GOES-13 views thermal signature of rocket launch explosion at Wallops Island Virginia

October 28th, 2014
GOES-13 3.9 µm shortwave infrared channel images (click to enlarge)

GOES-13 3.9 µm shortwave infrared channel images (click to enlarge)

The launch of an Antares rocket from Wallops Island, Virginia, failed on October 28th (NASA Statement on the failure). The thermal signature from the explosion and fire is evident in the animation of GOES-13 3.9 µm imagery above, within the red circle: the IR brightness temperature was 292.2K on the 22:30 UTC image (darker black pixel), compared to 286.9 and 286.7 K on the 22:15 UTC and 22:45 UTC images, respectively. The nominal time of the satellite image with the warm pixel is 22:30; however, the actual satellite scan time at Wallops Island’s latitude is 22:33 UTC. The launch was at 22:22 UTC.

On a side note, another feature that stands out in the GOES-13 3.9 µm images is the warm signature (darker black enhancement) of the waters of the Gulf Stream. A comparison of the Suomi NPP VIIRS Sea Surface Temperature product at 06:47 UTC (2:47 am local time) and 18:11 UTC (2:11 pm local time), below, showed a number of eddy features along the edges of the warm (darker red) Gulf Stream.  Strong winds associated with a Nor’easter storm several days earlier helped to create these eddies.

Suomi NPP VIIRS Sea Surface Temperature product (click to enlarge)

Suomi NPP VIIRS Sea Surface Temperature product (click to enlarge)

Shadow of partial solar eclipse

October 23rd, 2014
GOES-15 0.63 µm visible channel images

GOES-15 0.63 µm visible channel images

McIDAS images of GOES-15 (GOES-West) 0.63 µm visible channel data (above) showed the west-to-east progression of the lunar umbra (the Moon’s shadow) from a partial solar eclipse that occurred on 23 October 2014. The shadow was most obvious across the northern portion of the images, moving over Alaska, the Gulf of Alaska, western/northern Canada, and the far northwestern portion of the Lower 48 States of the US. The partial eclipse shadow could also be seen on GOES-13 (GOES-East) 0.63 µm visible channel images (below).

GOES-13 0.63 µm visible channel images

GOES-13 0.63 µm visible channel images

According to EarthSky.org the point of greatest eclipse (75% coverage of the solar disk by the Moon) was near Prince of Wales Island, Nunavut, Canada at 21:44 UTC. In a sequence of before, during, and after-eclipse AWIPS images of Suomi NPP VIIRS 0.64 µm visible channel data (below), a darkening of Canada’s Yukon Territory — which covered most of the center portion of the images — could be seen.

Suomi NPP VIIRS 0.64 µm visible channel images

Suomi NPP VIIRS 0.64 µm visible channel images

Hurricane Gonzalo moves towards Bermuda

October 16th, 2014
GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

Small and intense Hurricane Gonzalo is moving north-northeastward out of the western tropical Atlantic towards Bermuda (Bermuda is located at 32.3º N, 64.8º W). (See the National Hurricane Center Website for the latest Advisories on Gonzalo) GOES-13 Visible imagery (0.63 µm) from the morning of 16 October shows a well-defined eye, intense convection and good outflow in all quadrants. Mesovortices within the eye are also apparent as shown in a storm-centered animation of the eye, below, until mid- and high-level clouds develop near the end of the animation.

GOES-13 0.63 µm visible channel images, centered over the eye of Gonzalo (click to play animation)

GOES-13 0.63 µm visible channel images, centered over the eye of Gonzalo (click to play animation)

Gonzalo’s track will take it over sea surface temperatures that are not quite so warm (see image below, taken from the CIMSS Tropical Cyclones site). Cooler SSTs argue against any further strengthening, and the official forecast suggests peak intensity has already occurred.

Sea Surface Temperatures and Gonzalo's projected (and past) track and intensity (click to enlarge)

Sea Surface Temperatures and Gonzalo’s projected (and past) track and intensity (click to enlarge)

Suomi NPP overflew the storm at 0536 UTC in 16 October. A toggle between the VIIRS Day/Night Band and the 11.45 µm imagery is below. Note that lunar illumination is dropping as the Moon phase wanes so visible features are less distinct than they would be during a more Full Moon. A ragged eye is obvious in both images, however, and there is evidence of a lightning streak well east of the eye in the Day/Night Band.

Suomi NPP Day/Night Band Visible Imagery and 11.45 µm Infrared Imagery (click to enlarge)

Suomi NPP Day/Night Band Visible Imagery and 11.45 µm Infrared Imagery (click to enlarge)

Both Aqua and Metop-A overflew Gonzalo during the day on 16 October. The Aqua True-Color image (from the MODIS Today website) shows the storm and the cold front that will help guide Gonzalo’s future path. The ASCAT scatterometer data from METOP-A, below, showed a tight region of hurricane-force winds.

METOP-A ASCAT Scatterometer winds, 1353 UTC 16 October 2014 (click to enlarge)

METOP-A ASCAT Scatterometer winds, 1353 UTC 16 October 2014 (click to enlarge)

===== 18 October Update =====

Suomi NPP VIIRS 11.45 µm IR channel images

Suomi NPP VIIRS 11.45 µm IR channel images

A sequence of Suomi NPP VIIRS 11.45 µm IR channel images during the 15-17 October period (above) showed the pattern of very cold cloud-top IR brightness temperatures at various times as the storm curved northward toward Bermuda (station identifier TXKF); IR brightness temperatures of -80º C and colder (violet color enhancement) were seen on 15 and 16 October. A close-up view shows Gonzalo on 2 consecutive VIIRS IR images (16:38 and 18:18 UTC) on 17 October.

The MIMIC Total Precipitable Water (TPW) product (below; click image to play animation) showed a plume of high TPW ahead of a cold front moving off the East Coast of the US, which was then reinforced by a northward surge of high TPW from Ganzalo. As a result, the TPW value calculated using the morning rawinsonde data from Caribou, Maine (station identifier KCAR) was 1.68 inches — the highest for so late in the season.

MIMIC Total Precipital Water product (click to play animation)

MIMIC Total Precipital Water product (click to play animation)

Around 20:15 UTC on 17 October, a comparison of GOES-13 10.7 µm IR channel and SSMIS 85 GHz microwave images from the CIMSS Tropical Cyclones site (below), the microwave image revealed the very large size of the eye of Hurricane Gonzalo (which was not as apparent on conventional IR imagery).

GOES-13 10.7 µ IR image and SSMIS 85 GHz microwave image

GOES-13 10.7 µ IR image and SSMIS 85 GHz microwave image

A close-up view of GOES-13 10.7 µm IR channel images with overlays of wind barbs and wind gusts from Bermuda International Airport (below; click image to play animation) showed the development of a convective burst just as the eye of Gonzalo was approaching the island. The airport observations (text listing | time series plot) showed a wind gust to 83 knots (96 mph) as the northern eyewall passed, and a stronger gust to 98 knots (113 mph) as the southern eyewall passed over Bermuda.

GOES-13 10.7 µm IR channel images, with overlays of wind barbs and wind gusts at Bermuda (click to play animation)

GOES-13 10.7 µm IR channel images, with overlays of wind barbs and wind gusts at Bermuda (click to play animation)

The Bermuda Weather Service launched a rawinsonde balloon at 00 UTC on 18 October; winds at the surface were from the southeast at 64 knots (74 mph), which carried the instrument package into the eye of Gonzalo for a portion of its ascent. Note the the temperature profile was nearly moist adiabatic from about 700 hPa to 200 hPa (below).

Bermuda rawinsonde report and GOES-13 10.7 µm IR image

Bermuda rawinsonde report and GOES-13 10.7 µm IR image

Suomi NPP and GOES Views of Hurricane Gonzalo

October 14th, 2014
Suomi NPP 11.45 µm Infrared Imagery and Day Night Band Imagery, 0617 UTC 14 October 2014 (click to enlarge)

Suomi NPP 11.45 µm Infrared Imagery and Day Night Band Imagery, 0617 UTC 14 October 2014 (click to enlarge)

The VIIRS instrument on Suomi NPP yielded compelling nighttime imagery of Hurricane Gonzalo in the western Atlantic. The toggle above of the Day Night Band and the 11.45 µm Infrared imagery shows a circular central dense overcast over the storm (imagery courtesy of William Straka, CIMSS). No eye structure is immediately apparent, although very cold cloud tops are present at the storm center. A larger-scale view of the Day Night Band and 11.45 µm imagery, below, shows a storm in a low to moderate wind shear environment with a well-defined outflow channel to the northeast. Note the pronounced “transverse banding” signature along the southern periphery of the hurricane – such transverse banding is often seen in areas of high-altitude of turbulence. Gonzalo was forecast to strengthen (see the National Hurricane Center website for more details).

Suomi NPP 11.45 µm Infrared Imagery and Day Night Band Imagery, 0617 UTC 14 October 2014 (click to enlarge)

Suomi NPP 11.45 µm Infrared Imagery and Day Night Band Imagery, 0617 UTC 14 October 2014 (click to enlarge)

During the subsequent daytime hours on 14 October, Hurricane Gonzalo did indeed continue to intensify, becoming a Category 3 storm by the late afternoon (ADT plot). The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as every 5-7 minutes; 0.63 µm visible channel images (below; click image to play animation; also available as an MP4 movie file) showed periodic convective bursts around the eye of Gonzalo as the tropical cyclone moved northwestward.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)