Geofluids,
Год журнала:
2022,
Номер
2022, С. 1 - 16
Опубликована: Июль 28, 2022
The
Qinghai-Tibetan
Plateau
(QTP)
has
undergone
an
increase
in
rainfall
and
a
drastic
alteration
the
moisture-heat
regime
active
layers
engineering.
To
investigate
water
heat
responses
of
natural
ground
engineering
to
rainfall,
differences
energy
on
surface
thermal-moisture
dynamics
different
permafrost
underlying
surfaces
were
discussed.
Based
meteorological
data
2013
observed
at
Beiluhe
observation
station,
three
types
(i.e.,
ground,
asphalt
pavement,
gravel
pavement)
selected
compare
balance
surface,
water-energy
transport
process,
coupling
mechanism
under
conditions
by
coupled
vapor-heat
model
unsaturated
frozen
soil.
results
show
that
pavement
greatly
increases
net
radiation
soil
flux,
decreases
evaporation
latent
heat,
cuts
off
moisture
migration
between
atmosphere
layer.
significantly
lower
amount
shallow
is
strongly
influenced
evaporation.
Therefore,
accumulation
are
dominated
vapor
flux
thermal
gradients,
whereas
liquid
potential
gradients
major
source
pavement.
transfer
layer
conduction.
effect
conduction,
migration,
phase
transition
temperature
evident
for
while
impact
significant
thawing
period.
As
result,
relationship
pavement>gravel
pavement>natural
ground.
thickness
gradually
decreases.
Although
infiltration
promotes
convection
decrease
less
than
conductivity.
In
general,
construction
accelerates
degradation
permafrost.
can
provide
theoretical
simulated
guidance
stability
prediction
analysis
various
central
QTP
where
increasing.
Journal of Cold Regions Engineering,
Год журнала:
2024,
Номер
38(2)
Опубликована: Апрель 5, 2024
The
Qinghai–Tibet
Plateau
shows
an
obvious
trend
of
warming
and
humidification,
the
increased
rainfall
is
mainly
concentrated
in
summer.
There
have
been
few
reports
on
effects
summer
variations
hydrothermal
states
embankments
permafrost
regions.
Therefore,
based
indoor
embankment-scale
model
experiment,
surface
energy,
temperature,
water
fields
highway
regions
were
investigated.
results
showed
that
led
to
increase
net
radiation.
However,
a
decreasing
pavement
temperature
shallow
heat
flux
embankment,
indicating
could
effectively
inhibit
temperature.
Simultaneously,
also
content
at
different
locations
embankment
following
order:
natural
site
>
shoulder
slope
pavement.
maximum
was
6.7%
after
twofold
rainfall.
In
addition,
within
exhibited
with
Compared
other
parts
although
relatively
small
lower
part
pavement,
asphalt
concrete
had
higher
when
acts
as
energy
cold
pulse
decreases
more
significantly
than
embankment.
affected
cooling
range
slope.
hysteresis
effect
autumn.
Frontiers in Earth Science,
Год журнала:
2024,
Номер
12
Опубликована: Авг. 30, 2024
The
Tibetan
Plateau
has
exhibited
a
discernible
trend
towards
increased
precipitation
over
the
past
50
years.
However,
previous
research
predominantly
focused
on
thermal
stability
of
permafrost
without
consideration
water
flux
boundary
conditions,
and
therefore
ignored
dynamics
migration
its
impacts
embankment
stability.
To
bridge
this
gap,
novel
water-heat
transfer
model
incorporating
rainfall
was
developed
subsequently
validated
using
monitored
data.
Comparative
analyses
were
then
conducted
across
three
distinct
intensities
to
investigate
variations
in
moisture
temperature
superficial
soil.
Results
indicate
events
exert
notable
cooling
effect
during
warm
seasons
but
have
little
influence
cold
seasons.
By
increasing
latent
heat
evaporation,
sensible
reducing
soil
flux,
results
cooling,
correlates
positively
with
intensity.
Disregarding
conditions
will
overestimate
underestimate
variation
content,
especially
at
Rainfall
decline
vapor
an
increase
liquid
which
facilitates
rapid
downward
transport
accumulation
water.
Despite
convective
water,
decrease
conduction,
evaporation
is
more
pronounced.
changes
mainly
by
adjusting
energy
distribution,
delays
increases
underlying
permafrost.
When
predicting
permafrost,
it
recommended
incorporate
conditions.
Journal of Geophysical Research Atmospheres,
Год журнала:
2024,
Номер
129(20)
Опубликована: Окт. 22, 2024
Abstract
Soil
freeze‐thaw
cycles
play
a
critical
role
in
ecosystem,
hydrological
and
biogeochemical
processes,
climate.
The
Tibetan
Plateau
(TP)
has
the
largest
area
of
frozen
soil
that
undergoes
low‐mid
latitudes.
Evidence
suggests
ongoing
changes
seasonal
during
past
several
decades
on
TP.
However,
status
diurnal
(DFTC)
shallow
their
response
to
climate
change
largely
remain
unknown.
In
this
study,
using
in‐situ
observations,
latest
reanalysis,
machine
learning,
physics‐based
modeling,
we
conducted
comprehensive
assessment
spatiotemporal
variations
DFTC
upper
Brahmaputra
(UB)
basin.
About
24
±
8%
basin
is
subjected
with
mean
frequency
87
55
days
1980–2018.
show
small
long‐term
Air
temperature
impacts
center
mainly
around
freezing
point
(0°C).
spatial
air
can
primarily
be
explained
by
three
factors:
precipitation
(30.4%),
snow
depth
(22.6%)
warming/cooling
rates
(14.9%).
Both
rainfall
events
reduce
fluctuations
temperature,
subsequently
reducing
frequency,
decreasing
daytime
through
evaporation‐cooling
albedo‐cooling
effects,
respectively.
These
results
provide
an
in‐depth
understanding
its
change.
Atmosphere,
Год журнала:
2023,
Номер
14(2), С. 296 - 296
Опубликована: Фев. 1, 2023
The
climate
of
the
Qinghai–Tibet
Plateau
is
distinct.
Given
large
temperature
difference
between
day
and
night,
drought
in
perennial
years,
low
rainfall
evaporation
volume,
frozen
soil
some
areas
will
occur
salt.
presence
salt
changes
water
thermal
characteristics
soil,
which
affect
its
activity
layer.
In
this
paper,
Beiluhe
area
was
selected
as
research
object,
numerical
calculation
model
water,
heat
salinised
established.
Considering
influence
crystallisation
on
freezing
active
layer,
effects
different
concentrations,
contents
type
thickness
layer
were
compared
analysed.
Therefore,
degenerates
under
action
sodium
chloride
sulphate,
sulphate
not
conducive
to
stability
for
many
years.
During
salinisation,
content
increases;
permafrost
initially
decreases
then
initial
time
postponed
cooling
stages,
when
with
a
concentration
0.2–0.8%
delayed
by
21,
32,
54
65
days;
decreases,
opposite
thawing
heating
increases
increase
concentration.
finally
contrary
warm
season.
(with
maximum
0.82
m)
has
little
effect
High
permafrost.
When
constant,
change
smaller;
season
lower;
smaller,
tends
be
more
stable.
generally
reduces
warm-season
(−6
m
30%
40%
−6
0.17
°C
0.24
lower
than
that
20%
content).
However,
analysis
containing
must
combine
temperature.
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,
Год журнала:
2023,
Номер
16, С. 6902 - 6916
Опубликована: Янв. 1, 2023
The
SM2RAIN
(Soil
Moisture
to
Rain)
model
has
been
widely
used
for
rainfall
estimation
worldwide.
However,
due
the
lack
of
sufficient
ground
observation,
driven
by
different
passive
microwave
soil
moisture
products
over
Tibetan
Plateau
not
fully
validated.
In
this
paper,
four
satellite
(including
SMAP,
ASCAT,
SMOS,
and
AMSR2)
were
as
input
data
estimation.
Rainfall
from
eight
observation
stations
during
2016-2018
evaluate
overall
performance
algorithm
under
various
at
time
aggregation
(AGGR)
scales.
addition,
merged
whether
combined
could
improve
model.
Finally,
estimates
with
further
evaluated
compared
two
benchmark
(IMERG
ERA5).
Results
indicate
that:
(1)
Overall,
SM2RAIN-SMAP
highest
accuracy,
but
scale
up
30
days,
mean
R
reach
above
0.8
value
Kling-Gupta
Efficiency
(KGE)
0.8.
(2)
Combined
can
significantly
estimates.
performed
best
when
SMAP
ASCAT
combined.
(3)
Using
product
or
yielded
more
accurate
than
