Iceberg near Innaarsuit, Greenland

July 20th, 2018 |

Landsat-8 False Color RGB image swaths, zoomed in to show the iceberg near Innaarsuit, Greenland [click to enlarge]

Landsat-8 False Color RGB image swaths, zoomed in to show the iceberg near Innaarsuit, Greenland [click to enlarge]

Landsat-8 False Color Red-Green-Blue (RGB) images viewed using RealEarth (above) is zoomed in (final image) to show a large iceberg (snow and ice appear as cyan) near the island community of Innaarsuit, Greenland (shades of light green) on 20 July 2018. Media stories about this iceberg can be found here and here.

Occluded cyclone in southern Canada

July 15th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, upper left), Low-level Water Vapor (7.3 µm, upper right), Mid-level Water Vapor (6.9 µm, lower left) and Upper-level Water Vapor (6.2 µm, lower right) images [click to play animation]

A 4-panel comparison of GOES-16 (GOES-East) “Red” Visible (0.64 µm), Low-level Water Vapor (7.3 µm), Mid-level Water Vapor (6.9 µm) and Upper-level Water Vapor (6.2 µm) images (above) showed a large occluded cyclone (surface analyses) over northern Saskatchewan and northern Manitoba on 15 July 2018. In the cold sector of the storm, morning temperatures were confined to the 40s F — especially at Churchill, Manitoba where strong easterly winds were blowing off Hudson Bay.

A closer examination of the GOES-16 images (below) revealed the presence of waves over southwestern Manitoba on the Water Vapor imagery — these appeared to vertically-propagating waves which formed due to the interaction of strong boundary layer winds with the topography of that area (some land features rise to 2600 feet). These waves then began breaking and propagating slowly westward late in the animation.

GOES-16 "Red" Visible (0.64 µm, upper left), Low-level Water Vapor (7.3 µm, upper right), Mid-level Water Vapor (6.9 µm, lower left) and Upper-level Water Vapor (6.2 µm, lower right) images [click to play animation]

GOES-16 “Red” Visible (0.64 µm, upper left), Low-level Water Vapor (7.3 µm, upper right), Mid-level Water Vapor (6.9 µm, lower left) and Upper-level Water Vapor (6.2 µm, lower right) images [click to play animation]

A NOAA-20 VIIRS True Color Red-Green-Blue (RGB) image (below) showed numerous smoke plumes from wildfires in southeastern Manitoba and western Ontario, as well as the light cyan color of ice in central and eastern portion of Hudson Bay (ice analysis: northern | southern).

NOAA-20 VIIRS True Color RGB image [click to enlarge]

NOAA-20 VIIRS True Color RGB image [click to enlarge]

The Air Mass RGB views two different cyclones

July 9th, 2018 |

GOES-16 Air Mass RGB, 1542 – 2042 UTC on 9 July 2018 (Click to animate)

Two similarly-sized cyclones over the western Atlantic Ocean have very different representations in the Air Mass RGB product. Tropical Cyclone Chris is mostly white surrounded by green. The ‘Red’ component of the Air Mass RGB is the Split Water Vapor Difference Product, and when that value is small, a large red component is present. In tropical airmasses with abundant moisture, the 6.2 µm and 7.3 µm water vapor infrared brightness temperatures are similar. The different colors in the extratropical cyclone to the northeast of Chris arise because of subsiding dry air that affects all three components of the Air Mass RGB product.

One way to help interpret the RGB product is to load all three component parts, as shown below. The Split Water Vapor Difference (Red Component of the Air Mass RGB, upper right), the Split Ozone Difference (Green Component of the RGB, lower left) and the Upper Level Water Vapor (6.19 µm, Blue Component of the RGB, lower right). These are shown in 2037 UTC in the default enhancement, and then color-coded Red, Green, Blue using the Brightness Temperature limits in the RGB definition.

Air Mass RGB (Upper Left), Split Water Vapor Difference (Upper Right), Split Ozone Brightness Temperature Difference (Lower Left) and 6.19 Upper-level Water Vapor Imagery (Lower Right) at 2037 UTC on 9 July (Click to enlarge)

Added: The Band 13 image (Clean Infrared Window, 10.3 µm) for 2037 UTC is shown below.

GOES-16 “Clean Window” Infrared Image (10.3 µm), 2037 UTC on 9 July 2018 (Click to enlarge)

Thanks to Paul Ford, ECC Canada, for alerting us to this very interesting juxtaposition!

Blooming canola fields in North Dakota and Manitoba

July 9th, 2018 |

Terra MODIS True Color RGB images on 06 June, 05 July and 09 July 2018 [click to enlarge]

Terra MODIS True Color RGB images on 06 June, 05 July and 09 July 2018 [click to enlarge]

A toggle between Terra MODIS True Color Red-Green-Blue (RGB) images (from the MODIS Today site) on 06 June, 05 July and 09 July 2018 (above) revealed the brightening yellow-green hues of blooming canola fields across parts of northeastern North Dakota and southern Manitoba. Note that changes can even be seen between the 2 days in early July!

Credit to NWS Grand Forks for alerting us to this interesting phenomenon.