Abstract:
This dataset contains Rayleigh corrected reflectance data from 19 MODIS images collected between April and July 2010, along with their corresponding maps of surface oil volume, maps of relative oil thickness of different classes, and maps of probability distributions of different thicknesses. Surface oil was estimated by spatially scaling up AVIRIS observations to synoptic MODIS measurements, which were the used to derived oil classification and probability maps.
Suggested Citation:
Feng, Lian and Chuanmin Hu. 2017. Remote Sensing Estimation of Surface Oil Volume During the 2010 Deepwater Horizon Oil Blowout in the Gulf of Mexico: Scaling up AVIRIS Observation with MODIS Measurements. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7RJ4GGB
Data Parameters and Units:
This folder contains the MODIS surface oil products for all the golden days between April and July of 2010. This dataset contains five sub-folders. The names and contents of the five sub-folders are: AVIRIS: AVIRIS estimated oil thickness products on 05-17-2010 from USGS. The details of the method can be found in Clark et al (2010). Briefly, the AVIRIS data collected on 17 May, 2010, were processed by the USGS using the ACORN atmospheric correction module. Ground calibration sites were used to produce apparent surface reflectance (R(l), dimensionless). Based on R(l), the USGS used the Tetracorder spectral shape-matching system to derive oil/water mixing ratio, areal fraction coverage, thickness, and oil volume for each AVIRIS pixel containing thick emulsified oil. The continuum-removed absorption feature strength and shapes for multiple absorption features were used by Clark et al. (2010) to determine the oil:water ratio and thickness. The observed level relative to the reference spectra for a specific oil:water ratio and thickness was used to determine fractional coverage using a model with ocean water. The emulsions generated in the USGS laboratory from oil samples collected at the surface of the ocean during the DWH blowout were used to construct the relationships between sample properties (e.g., oil/water mixing ratios, effective oil thickness, oil volume) and reflectance spectral shapes and magnitudes in the Shortwave Infrared (SWIR) bands. The unit of the AVIRIS oil thickness file is mm. Clark, R.N., Swayze, G.A., Leifer, I., Livo, K.E., Kokaly, R., Hoefen, T., Lundeen, S., Eastwood, M., Green, R.O., & Pearson, N. (2010). A method for quantitative mapping of thick oil spills using imaging spectroscopy. US Geological Survey Open-File Report, 1167, 1-51 MODIS_data: Each hdf file contain 16 bands of MODIS Rayleigh corrected reflectance data (with a variable name of CorrRefl_xx, xx=01,02 … 16), the unit of reflectance is dimensionless. The png file associated with each hdf is the corresponding Red-Green-Blue composites. Continuous_thickness: Continuous maps of oil thickness for each date, where the tiffs have concentration data (liters). The png files are the corresponding color stretched maps. The file named “Lengend.PNG” is the legend for the png files. Probability: Oil probability maps for each date, which is defined as the likelihood that oil of a given thickness (Band 1: No data; Band 2: 0 µm; Band 3: >0 - < 1.7 µm; Band 4: 1.7 – 20 µm; Band 5: > 20 µm. The unit is x100%.) will occur in a MODIS pixel. The color stretched probability maps for each thickness classes are under “png” sub-folder. Thickess_classification: The classified oil thickness products, with thickness of >0 but <0.08 µm as sheen (pixel value of 1), 0.8-8 µm as thin (pixel value of 2) and >8 µm (pixel values of 3 and 4) as thick.
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