wei xiao, xuhui lee, jingming chen shoudong liu, wei wangwei xiao, xuhui lee, jingming chen shoudong...
TRANSCRIPT
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGY
Eddy Covariance measurement on Lake Taihu
Wei Xiao, Xuhui Lee, Jingming ChenShoudong Liu, Wei Wang
Motivation of the research
• As a big shallow lake (~2m depth & ~2460 km2), Lake Taihu should have significant effect on regional weather processes and climate change.
• The surface parameterization in weather forecasting model was not validated due to the lack of detailed measurement.
• Algae bloom is a big environmental problem for Lake Taihu and the basin, but the meteorological and ecological mechanisms controlling the algae bloom were not clearly identified.
• As a powerful tool in land ecosystem research, only a few papers reports the use of eddy covariance method in lake ecosystem.
History meteorology in the Taihu Basin
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 201015
15.5
16
16.5
17
17.5
18
Year
Air
tem
pera
ture
at 2
m, d
eg C
58358Dongshan
31.04N,120.2 6E
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20102.8
3
3.2
3.4
3.6
3.8
4
4.2
4.4
Year
Win
d sp
eed,
m s
-2
58358 Dongshan
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 20100
200
400
600
800
1000
1200
1400
1600
1800
Year
Pre
cipi
tatio
n, m
m
58358 Dongshan Temperature increased and wind speed decreased in the past 50 years.
Similar trends were found in almost all the land meteorology site.
Buoy
Eddy covarince
In-lake platform
Microwave radar/Lidar
Surface Met station
Ship-borne isotopemeasurement
Helicopter profiling
Automated surface station
Buoy
Eddy covariance system
Microwave radar/lidar
Helicopter Profiling Ship-borne isotope measurement
Data Center
NUIST & other collaborators
Suzhou Met Bureau
In-lake platform
Our Experimental Site
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGY
EC
microclimate
raingaugedataloggerAC
water temp
EC and microclimate measurement at Taihu site
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGYEC installation
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGY
EC system
south
southeast
3.57m
EC system
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGY
Microclimate system
Total radiation
Temp and humidity
Wind speed and direction
Solar power
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGYWater temp
NANJING UNIVERSITY OF INFORMATION SICENCE & TECHNOLOGY
Water surface
20cm100cm
50cm
Water temp
Wind direction
160 180 200 220 240 260 280 300 320 3400
50
100
150
200
250
300
350
DOY of 2010
Win
d di
rect
ion,
deg
Good fetch: wind direction 90~270o, 48%
Energy budget
0 4 8 12 16 20 240
20
40
60
80
100
120
140
160
180
200
Time (hour)
Late
nt h
eat f
lux,
W m
-2
JuneJulyAugustSeptemberOctoberNovember
0 4 8 12 16 20 24-5
0
5
10
15
20
25
30
35
40
45
Time (hour)
Sen
sibl
e he
at fl
ux, W
m-2
JuneJulyAugustSeptemberOctoberNovember
June 0.25July 0.19August 0.17September 0.30October 0.17November 0.18
Monthly Bowen ratio
Lake-land CO2 exchange
0 4 8 12 16 20 24-0.2
-0.1
0
0.1
Time (hour)
Net
CO
2 exc
hang
e, m
g m
-2 s
-1
JuneJulyAugustSeptemberOctoberNovember
229 230 231 232 233 234 235 236 237-0.2
-0.15
-0.1
-0.05
0
DOY of 2010
NE
E, m
g m
-2 s
-1
Solar angle and cloudiness are the main drivers of abledo variations. We need to identify the effect of water quality on water suface albedo.
Water albedo
-10 0 10 20 30 40 50 60 70 80 900
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Solar elevation angle, rad
Alb
edo
JuneJulyAugustSeptemberOctoberNovemberHenderson-sellers Simulation
223 224 225 226 227 228 229 230 231 232 23329
30
31
32
33
34
35
36
DOY of 2010
Tem
pera
ture
, deg
C
20cm depth50cm depth100cm depth150cm depthLake bottom
160 180 200 220 240 260 28020
22
24
26
28
30
32
34
DOY of 2010
Wat
er te
mpe
ratu
re, d
eg C
Water temperature
164 166 168 170 172 174 176 178
22
24
26
28
30
32
Wat
er te
mpe
ratu
re, d
eg C
184 186 188 190 192 194 196 198
22
24
26
28
30
32
DOY of 2010
Wat
er te
mpe
ratu
re, d
eg C
100cm depth50cm depth20cm depth
Net radiation siteNet radiation site