VISIT: Meteorological Interpretation Blog

NOAA-21 Designated as the Secondary JPSS Satellite

Per NOAA Office of Satellite and Product Operations (OSPO), the last requirement was fulfilled to declare NOAA-21 operational and as the secondary satellite of the JPSS constellation. As of 3 November 2023, the three existing JPSS satellites are now designated in the following order: Primary – NOAA-20, Secondary – NOAA-21, and Tertiary – SNPP. This change should not effect the data distribution, however, the 3 JPSS satellites are operated in the new prioritized order. For instance, the primary and secondary satellites (in this case, NOAA-20 and NOAA-21) take priority in data processing and spacecraft maneuvers.

In the incoming months, once the majority of NOAA-21 datasets reach provisional maturity or better, the NOAA-21 satellite will be assigned as the primary satellite. NOAA-20 will then become the secondary satellite, and SNPP, the tertiary satellite. With respect to SNPP, the tertiary designation indicates that any non-nominal issue or ground resource constraint will be addressed under a best-effort basis, unless a satellite or instrument health and safety issue occurs.

The current and future JPSS satellite designations and orbital configurations can be seen in the image below. Refer to the current phase highlighted in the green box, and the last phase located to the right, titled, ‘After Early 2024’. Image credit, thanks to TOWR-S/NOAA.

We look forward to NOAA-21 becoming the primary satellite in the JPSS constellation in 2024, along with the updated JPSS orbital configuration. Once NOAA-21 becomes the primary satellite, NOAA-20 and NOAA-21 will be separated by a 1/2 orbit (~50-min apart), with SNPP placed 1/4 orbit between the two.

Sources: NOAA OSPO – N21 Secondary Satellite in Constellation Declaration, NOAA NESDIS – N21 is Operational, and NOAA/NWS/TOWR-S. 

Posted in: POES, Satellites, VIIRS, | Comments closed

Bolivia Fires

Over the past week, fires were raging in the country of Bolivia. Numerous fires were observed by the GOES-16 geostationary satellite, and were spotted across the country. The largest fires were seen in central Bolivia, specifically located northwest of the city of Santa Cruz. On 22 October 2023, the GOES-16 ABI Day Fire RGB, which is sensitive to fire hotspots, burn scars and fire smoke observed the active fires (red colors) and the corresponding smoke plumes (blue colors) covering central Bolivia. The smoke plumes advected to the southeast and impacted the neighboring towns and cities. Refer to the animation below.

Animation 1: GOES-16 ABI Day Fire RGB observations from 17-1930Z, 22 October 2023.

During the same timeframe, VIIRS daytime overpasses from SNPP and NOAA-20 captured the fires at a high spatial resolution of 375-m. Although the polar-orbiters are not as timely as geostationary satellites (i.e., exhibit a coarser temporal resolution), they can provide the finer details of atmospheric and surface features, such as fire and smoke. The VIIRS version of the Day Fire RGB can be seen below, provided by SNPP and NOAA-20.

Animation 2: SNPP and NOAA-20 VIIRS Day Fire RGB observations at 1730Z and 1821Z, 22 October 2023.

Another RGB that can be employed for the fire monitoring is the Fire Temperature RGB, which provides a qualitative estimate of fire intensity. In the RGB imagery, active fires are depicted from red (i.e., cool, less intense fires) to orange to yellow to white pixels (i.e., most intense fires). The animation below highlights a comparison between the VIIRS Day Fire RGB and the VIIRS Fire Temperature RGB from the 1821Z NOAA-20 overpass. The most intense fires are seen near and south of 16 degrees latitude. Note, that the VIIRS Fire Temperature RGB is at 750-m spatial resolution.

Animation 3: A comparison between the NOAA-20 VIIRS Day Fire RGB and VIIRS Fire Temperature RGB at 1821Z, 22 October 2023.

Note to users: the GOES ABI Day Fire RGB can be accessed via CIRA SLIDER. The VIIRS Day Fire RGB and VIIRS Fire Temperature RGB can be accessed via 3 JPSS sectors on CIRA SLIDER: CONUS, Northern Hemisphere, and the Southern Hemisphere.

Posted in: Data Access, Fire Weather, POES, Satellites, VIIRS, | Comments closed

Satellite Moisture Products and Analysis Tools for Three Heavy Precipitation / Flooding Events in the Summer of 2023

Source: JPSS River Ice and Flood Initiative call from September 19, 2023

Author: Sheldon Kusselson:

Click on the image to start the video:

Download Powerpoint file

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NOAA-21 VIIRS NCC Imagery Available in AWIPS via SBN

This summer 2023, NOAA-21 VIIRS Near-Constant Contrast (NCC) imagery has become available for National Weather Service (NWS) users to access in the Advanced Weather Interactive Processing System – II (AWIPS-II) via the Satellite Broadcast Network (SBN). With the addition of NOAA-21 VIIRS NCC, users can now access the nighttime visible imagery from three JPSS polar-orbiting satellites: Suomi-National Polar-orbiting Partnership (S-NPP), NOAA-20 and NOAA-21.

Refer to the screenshot below that shows how users can access CONUS VIIRS NCC imagery from all three satellites in AWIPS-II. In AWIPS, simply click on the ‘Satellite’ tab, scroll down to ‘SNPP and NOAA-20’, then to ‘S-NPP and NOAA-20 Near Constant Contrast’, and select ‘CONUS S-NPP and NOAA-20 NCC (0.7 um)’.  Be aware that the AWIPS menu entries are not updated with the NOAA-21 VIIRS NCC menus. The current menu configurations are planned to be updated in the next TOWR-S RPM release, v24, tentatively scheduled for later this fall (~October 2023). However, users can update the NOAA-21 menu entries manually from the TOWR-S instructions that are described here. The instructions also provide details on how to fix an overlap issue that may be seen between VIIRS satellite swaths. Note, per TOWR-S, the current menu configuration may not be applicable for other regions (e.g., Alaska sector) who receive VIIRS imagery from Direct Broadcast (DB).

The animation below displays the VIIRS NCC imagery from all 3 satellites over CONUS during the overnight hours on 17 August 2023. The imagery is shown during the new moon phase of the lunar cycle. Notice how NOAA-21 VIIRS NCC imagery is placed in between NOAA-20 and SNPP VIIRS NCC imagery by 1/4 orbit (~25 minutes apart).

Over the CONUS sector, there is an additional way to access NOAA-21 VIIRS NCC imagery in the AWIPS menu. Users can click on the Satellite tab, scroll down to ‘SNPP and NOAA-20’, then to ‘S-NPP CONUS’ and select ‘0.7 um Near Constant Contrast’ (see the image below). For now, SNPP and NOAA-21 VIIRS imagery can be accessed here as well, however, the menu configurations will be updated in the future by TOWR-S RPM v24.

An AWIPS VIIRS NCC example from NOAA-21 observes the eye and areal extent of Hurricane Hilary. At ~0914Z, 19 August 2023, the hurricane was located southwest of the Baja California Peninsula. The hurricane proceeded to move into Southern California the next day and produced significant precipitation totals over the region.

Posted in: AWIPS, Miscellaneous, POES, Satellites, VIIRS, | Comments closed

When can users expect JPSS Data over CONUS?

The Joint Polar Satellite System (JPSS) constellation consists of 5 satellites: SNPP, NOAA-20, NOAA-21, and the upcoming JPSS-3 and JPSS-4 satellites that will launch within the next decade. Focusing on the three active satellites, the current JPSS orbital configuration has NOAA-20 and SNPP at a 1/2 orbit apart (or ~50-minutes apart) where NOAA-21 is placed 1/4 orbit between the two.

Now this orbital configuration (see the image below) will change once NOAA-21 is designated as the primary satellite later this year. Users can look forward to a future blog entry on that topic.

With the current orbital configuration, how does it translate to when users can expect JPSS data over CONUS? Typically over the lower-48, at any one location, users can expect 3 to 5 overpasses during the overnight hours from approximately 05 to 12Z. During the daytime, 3 to 5 overpasses are expected between ~16-22Z over CONUS.

A nighttime and daytime animation are shown below that highlight JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) swaths over CONUS on 30 July 2023.

Nighttime: 05-12Z, 30 July 2023 – VIIRS swaths from the 11.45 um (I-5 band). 

Daytime: 16-22Z, 30 July 2023 – VIIRS GeoColor imagery. 

Users should also be aware of the orbital sequence of the satellites. The sequence starts with a NOAA-20 satellite overpass, then a NOAA-21 overpass ~25-minutes later, and then a SNPP overpass ~25 minutes after that. Then there is a 50-minute gap, which then the sequence starts again with another satellite overpass from NOAA-20. Note, this sequence continues as the polar-orbiting satellites move from east to west across CONUS. A VIIRS GeoColor daytime animation (see below) highlights the satellite sequence across CONUS on 19 July 2023.

Additionally, users can identify JPSS orbit tracks (i.e., from near-real-time or archived data) via the Space Science and Engineering Center (SSEC) at the University of Wisconsin polar orbit tracks website. Users can access orbit tracks from SNPP, NOAA-20, and NOAA-21 and can be viewed in a global domain or via regional sector. The length of the archives depends on the satellite. For example, SNPP will have the longest archive, since it is the oldest satellite within the JPSS constellation and contains an archive since 2011. JPSS orbit tracks can be accessed via the NASA SPoRT Viewer webpage as well.

Posted in: Data Access, Miscellaneous, POES, Satellites, VIIRS, | Comments closed