All posts by Scott Bachmeier

Eruption of Mount Sinabung volcano

Himawari-8 RGB images [click to play animation]

Himawari-8 RGB images [click to play animation]

An explosive eruption of Mount Sinabung began at 0153 UTC on 19 February 2018. Himawari-8 False-color Red-Green-Blue (RGB) images from the NOAA/CIMSS Volcanic Cloud Monitoring site (above) showed the primary plume of high-altitude ash moving northwestward, with ash at lower altitudes spreading out to the south and southeast of the volcano.

Mutli-spectral retrievals of Ash Cloud Height (below) indicated that the explosive eruption injected volcanic ash to altitudes generally within the 12-18 km range, possibly reaching heights of 18-20 km. Advisories issued by the Darwin VAAC listed the ash height at 45,000 feet (13.7 km).

Himawari-8 Ash Height product [click to play animation]

Himawari-8 Ash Height product [click to play animation]

Ash Loading values (below) were also very high within the high-altitude portion of the plume.

Himawari-8 Ash Loading product [click to play animation]

Himawari-8 Ash Loading product [click to play animation]

The Ash Effective Radius product (below) indicated that very large particles were present within the plume immediately downwind of the eruption site.

Himawari-8 Ash Effective Radius product [click to play animation]

Himawari-8 Ash Effective Radius product [click to play animation]

In a comparison of Himawari-8 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.4 µm) images (below), note the very pronounced warm thermal anomaly or “hot spot” (large cluster of red pixels) on the 0150 UTC image — Himawari-8 was actually scanning that location at 01:54:31 UTC, just after the 0153 UTC eruption. Prior to the main eruption, beginning at 0120 UTC a very narrow volcanic cloud — likely composed primarily of condensed steam — was seen streaming rapidly southward from the volcano summit.

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.4 µm, right) images [click to play Animated GIF | MP4 also available]

The coldest Himawari-8 cloud-top infrared brightness temperature was -73 ºC at 0300 UTC, which roughly corresponded to an altitude of 15 km on the nearby WIMM Medan rawinsonde data at 00 UTC (below).

Medan, Indonesia rawinsonde data at 00 UTC on 19 February [click to enlarge]

Medan, Indonesia rawinsonde data at 00 UTC on 19 February [click to enlarge]

A Terra MODIS True-color RGB image viewed using RealEarth is shown below. The time of the Terra satellite overpass was 0410 UTC.

Terra MODIS True-color RGB image [click to enlarge]

Terra MODIS True-color RGB image [click to enlarge]

An animation of Himawari-8 True-color RGB images can be seen here.

Cyclone Kelvin makes landfall in Australia

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface plots at Broome [click to play Animated GIF | MP4 also available]

Himawari-8 Visible (0.64 µm, left) and Infrared Window (10.4 µm, right) images, with hourly surface plots at Broome, Australia [click to play Animated GIF | MP4 also available]

Himawari-8 Visible (0.64 µm) and Infrared Window (10.4 µm) images (above) showed Cyclone Kelvin as it made landfall in Western Australia as a Category 1 storm on 18 February 2018. Kelvin continued to intensify shortly after making landfall, with estimated winds of 80 gusting to 100 knots — and a distinct eye feature could be seen in the Visible and Infrared imagery (as well as Broome radar data).

A longer animation of Himawari-8 Infrared Window (10.4 µm) images (below) revealed a very large convective burst as Kelvin meandered near the coast early on 17 February — periodic cloud-top infrared brightness temperatures of -90 ºC or colder were seen. After making landfall, the eye structure eventually deteriorated by 18 UTC on 18 February.

Himawari-8 Infrared Window (10.4 µm) images, with hourly surface plots [click to play MP4 | Animated GIF also available]

Himawari-8 Infrared Window (10.4 µm) images, with hourly surface plots [click to play MP4 | Animated GIF also available]

The MIMIC-TC product (below) showed the development of Kelvin’s compact eye during the 17 February – 18 February period; the eye was well-defined around the time of landfall (2147 UTC image on 17 February), and persisted for at least 18 hours (1556 UTC image on 18 February) until rapidly dissipating by 21 UTC.

MIMIC-TC morphed microwave imagery [click to enlarge]

MIMIC-TC morphed microwave imagery [click to enlarge]

Himawari-8 Deep Layer Wind Shear values remained very low — generally 5 knots or less — prior to, during and after the landfall of Kelvin, which also contributed to the slow rate of weakening. In addition, an upward moisture flux from the warm/wet sandy soil of that region helped Kelvin to intensify after landfall; land surface friction was also small, since that portion of Northwest Australia is rather flat.

Himawari-8 Water Vapor images, with Deep Layer Wind Shear product [click to enlarge]

Himawari-8 Water Vapor images, with Deep Layer Wind Shear product [click to enlarge]

The eye of Cyclone Kelvin could also be seen in Terra MODIS and Suomi NPP VIIRS True-color Red-Green-Blue (RGB) images, viewed using RealEarth (below). The actual times of the Terra and Suomi NPP satellite overpasses were 0154 UTC and 0452 UTC on 18 February, respectively.

Terra MODIS and Suomi NPP VIIRS True-color RGB images [click to enlarge]

Terra MODIS and Suomi NPP VIIRS True-color RGB images [click to enlarge]

Ice motion in the Great Lakes

GOES-16 "Red" Visible (0.64 µm) images, with hourly plots of surface wind barbs in cyan and wind gusts (kn0ts) in red (click to play Animated GIF)

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface wind barbs in cyan and wind gusts (knots) in red (click to play Animated GIF | MP4 also available)

GOES-16 “Red” Visible (0.64 µm) images showed ice motion in the western Great Lakes (above) and the central/eastern Great Lakes (below) on 14 February 2018. A flow of southwesterly winds at the surface was helping to move the lake ice toward the northeast. With increasing winds and a return of warmer air, the ice coverage of Lake Superior, Lake Michigan and Lake Huron had decreased slightly from their seasonal peaks a few days earlier — while the ice coverage for Lake Erie remained neared its seasonal peak. The total ice coverage for the Great Lakes as a whole was 57.9% on this day.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface wind barbs in cyan and wind gusts (knots) in red (click to play Animated GIF | MP4 also available)

Closer views of southern Lake Michigan and southern Lake Huron are shown below. In Lake Huron, small ice floes can be seen breaking away from the land fast ice.

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface wind barbs in cyan and wind gusts (knots) in red (click to play Animated GIF | MP4 also available)

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with hourly plots of surface wind barbs in cyan and wind gusts (knots) in red (click to play Animated GIF | MP4 also available)

250-meter resolution Terra and Aqua MODIS True-color Red-Green-Blue (RGB) images from the MODIS Today site (below) provided more detailed views of the ice floes in southern Lake Michigan, southern Lake Huron and western Lake Erie. The Aqua satellite overpass was about 90 minutes later than that of Terra.

Terra and Aqua MODIS True-color RGB images of southern Lake Michigan [click to enlarge]

Terra and Aqua MODIS True-color RGB images of southern Lake Michigan [click to enlarge]

Terra and Aqua MODIS True-color RGB images of southern Lake Huron [click to enlarge]

Terra and Aqua MODIS True-color RGB images of southern Lake Huron [click to enlarge]

Terra and Aqua MODIS True-color RGB images of western Lake Erie [click to enlarge]

Terra and Aqua MODIS True-color RGB images of western Lake Erie [click to enlarge]

Temporary transition from Himawari-8 to Himawari-9

Himawari-8 and Himawari-9

Himawari-8 and Himawari-9 “Clean” Infrared Window (10.4 µm) images [click to play Animated GIF | MP4 also available]

Himawari-9 temporarily took over for Himawari-8 beginning at 0250 UTC on 13 February 2018, as Himawari-8 underwent a 2-day scheduled maintenance. “Clean” Infrared Window (10.3 µm) images of Category 4 Cyclone Gita in the South Pacific Ocean during the satellite transition is shown above.

Himawari-9 was launched on 02 November 2016.

Cyclone Gita in the South Pacific Ocean

Himawari-8

Himawari-8 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.4 µm, bottom) images, with hourly plots of surface reports [click to play Animated GIF | MP4 also available]

Himawari-8 “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed Cyclone Gita as it moved toward Tonga in the South Pacific Ocean during 11 February – 12 February 2018. The tropical cyclone reached Category 4 intensity (ADT | SATCON) near the end of the animation period.

A longer animation of Himawari-8 Infrared images (below) revealed that the center of Gita moved just south of the main island of Tongatapu. Surface observations from Fua’Amotu (NFTF) ended after 0735 UTC.

Himawari-8

Himawari-8 “Clean” Infrared Window (10.4 µm) images, with hourly surface plots [click to play Animated GIF | MP4 also available]

MIMIC-TC morphed microwave imagery (below) showed that Gita underwent an eyewall replacement cycle after moving to the southwest of Tongatapu — a small eyewall was replaced by a larger eyewall, which was very apparent in DMSP SSMIS Microwave (85 GHz) images at 1533 and 1749 UTC.

MIMIC-TC morphed microwave imagery

MIMIC-TC morphed microwave imagery

Metop ASCAT scatterometer surface winds (below) showed Gita around the time that the storm center was just south of Tongatapu at 0850 UTC.

Metop ASCAT scatterometer surface winds [click to enlarge]

Metop ASCAT scatterometer surface winds [click to enlarge]

Large hail in Argentina

GOES-16

GOES-16 “Red” Visible (0.64 µm, top) and “Clean” Infrared Window (10.3 µm, bottom) images, with hourly surface reports (metric units) for Córdoba, Argentina [click to play animated GIF — MP4 also available]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed the development of severe thunderstorms which produced very large hail in Córdoba, Argentina on 08 February 2018. Distinct above-anvil plumes were evident on the Visible imagery, with pulses of overshooting tops exhibiting Infrared brightness temperatures in the -70 to -80ºC range (black to white enhancement). The hail reportedly began around 1930 UTC or 4:30 PM local time.

The above-anvil plumes could also be seen in GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images (below).

GOES-16 Near-Infrared

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images, with hourly surface reports (metric units) for Córdoba, Argentina [click to play animated GIF — MP4 also available]

An Aqua MODIS True-color Red-Green-Blue (RGB) image viewed using RealEarth (below) showed the thunderstorm just west of Córdoba around 1850 UTC.

Aqua MODIS True-color RGB image [click to enlarge]

Aqua MODIS True-color RGB image [click to enlarge]

According to the Worldview site, the coldest Aqua MODIS cloud-top infrared brightness temperature at that time was -78ºC (below).

Aqua MODIS True-color and Infrared Window (11.0 µm) images [click to enlarge]

Aqua MODIS True-color and Infrared Window (11.0 µm) images [click to enlarge]

A time series plot of surface observations at Córdoba (below) showed the warm temperatures and high dew points prior to the arrival of the thunderstorms; there were a number of hail reports between 19 UTC and 02 UTC (4 PM to 11 PM local time).

Time series of surface observations at Córdoba, Argentina [click to enlarge]

Time series of surface observations at Córdoba, Argentina [click to enlarge]

Satellite signatures of SpaceX Falcon Heavy rocket launch

GOES-16 "Red" Visible <em>(0.64 µm, top),</em> Near-Infrared "Snow/Ice" <em>(1.61 µm, middle)</em> and Shortwave Infrared <em>(3.9 µm, bottom)</em> images, with plots of surface reports [click to play animation]

GOES-16 “Red” Visible (0.64 µm, top), “Blue” Visible (0.47 µm, middle) and Near-Infrared “Snow/Ice” (1.61 µm, bottom) images, with plots of surface reports [click to play animation]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), “Blue” Visible (0.47 µm) and Near-Infrared “Snow/Ice” (1.61 um) images (above) captured the signature of rocket plumes from the SpaceX Falcon Heavy launch at Kennedy Space Center, Florida on 06 February 2018. Bright areas of water droplet clouds were seen both at the surface near Launch Complex 39A and aloft just east of the Florida coast on the 20:47:28 UTC and 20:52:28 UTC images (the satellite was scanning those cloud features at 20:48:33 / 20:55:33 UTC or 3:48:33 / 3:55:33 PM Eastern Standard Time, respectively). The plume aloft looked like this from the surface. Due to significant lower-tropospheric wind shear, the near-surface launch pad plume drifted slowly toward the northwest, while the higher-altitude plume moved more quickly toward the northeast. Strong upper-tropospheric winds — 86 knots at 140 hPa or 14.4 km on the 12 UTC sounding — led to a 2 hour launch delay until speeds dropped to within safe flight criteria.

Looking farther to the east-northeast over the Atlantic Ocean, a pair of warm thermal anomalies — likely from the recently-separated twin Side Core booster engines (left) and the still-active single Center Core booster engine (right) — were seen on the corresponding 20:47:28 UTC GOES-16 Upper-level (6.2 µm), Mid-level (6.9 µm) and Low-level (7.3 µm) Water Vapor images (below). A similar warm signature in Water Vapor imagery was observed following a previous SpaceX rocket launch in March 2017.

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm) images [click to play animation]

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Low-level (7.3 µm, bottom) images [click to play animation]

While Shortwave Infrared (3.9 µm) imagery is useful for detection of thermal anomalies associated with wildfires or volcanic eruptions, in this case the warm signature (darker gray) was much less distinct compared to what was seen on the water vapor imagery (below).

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Shortwave Infrared (3.9 µm, bottom) image [click to enlarge]

GOES-16 Upper-level (6.2 µm, top), Mid-level (6.9 µm, middle) and Shortwave Infrared (3.9 µm, bottom) image [click to enlarge]

Sensing the surface with water vapor imagery

GOES-16 Low-level (7.3 µm) Water Vapor images [click to play animation]

GOES-16 Low-level (7.3 µm) Water Vapor images [click to play animation]

As a cold, dry arctic air mass moved across the western Great Lakes on 06 February 2018, portions of the land-water boundaries of Lake Superior, Lake Michigan and Lake Huron were very distinct on GOES-16 (GOES-East) Low-level (7.3 µm) Water Vapor images (above). The motion of low-altitude lake effect clouds were also apparent in the imagery.

Plots of weighting functions for the three GOES-16 ABI Water Vapor bands (7.3 µm, 6.9 µm and 6.2 µm) are shown below, calculated using rawinsonde data from Green Bay, Wisconsin and Gaylord, Michigan. With cold air and low values of Total Precipitable Water at these 2 sites (1.53 mm / 0.06 in and 1.88 mm / 0.07 in, respectively), the height of their weighting functions was shifted to significantly lower altitudes compared to what would be observed in a standard atmosphere. This enabled the contrasting thermal signature of the land/water boundaries to easily reach the satellite sensors, passing through what little moisture existed within the atmospheric column. While the peak of the violet 7.3 µm weighting function plots descended to the 879 hPa pressure level at both sites (which was approximately 1.2 km above the surface), a significant contribution could be seen originating from the surface itself.

Weighting function plots for the three GOES-16 Water Vapor bands, calculated using rawinsonde data from Green Bay, Wisconsin [click to enlarge]

Weighting function plots for the three GOES-16 Water Vapor bands, calculated using rawinsonde data from Green Bay, Wisconsin [click to enlarge]

Weighting function plots for the three GOES-16 Water Vapor bands, calculated using rawinsonde data from Gaylord, Michigan [click to enlarge]

Weighting function plots for the three GOES-16 Water Vapor bands, calculated using rawinsonde data from Gaylord, Michigan [click to enlarge]

Note that the peaks of the blue 6.9 µm weighting function plots were also anomalously low, reaching the 802 and 754 hPa pressure levels — however, in contrast to the 7.3 µm plots there was very little contribution from the actual surface, and the presence of secondary peaks at higher altitudes led to some absorption and subsequent re-emission of upwelling radiation by that layer of colder moisture aloft. As a result, only the faint outline of Lake Superior and its lake effect clouds were occasionally seen on Mid-level 6.9 µm Water Vapor imagery (below).

GOES-16 Mid-level (6.9 µm) Water Vapor images [click to play animation]

GOES-16 Mid-level (6.9 µm) Water Vapor images [click to play animation]

Lee-side cold frontal gravity wave

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, middle) and Upper-level (6.2 µm, right) Water Vapor images, with hourly surface wind barbs plotted in cyan [click to play animation]

GOES-16 Low-level (7.3 µm, left), Mid-level (6.9 µm, middle) and Upper-level (6.2 µm, right) Water Vapor images, with hourly surface wind barbs plotted in cyan [click to play animation]

As a cold front moved rapidly southward across the Great Plains (surface analyses) on 05 February 2018, the signature of a deep-tropospheric lee-side cold frontal gravity wave (reference) could be seen on GOES-16 Low-level (7.3 µm), Mid-level (6.9 µm) and Upper-level (6.2 µm) Water Vapor images (above; also available as an MP4 animation). In addition, the initial gravity wave was soon followed by a secondary lee-side gravity wave, which could be seen moving southward over the northern Texas Panhandle by the end of the animation.

Plots of the weighting function (or “contribution function”) for each of the three GOES-16 Water Vapor bands (below) are calculated using 05 February/12 UTC rawinsonde data from Dodge City, Kansas — which was south of the cold front at that time. The peak pressure level for all three weighting function plots was in the 442-497 hPa range, giving some indication of the depth of these vertically-propagating gravity waves.

Weighting function plots for each of the three GOES-16 Water Vapor bands, calculated using 05 February/12 UTC rawinsonde data from Dodge City, Kansas [click to enlarge]

Weighting function plots for each of the three GOES-16 Water Vapor bands, calculated using 05 February/12 UTC rawinsonde data from Dodge City, Kansas [click to enlarge]

GOES-16 Water Vapor weighting functions using 06 February/00 UTC rawinsonde data from Amarillo, Texas — where the surface cold front had passed about 3 hours earlier — are shown below. Note that in the drier post-frontal air mass, the peak pressures for the 3 water vapor bands had increased, descending to the 477 to 684 hPa pressure levels. This comparison helps to underscore the dependence of water vapor weighting function height on the temperature and/or moisture profile of the atmosphere.

Weighting function plots for each of the three GOES-16 Water Vapor bands, calculated using 06 February/00 UTC rawinsonde data from Amarillo, Texas [click to enlarge]

Weighting function plots for each of the three GOES-16 Water Vapor bands, calculated using 06 February/00 UTC rawinsonde data from Amarillo, Texas [click to enlarge]

Ice in the western Great Lakes

GOES-16 "Red" Visible (0.64 µm) images, with plots of hourly surface reports [click to play animation]

GOES-16 “Red” Visible (0.64 µm) images, with plots of hourly surface reports [click to play animation]

After several days of cold temperatures, ice coverage in the western half of Lake Superior began to increase — and GOES-16 (GOES-East) “Red” Visible (0.64 µm) images (above) showed the motion of some of this lake ice (which was driven by a combination of surface winds and lake circulations) on 04 February 2018. That morning a number of locations in northern and northeastern Minnesota reported low temperatures in the -20 to -40 ºF range, with -43 ºF at Embarrass (the coldest location in the Lower 48 states).

With an overpass of the Landsat-8 satellite at 1646 UTC, a 30-meter resolution False-color Red-Green-Blue (RGB) image (below) provided a very detailed view of a portion of the Lake Superior ice. NOAA-GLERL analyzed the mean ice concentration of Lake Superior to be at 23.9% ; the Canadian Ice Service analyzed much of the new lake ice to have a concentration of 9/10ths to 10/10ths.

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Magnified sections of the Landsat-8 RGB image swath are shown below, moving from northeast to southwest.

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Landsat-8 False-color RGB image [click to enlarge]

Moving to the south, a closer look at Green Bay in northeastern Wisconsin revealed a few small ice floes drifting from the north end of the bay into Lake Michigan (below).

GOES-16

GOES-16 “Red” Visible (0.64 µm) images, with plots of hourly surface reports [click to play animation]