Scott Bachmeier « CIMSS Satellite Blog

Plumes of blowing dust and salt in Bolivia

July 7th, 2020 | Scott Bachmeier

GOES-16 True Color RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) displayed widespread plumes of blowing dust and salt originating from Salar de Uyuni in southwestern Bolivia on 07 July 2020. These aerosol sources are located within an elevated plateau with altitudes of 11-12,000 feet (3.3-3.6 km) — and similar episodes of blowing dust/salt are not uncommon during the austral winter (reference).

A longer animation of GOES-16 Dust RGB images (below) showed the continued eastward transport of dust/salt plumes for a few hours after sunset.

GOES-16 Dust RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

A sequence of GOES-16 Natural Color RGB, Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images from AWIPS (below) provided a less detailed view of the plumes — the spatial resolution of Full Disk GOES imagery in AWIPS is reduced to 6 km.

GOES-16 Natural Color RGB, Dust RGB and Split Window Difference (10.3 µm – 12.3 µm) images [click to play animation | MP4]

Winds across that region increased on 07 July as an intensifying subtropical jet streak was passing just to the north/northeast, as shown in plots of 700 hPa geopotential height and integrated water vapor transport from this site (below). Clouds associated with this jet streak could be seen in the northern portion of the GOES-16 images above.

Plots of 700 hPa geopotential height and integrated water vapor transport [click to enlarge]

Plots of rawinsonde data from Antofagasta, Chile at 12 UTC on 06, 07 and 08 July (below) showed the increase in northwesterly 700 hPa winds to 40 knots on 07 July. Antofagasta is located about 300 miles southwest of the Salar de Uyuni region.

Plots of rawinsonde data from Antofagasta, Chile at 12 UTC on 06, 07 and 08 July [click to enlarge]

Posted in GOES-16, Red-Green-Blue (RGB) images | No Comments »

Severe thunderstorms exhibiting Above-Anvil Cirrus Plumes over the Dakotas

July 4th, 2020 | Scott Bachmeier

GOES-16 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed two severe thunderstorms along the North Dakota / South Dakota border region, which exhibited Above-Anvil Cirrus Plumes (reference | VISIT training).

GOES-16 “Red” Visible (0.64 µm) images, with time-matched SPC Storm Reports plotted in red [click to play animation | MP4]

A longer animation of GOES-16 Visible images with plots of time-matched SPC Storm Reports is shown above, with GOES-16 Infrared images shown below.

GOES-16 “Clean” Infrared Window (10.35 µm) images, with time-matched SPC Storm Reports plotted in cyan [click to play animation | MP4]

Pulsing overshooting tops were seen whose cloud-top infrared brightness temperatures were in the -70 to -78ºC range — according to a plot of 00 UTC rawinsonde data from Aberdeen, South Dakota (below), this represented a 1-2 km overshoot of the Most Unstable (MU) air parcel’s Equilibrium Level (EL).

Plot of 00 UTC rawinsonde data from Aberdeen, South Dakota [click to enlarge]

Several hours later, another thunderstorm that produced damaging winds in southwestern North Dakota exhibited a residual Above-Anvil Cirrus Plume in central North Dakota as the storm was dissipating, seen in Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images at 0915 UTC (below). Coldest cloud-top infrared brightness temperatures in the overshooting top region were in the -60 to -66ºC range, while within the warmer AACP feature extending eastward they were in the -52 to -55ºC range.

Suomi NPP VIIRS Infrared Window (11.45 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Posted in GOES-16, Severe convection, Suomi NPP, VIIRS | No Comments »

Blowing dust in southern Bolivia

July 4th, 2020 | Scott Bachmeier

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images (credit: Tim Schmit, ASPB/CIMSS) [click to play animation | MP4]

GOES-16 (GOES-East) True Color Red-Green-Blue (RGB) images created using Geo2Grid (above) showed plumes of blowing dust originating from dry river beds along portions of the Río Grande O Guapay and Río Parapetí in southern Bolivia on 04 July 2020. Strong northerly winds developed across that region, just east of the axis of a deepening trough of low pressure.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 as visualized using RealEarth (below) provided a more detailed view at the blowing dust plumes.

VIIRS True Color RGB images from Suomi NPP and NOAA-20 [click to enlarge]

A plot of surface report data from Viro Viru International Airport, Santa Cruz de la Sierra — located not far to the north of the blowing dust plumes — showed northerly winds gusting as high as 36 knots (41 mph) at 20 UTC (below).

Plot of surface report data from Viro Viru International Airport [click to enlarge]

Thanks to Santiago Gassó for pointing out these dust features.

Dust activity yesterday at sunset in Bolivia pic.twitter.com/WmgaRRuVX4

— Santiago Gassó (@SanGasso) July 5, 2020

Posted in Air quality, GOES-16, NOAA-20, RealEarth, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS | No Comments »

Actinoform clouds near Hawai’i

June 30th, 2020 | Scott Bachmeier

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

GOES-17 (GOES-West) “Red” Visible (0.64 µm) images (above) revealed 3 cyclonically-rotating actinoform cloud structures that were moving west-southwestward toward the Hawaiian Islands on 30 June 2020 (surface analyses).

A closer look at the northernmost actinoform feature showed it moving over Buoy 51000 (located northeast of Hawai’i) around 04 UTC on 01 July — there was somewhat of an increase in 1-minute wind speeds and wind gusts as it approached, but no obvious perturbation was seen in the air pressure (it appeared to have arrived during the typical ~12-hourly drop in pressure).

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

A sequence of 3 hourly (at 0010, 0110 and 0210 UTC) panoramic camera views from Buoy 51000 (below) suggested that there were rain showers reaching the ocean surface beneath one of the actinoform’s radial arms at 0210 UTC (GOES-17 Visible image).

Sequence of 3 hourly (at 0010, 0110 and 0210 UTC) panoramic camera views from Buoy 51000 [click to enlarge]

Sequence of 3 hourly panoramic camera views from Buoy 51000, at 0010, 0110 and 0210 UTC [click to enlarge]

True Color Red-Green-Blue (RGB) and Infrared Window (11.45 µm) VIIRS images from NOAA-20 and Suomi NPP as visualized using RealEarth (below) provided a detailed view of 2 of the actinoform clouds. The radial arms that comprised the cloud features remained within the marine boundary layer, so they exhibited fairly warm cloud-top infrared brightness temperatures.

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

Plots of rawinsonde data from Hilo, Hawai’i (below) indicated that the marine boundary layer was strongly capped by a temperature inversion at an altitude of 1.3-1.5 km (where the air temperature was around +15ºC — which was very close to the minimum cloud-top infrared brightness temperatures exhibited by the actinoform clouds).