Aerosol Remote Sensing https://sites.google.com/view/remotesensing-nguyenminh/trang-ch%E1%BB%A7/hanoisubsidence

1. Aerosol Remote Sensing
Project
Advisor: Prof. Tang-Huang Lin
Presenter: Minh Nguyen
10/01/2018

2. 2
Aerosol Optical Depth Retrieval:
- Structure Function
- Dispersion Coefficient
01
NDVI Variation04
Calculate Surface Reflectance
(Atmospheric Correction)
03
Methods Comparison02
Outline

3. 3
1. Aerosol Optical Depth Retrieval
High Reflectance Low Reflectance
Aerosol (Atmosphere)
Contrast
Contrast Reduction

4. 4
Window Size 545nm (B1)/Error 645nm (B2)/Error 835nm (B3)/Error
5*5 0.6665/0.15 0.1224/-0.74 0.3552/0.15
7*7 0.7367/0.27 0.4099/-0.13 0.4089/0.32
9*9 0.8051/0.39 0.5057/0.07 0.504/0.63
11*11 0.7373/0.27 0.468/-0.01 0.4457/0.44
13*13 0.5692/-0.02 0.3636/-0.23 0.3206/0.04
15*15 0.7077/0.22 0.4906/0.04 0.4662/0.51
17*17 0.7019/0.21 0.4991/0.06 0.4834/0.57
19*19 0.7285/0.26 0.5754/0.22 0.4711/0.53
21*21 0.7217/0.25 0.5787/0.22 0.4024/0.3
23*23 0.7155/0.24 0.5693/0.2 0.4268/0.38
25*25 0.7249/0.25 0.5882/0.24 0.4416/0.43
27*27 0.6885/0.19 0.5823/0.23 0.4308/0.4
Tab. AOD/Error(x100%) of NCU derived by Structure Function in bands and window sizes.
Structure Function
(SF)

5. 5
Structure Function
(SF)
Fig. AOD derived by Structure Function at different bands and odd window sizes in 2008.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
5*5 7*7 9*9 11*11 13*13 15*15 17*17 19*19 21*21 23*23 25*25 27*27
AODDERIVEDBYSF
WINDOW SIZE (ODD)
AEROSOL OPTICAL DEPTH
545nm (B1) 645nm (B2) 835nm (B3)

6. 6
-100
-50
0
50
100
150
5*5 7*7 9*9 11*11 13*13 15*15 17*17 19*19 21*21 23*23 25*25 27*27
ERROR(%)
WINDOWS SIZE
WINDOW SIZE ERROR
B1 Error B2 Error B3 Error Total Error
Fig. Window Size Error (%) in AOD Retrieval by Structure Function in 2008.
Window Size 11*11 is the most
optimal to retrieve AOD for SF.

7. 7
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
4*4 6*6 8*8 10*10 12*12 14*14 16*16 18*18 20*20 22*22 24*24 26*26
AODVALUE
WINDOW SIZE (EVEN)
AEROSOL OPTICAL DEPTH
545nm (B1) 645nm (B2) 835nm (B3)
Fig. AOD derived by Structure Function at different bands and even window sizes in 2008.

8. 8
Dispersion Coefficient
(DC)Window Size 545nm (B1)/Error 645nm (B2)/Error 835nm (B3)/Error
5*5 0.76084/0.31 0.41308/-0.13 0.05648/-0.82
7*7 0.85398/0.48 0.63633/0.35 0.02507/-0.92
9*9 0.83904/0.45 0.63977/0.35 0.12697/-0.59
11*11 0.81987/0.42 0.62701/0.33 0.18098/-0.41
15*15 0.75274/0.3 0.57787/0.22 0.31893/0.03
17*17 1.06179/0.83 0.76521/0.62 0.29277/-0.05
19*19 1.07586/0.86 0.7551/0.6 0.33116/0.07
21*21 0.78019/0.35 0.63619/0.35 0.27071/-0.12
23*23 0.80537/0.39 0.65869/0.39 0.3309/0.07
25*25 0.81992/0.42 0.67444/0.43 0.36835/0.19
27*27 0.80184/0.39 0.67068/0.42 0.378/0.22
AERONET 0.57893 0.47269 0.3088
Tab. AOD of NCU campus derived by Dispersion Coefficient in bands and window sizes.

9. 9
0
0.2
0.4
0.6
0.8
1
1.2
5*5 7*7 9*9 11*11 15*15 17*17 19*19 21*21 23*23 25*25 27*27
AODDERIVEDBYDC
WINDOW SIZE
AEROSOL OPTICAL DEPTH
545nm (B1) 645nm (B2) 835nm (B3)
Fig. AOD derived by Dispersion Coefficient at different bands and odd window sizes in 2008.
Dispersion Coefficient
(DC)

10. 10
-150
-100
-50
0
50
100
150
200
5*5 7*7 9*9 11*11 15*15 17*17 19*19 21*21 23*23 25*25 27*27
ERROR()%
WINDOW SIZE
WINDOW SIZE ERROR
B1 Error B2 Error B3 Error Total Error
Fig. Window Size Error (%) in AOD Retrieval by Dispersion Coefficient in 2008.
Window Size 15*15 is the most
optimal to retrieve AOD for DC.
0
0.5
1
0 10 20 30
B1Error
Window Size
Relationship between Window Size
and Windows Size Error
Corr: 0.087

11. 11
2. Comparison DC
vs SF
Window Size B1 Error by SF B1 Error by DC
5*5 0.15 0.31
7*7 0.27 0.48
9*9 0.39 0.45
11*11 0.27 0.42
15*15 0.02 0.3
17*17 0.22 0.83
19*19 0.21 0.86
21*21 0.26 0.35
23*23 0.25 0.39
25*25 0.24 0.42
27*27 0.25 0.39
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
5*5 7*7 9*9 11*11 15*15 17*17 19*19 21*21 23*23 25*25 27*27
AOD B1 Error
Error by SF Error by DC
- The blurring effects due to the scattering.
- Assuming ground reflectance to be constant, variations of signal due to atmospheric error.
- Neglected multiple ground-atmosphere interactions.
- A reference image acquired under clear atmospheric conditions.
- After correction for solar and observation angle variations.

12. 12
3. Calculate Surface Reflectance (Atmospheric Correction)
< 0.5

13. 13
< 0.4

14. 14
< 0.6

15. 15
4. NDVIVariation

16. 16

17. 17
Conclusion
- Aerosol plays a vital role in Earth system that why aerosol measurement and observation are necessary. Structure
Function and Dispersion Coefficient based on contrast reduction are available to retrieve Aerosol Optical Depth (AOD).
The experiments reveal a better performance of Structure Function due to its methodology consider a higher level of
contrast variation in satellite imagery.
- Atmospheric correction (to various components and AOD is one of them) provides corrected surface reflectance which
determines the accuracy for applications accounting on ground albedo such as NDVI.
- The magnitude of the blurring effect depends on the atmospheric characteristics and particularly on the aerosol optical
thickness, phase function, and vertical profile.

18. www.websitename.com 18
Reference
Tanre, D., Deschamps, P. Y., Devaux, C., & Herman, M. (1988). Estimation of Saharan aerosol optical thickness from
blurring effects in Thematic Mapper data. Journal of Geophysical Research: Atmospheres, 93(D12), 15955-15964.
Sifakis, Nicolas, and Pierre-Yves Deschamps. "Mapping of Air Pollution Using SPOT Satellite." Photogrammetric
Engineering & Remote Sensing 5 (1992): 4.
http://gisgeography.com/ndvi-normalized-difference-vegetation-index/