VIIRS Imagery Viewer is online at CIMSS

September 15th, 2021 |
VIIRS imagery over the eastern United States and Canada from 13 September 2021

The VIIRS Imagery Viewer hosts 7 days’ worth of imagery over North America — refreshed daily — for all 22 VIIRS channels. Five of these channels are imaging-resolution bands (I-Bands) with a resolution of 375 m, and sixteen are moderate-resolution bands (M-Bands) with a resolution of 750 m. The viewer also hosts Day Night Band (DNB) images that provide unique nighttime perspectives. CIMSS acquires the data from the Suomi-NPP and NOAA-20 polar-orbiting satellites via Direct Broadcast antennas.  As new images become available from the Visible Infrared Imaging Radiometer Suite (VIIRS), they are processed via CSPP software and presented in a thumbnail directory, usually within 60 minutes of acquisition onboard the spacecraft. The thumbnails link to high resolution full overpass images. In addition to the individual bands, the VIIRS Imagery Viewer features multiple Level-2 products. The most popular are True and False Color images.  

CIMSS Direct Broadcast is one of the few places to access images in all 22 bands collected by VIIRS. Previously (and still) available via ftp (at https://ftp.ssec.wisc.edu/pub/eosdb/), the VIIRS Imagery Viewer makes it easier for students and citizen scientists to access the data, especially students participating in the JPSS Virtual Science Fair.  

Visit the VIIRS Imagery Viewer at https://cimss.ssec.wisc.edu/viirs/imagery-viewer/

ACSPO SSTs off the Oregon Coast

September 14th, 2021 |
ACSPO SST values derived from VIIRS data, 12-14 September 2021, at times indicated (Click to enlarge)

Clear skies to the west of Oregon and California in the past two days have allowed VIIRS data (VIIRS — the Visible-Infrared Imaging Radiometer Suite flying on both Suomi-NPP and NOAA-20) to produce compelling imagery of the Sea Surface using Advanced Clear Sky Processing for Ocean (ACSPO) algorithms. VIIRS imagery is downlinked at the Direct Broadcast site at the UW-Madison; data are processed using CSPP. Purple values are just a bit cooler than 50º F; Yellow values are in the mid-60s ºF.

ACSPO estimates of SSTs are important over the Pacific Northwest because the Level 2 SST GOES-16 product is not computed near the GOES-16 limb. Level 2 Clear Sky mask is not computed out to the limb, as shown below, and GOES-16 SSTs (Full-Disk only products) are not computed out to the edge of the Clear Sky mask! So, if you want satellite-derived SSTs (GOES-17 Level 2 products are not yet widely available), Polar-Orbiting data are the way to go.

GOES-16 Level Clear Sky Mask (white=clouds; black=no clouds) and derived SSTs, 1600 UTC on 14 September 2021 (Click to enlarge)

AWIPS-ready ACSPO SST files are available from via an LDM feed from CIMSS.

Super Typhoon Chanthu regains Category 5 intensity

September 11th, 2021 |

JMA Himawari-8 Infrared Window (10.4 µm) images [click to play animation | MP4]

2.5-minute rapid scan JMA Himawari-8 Infrared Window (10.4 µm) images (above) displayed Typhoon Chanthu as it regained Category 5 intensity for a period of over 24 hours (track) as it moved north-northwestward between the Philippines and Taiwan during 10-11 September 2021. 

A VIIRS Infrared Window (11.45 µm) image from NOAA-20 as viewed using RealEarth (below) showed Chanthu around 17 UTC on 10 September.

VIIRS Infrared Window (11.45 µm) image from NOAA-20 [click to enlarge]

 

Great Lakes water temperatures in early September

September 10th, 2021 |
NOAA-20 True-Color imagery over the Great Lakes, along with ACSPO SST values derived from VIIRS data, 1806 UTC on 10 September 2021 (Click to enlarge)

The early afternoon NOAA-20 overpass over the Great Lakes saw mostly clear skies, allowing for an accurate measurement — from satellite — of the lake surface temperatures, scaled in the image above to be between 55º and 75º F. Western Lake Erie has the warmest temperatures (peaking just below 75º, but a warm plume also exists in southern Lake Michigan. The zoomed-in image below shows Buoy observations in/around the lakes; buoy observations were very close to satellite measurements.

NOAA-20 SSTs along with Buoy observations, 1800 UTC on 10 September 2021 (Click to enlarge)

True Color and ACSPO SST imagery are available for AWIPS via an LDM feed from CIMSS. True-Color imagery is also available at the VIIRS Today website.