Abstract:

This dataset includes Moderate Resolution Imaging Spectroradiometer (MODIS), Airborne Visible-InfraRed Imaging Spectrometer (AVIRIS), Landsat and Hyperspectral Imager for the Coastal Ocean (HICO) images used in the paper: Hu, C., Feng, L., Hardy, R. F., & Hochberg, E. J. (2015). Spectral and spatial requirements of remote measurements of pelagic Sargassum macroalgae. Remote Sensing of Environment, 167, 229–246. doi:10.1016/j.rse.2015.05.022, together with the delineated sargassum features. The in situ spectral measurements used as endmembers to simulate the results are also included.

Suggested Citation:

Feng, Lian and Chaunmin Hu. 2017. Sargassum detection using MODIS, AVIRIS, Landsat, and HICO imagery. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7ZS2THF

Publications:

Hu, C., Feng, L., Hardy, R. F., & Hochberg, E. J. (2015). Spectral and spatial requirements of remote measurements of pelagic Sargassum macroalgae. Remote Sensing of Environment, 167, 229–246. doi:10.1016/j.rse.2015.05.022

Purpose:

To determine the optimal band centers and bandwidths required for sargassum detection, and to estimate the spatial detection limit once these spectral requirements are met.

Data Parameters and Units:

1. “T2012183141500.L0_LAC.bz2” is the MODIS Terra file on July 1, 2012, which was used to generate Figure 1 in the corresponding publication. “T2009342150000.L0_LAC.bz2” is the MODIS Terra file on December 8, 2009, which was used to show surface sargassum slicks close to Bermuda (Figure 9) in the corresponding publication. MODIS Terra data can be accessed at https://oceandata.sci.gsfc.nasa.gov/cgi/getfile/T2012183141500.L0_LAC.bz2 and https://oceandata.sci.gsfc.nasa.gov/cgi/getfile/T2009342150000.L0_LAC.bz2 Geographic extents for the MODIS Terra datasets (T2009342150000.L0_LAC, T2012183141500.L0_LAC) a. T2012183141500.L0_LAC: Extent: -63.8366, 31.1434; -39.9601, 27.6724; -45.1888, 9.997; -66.4776, 12.965 b. T2009342150000.L0_LAC: Extent: -74.4966, 48.3555; -44.3253, 44.0149; -52.2678, 26.8328; -76.1668, 30.0763 2. “Spectral.tar” contains the in situ spectral data that are shown in Figure 2 in the corresponding publication. And these data were used as endmembers to simulate the results in Table 2 and Table 3 in the corresponding publication. Below is a list of the data parameters for each directory in this folder: Chl – Lambda (nm), Lo (w sr^-1 nm^-1 m^2), Ls (w sr^-1 nm^-1 m^2)), Downwelling irradiance-Ed+ (w sr^-1 nm^-1 m^2)), Lw (w sr^-1 nm^-1 m^2)), Spectral remote-sensing reflectance-Rrs ((λ), sr^− 1); Oil – Wavelength (nm), Reflectance-T1 (dimensionless), Reflectance-T2 (dimensionless), Reflectance-T3 (dimensionless), Reflectance-T4 (dimensionless), Reflectance-T5 (dimensionless), Reflectance-T6 (dimensionless); Sargassum – Field_spectra.xlsx: Column1 – Wavelength (nm), Shallow water – Rrs ((λ), sr^− 1); S0913AS_reflectance.txt, S0913AW_reflectance.txt: Lambda (nm), Lo (w sr^-1 nm^-1 m^2), Ls (w sr^-1 nm^-1 m^2), Ed+ (w sr^-1 nm^-1 m^2), Lw (w sr^-1 nm^-1 m^2), Rrs ((λ), sr^− 1); Tircho – Armstrong_rrs.txt: Column1 (dimensionless), Column2 (dimensionless); tricho_rrs.txt: Wavelength (nm), Rrs (sr^-1); Ulva – Ulva_reflectance.txt: x - Wavelength (nm), y (dimensionless); Ulva_sample_spectra.xlsx: lambda (nm), Ulva (dimensionless), Water (dimensionless); water_reflectance.txt: x - Wavelength (nm), y (dimensionless); 3. “H2012183122008.L1B_ISS.bz2” is the HICO data on 1 July 2012 (12:20 GMT), which was used to show the spectral features of the surface sargassum slicks in Figure 3 in the corresponding publication. 4. “AVIRIS.tar” contains all the AVIRIS files on May 24th, 2010 that used in the corresponding publication. The AVIRIS data were used to show the spectral features (Figure 4), and the delineated sargassum were compared with that of the Landsat images in Figures 5 -7. Geographic extents for all AVIRIS data and their wavelengths a. f100524t01p00r05rdn_sc01_ref_img_s1 through f100524t01p00r05rdn_sc01_ref_img_s3 i. Extent: -89.40953831, 28.54846751; -92.70168723, 29.59781232; -92.66947009, 29.67883508; -89.37519139 ii. Bands: The wavelength used for RGB image compositions are 0.675401um, 0.560048um and 0.443366 um bands. b. f100524t01p00r06rdn_sc01_ref_img_s1 through f100524t01p00r06rdn_sc01_ref_img_s3 i. Extent: -89.39125991, 28.65850659; -92.44605698, 29.63517067; -92.40878938, 29.72818287; -89.35172555, 28.75053291 ii. Bands: The wavelength used for RGB image compositions are 0.675401um, 0.560048um and 0.443366 um bands. 5. “L71022040_04020100524_fai.TIF” is the Landsat FAI image on May 24th, 2010, which were used to compare the slick features with that of AVIRIS observations Figures 6-7 in the corresponding publication. LANDSAT 7 source imagery can be accessed at https://earthexplorer.usgs.gov/metadata/12267/LE70220402010144EDC00/

Individual Files: