Worldview has expanded its suite of satellite based remote sensing measurements of Aerosol Optical Depth and Angstrom Parameter to include ground based measurements from the AERONET program. Users can now quickly and easily compare ground based measurements to satellite based measurements within the same interface to validate their findings.

Aerosols are suspended liquid or solid particles that are small enough to be easily transported by air currents. Water vapor, smoke, dust, sea salt, and industrial pollutants are all examples of aerosols. It is important to monitor aerosols in the atmosphere as aerosols can compromise human health when inhaled by people, particularly those with asthma or other respiratory illnesses. Aerosols also have an effect on the weather and climate by cooling or warming the Earth, helping or preventing clouds from forming. Sources of aerosols include pollution from factories, smoke from fires, dust from dust storms, sea salt, volcanic ash and smog. 

Each AERONET ground-based remote sensing aerosol network site consists of a sun photometer and satellite transmission system. Sun photometer measurements of the direct (collimated) solar radiation provide information to calculate the columnar aerosol optical depth (AOD). AOD can be used to compute columnar water vapor (Precipitable Water) and estimate the aerosol size using the Angstrom parameter relationship.

Sun photometer at Thule Air Base (now known as Pituffik Space Base), Greenland

Worldview added four data layers from AERONET which include near real-time and daily layers - version 3 Aerosol Optical Depth 500 nanometers (nm) and Angstrom Parameter 440-870 nanometers (nm). 

• Aerosol Optical Depth 500 nm (Near Real-Time)
• Angstrom Parameter 440-870 nm (Near Real-Time)
• Aerosol Optical Depth 500 nm (Daily)
• Angstrom Parameter 440-870 nm (Daily)

The near real-time data layer displays the site reading from the past hour, and inactive sites are denoted in gray. The daily data layer displays the daily average value based on the UTC solar day. The data are from the Level 1.5 data quality level which are automatically cloud cleared but may not have final calibration applied, therefore these data are not quality assured. 

Aerosol Optical Depth (AOD) values range from <0.0 to 5.0. AOD indicates the level at which particles in the air (aerosols) prevent light from traveling through the atmosphere. Aerosols scatter and absorb incoming sunlight, which reduces visibility. From an observer on the ground, an AOD of less than 0.1 is “clean” - characteristic of clear blue sky, bright sun and maximum visibility. As AOD increases to 0.5, 1.0, and greater than 3.0, aerosols become so dense that the sun is obscured. 

The angstrom parameter values range from <0.0 to >=2.5. The angstrom parameter provides additional information related to the aerosol particle size (larger the value, the smaller the particle size). Values < 1 suggest optical dominance of coarse particles (e.g. dust) and values > 1 suggest optical dominance of fine particles (e.g. smoke).

The angstrom parameter is calculated for all available wavelengths within the Angstrom parameter range. For example, the Angstrom 440-870nm includes the 870, 670, 500 and 440 nm AOD data. A special case for a polarized instrument is Angstrom 440-870nm which only includes 870, 670 and 440 nm AOD data (polarized instruments do not have 500nm channel). 

The AERONET (AErosol RObotic NETwork) program is a federation of ground-based remote sensing aerosol networks established by NASA and PHOTONS (PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire; Univ. of Lille 1, CNES, and CNRS-INSU) and is greatly expanded by networks (e.g., RIMA, AeroSpan, AEROCAN, AEROSPAIN, NEON, NCU, and CARSNET) and collaborators from national agencies, institutes, universities, individual scientists, and partners.

The example above shows high aerosol optical depth values due to wildfires and smoke in the Pacific Northwest region.

The example above shows dust blowing off the coast of northwestern Africa from the Sahara Desert over the island of Capo Verde. The Angstrom parameter site reading at Capo Verde is below 1 which indicates fine particles.

To load the AERONET layers in Worldview, simply click on the orange “Add Layers” button (circled in red), and type in “AERONET” in the search bar. 

Figure 1: Sea Ice classification layer from the MODIS instrument aboard the Terra satellite. Sea ice is shown in dark pink, overlaid on a corrected reflectance image from the same satellite and sensor.

Figure 2. Sea Ice classification layer from the MODIS instrument aboard the Terra satellite. Sea ice is shown in dark pink, cloud in light blue, ocean in dark blue, and land in green. With these other classifications displayed, we now have a better idea of what areas that may have had sea ice were actually obscured by cloud, and the areas that are land masses.

We've recently made some updates and additions to our GIBS API documentation and examples of using GIBS with various web mapping libraries, so If you're interested in retrieving NASA Earth Science imagery visualizations via the Global Imagery Browse Services (GIBS) to use in your own applications, you've come to the right place!

NASA's Global Imagery Browse Services (GIBS) system provides visualizations of NASA Earth Science observations through standardized web services. You can access these via GIS Applications, Map Libraries and GDAL Scripts, and via Python.

The Accessing via Python is our newest addition to the GIBS API documentation. This section covers topics showing you how to connect to GIBS via Web Map Service (WMS) and Web Map Tile Service (WMTS), how to visualize raster and vector data/imagery, and provides examples of simple analyses and applications. All of the examples are also downloadable as a Jupyter Notebook. 

We also recently updated our GitHub GIBS Web Examples repository, gibs-web-examples, which has examples of using GIBS with various web mapping libraries, like OpenLayers, Leaflet, Cesium, Mapbox GL, Bing, and Google Maps. We updated all the libraries to the latest working versions and we've also added a MapLibre GL example. All you have to do is clone and install the repo, then you can get started! You can also view Live Examples listed in the README section like a Rolling Seven Day Slider in OpenLayers or Global Web Mercator imagery in Cesium, visit the Live Examples section to see more.

Relevant Links

• GIBS API Documentation: GIBS API for Developers
• GIBS Imagery Visualization Layers: GIBS Visualization Product Catalog
• GitHub GIBS Web Examples repo: GIBS Web Examples 

Screenshot of the GIBS API Documentation, Accessing via Python, Visualize WMS Raster Data with a Legend section.

Screenshot of GIBS imagery displayed on a 3D globe in Cesium. 

2022 Atlantic Hurricane Season thus far ( 1 June  - 1 Nov 2022) - Image above shows Worldview displaying severe storm tracks gleaned from the EONET API (View in Worldview).

The season officially begins on 1 June and ends 22 November 2022.  The criteria for displaying "Severe Storms" as defined by EONET is as follows:

Tropical cyclones are added to EONET when they first achieve tropical storm designation—wind speeds of at least 34 knots (39 mph or 17.5 m/s).

Cyclonic events are closed after 5 days of inactivity (i.e., since the last reported location from our sources).

Sources

• National Hurricane Center
• Joint Typhoon Warning Center

Try it out!

1. Go to https://worldview.earthdata.nasa.gov.
2. Click on the “Events” tab.
3. Click on the blue filter/funnel icon to the right of the date. This opens the “Filter Events” menu.
4. Check the box for “Show tracks for all events”. You may also want to check the box for "Only list events in the current map view" to further filter the events. Event tracks are only available for "Severe Storms" and "Sea and Lake Ice" events.
5. Pick the date range of interest.
6. Click the Apply button and you’ll see all of your requested event tracks!

We have made some changes to the Chlorophyll a layers in Worldview and GIBS.

We are no longer processing the "Chlorophyll a Terra/MODIS" (MODIS_Terra_Chlorophyll_A) and "Chlorophyll a Aqua/MODIS" (MODIS_Aqua_Chlorophyll_A). Comparable layers are available for Terra/MODIS, Aqua/MODIS and now, Suomi NPP/VIIRS. The table below outlines the changes in the Worldview Title and GIBS Identifiers. Please transition to the new layers as the old layers will not have any imagery past 2022 MAR 28. 

In addition to this, the new Terra/MODIS, Aqua/MODIS and Suomi NPP/VIIRS layers are all utilizing a new colormap. The colormap now includes an entry for "< 0.0100 mg/m³" to better reflect the breadth of the Chlorophyll a presence in water (or lack of presence in this case!), and the imagery was reprocessed to match the new colormaps. 

New colormap legend now includes "< 0.0100 mg/m³". Previous colormap started at 0.01 mg/m³ and did not include values lower than that.

Temperature Unit Conversion

Temperature unit conversions are now available for relevant temperature layers.

We've also added twelve new Land Surface Temperature (LST) layers for you to convert units to your heart's desire! These include the MOD/MYD21 Land Surface Temperature Day | Night, Daily, 8-Day and Monthly layers.

The MOD/MYD21 Temperature/Emissivity Separation (TES) algorithm is a physics-based algorithm used to dynamically retrieve both LST and spectral emissivity simultaneously from the MODIS thermal infrared (TIR) bands 29, 31, and 32. The TES algorithm is combined with an improved Water Vapor Scaling (WVS) atmospheric correction scheme to stabilize the retrieval during warm and humid conditions. The MOD/MYD21 LST&E algorithm differs from the MOD11/MYD11 L2 algorithm in that the MOD21/MYD21 algorithm is based on the ASTER TES technique, whereas the MOD11/MYD11 L2 products uses a generalized split-window (GSW) technique. Learn more about MOD/MYD21 in its User Guide.

• Terra/MODIS LST Day | Night, Daily, 8-Day and Monthly layers: https://go.nasa.gov/3KnArVa
• Aqua/MODIS LST Day | Night, Daily, 8-Day and Monthly layers: https://go.nasa.gov/3KpmhTe

Settings Panel to convert temperature units can be accessed from the "i" menu in the upper right corner. Keep your eyes peeled for other settings that can be changed from this panel in the future!

DAAC/SIPS Facet

The Layer Picker has a new facet for DAAC/SIPS (that is Distributed Active Archive Centers/Science Investigator-led Processing Systems) who have provided the imagery visualizations.

Click on the orange "+ Add Layers" in the Layer List, then the orange Filter icon in the upper left corner to filter the imagery by facets.

Tour Stories

• A new tour story about the Geostationary imagery layers we have from GOES-East, GOES-West and Himawari-8.
• The Satellite Detections of Fire (2021 update) tour story was updated with new events and imagery.
• There's also a new Introduction to Worldview tour story that walks you through all the elements of Worldview.

Screenshot of the second step of the Geostationary Imagery Tour Story.

Moving to the Cloud

• The Global Imagery Browse Services (GIBS) is in the process of migrating its visualization archive into the cloud. Current status:
  • 5% of total visualization layers (20% by volume) are actively being forward processed in the cloud.
  • 80% of the on-premises visualization archive has been transferred to the cloud.
  • The system is expected to be 100% in the cloud in Fall 2022.
• This transition should be transparent to users as all existing visualization layers and URLs will continue to work (but please let us know if you notice any problems support@earthdata.nasa.gov).
• Once fully migrated, we'll be able to more easily scale out the system and provide new features for more flexible visualizations.

AWS Snowball getting loaded up with data from our on-premises servers to its future home in the cloud!

New Features

Historical Events

Worldview now provides access to the entire curated list of archived events from the NASA Earth Observatory Natural Event Tracker (EONET).

Click on the "Events" tab in the sidebar and you will be presented with the first 50 events from the past few months. Just click on the blue filter icon to start narrowing down the events. You can filter events by date, event type, and events in the current map view. Events go back to 1 January 2000, though not all event types/categories have events populated back to 1 January 2000. Event types include Dust and Haze, Manmade, Sea and Lake Ice, Severe Storms, Snow, Volcanoes, Water Color and Wildfires. You can also check the box to "Only list events in current map view" to further filter your search results. 

Screenshot of the Events tab and event filter options. https://go.nasa.gov/3iHrvNn

GeoColor, GOES-East and GOES-West

Worldview has added GeoColor imagery from the geostationary satellites, GOES-East and GOES-West along with the existing Red Visible, Clean Infrared and Air Mass layers. 

All geostationary imagery are available in Worldview on a rolling 90-day window.

The GeoColor (True Color (Day), Multispectral blended infrared (IR; at Night)) layer from the GOES-East and GOES-West Advanced Baseline Imager (ABI) provides an approximation to daytime True Color imagery. The combination of spectral bands yields an appearance similar to what the human eye would perceive for land surface, oceanic and atmospheric features, with atmospheric correction used to make the appearance of these features sharper. Thus it is used primarily for the intuitive interpretation of meteorological and surface-based features such as smoke, blowing dust, and vegetation types (forests, deserts, croplands, etc.). At night, the true color imagery gives way to IR-based blended multispectral imagery that provides differentiation between low liquid water clouds (shown in light-blue) and higher ice clouds (shown in gray/white). It also includes a static city lights/night lights database derived from the VIIRS Day/Night Band, which aids in geo-referencing and can help determine the proximity of clouds (such as fog) or weather hazards (such as thunderstorms or tropical cyclones) to population centers. Please note that as these lights are static, they will not change even if, for example, a weather-induced power outage occurs.

Learn more: NASA Worldview Adds GeoColor Imagery from the joint NASA/NOAA GOES-East and GOES-West Satellites.

Screenshot of GeoColor from ABI aboard the GOES-East satellite on 20 July 2021 at 11:50Z. https://go.nasa.gov/3eJNvWu

Wind Speed (CDR, Daily), CYGNSS/DDMI

The CYGNSS/DDMI Level 3 Wind Speed (CDR, Daily) layer is the daily ocean surface wind speed in meters per second (m/s) as provided by the Delay Doppler Mapping Instrument (DDMI) on board the CYGNSS spacecraft constellation. The layer provides high resolution wind speed data that allows for global tropical ocean observation. The primary mission objective for CYGNSS is to provide frequent space‐based measurements of ocean surface wind speed in the inner core of tropical cyclones. The orbital asynchronicity with respect to the local solar daytime/nighttime patterns may provide additional scientific opportunity to study wind speed variations and patterns due to the diurnal cycle. The data imagery is provided by the CYGNSS Version 1.0 CYGNSS Level 3 Climate Data Record (CDR). The Version 1.0 CDR represents the first climate-quality release and is a collection of reanalysis products derived from the Science Data Record v2.1 Level 1 data.

Sea Surface Height Anomalies (GDR Cycles), TOPEX/POSEIDON, JASON-1, OSTM/Jason-2, and Jason-3

The Sea Surface Height Anomalies (GDR Cycles) layer displays along track Sea Surface Height Anomalies (SSHA) for individual 10-day cycles from the TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 missions geo-referenced to a mean reference orbit. 

Deep Blue Aerosol Type, Suomi NPP / VIIRS

The VIIRS Deep Blue Aerosol Type layer provides information related to the aerosol composition over land and ocean. Types include Dust, Smoke, High Altitude Smoke, Pyrocumulonimbus Clouds, Non-Smoke Fine Mode, Mixed, Background and Fine Dominated.

The Deep Blue (DB) algorithm is employed for over-land use and the Satellite Ocean Aerosol Retrieval (SOAR) algorithm is used over water to determine atmospheric aerosol type for day time cloud-free snow-free scenes. The combined Aerosol Type over land and ocean layer is derived from pixels that pass high-quality assurance tests. Over water, aerosol type is retrieved via the aerosol type optical model that yields the best fit. Over land, aerosol type is classified based on Aerosol Optical Depth (AOD), Ångström exponent, Lambert Equivalent Reflectivity (LER), and brightness temperature.

Land Surface Temperature, MODIS/Aqua | Terra/ASTER

The Land Surface Temperature (Day | Night) layers are from the new Land Surface Temperature and Emissivity (LST&E) product (MOD/MYD21), which is in addition to the heritage MOD11/MYD11 Land Surface Temperature (LST) product. These layers show the temperature of the land surface in Kelvin (K).

Black Sky Albedo, MODIS/Terra and Aqua

The Black Sky Albedo (L3, Daily) layer is created from the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A3 Albedo Model dataset is produced daily using 16 days of Terra and Aqua MODIS data at 500 meter (m) resolution. Data are temporally weighted to the ninth day of the 16 day.

The MCD43A3 provides black-sky albedo (directional hemispherical reflectance) and white-sky albedo (bihemispherical reflectance) data at local solar noon.

Screenshot of Aerosol Type from VIIRS aboard the joint NASA/NOAA Suomi NPP satellite on 20 July 2021. https://go.nasa.gov/3By9wl2

Updated and Removed Layers

• All MODIS Land NRT and STD layers are in the process of being updated to collection 6.1. It will currently be a mix of v6.0 and 6.1.
• Snow Water Equivalent, AMSR-2 (Daily, 5-Day, Monthly) have been updated to v2 for NRT and vB02 for STD.
• Deep Blue Aerosol Optical Thickness and Aerosol Angstrom Exponent from Suomi NPP/VIIRS have been updated to v1.1.
• G1SST Sea Surface Temperature from GHRSST has been retired.
• Cloud Liquid Water, Columnar Water Vapor, Surface Precipitation Rate, Rain Rate and Wind Speed from AMSR-2 (Rain Ocean Products) have been retired.

The beta version of the Moderate Resolution Imaging Spectroradiometer (MODIS) Near Real-Time (NRT) Global Flood Product (MCDWD) provides a daily global map of flooding. It is derived from the NRT MODIS Surface Reflectance (MOD09) datasets from both the Terra and Aqua satellites. The Flood Product is available for 3 compositing periods: 1-day, 2-day, and 3-day. A pixel is marked as water when water detections from all observations from Terra/MODIS and Aqua/MODIS are gathered for each compositing period, with the 3-day window accumulating 3 days worth of observations thereby most likely to include the least number of false positive detections. (Note: 1-day product not yet available in Worldview). Users are advised to compare the flood product against the contributing MODIS reflectance imagery (such as 7-2-1 Corrected Reflectance; search for “721” after clicking “+ Add Layers”) for the compositing period to ensure reported flood areas do not correspond to areas of cloud shadow and other obscurations. Imagery is available starting 1 January 2021. Learn more about the MODIS Flood Product in the User Guide and the FAQs. 

Image of flooding in a river flood plain in northwestern Australia as highlighted by the Flood 3-Day Window layer in red. Visit Worldview to interact with the layers: https://go.nasa.gov/2Qm9dq7

CYGNSS Soil Moisture layer in Worldview: https://go.nasa.gov/3a4RDxT

Worldview and GIBS also added the Cyclone Global Navigation Satellite System (CYGNSS) Soil Moisture layer which provides volumetric water content estimates for soils between 0-5 cm depth in units of cm³/cm³ for most of the subtropics. The data were produced by CYGNSS investigators at the University Corporation for Atmospheric Research (UCAR) and the University of Colorado at Boulder (CU), and derived from version 2.1 of the CYGNSS L1 Science Data Record (SDR). The soil moisture algorithm uses collocated soil moisture retrievals from Soil Moisture Active Passive (SMAP) satellite to calibrate CYGNSS observations from the same day. For a given location, a linear relationship between the SMAP soil moisture and CYGNSS reflectivity is determined and used to transform the CYGNSS observations into soil moisture. The spatial resolution is 36km and temporal resolution is daily. The temporal coverage is 18 March 2017 - 16 August 2020. Dataset doi: 10.5067/CYGNU-L3SM1

Worldview v3.9.0 was released in early March including new features like Location Search, Data download via Earthdata Search and layer grouping in the Layer List.

Location Search allows users to type in a location name, or coordinates and a marker will be placed on the map. Conversely, a marker can be placed on the map to retrieve the coordinates and place name (if available). Location Search is in the upper right corner of Worldview. 

Data Download via Earthdata Search: While Worldview has had a data download capability before, in the past it had been limited to only about a third of the layers. We have now extended this capability to almost all of the layers available in Worldview and provided a more robust method of getting users into Earthdata Search, EOSDIS' data discovery and access tool.

Layer Grouping: Layers in the Layer List can now be grouped to more effectively place similar layer visualization types together in the same category making it easier to manipulate a group than individual layers.

Read more about these updates in the Earthdata article, "EOSDIS Worldview Version 3.9.0 Makes Finding, Viewing, and Downloading NASA Earth Data Easier than Ever".

Screenshot of Worldview directing the user to download data via Earthdata Search. In Worldview, users select their desired layer, desired date and can set their area of interest. They are then directed to Earthdata Search with those options selected and can then access data download options.