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Aqua Science Publication Highlights

 

January 2024

Continuity between NASA MODIS Collection 6.1 and VIIRS Collection 2 land products

Román, M. O., Justice, C., Paynter, I., Boucher, P. B., Devadiga, S., Endsley, A., ... & Wolfe, R. (2024). Continuity between NASA MODIS Collection 6.1 and VIIRS Collection 2 land products. Remote Sensing of Environment, 302, 113963. https://doi.org/10.1016/j.rse.2023.113963

A recent review and summary of current research by the NASA Terra Aqua Suomi-NPP Land Discipline Team has recently been published in regards to their efforts to provide continity of global land data products between two instruments: NASA MODIS and the Visible Infrared Imaging Radiometer Suite (VIIRS). The two MODIS instruments on Terra and Aqua have provided valuable data for more than 20 years, and as these satellite platforms age, it is imperative to maintain data continuity with other instruments in orbit, such as VIIRS. Hence, the land data products from MODIS are now being transitioneed to being producing using VIIRS data. This publications highlights the intercomparison and evaluation between these two products. The results provide primising levels of agreement and accuracy between the two products in in several cases. The image below shows an example of MODIS (MYD10A1) and VIIRS (VNP10A1, VJ110A1) product comparison of maps showing land surface classifciations between ocean, land, snow cover and clouds.   

 

 

Binary snow cover extent (SCE) maps from MYD10A1F, VNP10A1F, and VJ110A1 for 1–3 March 2021 for tile h09v04 covering the northwestern USA.

 

July 2023

Global climate-change trends detected in indicators of ocean ecology

 Cael, B.B., Bisson, K., Boss, E. et al. Global climate-change trends detected in indicators of ocean ecology. Nature (2023). https://doi.org/10.1038/s41586-023-06321-z

 

 

 

 

Figure: Map of locations where the ocean-colour trend SNR is higher than 2 for a 20-year annual time series. The intensity of the purple colour indicates the signal to noise ratio. Black stippling indicates regions with significant trends in Chl as well (12% of the ocean). MODIS-Aqua data from July 2002 to June 2022.

 

Climate change is altering the earth's oceans, specifically in marine ecosystems and it has been hypothosized that this could alter the ocean color. However, determining if this was occuring on a global scale has been difficult due to the lack of a long-term satellite data record, especially with intercalibration between different instruments being an issue. Having MODIS on Aqua for 20+ years has allowed for this type of study to take place, and for long term changes to be found.

 

A new study, published in Nature using Aqua MODIS reflectance data found that there are large areas of the global oceans where the color of the ocean has changed over the 20-year record and is becoming more green due to more phytoplantion. This change in ocean color is driven by climate change. This change is important because it alters the light environment of the oceans, which drive primary production and can lead to an overall change in the surface-ocean ecosystem, which could have potential effects on fisheries worldwide.

 

 

 

June 2023

Atmospheric nourishment of global ocean ecosystems

T.K. Westberry, et al., Atmospheric noursiment of global ocean ecysystems. Science 380, 515-519 (2023). DOI: 10.1126/science.abq5252

A new study by Westberry et al. published in Science titled, 'Atmospheric Nourishment of Global Ocean Ecoystems', detects the extent and magnitude of dust-deposition on the oceans globally. Dust-deposited on the ocean provides nutritents for phytoplankton. This new dataset was produced using Aqua MODIS data. 

 

Figure. Model-based dust deposition and satellite-observed chlorophyll concentration over the global ocean.
(A) Average GEOS dust deposition rates (milligrams per square meter per day) over the period 2003 to 2016. (B) Average MODIS-Aqua chlorophyll concentration (milligrams per cubic meter) over the period 2003 to 2016. Red boxes outline a single 5°-by-10° grid cell centered on 42.5°N, 45°W, whose time series are shown in subsequent panels. (C) Fourteen-year time series of 4-day average dust deposition (thin black line) over red-outlined region in (A). Also shown is a repeating average annual cycle of dust deposition (solid red line) for the same location. (D) Similar to (C), but for MODIS-Aqua chlorophyll concentration (milligrams per cubic meter).

 

 

 

March 2023

Coastal phytoplankton blooms expand and intensify in the 21st century

Dai, Y.,Yang, S., Zhao, D. et al. Coastal phytoplankton blooms expand and intensify in the 21st century. Nature 615, 280–284 (2023). https://doi.org/10.1038/s41586-023-05760-y

 

Figure: MODIS-dectected bloom count within certian years for several coastal regions with frequency reported blooms. The MODIS observational year is annotated within each panel, and overlaid points indicate in situ recorded harmful algal bloom events from the Harmful Algae Event Database (HAEDAT) within the same year. The lower right panel shows the locations of all the HAEDAT records that were used for algorithm validations in this study, which also demonstrates the increase in sampling effort in the most recent years.

A new study, published in Nature, found that globally coastal algae blooms are increasing in frequency and extent between 2003-2020. These blooms were detected by a algae bloom detection dataset, which was produced using 0.76 million MODIS-Aqua images. While some algae blooms are beneficial providing food to fisheries and the ecosystems worldwide, other blooms called 'Harmful Algae Blooms' are becoming more prevalaent and can put toxins in the food chain, affecting animals and humans, and can depelete the oxygen in areas creating 'Dead Zones' that can kill many species. This daily coastal phytoplanton bloom dataset is important because it can be used to inform future management and policy actions and provides locations and timing of these algae blooms.