energy balance closure at wisconsin sites
DESCRIPTION
Energy balance closure at Wisconsin sites. Nan Lu Lees Lab, EEES, University of Toledo March 24, 2006. Energy balance closure. Hs + LE = Rn - G. - S. Rn net radiation Hs sensible heat flux LE latent heat flux G soil heat flux. - PowerPoint PPT PresentationTRANSCRIPT
Energy balance closure at Wisconsin sites
Nan Lu
Lees Lab, EEES, University of Toledo
March 24, 2006
Energy balance closure
Rn net radiation
Hs sensible heat flux
LE latent heat flux
G soil heat flux
Hs + LE = Rn Hs + LE = Rn - G- G
- S- S
S storage heat flux between the soil heat plate surface and the level of the eddy covariance instruments
0
200
400
600
800
0 200 400 600 800
Rn-G-S(W/ m2)
Hs+LE(W/m2)
Energy balance ratio=1Energy balance ratio=1
Storage heat flux subcomponents
Qg soil heat storage between Qg soil heat storage between soil heat plate and soil soil heat plate and soil surfacesurface
Qa air column heat storageQa air column heat storage
Qv biomass heat storageQv biomass heat storage
Qp photosynthetic heat Qp photosynthetic heat componentcomponent
SS = Qg + Qa + Qv = Qg + Qa + Qv + Qp+ Qp
Objectives
1 To evaluate the potential source of differences in the energy balance within and among sites.
3 To evaluate the quality of energy balance closure under a range of conditions in order to identify possible causes for lack of closure in the forest.
2 To examine how much of the energy balance closure is improved by adding each of the subcomponent of storage heat flux.
Study site
Northern part of Chequamegon - Nicolet National Forest in Wisconsin, USA
Site information
Full name Site Code 2002 2003 2004 2005 Age, years GPS coordinates
Mature hardwood MHW ☆ ☆ ☆ 65 46º 38' 05.0'', 91º 05' 55.2''
Mature red pine MRP ☆ ☆ ☆ ☆ 64 46º 44' 21.6'', 91º 09' 58.5''
Pine barrens #1 PB1 ☆ 12 46º 37' 29.6'', 91º 17' 53.6''
Young hardwood clearcut YHW ☆ 3 46º 43' 20.4'', 91º 15' 08.7''
Young red pine YRP ☆ 8 46º 37' 07.6'', 91º 04' 53.2''
Pine barrens #2 PB2 ☆ 2 46º 37' 29.6'', 91º 17' 53.6''
Intermedate hardwood IHW ☆ 17 46º 43' 49.7'', 91º 13' 58.6''
Intermediate red pine IRP ☆ 21 46º 41' 12.8'', 91º 09' 10.2''
Mixed young jack pine MYJP ☆ ~10-15 46º 39' 11.1'', 91º 05' 08.9''
Young jack pine YJP ☆ ☆ ~20 46º 37' 07.6'', 91º 04' 53.2''
Red pine clearcut RPCC ☆ new growth <5, cut >5 46º 38' 56.8'', 91º 04' 09.4''
Mature thinned red pine TRP ☆ 65 46º 45' 14.3'', 91º 03' 50.5''
Methods
Estimated components:
Qg Qa QvQg Qa Qv
Directly-measured components:
Rn, Hs and LE, GRn, Hs and LE, G
Initial data (data during rain time are removed)
Different months in A year
Different times in A dayMorning 7:00 am<=time<=12:30 pm;Afternoon 1:00 pm<=time<=18:30 pm;Evening 19:00 pm <=time<=0:30 am;Midnight 1:00 am <=time<= 6:30 am.
The data where fraction velocity (u*)<ucrit were included and excluded.Values of ucrit are different for different sites
Clear sky and cloudy sky daytimeRn - meanRn> 0 when 7:00 am<=time<=18:30 pm clear sky day time
Definition of “conditions”
Preliminary results
Energy fluxes differences among sites in 2002
PLOT mhw2003_ HS mr p2003_ HS i hw2003_ HS i r p2003_ HS
mhw2003_ HS
- 100
0
100
200
300
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ hf t mr p2003_ hf t i hw2003_ hf t i r p2003_ hf t
mhw2003_ hf t
- 20
- 10
0
10
20
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ Rn mr p2003_ Rn i hw2003_ Rn i r p2003_ Rn
mhw2003_ Rn
- 100
0
100
200
300
400
500
600
700
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ LE mr p2003_ LE i hw2003_ LE i r p2003_ LE
mhw2003_ LE
- 40
- 30
- 20
- 10
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
Rn
Hs
LE
G
PLOT mhw2003_ hf t mr p2003_ hf t i hw2003_ hf t i r p2003_ hf t
mhw2003_ hf t
- 20
- 10
0
10
20
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ hf t mr p2003_ hf t i hw2003_ hf t i r p2003_ hf t
mhw2003_ hf t
- 20
- 10
0
10
20
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ hf t mr p2003_ hf t i hw2003_ hf t i r p2003_ hf t
mhw2003_ hf t
- 20
- 10
0
10
20
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
PLOT mhw2003_ hf t mr p2003_ hf t i hw2003_ hf t i r p2003_ hf t
mhw2003_ hf t
- 20
- 10
0
10
20
sas t i me
0 10000 20000 30000 40000 50000 60000 70000 80000 90000
mont h 3 5 6 7 8 9 10 12
l ehs
- 1000
- 800
- 600
- 400
- 200
0
200
400
600
800
1000
r ng
- 400 - 300 - 200 - 100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200
mont h 3 4 5 6 78 9 10 12
l ehs
- 1000
- 800
- 600
- 400
- 200
0
200
400
600
800
1000
r ng
- 100 0 100 200 300 400 500 600 700 800 900
IHW_2003
R-Square 0.8060Slope 0.6673Inter -8.9054
R-Square 0.6380Slope 0.5309Intercept -1.1968
MHW_2003
Rn-G(W/m2)
Hs+
LE
(W/m
2)
Energy balance closure through a year
Comparison of energy closure among sites using initial data
Site R2 Slope Intercept
ihw2003 0.8060 0.6673 -8.9054
irp2003 0.7212 0.6170 0.9910
mhw2002 0.6405 0.5534 5.9272
mhw2003 0.6380 0.5309 -1.1968
mhw2004 0.5162 0.5944 11.0128
mrp2002 0.7957 0.5780 0.7851
mrp2003 0.8738 0.5565 1.1343
mrp2004 0.7846 0.6016 1.0219
mrp2005 0.7810 0.5535 2.0516
yhw2002 0.4965 0.3781 38.6724
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
900
Rn- G
- 100 0 100 200 300 400 500 600 700 800 900
- 300
- 200
- 100
0
100
200
300
400
500
600
700
Rn- G
- 100 0 100 200 300 400 500 600 700 800
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
900
Rn- G
- 100 0 100 200 300 400 500 600 700 800 900
- 2000
- 1000
0
1000
Rn- G
- 100 0 100 200 300 400 500 600
- 800
- 700
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
Rn- G
- 100 0 100 200 300 400 500 600 700 800
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
Rn- G
- 100 0 100 200 300 400 500 600 700 800
- 700
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
Rn- G
- 100 0 100 200 300 400 500 600 700
- 400
- 300
- 200
- 100
0
100
200
300
400
500
Rn- G
- 100 0 100 200 300 400 500
- 200
- 100
0
100
200
300
Rn- G
- 100 0 100 200 300
Breaking data into months (IHW2003)
MarR2 0.1998S 0.4673Int -6.8146
AprR2 0.7673S 0.5059Int -3.0066
MayR2 0.8657S 0.6555Int 3.6799
JunR2 0.9015S 0.6708Int -3.4106
JulR2 0.8438S 0.7017Int -9.6442
AugR2 0.8986S 0.6703Int -11.7049
SepR2 0.7537S 0.7099Int -10.0250
OctR2 0.8932S 0.7323Int -18.6266
DecR2 0.5242S 0.5815Int -0.8381
Hs
+L
E
Rn_G
Breaking A day by time (IHW2003)
mont h 6 7 8
l ehs
- 200
- 100
0
100
200
300
400
500
600
700
800
r ng
- 100 0 100 200 300 400 500 600 700 800
mont h 6 7 8
l ehs
- 100
0
100
200
300
400
500
600
700
800
900
r ng
0 100 200 300 400 500 600 700 800 900
mont h 6 7 8
l ehs
- 400
- 300
- 200
- 100
0
100
200
r ng
- 100 0 100 200
mont h 6 7 8
l ehs
- 400
- 300
- 200
- 100
0
100
200
r ng
- 100 0 100 200 300
R-Square 0.8166Slope 0.64451Inter -7.58179
R-Square 0.7263Slope 0.64669Inter 26.33762
R-Square 0.1026Slope 0.52481Inter -23.19575
R-Square 0.4604Slope 0.7004Inter 5.17703
Morning Afternoon
Late evening Midnight
Breaking A day by time (Mhw2003)
mont h 6 7 8
l ehs
- 200
- 100
0
100
200
300
400
500
600
700
800
900
r ng
- 100 0 100 200 300 400 500 600 700 800 900 1000
mont h 6 7 8
l ehs
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
r ng
- 200 - 100 0 100 200 300 400 500 600 700 800 900 1000 1100
mont h 6 7 8
l ehs
- 1100
- 1000
- 900
- 800
- 700
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
r ng
- 200 - 100 0 100 200 300 400
mont h 6 7 8
l ehs
- 1300
- 1200
- 1100
- 1000
- 900
- 800
- 700
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
r ng
- 300 - 200 - 100 0 100 200 300 400
R-Square 0.6525Slope 0.5154Intercept -4.9549
R-Square 0.3720Slope 0.4000 Intercept 78.4817
R-Square 0.0023Slope 0.0534Intercept -25.0351
R-Square 0.0425 Slope 0.3238 Intercept -7.7102
mont h 6 7 8
l ehs
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
900
r ng
- 100 0 100 200 300 400 500 600 700 800 900
mont h 6 7 8
l ehs
- 600
- 500
- 400
- 300
- 200
- 100
0
100
200
300
400
500
600
700
800
900
r ng
- 100 0 100 200 300 400 500 600 700 800 900
Ihw2003
R-Square 0.8750 Slope 0.6852Intercept -8.7129
R-Square 0.8783 Slope 0.6820Intercept -8.0230
• mhw2003
0.6864, 0.52639, -4.42957
0.6678 0.53572 -2.92671• mhw2002
0.7400 0.55027 0.57966
0.7171 0.55533 0.92489• Mhw2004
0.6826 0.62029 -8.83475
0.6773 0.62829 -8.46399• irp2003
0.7691 0.61747 -1.41003
0.7405 0.61868 -0.16168
• mrp2002
0.8157 0.56418 1.01026
0.7861 0.56876 0.69437• Mrp2003
0.8719 0.55328 1.03014
0.8555 0.55954 -1.29397• Mrp2004
0.8493 0.61163 -4.40165
0.8387 0.61772 -7.33496• Mrp2005
0.8294 0.54967 3.38856
0.8111 0.55669 0.20877
Comparison of energy closure with u*<ucrit included and excluded
R2, Slope, Intercept
Clear sky vs. cloudy sky time
mont h 6 7 8
l ehs
- 200
- 100
0
100
200
300
400
500
600
700
800
900
r ng
- 100 0 100 200 300 400 500 600 700 800 900
mont h 6 7 8
l ehs
- 200
- 100
0
100
200
300
400
500
600
700
800
r ng
- 100 0 100 200 300 400 500 600 700 800
R-Square 0.7839Slope 0.6783Intercept -1.9221
R-Square 0.7601Slope 0.6550Intercept 5.0714
Cloudy sky
Clear sky
Ihw2003
mhw2003 0.4583 0.4478 34.1210
mhw2002 0.5791 0.5692 -8.3515
Mhw2004 0.6347 0.6372 -11.5435
irp2003 0.6885 0.6616 -27.7009
mrp2002 0.6704 0.5689 2.7484
Mrp2003 0.7820 0.5593 -3.4809
Mrp2004 0.7303 0.6455 -21.7825
Mrp2005 0.7199 0.5673 -13.3668
ClearR2 Slope Intcpt
0.5141 0.4918 31.9535
0.6118 0.5695 -6.0921
0.3886 0.5926 -4.9742
0.6285 0.6234 -2.3322
0.6602 0.5724 -3.0070
0.7412 0.5858 -15.6822
0.6737 0.6145 -11.3552
0.6484 0.5876 -9.9027
Cloudy R2 Slope Intcpt
Comparison of energy closure in cloudy-sky and clear-sky daytime
Preliminary conclusion• Rn, HS, LE and G are different among sites in the same year, and
within sites through years.
• Energy balance closures are different among sites in the same year, and within sites through years.
• Energy balance closure is better in the morning of a day, and in the summer months of a year.
• Energy balance closure is better where u*>ucrit, but the difference is not much.
• Energy balance closure is better when the sky is clear in the daytime, but the difference is not much.
Further analysis
Estimated components:
Ts average soil temperature (K) above the heat flux plates, t is time, Cs is the soil heat capacity
ρ b is the bulk density of soil, csw (4190 J /kg/ K) and csd
(890 J/ kg/ K for clay soils) are the specific heats of the soil water and dry mineral soil . volumetric water content (%)
ρ is the air density, cp is the specific heat of air, zr is the height of the net radiation measurement
Mveg is the mass of vegetation per unit horizontal area, Cveg is a representative specific heat of vegetation Tveg is a representative biomass temperature
Directly-measured components:
Rn, Hs and LE, G
Estimate soil temperature• Ts = exp (k*depth)• K = f (soil water content, thickness of forest duff, accumulative vegetation
cover)
• To estimate the soil temperature of the surface of soil heat plate by using the measurements at 10cm and 30cm depths.
Thank you!