Abstract:

These data have been collected by NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument, and the Visible Infrared Imager Radiometer Suite (VIIRS) satellite instrument, as part of their regular sampling. The data is composed of MODIS sea surface temperature imagery, as well as Red-Green-Blue (RGB) and enhanced RGB (ERGB) images from the MODIS and VIIRS instruments. The RGB and ERGB images were processed by the University of South Florida Optical Oceanography laboratory. The imagery was sampled over the Louisiana Bight in the Gulf of Mexico on 2017-05-02. This dataset supports the publication: Solodoch, A., Molemaker, J. M., Srinivasan, K., Berta, M., Marie, L., & Jagannathan, A. (2020). Observations of Shoaling Density Current Regime Changes in Internal Wave Interactions. Journal of Physical Oceanography, 50(6), 1733–1751. doi:10.1175/jpo-d-19-0176.1

Suggested Citation:

Solodoch, Aviv, Jeroen Molemaker and Chuanmin Hu. 2021. Dataset for: Observations of Shoaling Density Current Regime Changes in Internal Wave Interactions. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/QXFRAZKS

Publications:

Solodoch, A., Molemaker, J. M., Srinivasan, K., Berta, M., Marie, L., & Jagannathan, A. (2020). Observations of Shoaling Density Current Regime Changes in Internal Wave Interactions. Journal of Physical Oceanography, 50(6), 1733–1751. doi:10.1175/jpo-d-19-0176.1

Purpose:

To identify a Mississippi plume front, characterize it, and its propagation across the bight.

Data Parameters and Units:

1. Red-Green-Blue images at 469 nm (B), 555 nm (G), and 645 nm (R). [Unitless]. Variable name: RGB. 2. Enhanced Red-Green-Blue composite images at 443 nm (B), 488 nm (G), and 547 nm (R). [Unitless]. Variable name: ERGB. 3. Sea surface temperature image [degrees Celsius] captured in the MODIS 4 um channel. Variable name: sst4. 4. Sea surface temperature variable quality level [0-5]. Numeric value meanings are described in: https://oceancolor.gsfc.nasa.gov/atbd/sst4/. Variable name: qual_sst4. 5. longitude [degrees]. Variable name: lon. 6. latitude [degrees]. Variable name: lat. Each of the variables 1-3 appears in a different .mat file, with the naming convention: Date_Time_Instrument_Variable. Here "Date" is the date of the satellite overpass, in the format: YYYYMMDD. In all cases, it is 20170502 (May 2nd, 2017). "Time" is the UTC time of day of the satellite overpass. "Instrument" is the satellite instrument used to capture the imagery, i.e., MODIS Aqua (MODISA), MODIS Terra (MODIST), or VIIRS. "Variable" is the variable name, i.e., RGB, ERGB, or SST4. Variable 4 (qual_sst4) appears in the same file as the sst4 variable. Variables 5&6 (lon & lat) appear in each of the files; they are identical between the RGB and ERGB files, but the grid variables lon and lat are different in the SST4 file.

Methods:

The Red-Green-Blue (RGB) composite image was generated by the University of South Florida Optical Oceanography laboratory (https://optics.marine.usf.edu/) using the SeaDAS software (credit: the SeaDAS team; https://seadas.gsfc.nasa.gov/), from normalized water-leaving radiance measured by the MODIS TERRA satellite instrument channels at 645 nm (Red); 555 nm (Green), and 469 nm (Blue). The calibrated radiance was first converted to reflectance and then corrected for atmospheric absorption and scattering effects using SeaDAS. The resulting reflectance in the three bands is then stretched to the range 0-255. Enhanced RGB (ERGB) images were also generated by the University of South Florida Optical Oceanography laboratory using the SeaDAS software, from normalized water-leaving radiance satellite instrument (MODIS AQUA/TERRA or VIIRS) channels at 547 nm (R), 488 nm (G), and 443 nm (B). The RGB and ERGB images were mapped to a cylindrical equidistant projection at 250-meter resolution (source: https://optics.marine.usf.edu/cgi-bin/optics_data?roi=MRIVER¤t=1). The Sea surface temperature (SST) image was downloaded from the JPL product: "MODIS Aqua Level 3 SST MID-IR Daily 4km Nighttime V2019.0". The data product is available on JPL's archive, PODAAC, at the following URL: https://podaac.jpl.nasa.gov/dataset/MODIS_AQUA_L3_SST_MID-IR_DAILY_4KM_NIGHTTIME_V2019.0?ids=&values=&search=%22V2019.0%22 Full documentation of the data processing methods and of quality control variables for the product is available from JPL as well: https://podaac.jpl.nasa.gov/dataset/MODIS_AQUA_L3_SST_MID-IR_DAILY_4KM_NIGHTTIME_V2019.0?. Note that in the (Solodoch et al 2020) paper a previous JPL SST product was used, MODIS Aqua Level 3 SST MID-IR Daily 4km Nighttime V2014.0. The former product is not supported or available anymore in PODAAC, and hence the new product is used here. Differences between the products in this specific date and positions are found to be minor. All variables were limited, relative to their original spatial extent, to the area analyzed in the (Solodoch et al 2020) paper: (28.6N-29.3N), (-90.1E)-(-89.4E). The full (larger) spatial extent of the SST4 variable is obtainable through "Data Access" tab in the data product link given above, e.g., from https://podaac-opendap.jpl.nasa.gov/opendap/allData/modis/L3/aqua/4um/v2019.0/4km/daily/2017/122/contents.html The full spatial extent of the RGB and ERGB variables processed by the University of South Florida Optical Oceanography laboratory website (URL is given above).

Individual Files: