Post-Calibration of Fluorescence Data from Continuous Monitors (To adjust or not to adjust, and if...
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Post-Calibration of Fluorescence Data from Continuous Monitors (To adjust or not to adjust, and if so, how?) A “Gang of N” Production Elgin Perry - Statistics Consultant Marcia Olson - NOAA/CBP Beth Ebersole - MD DNR Bill Romano - MD DNR Presented to the Tidal Monitoring and Analysis Workgroup on 3 December 2003
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Transcript of Post-Calibration of Fluorescence Data from Continuous Monitors (To adjust or not to adjust, and if...
Post-Calibration of Fluorescence Data from Continuous Monitors(To adjust or not to adjust, and if
so, how?)
A “Gang of N” Production
Elgin Perry - Statistics Consultant
Marcia Olson - NOAA/CBP
Beth Ebersole - MD DNR
Bill Romano - MD DNR
Presented to the Tidal Monitoring and Analysis Workgroup on 3 December 2003
Comparison of PAR, Sensor, and Extractive Chlorophyll Data
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10
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60
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80
90
2 March - 20 March 2001
Chl
orop
hyll-
a (u
g/l)
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200
400
600
800
1000
1200
1400
PA
R
Chl a - sensor
Chl a - extraction
PAR
(Kim Mikita’s data)
Tidal cycle
Diel cycle
log(x/y)=log x - log y
LNRAT = LNCHL_F – LNCHL_A
Model Evaluated
• Season
• Sonde deployed
• Light
• Turbidity
Log ratio as a function of:
Station
Signed-rank Test Season Sonde Light Turbidity
Turville Creek P<0.0001 NS NS NS NS
Bishopville NS NS NS NS NS
Shelltown 0.0042 NS NS NS NS
CHWS NS NS NS NS NS
Rehobeth 0.0008 NS NS NS NS
Chicamacomico NS 0.0135 0.0045 NS NS
Ben Oaks NS NS 0.0020 NS NS
Sherwood 0.0425 0.0316 NS 0.0276 NS
Whitehurst NS NS NS NS NS
Stonington NS NS NS NS NS
Model Results
At higher light levels, extractive samples exceed fluorescence data?
Fluorescence exceeds extractive at all light levels, so no light effect.
Fluorescence exceeds extractive under all light levels, so no light effect.
Similar pattern to Turville Creek and Shelltown.
Chlorophyll Adjustment Methods
• Regression method – CF(adj) = ß0 + ß1CF
(Model CS = CF)
• Multiple regression – CF(adj) = ß0 + ß1CF + ß2Turb
(Model CS = CF, Turbidity)
• Ratio method – CF(adj) = CF x (CS/CF)
• Subtract “background fluorescence”
Linear Regression Assumptions
• Y is linearly related to X• Expected value of the error term is zero• Constant variance in the error terms, which
are uncorrelated• Independent variable(s) is measured
without error• Independent variables are not linearly
related
Observation Station In Vivo DateTime Extractive Ratio of CS:CF
1 TURVILLE 45.3 02MAY2002:13:00:00 10.66 0.2353200882 TURVILLE 59 09MAY2002:12:00:00 38.53 0.6530508473 TURVILLE 74 16MAY2002:11:00:00 44.66 0.603513514
4 TURVILLE 21.8 23MAY2002:11:30:00 18.01 0.8261467895 TURVILLE 88 30MAY2002:11:45:00 192.14 2.183409091
6 TURVILLE 43 06JUN2002:14:30:00 37.72 0.8772093027 TURVILLE 68.2 13JUN2002:12:30:00 46.67 0.684310858 TURVILLE 44 20JUN2002:13:30:00 40.72 0.925454545
9 TURVILLE 103.3 25JUN2002:10:00:00 67.57 0.6541142310 TURVILLE 69.5 01JUL2002:11:30:00 68.44 0.984748201
11 TURVILLE 54.7 10JUL2002:12:00:00 52.82 0.96563071312 TURVILLE 36.4 17JUL2002:11:30:00 21.65 0.5947802213 TURVILLE 61.6 23JUL2002:11:15:00 38.79 0.629707792
14 TURVILLE 60.6 31JUL2002:10:30:00 34.64 0.57161716215 TURVILLE 56.2 07AUG2002:11:15:00 46.87 0.83398576516 TURVILLE 47.9 15AUG2002:08:15:00 35.19 0.734655532
17 TURVILLE 78.3 21AUG2002:10:15:00 55.24 0.70549169918 TURVILLE 58 28AUG2002:10:00:00 46.69 0.805
19 TURVILLE 34.1 05SEP2002:11:00:00 29.9 0.87683284520 TURVILLE 28.1 11SEP2002:10:45:00 27.27 0.97046263321 TURVILLE 38.9 19SEP2002:11:15:00 20.98 0.53933162
22 TURVILLE 36.1 25SEP2002:10:45:00 32.23 0.89279778423 TURVILLE 30.7 02OCT2002:11:15:00 22.65 0.737785016
24 TURVILLE 20.7 09OCT2002:12:30:00 14.56 0.70338164325 TURVILLE 17 16OCT2002:12:30:00 11.91 0.70058823526 TURVILLE 48.4 23OCT2002:10:15:00 32.18 0.664876033
27 TURVILLE 48 30OCT2002:10:45:00 23.6 0.491666667Average Ratio 0.779476623
Correction Using Ratio of Extractive to In Vivo
Conclusions
• Stop collecting data• Full speed ahead (one size fits all)• Test various models and select one that minimizes
root mean square error on a per station basis• Hire an expert to assess covariate measurement
error problem• Log transform for correction and then back
transform
Whitehurst Fluorescence and Chlorophyll Data for 2002
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70
80
May Jun Jul Aug Sep Oct
CH
LA
(u
g/L
)
ExtractiveNighttimeAveMatchedTime
Drawbridge Fluorescence and Chlorophyll Data for 2002
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60
80
100
120
140
160
180
May Jun Jul Aug Sep Oct
Ch
loro
ph
yll
(ug
/L)
Extractive
NighttimeAve
MatchedTime
Shelltown Fluorescence and Chlorophyll Data for 2002
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10
20
30
40
50
60
Jul Aug Sep Oct
CH
LA
(u
g/L
)
ExtractiveNighttimeAveMatchedTime
Rehobeth Fluorescence and Chlorophyll Data for 2002
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5
10
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May Jun Jul Aug Sep Oct
CH
LA
(u
g/L
)
ExtractiveNighttimeAveMatchedTime
Sherwood Fluorescence and Chlorophyll Data for 2002
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70
May Jun Jul Aug Sep Oct
CH
LA
(u
g/L
)
ExtractiveNighttimeAveMatchedTime
