Cyclone Damien makes landfall in Western Australia

February 8th, 2020 |

Himawari-8

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

2.5-minute rapid scan JMA Himawari-8 “Clean” Infrared Window (10.4 µm) images (above) showed Cyclone Damien making landfall as a Category 2 storm in Western Australia on 08 February 2020. Well west of the storm center, winds gusted to 49 knots at Barrow Island (YBWX). The eye remained intact for several hours after Damien moved inland.

GCOM-W1 AMSR2 Microwave (85 GHz) imagery from the CIMSS Tropical Cyclones site (below) showed the eye at 1710 UTC.

GCOM-W2 AMSR2 Microwave (85 GHz) image [click to enlarge]

GCOM-W2 AMSR2 Microwave (85 GHz) image [click to enlarge]

Just prior to landfall. cloud-top gravity waves were evident in VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP, as viewed using RealEarth (below).

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]

VIIRS Infrared Window (11.45 µm) images from NOAA-20 and Suomi NPP [click to enlarge]


Tropical Storm Damien was also seen in the first-light image from Russia’s Elecro-L3 satellite, a few hours before Damien reached Category 1 hurricane intensity.

MIRS Ice Concentration Products over the Great Lakes

January 20th, 2020 |

MIRS Lake Ice Concentration (as a percentage) from NOAA-20 ATMS at 0735 UTC on 19 January 2020 (Click to enlarge)

CIMSS is now providing via LDM MIRS Lake Ice Products over the Great Lakes. These data are created using the Community Satellite Processing Package (CSPP) Software and NOAA-20/Suomi-NPP ATMS data downlinked at the Direct Broadcast Antennas in Madison WI. Imagery is shown above from 0735 UTC on 19 January 2020; the image below is from 0717 UTC on 20 January 2020, from NOAA-20, about 24 hours later, and then from 0808 UTC on 20 January 2020, from Suomi NPP (although it is labeled as NOAA-20). A great benefit of these microwave products is that they are not affected by persistent cloud cover that is common over the Great Lakes in winter.

MIRS Lake Ice Concentration (as a percentage) from NOAA-20 ATMS at 0717 UTC on 20 January 2020 (Click to enlarge)

MIRS Lake Ice Concentration (as a percentage) from NOAA-20 ATMS at 0806 UTC on 20 January 2020 (Click to enlarge)

Ice concentration estimates from microwave are very strongly influenced by view angle. Make certain in your comparisons (if you are trying to ascertain changes in lake ice coverage during Lake-Effect Snow events, for example) that you understand this! If the footprint sizes are similar, a comparison to different passes is valid; if the footprint sizes differ, the effects of view angle must be considered. Orbital paths can be viewed here (NOAA-20 it passed right over Lake Erie at 0722 UTC on 20 January; Suomi-NPP passed over Duluth at 0812 UTC on 20 January). In the two examples above, note how ice cover estimates differ over Lake Ontario. In the later example, from ATMS on Suomi-NPP, Lake Ontario is far closer to the limb; the ATMS footprint is much larger and the estimate of lake ice concentration is affected. This toggle compares the VIIRS Day Night band image to the ATMS observations; Lake Ontario is close to the limb for NPP’s pass over western Lake Superior at this time.

For instructions on how to access these data, please contact the blogpost author. Many thanks to Kathy Strabala and Lee Cronce, CIMSS, for their work in making these data available. Click here for short video explaining MIRS Ice Concentration).

Added: A consequence of the relatively poor resolution of ATMS (compared to, say, AMSR-2 on GCOM) is that a footprint in the Great Lakes will often not be over only water or over only land. A mixed surface (land and water within the ATMS footprint) means that the ice concentration algorithm will struggle to interpret the signal and reach the right solution. Best resolution from ATMS occurs near the sub-satellite point (from 15-50 km, depending on the frequency), and that’s where this product give the best information. (Thanks to Chris Grassotti, NOAA/CISESS for this information)

Chinook winds and an atmospheric river affect south-central Alaska

December 9th, 2019 |

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images, along with

GOES-17 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images, along with “Red” Visible (0.64 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) Low-level Water Vapor (7.3 µm), Mid-level Water Vapor (6.9 µm), Upper-level (6.2 µm) Water Vapor and “Red” Visible (0.64 µm) images (above) showed orographic wave clouds and banner clouds associated with strong winds across south-central Alaska on 09 December 2019. These strong winds were associated with flow around a deepening Storm Force low that was moving from the Gulf of Alaska to the Bering Sea (surface analyses). Downsloping (southeasterly) chinook winds (topography) caused the air temperature at Anchorage International Airport (PANC) to rise to 51ºF** at 2200 UTC (11:00 am local time) — which set a new record high for the month of December at that site (** the 5-minute ASOS temperatures are reported in ºC — and rounding errors caused the converted temperature to be listed as 52ºF).



The Storm Force low was also helping to advect an atmospheric river of moisture northward toward south-central Alaska, which was depicted in hourly images of the MIMIC Total Precipitable Water product (below). Heavy rainfall (including 1.30 inch at Homer) resulting from this influx of moisture produced rises in some rivers in the Kenai Peninsula south of Anchorage.

MIMIC Total Precipitable Water product [click to play animation | MP4]

MIMIC Total Precipitable Water product [click to play animation | MP4]

 

Typhoon Kammuri makes landfall in the Philippines

December 2nd, 2019 |

Himawari-8

Himawari-8 “Clean” Infrared (10.4 µm) images [click to play animation | MP4]

2.5-minute interval rapid scan JMA Himawari-8 AHI “Clean” Infrared (10.4 µm) images (above) showed Typhoon Kammuri as it made landfall in the Philippines around 1500 UTC on 02 December 2019. Kammuri rapidly intensified from a Category 2 to a Category 4 storm (ADT | SATCON) shortly before landfall — it had been moving over very warm water (Sea Surface Temperature | Ocean Heat Content) in the Philippine Sea.

VIIRS Infrared Window (11.45 µm) from Suomi NPP at 1707 UTC and NOAA-20 at 1757 UTC viewed using RealEarth (below) depicted Kammuri 2-3 hours after landfall.

VIIRS Infrared Window (11.45 µm) from Suomi NPP at 1707 UTC and NOAA-20 at 1757 UTC [click to enlarge]

VIIRS Infrared Window (11.45 µm) from Suomi NPP at 1707 UTC and NOAA-20 at 1757 UTC [click to enlarge]

GCOM-W1 AMSR2 Microwave (85 GHz) imagery at 1725 UTC (below) revealed a large eye and nearly circular eyewall.

GCOM-W1 AMSR2 Microwave (85 GHz) image at 1725 UTC [click to enlarge]

GCOM-W1 AMSR2 Microwave (85 GHz) image at 1725 UTC [click to enlarge]