i Detection of Smoke and Dust Aerosols Using Multi-sensor Satellite ...

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CHAPTER 6 VALIDATION OF SMOKE AND DUST AEROSOLS DETECTION WITH MULTI-SENSOR In Chapters three and four, the detection of smoke and dust aerosols is performed by combining MODIS RSB and TEB measurements based on the multi-spectra technique. The detection results are validated roughly with MODIS true color images. Visual validation provides, however, only basic verification. Validating results with the same sensor offers relatively low confidence. The further quantitative validation with other sensors, such as OMI and CALIPSO, is executed in this chapter. 6.1 Validation of Aerosol Detection with OMI OMI onboard EOS AURA is one of key instruments designed for monitoring the ozone and other atmospheric species including aerosols. It is a hyperspectral sensor, observing the solar backscatter radiation in the ultraviolet (UV) and visible spectrum (Ahmad et al., 2003; Levelt et al., 2000). The wavelengths and algorithms used for retrieving OMI aerosol parameters are significantly different from those of MODIS. These differences produce some advantages, such as the high sensitivity of the OMI UV retrieval algorithm to aerosol absorption and the ability to retrieve aerosol information over bright surfaces and clouds (Livingston et al., 2007). Moreover, both AURA and 77
Aqua spacecrafts are operated in the A-train orbit. Therefore, OMI is selected for validating smoke and dust detection derived with MODIS measurements. 6.1.1 OMI sensor OMI was launched successfully on July 15, 2004 onboard Aura. The Aura spacecraft is rotating in a 705 km sun-synchronous polar orbit (98.2 0 inclination angle) with a period of approximate 100 minutes. The local equatorial crossing time is 1:45 p.m. in the ascending mode. The OMI views the Earth with a wide view angle, ±57 0 relative to nadir. The large swath, up to 2600 km in scan direction, enables OMI to achieve almost daily global coverage in 14 orbits. OMI instrument employs hyperspectral imaging in a push-broom, nadir-viewing mode to measure the solar backscatter radiation in the wavelength range from 270 to 500 nm, at a spectral resolution about 0.5 nm (Levelt et al., 2006). OMI instrument characteristics (Ahmad et al., 2003) are given in Table 6.1. Wavelength range Table 6.1: OMI instrument characteristics Item Parameter Visible 365 - 500 nm UV-1 270 to 310 nm UV-2 310 to 365 nm View angle 114 0 (±57 0 ) Swath 2600 km IFOV 3 km, binned to 13 x 24 km 78
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Detection of Smoke and Dust Aerosol
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DEDICATION This is dedicated to my
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TABLE OF CONTENTS Page LIST OF TABL
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LIST OF TABLES Table Page Table 1.1
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Figure 6.2 The UVAI images and the
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VFM Vertical Feature Mask VIS Visib
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are validated not only visually wit
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1.1 Importance of Studying Smoke an
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1.3 Objectives and Scopes The main
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originalities, and discussions of f
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1.6 Principal Results The principle
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CHAPTER 2 REVIEW OF APPROACHES FOR
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cooperatively: the reflectance at 0
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more information about dust charact
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CHAPTER 3 SMOKE AEROSOL DETECTION W
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with a two-side scan mirror which r
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3.1.2 MODIS data The 55 0 scan angl
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Sun Satellite Figure 3.2: Basic rad
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1 0 /2 b ( 0 0, 0; , ) k1 e
Page 39 and 40: 3.2.3 Training data collection Surf
Page 41 and 42: Reflectance Reflectance Response cu
Page 43 and 44: Figure 3.6: The normalized ratio of
Page 45 and 46: all pixels over both land and ocean
Page 47 and 48: NDDI 1 0.8 0.6 0.4 0.2 0 -0.2 Figur
Page 49 and 50: MODIS L1B measurements Pixels over
Page 51 and 52: is clear that most of smoke plumes
Page 53 and 54: a b c b Figure 3.10: Smoke images o
Page 55: 3.4.2 California 2007 fire The 2007
Page 58 and 59: The multi-spectral approach is test
Page 60 and 61: 4.1 Physical Principle of Dust Aero
Page 62 and 63: Aqua 2006 102-04/12 04:15 Terra 200
Page 64 and 65: The dust has a high reflectivity at
Page 66 and 67: 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2
Page 68 and 69: 7 a Dust pixel 0.5 b 6 Cloud pixel
Page 70 and 71: 4.3 Results Three dust events occur
Page 72 and 73: c c Figure 4.6: Dust storm over TAK
Page 74: 4.4 Chapter Summary In this chapter
Page 77 and 78: operated in the A-train orbit with
Page 79 and 80: 5.1.2 CALIPSO measurements and VFM
Page 81 and 82: Altitude (km) 20 15 10 5 UTC: 2006-
Page 83 and 84: After spatial registration, the ove
Page 85 and 86: Figure 5.4(a) The MODIS true color
Page 87 and 88: Altitude (km) BTD (K) 20 15 10 15 4
Page 89: in the same A-train orbit with simi
Page 93 and 94: the Fig. 6.1a. For easy comparison,
Page 95 and 96: esolutions, the number of smoke pix
Page 97 and 98: 6.1.4 Validation of dust monitoring
Page 99 and 100: Figure 6.3 Validation of dust image
Page 101 and 102: eflectance in red band. Therefore,
Page 103 and 104: Altitude (km) 20 15 10 5 UTC: 2006-
Page 105 and 106: image at the same location. The rea
Page 107 and 108: accuracy could be increased further
Page 109 and 110: FPAs and cold FPAs (because of diff
Page 111 and 112: development of future remote sensin
Page 113 and 114: Figure 7.3: SRCA spatial mode retic
Page 115 and 116: 7.1.3.2 Date Source MODIS L1B data
Page 117 and 118: characterization. Only the measurem
Page 119 and 120: these bands, including reflective s
Page 121 and 122: different spectral bands are slight
Page 123 and 124: SZA (Degree) SZA (Degree) 65 60 55
Page 125 and 126: 7.2.1.2 Real Impact on L1B Measurem
Page 127 and 128: 7.2.2.1 Theoretical impact analysis
Page 129 and 130: spatial characterization, the bigge
Page 131 and 132: Difference NDDI with spatial correc
Page 133 and 134: 8.1 Conclusions CHAPTER 8 CONCLUSIO
Page 135 and 136: Based on the detection results, the
Page 137 and 138: 3) Validating aerosol detection qua
Page 139 and 140: REFERENCES Ackerman, S. A., 1989, U
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imagery, Atmospheric Environment, v
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Salomonson, V. V., Privette, J. L.,
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Martinez, A., and Gros, G., 2007-10
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Wang W., Qu, J. J., Liu, Y., Hao, X
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CURRICULUM VITAE Yong Xie is a Ph.D
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