Geoscience Reference
In-Depth Information
20
CHAPTER
Area and Positional Accuracy of DMSP
Nighttime Lights Data
Christopher D. Elvidge, Jeffrey Safran, Ingrid L. Nelson, Benjamin T. Tuttle,
Vinita Ruth Hobson, Kimberly E. Baugh, John B. Dietz, and Edward H. Erwin
CONTENTS
20.1
Introduction...........................................................................................................................281
20.2
Methods ................................................................................................................................283
20.2.1 Modeling a Smoothed OLS Pixel Footprint ............................................................283
20.2.2 OLS Data Preparation ..............................................................................................284
20.2.3 Target Selection and Measurement ..........................................................................285
20.3
Results...................................................................................................................................286
20.3.1 Geolocation Accuracy ..............................................................................................286
20.3.2 Comparison of OLS Lighting Areas and ETM
Areas............................................288
20.3.3 Multiplicity of OLS Light Detections......................................................................288
20.4 Conclusions...........................................................................................................................289
20.5 Summary...............................................................................................................................291
Acknowledgments ..........................................................................................................................291
References ......................................................................................................................................291
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20.1 INTRODUCTION
oscillating scan radiometer designed for cloud
imaging with two spectral bands (visible and thermal) and a swath of approximately 3000 km. The
OLS is the primary imager flown on the polar orbiting Defense Meteorological Satellite Program
(DMSP) satellites. The OLS nighttime visible band straddles the visible and near-infrared (NIR)
portion of the spectrum from 0.5-0.9 µm and has six-bit quantitization, with digital numbers (DNs)
ranging from 0 to 63. The thermal band has eight-bit quantitization and a broad band-pass from
10-12 µm. The wide swath widths provide for global coverage four times a day: dawn, daytime,
dusk, and nighttime. DMSP platforms are stabilized using four gyroscopes (three-axis stabilization)
and platform orientation is adjusted using a star mapper, Earth limb sensor, and a solar detector.
At night the OLS visible band is intensified using a photomultiplier tube (PMT), enabling the
detection of clouds illuminated by moonlight. With sunlight eliminated, the light intensification results
in a unique data set in which city lights, gas flares, lightning-illuminated clouds, and fires can be
The Operational Linescan System (OLS)
is an
281
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