number
additional
outputs
obtained
by
editing
further
advance
understand
catchment
processes.
Water Resources Research,
Год журнала:
2015,
Номер
51(6), С. 4840 - 4847
Опубликована: Июнь 1, 2015
Abstract
We
discuss
a
recent
theoretical
approach
combining
catchment‐scale
flow
and
transport
processes
into
unified
framework.
The
is
designed
to
characterize
the
hydrochemistry
of
hydrologic
systems
meet
challenges
posed
by
empirical
evidence.
StorAge
Selection
functions
(SAS)
are
defined
represent
way
catchment
storage
supplies
outflows
with
water
different
ages,
thus
regulating
chemical
composition
out‐fluxes.
Biogeochemical
also
reflected
in
evolving
residence
time
distribution
age‐selection.
Here
we
make
case
for
routine
use
SAS
look
forward
areas
where
further
research
needed.
Water Resources Research,
Год журнала:
2017,
Номер
53(3), С. 1864 - 1878
Опубликована: Фев. 11, 2017
Abstract
We
use
high‐resolution
tracer
data
from
an
experimental
site
to
test
theoretical
approaches
that
integrate
catchment‐scale
flow
and
transport
processes
in
a
unified
framework
centered
on
selective
age
sampling
by
streamflow
evapotranspiration
fluxes.
Transport
operating
at
the
catchment
scale
are
reflected
evolving
residence
time
distribution
of
water
storage
selection
operated
out‐fluxes.
Such
described
here
through
StorAge
Selection
(SAS)
functions
parameterized
as
power
laws
normalized
rank
storage.
computed
appropriate
solution
master
equation
defining
formally
evolution
travel
times.
By
representing
way
which
generates
outflows
composed
different
ages,
main
mechanism
regulating
composition
runoff
is
clearly
identified
detailed
comparison
with
empirical
sets
possible.
Properly
calibrated
numerical
tools
provide
simulations
convincingly
reproduce
complex
measured
signals
daily
deuterium
content
stream
waters
during
wet
dry
periods.
Results
for
under
consideration
consistent
other
recent
studies
indicating
tendency
natural
catchments
preferentially
release
younger
available
water.
The
study
shows
law
SAS
prove
powerful
tool
explain
also
has
potential
less
intensively
monitored
sites.
Water Resources Research,
Год журнала:
2015,
Номер
51(11), С. 9256 - 9272
Опубликована: Ноя. 1, 2015
Abstract
We
combine
experimental
and
modeling
results
from
a
headwater
catchment
at
the
Hubbard
Brook
Experimental
Forest
(HBEF),
New
Hampshire,
USA,
to
explore
link
between
stream
solute
dynamics
water
age.
A
theoretical
framework
based
on
age
dynamics,
which
represents
general
basis
for
characterizing
transport
scale,
is
here
applied
conservative
weathering‐derived
solutes.
Based
available
information
about
hydrology
of
site,
an
integrated
model
was
developed
used
compute
hydrochemical
fluxes.
The
designed
reproduce
deuterium
content
streamflow
allowed
estimate
storage
dynamic
travel
time
distributions
(TTDs).
innovative
contribution
this
paper
simulation
dissolved
silicon
sodium
concentration
in
streamflow,
achieved
by
implementing
first‐order
chemical
kinetics
explicitly
TTD,
thus
upscaling
local
geochemical
processes
scale.
Our
highlight
key
role
stored
within
subsoil
glacial
material
both
short‐term
long‐term
circulation.
analysis
provided
their
evolution
related
wetness
conditions.
use
14
year
data
set
shows
that,
scales,
such
geogenic
solutes
are
mostly
controlled
hydrologic
drivers,
determine
contact
times
mineral
interfaces.
Justifications
limitations
toward
theory
reactive
circulation
scales
discussed.
Water Resources Research,
Год журнала:
2024,
Номер
60(7)
Опубликована: Июль 1, 2024
Abstract
GRACE
(Gravity
Recovery
and
Climate
Experiment)
has
been
widely
used
to
evaluate
terrestrial
water
storage
(TWS)
groundwater
(GWS).
However,
the
coarse‐resolution
of
data
limited
ability
identify
local
vulnerabilities
in
changes
associated
with
climatic
anthropogenic
stressors.
This
study
employs
high‐resolution
(1
km
2
)
generated
through
machine
learning
(ML)
based
statistical
downscaling
illuminate
TWS
GWS
dynamics
across
twenty
sub‐regions
Indus
Basin.
Monthly
anomalies
obtained
from
a
geographically
weighted
random
forest
(RF
gw
model
maintained
good
consistency
original
at
25
grid
scale.
The
downscaled
1
resolution
illustrate
spatial
heterogeneity
depletion
within
each
sub‐region.
Comparison
in‐situ
2,200
monitoring
wells
shows
that
significantly
improves
agreement
data,
evidenced
by
higher
Kling‐Gupta
Efficiency
(0.50–0.85)
correlation
coefficients
(0.60–0.95).
Hotspots
highest
decline
rate
between
2002
2023
were
Dehli
Doab
(−442,
−585
mm/year),
BIST
(−367,
−556
Rajasthan
(−242,
−381
BARI
(−188,
−333
mm/year).
Based
on
general
additive
model,
47%–83%
was
stressors
mainly
due
increasing
trends
crop
sown
area,
consumption,
human
settlements.
lower
(i.e.,
−25
−75
mm/year)
upstream
(e.g.,
Yogo,
Gilgit,
Khurmong,
Kabul)
where
factors
(downward
shortwave
radiations,
air
temperature,
sea
surface
temperature)
explained
72%–91%
TWS/GWS
changes.
relative
influences
varied
sub‐regions,
underscoring
complex
interplay
natural‐human
activities
basin.
These
findings
inform
place‐based
resource
management
Basin
advancing
understanding
vulnerabilities.
International Journal of Digital Earth,
Год журнала:
2025,
Номер
18(1)
Опубликована: Янв. 6, 2025
This
study
provides
unprecedented
insights
into
water
scarcity
dynamics
across
Africa's
diverse
climatic
zones,
utilizing
the
Standardized
Precipitation-Evapotranspiration
Index
(SPEI)
multiple
timescales
from
1960
to
2018.
Employing
Modified
Mann-Kendall
test,
Sen's
Slope
estimator,
and
copula
functions,
we
analyzed
drought
characteristics
eight
African
subregions
using
CRU
TS4.05
dataset.
Key
findings
reveal
significant
spatial
heterogeneity
in
trends,
with
increasing
dryness
particularly
evident
Mediterranean
Sahara
regions.
A
pronounced
shift
towards
drier
conditions
emerged
post-1990,
mean
duration
expanding
1.5
months
(SPEI-3)
over
6
(SPEI-24).
Drought
intensity
increased
by
0.2
unit
annually,
while
frequency
decreased
20%.
The
region
demonstrated
highest
trend
timescales.
Return
period
analyses
showed
most
sub-regions
experiencing
short-term
droughts
low
severity,
extreme
events
remained
less
frequent.
These
underscore
complex
nature
of
patterns,
emphasizing
critical
need
for
region-specific,
adaptive
climate
strategies
address
unique
ecological
challenges.
International Journal of Digital Earth,
Год журнала:
2025,
Номер
18(1)
Опубликована: Янв. 8, 2025
Climate
change,
population
growth,
and
economic
development
exacerbate
water
scarcity.
This
study
investigates
the
impact
of
drought
on
availability
in
Belt
Road
region
using
high-resolution
remote
sensing
data
from
2001
to
2020.
The
results
revealed
an
average
(precipitation
minus
evapotranspiration)
249
mm/year
a
declining
trend
region.
Approximately
13%
faces
deficits
(evapotranspiration
exceeds
precipitation),
primarily
arid
semi-arid
regions
with
high
frequency.
area
deficit
is
expanding,
intensity
increasing.
annual
strongly
related
frequency
droughts,
i.e.
decreases
increased
Drought
exacerbates
seasonal
stress
approximately
one-third
region,
mainly
Europe
northern
Asia,
where
frequently
occurs
during
seasons
low
availability.
more
severe
drought,
larger
negative
anomaly
critical
role
evapotranspiration
variability
also
highlighted.
research
underscores
importance
understanding
drought-induced
changes
availability,
which
crucial
for
sustainable
resource
management.
