Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua Ocean Color Products Robert Arnone...
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Transcript of Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua Ocean Color Products Robert Arnone...
Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua
Ocean Color Products
Robert Arnone(1), Sherwin Ladner(2), Giulietta Fargion(3), Paul Martinolich (4), Ryan Vandermeullen (1), Jennifer Bowers(3), Adam Lawson(2)
1 University of Southern Mississippi, Stennis Space Center, MS.
2 Naval Reserach laboratory, Stennis Space Center MS. 3 San Diego State University, San Diego, CA.4 QinetiQ Corp, Stennis Space Center, MS.
SPIE – Baltimore - April 2013
Monitoring ocean Processes Uncertainty in Ocean products
Objective –
How rapidly do bio-optical processes change and “Can they be detected using ocean color? “
How do these “ color” changes affect Calibration and Validation Procedures? ---------------------------------------------------Evaluate changes from satellite retrieved bio-optical products Assess sensor and processing characteristics that impact hourly changes
Assess the satellite retrieved products uncertainty .
- Short term variability – (Hours) - Assumption is satellite is looking at Same ocean color water ..
- Uncertainty associated with Inter-comparison of sensors (MODIS / VIIRS)
What must we consider in evaluating time change of bio-optical processes ? 1) Water mass advection and physical processes
2) Ocean Color Changes from bio-optical changes -Biological Changes - Growth / decay particle resuspension,
3) Sensor and processes calibration, characterization , angular affects , BRDF, Atmosperhc correction etc . Half Angle Mirror (HAM) left and right side.
Ocean Color products Uncertainty MODIS – VIIRS
Optimum “tracking” is to use the “same” sensor, for assessing changes. Such as - Geostationary Satellite (example – GOCI)
0 800 1600 2400 3200
Pixel
Sensor Zenith degrees 70 35 0 35 70
-70 56
42 28
14
S-NPP - Daily Orbital Overlap at ~ 30 degree latitude ~ 700 pixel Overlap - Very Similar Solar Zenith ~ 40 degrees.
3 Overlapping ocean Color Products with 110 minutes !
MODIS – Aqua 18:45
Approach- - Sequential orbits from MODIS and S-NPP – VIIRS
S-NPP Left Side of Scan 18: 15
S-NPPRight Side of Scan 19:56
Nov1, 2012
Processed using L2gen Examine the “nLw445” and “ nLw555” and Chlorophyll (OC2)
ratio (445/555) (488/555)
S- Npp 306.1101.195623S- NPP 306.1101.181524
MODIS 306 18:45
18:15 - NPP18:45 – MODIS 19:56 –NPP
Line 1- Plumes
Line 2 – WavCis
WavCis -90 29’ 28 52’
Transect #2- - Wide range of water “type”
Open and Coastal - East West Angle dependence - Transect through Aeronet – SeaPrism Site
-Cloud Development And formation
18:15 - NPP18:45 – MODIS 19:56 –NPP
Line 1- Plumes
Line 2 – WavCis
South Pass
WaveCis
cloud
18:15 - NPP18:45 – MODIS 19:56 –NPP
Line 1- Plumes
Line 2 – WavCis
South Pass
WaveCis
cloud
Wavcis -90 29’ 28 52’
Line
4
Offs
hore
55
Aqua 1845
NPP 19:55 Eastern Side
NPP 18:15 Western Side
Aeronet
Along Line 2 transect - NPP and MODIS variations of radiance with 110 minutes
Sensor Zenith Angle variations
0 0.5 1 1.5 2 2.50
0.5
1
1.5
2
2.5f(x) = 1.04970726488793 xR² = 0.982119859455613Nov 1, 2012 nLw 551
nLw 551
nLw (uw/cm2/nm ) 18:15 GMT
nLw
(uW
/cm
2/nm
) 19
:55
GM
T 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6f(x) = 1.37960412416426 xR² = 0.93891301960804
Nov 1, 2012 nLw 443
nLw 443Linear (nLw 443)
nLw (uw/cm2/nm ) 18:15 GMT nL
w (u
W/c
m2/
nm)
19:5
5 G
MT
Variation Sequential along the Transect NPP- Orbits How does the 110 minutes Difference changes affects Open and coastal waters - - High scatter at 443 - 19:55 Bias Higher
-
Low scatter at 551
How impacts Chlorophyll Product?
1:1
1:1
0 1 2 3 4 5 6 70
1
2
3
4
5
6
7
f(x) = 0.774082026150703 xR² = 0.968844775027985
Nov 1, 2012 Chlorophyll
chlorophyll
Chlorophyll (mg/m3) 18:15 GMT
Chlo
roph
yll (
mg/
m3)
19:
55 G
MT 1:1
NPP Chlorophyll variation with 110 minutes along transect
Note linear Chlorophyll scale . 18:15 orbit – lower chlorophyll at high concentrations /
This results address the “Product Uncertainty” with 110 minutes with same sensor. Differences results from a) Biological Processes, b) water mass advection or c) Sensor processing
Impact of Sensor Zenith Angle of ocean color retrievals NPP 18:15 – 1955 difference along the Transect Line
nLw 555
Aeronet
Impact of Sensor Zenith Angle of ocean color retrievals NPP 18:15 – 1955 difference along the Transect Line
nLw 445
Aeronet
Impact of Sensor Zenith Angle of ocean color retrievalsNPP 18:15 – 1955 difference along the Transect Line
19:55 110 minute
Chlorophyll Bloom ?
Evaluation of the Atmosphere Correction on sequential NPP products
NPP 18:15 – 1955 difference along the Transect Line
Lt(l) = Lr(l) + La(l) + Lu(l)
La 865 used for determining Aerosol Model and Epsilon (spectral La(l) )
Evaluation of the Atmosphere Correction on sequential retrievals NPP 18:15 – 1955 difference along the Transect Line
Lt(l) = Lr(l) + La(l) + Lu(l)
La 865 used for determining Aerosol Model and Epsilon (spectral La(l)
Aerosol model pair used NPP 18:15 used 35-36, 34 – 35 ) , Modis used 35- 36. NPP 19: 56 used 32-33 and 33-34
All very Similar .
Changes in ocean color products over short time scales
-Examined changes of the Spectral Channels 443 – 555 - Examined difference in Open and coastal water - Examined angular differences within NPP - Examine the Atmosphere channels – correction .
Examples of changes in short scale chlorophyll retrievals from MODIS and NPP
20: 16 NPP21: 22 MODIS22:27 NPP
Southern California Current June 25 , 2012
121 – Minutes 20: 16 NPP 21: 22 MODIS 22:27 NPP
Changes in ocean color products over short time scales
Figure 8 - Southern California Chlorophyll Sequence within 111 minutes derived from S-NPP and MODIS from June 25, 2012 from 20:16 – 22:27 GMT . The lower “zoomed in” panels showpossible bio-optical changes from upwelling and advective changes along the coasts.
20: 16 S- NPP 21: 22 MODIS 22:27 S- NPP
A
B
A
BMonterey Bay
C C
20: 16 S- NPP21: 22 MODIS22:27 S- NPP
Monterey Bay
Changes in Satellite retrievals Chlorophyll with 121 minutes
A
B
Gulf Stream Florida Coast
Sequential NPP Orbits
101 Minutes
17:37 GMT 19:18
17:3719:18
Florida
17:37
17:37
19:18
AA
BB
C C
Gulf Stream
A.
B.
Figure 9- a) November 3, 2012, NPP Chlorophyll products along the North Wall of the Gulf Stream off of Florida from 17:37 and 19:18 GMT b) Enlarged area along the chlorophyll from at changes at different locations.
SUMMARY: Monitoring Bio-Optical Processes Using NPP-VIIRS And MODIS-Aqua Ocean Color Products
1) Sequential Orbits of NPP and MODIS within the same day were used to evaluate Ocean Color Products for monitoring changes in bio-optical processes.
2) Explored variability of bio-optical products within approximately 100 minutes
3) Evaluated capability of ocean color to monitoring short scales bio-optical processes. Examined : 1. Water mass advection and bio-optical processes 2. Examined uncertainty possibly resulting from sensor characteristics and
ocean color processing .
Demonstrated sequential satellite orbits can establish the satellite products uncertainty for calibration / validation.
Demonstrated ocean color capability to characterize the bio-optical processes by using overlapping orbits and multiple satellites.
SPIE – Baltimore 2013
Questions?
Acknowledgements:
Thanks is given to the NOAA JPSS program for funding support
19:31- NPP
17:50 – NPP
Nov 1 - 18:15 Sensor Zenith 19:56
Solar Zenith – Very Simialr
66 52 52 56
Day 308 19:18 33 Nov 3 , 2013
308. 1103. 173733
Mosaic
#2 South East US –
Nov 3 Mosaic
2 scenes from 1737Can use the 2 boxes to extract .
# 4 Feb 17, 2012 -- Have additional slides .Northern Gulf of Mexico VIIRS and MODIS2 areas . Sequential orbits
2013 048 0217 -1750 2013 048 0217 1931 18
101 minutes
MODIS