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SAR data over Hawai’i

This NOAA/OSPO website shows regions where SAR data are available each day. SAR data can also be imported into AWIPS, as shown in the animation above, which animation has the SAR data overlain on top of GOES-17 Band 7 (Shortwave IR, 3.9 µm) data. Note that SAR winds are not valid... Read More

Sentinel-1 SAR data around 0430 UTC overlain on top of GOES-17 ABI Shortwave IR (3.9 µm) at 0430 UTC on 5 May 2022 (Click to enlarge)

This NOAA/OSPO website shows regions where SAR data are available each day. SAR data can also be imported into AWIPS, as shown in the animation above, which animation has the SAR data overlain on top of GOES-17 Band 7 (Shortwave IR, 3.9 µm) data. Note that SAR winds are not valid over the land — the stronger returns over the islands are instead telling you something about the surface. (Compare this image to a Landsat image — there’s a good correlation!)

A zoomed-in version of the imagery over the ?Alenuih?h? Channel between the Big Island of Hawai’i and Maui is shown below as a toggle between the 3.9 µm and the winds. The significant funneling between the two islands is readily apparent, with winds increasing from about 15 knots northeast of the Big Island to closer to 25 knots within the channel.

GOES-17 Band 7 shortwave infrared (3.9 µm) imagery with SAR winds overlain, 0430/0431 UTC on 5 May 2022 (click to enlarge)

A zoom-in over Maui and Molokai, below, details winds around those islands as well, with strong winds between Molokai and Lanai, and an apparent col to the lee of Maui.

GOES-17 Band 7 shortwave infrared (3.9 µm) imagery with SAR winds overlain, 0430/0431 UTC on 5 May 2022 (click to enlarge)

Farther north, over the open Pacific to the north of the Hawai’ian Islands, SAR data shows enhancements in wind underneath structures that are apparent in the Band 7 imagery!

GOES-17 Band 7 shortwave infrared (3.9 µm) imagery with SAR winds overlain, 0430/0432 UTC on 5 May 2022 (click to enlarge)

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SAR Observations of Red River of the North Flooding

Data on this website (if you click through to 5 May 2022) shows regions where the RCM constellation has produced data. There are very small footprint scenes (shown below) over the Red River of the North, where flooding is ongoing (blog post 1; blog post 2). The Normalized Radar Cross Section (NRCS) imagery within those small footprints... Read More

RCM3 NRCS footprints from south to north, 00:13:28 through 00:13:55 on 5 May 2022 (click to enlarge)

Data on this website (if you click through to 5 May 2022) shows regions where the RCM constellation has produced data. There are very small footprint scenes (shown below) over the Red River of the North, where flooding is ongoing (blog post 1; blog post 2). The Normalized Radar Cross Section (NRCS) imagery within those small footprints is shown sequentially, from south to north, above. The NRCS imagery gives very high-resolution snapshots of flooded regions. This NRCS image from 00:13:39 has the largest extent of flooding within it.

A single image that shows the 6 scenes, aligned from south to north, is available here. (Warning: It’s large)

SAR Wind Imagery site, zoomed in over the North Dakota/Minnesota border (Click to enlarge)

Data were also available from earlier in May. Compare this RCM2 NRCS image from 00:29:27 on 3 May to this RCM3 NRCS image from 00:05:41 on 4 May to this RCM3 NRCS from 00:13:39 on May 5th. Flooding has expanded slightly over the two days.

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First thunderstorm of the season in the Anchorage, Alaska area

First thunderstorms of the year around here. @DaveSnider @capture907 @AlaskaWx pic.twitter.com/xeMhNiLSiU— Brian Brettschneider (@Climatologist49) May 5, 2022 1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed these isolated thunderstorms as they moved north-northwestward up the Susitna Valley (northwest of Anchorage).In the corresponding 1-minute GOES-17 “Clean” Infrared Window... Read More

GOES-17 “Red” Visible (0.64 µm) images [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) showed these isolated thunderstorms as they moved north-northwestward up the Susitna Valley (northwest of Anchorage).

In the corresponding 1-minute GOES-17 “Clean” Infrared Window (10.35 µm) images (below), the coldest cloud-top infrared brightness temperatures of the thunderstorms were around -35ºC (darker blue enhancement).

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to play animated GIF | MP4]

A toggle between Suomi-NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images around 2201 UTC (below) included a plot of available NUCAPS sounding points from NOAA-20.

Suomi-NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images and 2201 UTC [click to enlarge]

The NOAA-20 NUCAPS profile for the green (infrared + microwave) sounding point 25 miles WSW of Big Lake (below) diagnosed a surface parcel CAPE value of 616 J/kg, with a Lifted Index of -3.  

NOAA-20 NUCAPS profile for the sounding point 25 miles WSW of Big Lake [click to enlarge]

A later toggle between Suomi-NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images and 2345 UTC is shown below; the coldest cloud-top infrared brightness temperature of the thunderstorms was -38ºC (near Big Lake), which closely corresponded to the altitude of the Equilibrium Level on the NUCAPS profile.

Suomi-NPP VIIRS Visible (0.64 µm) and Infrared Window (11.45 µm) images and 2345 UTC [click to enlarge]

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Comparisons of LIS and GLM Lightning observations

The Geostationary Lightning Mapper (GLM) on GOES-16 and the Lightning Imaging Sensor (LIS, additional information here) on the International Space Station (ISS) both observe lightning. The GLM has nadir resolution of approximately 8 km, and is in geostationary orbit, about 36000 km above the Earth’s surface. In contrast, the LIS... Read More

GOES-16 5-minute Flash Extent Density (updated every minute) and ISS LIS Flash Events, 1318-1320 UTC on 4 May 2022 (Click to enlarge)

The Geostationary Lightning Mapper (GLM) on GOES-16 and the Lightning Imaging Sensor (LIS, additional information here) on the International Space Station (ISS) both observe lightning. The GLM has nadir resolution of approximately 8 km, and is in geostationary orbit, about 36000 km above the Earth’s surface. In contrast, the LIS has a resolution of approximately 4 km, and it’s on the ISS, only 400 km above the Earth’s surface. Both sensors detect the optical signal of the lightning. The animation above shows 2 minutes of LIS Flash Events plotted (in yellow) on top of 5-minute aggregates of GLM Flash Extent Density (updated at 1-minute time-steps). The animation below shows the same LIS observations, but plotted in black, on top of GOES-16 ABI Band 13 imagery. Many of the LIS flash events are colocated with cold cloud top as defined by the GOES-16 Band 13 (10.3 µm) brightness temperatures — meaning that the optical signal is strongest there. That’s not always the case though, as shown in this image with LIS data from 13:19:48.

GOES-16 Band 13 Infrared (10.3 µm) imagery and LIS Flash Events, 1318-1320 UTC on 4 May 2022 (Click to enlarge)

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