analysis of the surface temperature distribution at badain jaran … · badain jaran desert using...
TRANSCRIPT
Analysis of the surface temperature distribution at Badain Jaran Desert using fully coupled hydro-
thermal method
Haijun Hu, Teodolina Lopez, Yujun Cui, Raphaël Antoine, Ni An, Weikang Song
1. Introduction
Contents
4. Discussion
2. Materials and methods
3. Results
5. Conclusions
Badain Jaran Desert site
Surface Temperature at the site
Nighttime
Daytime
31st August 2008
(MODIS TERRA)
Motivation
Water table depth /m
0.5
…
32
…
165
Surface temperature Ts ?
Meteorological Data
2008/1
/1
2008/2
/1
2008/3
/1
2008/4
/1
2008/5
/1
2008/6
/1
2008/7
/1
2008/8
/1
2008/9
/1
2008/1
0/1
2008/1
1/1
2008/1
2/1
-30
-20
-10
0
10
20
30
40
Date
Air
Tem
pera
ture
(℃
)
2008/1
/1
2008/2
/1
2008/3
/1
2008/4
/1
2008/5
/1
2008/6
/1
2008/7
/1
2008/8
/1
2008/9
/1
2008/1
0/1
2008/1
1/1
2008/1
2/1
0
5
10
DateW
ind s
pee
d (
m/s
)
Air temperature Wind speed
Minqin station
2008/1
/1
2008/2
/1
2008/3
/1
2008/4
/1
2008/5
/1
2008/6
/1
2008/7
/1
2008/8
/1
2008/9
/1
2008/1
0/1
2008/1
1/1
2008/1
2/1
0.0
1.0x10-7
2.0x10-7
3.0x10-7
4.0x10-7
Date
Rai
nfa
ll (
m/s
)
Meteorological Data – Cont’d
Rainfall
2008/1
/1
2008/2
/1
2008/3
/1
2008/4
/1
2008/5
/1
2008/6
/1
2008/7
/1
2008/8
/1
2008/9
/1
2008/1
0/1
2008/1
1/1
2008/1
2/1
0
50
100
Date
Hu
mid
ity
(%
)
2008/1
/1
2008/2
/1
2008/3
/1
2008/4
/1
2008/5
/1
2008/6
/1
2008/7
/1
2008/8
/1
2008/9
/1
2008/1
0/1
2008/1
1/1
2008/1
2/1
0
5
10
15
20
Date
S
unsh
ine
durt
ion (
h)
Humidity Sunshine duration
0.0 0.1 0.2 0.3 0.420
15
10
5
0
The depth to water table
0.7m (Zhou 2015)
5m (Gates et al. 2008)
6m (Gates et al. 2008)
7m (Gates et al. 2008)
16m (Gates et al. 2008)
Volumetric water content (%)
Dep
th (
m)
Gates et al. (2008); Zhou (2015)Ma and Eumunds
(2006)Zhao et al.(2011)
Surface: dry layer 35cm
w<0.5% ≈ 0.01%
Volumetric water content
Dong et al.(2015)
0 30 60 90 120 150 180 210 240 270 300 330 360
-10
0
10
20
30
40
Measured temperature of lake water
Fitted line
DOY
Tem
per
atu
re (
℃)
5 4 sin(DOY/44 ) DOY 44
5 25 sin[(DOY-44)/322 ) 44 DOY 366T
− =
+
Lake water temperature
Fully-coupled numerical method
The governing equation of liquid and vapor water mass flow can be expressed as:
T T l w
TC C K K T K
t t
+ = + +
(A1)
+=
+
TTTT KTK
tC
t
TC
The governing equation of heat flow can be expressed as:
The fully coupled hydro-thermal method developed by Anni et al. (2017)
Initial and boundary conditions(A1)
Initial temperature: 5℃ Initial suction: hydrostatic equilibrium line
Heat &water
transportHeat &water
transport
Top
× ×
Bottom
Bottom boundary condition:(A1)
0 30 60 90 120 150 180 210 240 270 300 330 360
-10
0
10
20
30
40
Measured temperature of lake water
Fitted line
DOY
Tem
per
atu
re (
℃)
5 4 sin(DOY/44 ) DOY 44
5 25 sin[(DOY-44)/322 ) 44 DOY 366T
− =
+
(2) Suction at bottom
(1) Temperature at bottom
φ = 0
(A1)
Heat flux at the top boundary
- + +htop n Eq R H L=LERn H
(A1)
The net solar radiation
SW 0.25 0.5 sa
nR
N
= +
SW SW=
4LW a aT=
4LW s surfT=
The net solar radiation
(A1)
Sensible heat and latent heat
( )a pa s a
a
C T TH
r
−=
1000E v aL L E=
The latent heat
The sensible heat
as
a
p
a
ee
ee
E
E
−
−= 0
( )( )-310
10086400
p aE a bu h= + − Song (2015)
(A1)
Water flux at the top boundary
-( - )wtop a offq E P R=P
Roff
Ea
Hydraulic property(A1)
1 10 100 10000.0
0.1
0.2
0.3
0.4
Arya and Paris(1981) Mearused value
Suction/kPa
Vo
lum
etri
c w
ater
conte
nt
Water retention curve
Parameter value
a(cm) 88.3
θs 0.382
θr 0.0237
n 2.87
ks (m/s) 1.06×10-4
( )=
1 ( )
s rr m
n
a
−+ +
VG model
0.5 1/ 2= [1 (1 ) ]m m
sk k − −
Thermal property
0.330.18+3.61 =
0.0 0.1 0.2 0.3 0.40
1
2
3
4 De Vries method (Wilson,1990)
Chung and Horton(1987) Coté and Konrad (2005) Fited line for Ottawa sand (Zhang et al. 2015)
Volumetric water content
T
her
mal
co
nd
uct
ivit
y
(Wm
-1K
-1)
Heat conductivity
Calculation vs measurement at about 1 m depth
Soil temperature at about 1m depth
0 30 60 90 120 150 180 210 240 270 300 330 360
-40-30-20-10
0102030405060
Ts at depth 1m
Ts at depth 1.1m measured (Hu et al.2015)
Tw
DOY
Tem
per
ature
(℃
)
0 30 60 90 120 150 180 210 240 270 300 330 360
-30-20-10
0102030405060
Temperature at day
Temperature at night
DOY
Tem
per
ature
(℃
)
Calculated and measured temperatures (B1)
Surface temperature difference between different WTB depths
Surface temperature difference for different water table depth (WTD)
0 30 60 90 120 150 180 210 240 270 300 330 360
-10-8-6-4-202468
10 T
s at WTD 32m-T
s at WTD 0.5m
DOY
Tem
per
ature
(℃
)
0 30 60 90 120 150 180 210 240 270 300 330 360
-2
-1
0
1
2
Ts at WTD 165m-T
s at WTD 32m
DOY
Tem
per
atu
re (
℃)
Conclusions
(1) The numerical approach can be used to correctly determine the soil surface
temperature changes with varying water table depth.
(2) The hydraulic and thermal parameters need to be refined to increase the
calculation quality.
(3) Slope direction seems to be important to be accounted for because it can greatly
affect the solar radiation, wind speed etc.