Ocean Data from Moderate Resolution Imaging Spectroradiometer (MODIS)
MODIS (or Moderate Resolution Imaging Spectroradiometer) is a key instrument aboard the Terra (originally known as EOS AM-1) and Aqua (originally known as EOS PM-1) satellites. Terra's orbit around the Earth is timed so that it passes from north to south across the equator in the morning, while Aqua passes south to north over the equator in the afternoon. Terra MODIS and Aqua MODIS are viewing the entire Earth's surface every 1 to 2 days, acquiring data in 36 spectral bands, or groups of wavelengths (see MODIS Technical Specifications). These data will improve our understanding of global dynamics and processes occurring on the land, in the oceans, and in the lower atmosphere. MODIS is playing a vital role in the development of validated, global, interactive Earth system models able to predict global change accurately enough to assist policy makers in making sound decisions concerning the protection of our environment. Terra NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): MODIS-Terra Ocean Color Data; NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group. http://dx.doi.org/10.5067/TERRA/MODIS_OC.2014.0 Accessed on 07/28/2015. Aqua NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group; (2014): MODIS-Aqua Ocean Color Data; NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group. http://dx.doi.org/10.5067/AQUA/MODIS_OC.2014.0 Accessed on 07/28/2015.
Secretariat of the Pacific Regional Environment Programme
This dataset contains rasters and a metadata file for global mean monthly sea surface temperature (°C) from 2010-2019. Rasters are in WGS84 coordinate system (EPSG 4326). Sea surface temperature is the temperature of the top millimeter of the ocean's surface. Sea surface temperatures influence weather, including hurricanes, as well as plant and animal life in the ocean. Like Earth's land surface, sea surface temperatures are warmer near the equator and colder near the poles. Currents like giant rivers move warm and cold water around the world's oceans. Some of these currents flow on the surface, and they are obvious in sea surface temperature images. Warm ocean waters help form clouds and affect weather patterns. The sea's surface temperature is also correlated to the availability of tiny ocean plants, called phytoplankton. For all of these reasons scientists monitor the sea's surface temperature. These maps show satellite measurements of the sea's surface temperature for a given day, or for a span of days. NASA standard processing and distribution of the Sea Surface Temperature (SST) products from the MODIS sensors is now performed using software developed by the Ocean Biology Processing Group (OBPG). The OBPG generates Level-2 SST products using the Multi-Sensor Level-1 to Level-2 software (l2gen), which is the same software used to generate MODIS ocean color products. The SST algorithm and quality assessment logic are the responsibility of the MODIS Science Team Leads for SST (currently P. Minnett and R. Evans of the Rosenstiel School of Marine and Atmospheric Science (RSMAS) at the University of Miami). Details of the SST processing implementation within l2gen are provided in this document. The description is valid for both the standard products distributed by the OBPG through the ocean color web and the products delivered to the Physical Oceanography DAAC, where the latter are subsequently repackaged for GHRSST distribution. An historical discussion on the transition of SST processing from MODAPS/DAAC/RSMAS to OBPG, with comparison of products, is available here. At the time of transition, the OBPG was able to demonstrate exact consistency with the previous products. However, file formatting now follows OBPG conventions. The Short-wave SST Algorithm makes use of MODIS bands 22 and 23 at 3.959 and 4.050 um. The brightness temperatures are derived from the observed radiances by inversion (in log space) of the radiance versus blackbody temperature relationship. For l2gen, these relationships were precomputed for the spectral response of each MODIS channel, and the tables were then stored in HDF files to be loaded at run-time. In modsst, the radiance versus blackbody temperature relationship was computed at run-time. The algorithm for computing short-wave SST (sst4) from observed brightness temperatures is shown below. The long-wave SST algorithm makes use of MODIS bands 31 and 32 at 11 amd 12 um. The brightness temperatures are derived from the observed radiances by inversion (in linear space) of the radiance versus blackbody temperature relationship. For l2gen, these relationships were precomputed for the spectral response of each MODIS channel, and the tables were then stored in HDF files to be loaded at run-time. In modsst, the radiance versus blackbody temperature relationship was computed at run-time. The nonlinear SST algorithm was tuned for two different regimes based on brightness temperature difference. The algorithm for computing long-wave SST (sst) from observed brightness temperatures is shown below. Support for the VIIRS mission is currently work in progress.
Mean Monthly Sea Surface Temperature (°C) for 2010-2019 - MODIS
This dataset contains rasters and a metadata file for global mean monthly ocean chlorophyll concentration (mg/m3) from 2010-2019. Rasters are in WGS84 coordinate system (EPSG 4326) . Chlorophyll-a is the light-harvesting pigment found in all photosynthetic plants. Its concentration in the ocean is used as an index of phytoplankton biomass and, as such, is a key input to primary productivity models. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Terra and Aqua satellites measures ocean color every day, from which global chlorophyll-a concentrations are derived. Ocean phytoplankton chemically fix carbon through photosynthesis, taking in dissolved carbon dioxide and producing oxygen. Through this process, marine plants capture about an equal amount of carbon as does photosynthesis by land vegetation. Changes in the amount of phytoplankton indicate the change in productivity of the oceans and provide a key ocean link for global climate change monitoring. Scientists use chlorophyll in modeling Earth's biogeochemical cycles such as the carbon cycle or the nitrogen cycle. Additionally, on short time scales, chlorophyll can be used to trace oceanographic currents, jets, and plumes. The 1-km resolution and nearly daily global coverage of the MODIS data thus allows scientists to observe mesoscale oceanographic features in coastal and estuarine environments, which are of increasing importance in marine science studies. The MODIS Chlorophyll-a product provides an estimate of the near-surface concentration of chlorophyll calculated using an empirical relationship derived from in situ measurements of chlorophyll and remote sensing reflectances (Rrs) in the blue-to-green region of the visible spectrum. The implementation is contingent on the availability of three or more sensor bands spanning the 440 - 670 nm spectral regime. The current implementation for the default chlorophyll algorithm (chlor_a) employs the standard band ratio algorithm (OCx) merged with the color index (CI) of Hu et al. (2012). As described in that paper, this refinement is restricted to relatively clear water, and the general impact is to reduce artifacts and biases in clear-water chlorophyll retrievals due to residual glint, stray light, atmospheric correction errors, and white or spectrally-linear bias errors in Rrs. As implemented, the algorithm diverges slightly from what was published in Hu et al. (2012) in that the transition between the CI and OCx now occurs at 0.15 < CI < 0.2 mg/m-3 to ensure a smooth transition. These imagery are produced using 2014.0 OCI chlorophyll data. References for above: Hu, C., Z. Lee, and B.A. Franz (2012). Chlorophyll-a algorithms for oligotrophic oceans: A novel approach based on three-band reflectance difference, J. Geophys. Res., 117, C01011, doi:10.1029/2011JC007395.
Mean Monthly Sea Surface Chlorophyll-a Concentration (mg/m3) for 2010-2019 - MODIS