GOES-15 3.9 µm shortwave IR images on 10 September (click image to play animation)

GOES-15, in service as GOES-West over the Equator at 135 W, has experienced navigation anomalies on each of the past three mornings, September 8, 9 and 10, 2013 (as noted here, for example). Navigation anomalies occur approximately between 0830 and 1100 UTC. GOES Engineers are investigating the source of the anomaly, which can be on the order of 40 km. The animation above is the shortwave infrared from Tuesday 10 September. Animations for 6, 7, 8 and 9 September are below. Note that even the 6 September and 7 September have small navigation issues.

(Update: From SATOPS: NOTE: GOES-15 (West) Image registration (alignment of images to earth grid coordinates) was shifted by approximately 40 kilometers on DOY251 (ed. note: 8 September) from 08:50z to 10:50z and shifted by approximately 25 kilometers on DOY252 & DOY253 (ed. note: 9 and 10 September) from 9:30z to 10:40z. The earth coordinate grid shift was due to a lack of available valid star data for predicting the proper attitude pointing profile around eclipse. The root cause is under investigation.) In other words, the Star Pointer was unable to find enough targets to produce accurate navigation. (Link)

Update, 11 September: The anomalies continued on 11 September, starting after the 0845 UTC image, peaking at the 1000 UTC image, and subsiding by 1045 UTC. Link.

Update, 17 September: Large navigation anomalies were not present overnight.

GOES-15 3.9 µm shortwave IR images on 6 September (click image to play animation)

GOES-15 3.9 µm shortwave IR images on 7 September (click image to play animation)

GOES-15 3.9 µm shortwave IR images on 8 September (click image to play animation)

GOES-15 3.9 µm shortwave IR images on 9 September (click image to play animation)

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GOES-15 3.9 µm shortwave IR images (click image to play animation)

The Morgan Fire began burning in the Mount Diablo State Park northeast of San Francisco during the afternoon hours on 08 September 2013, which caused the evacuation of dozens of homes near the fire. McIDAS images of 4-km resolution GOES-15 3.9 µm shortwave IR data (above; click image to play animation; also available as a .mp4 file) revealed that the fire “hot spot” (red color enhancement) first appeared on the 21:30 UTC (2:30 PM local time) image. The fire appeared to “settle down” for a few hours after sunset, but then there was an apparent flare-up of the fire from 04:00 – 06:30 UTC.

One thing to note on the GOES-15 shortwave IR animation above is that there was a significant Image Navigation and Registration (INR) anomaly during the 08:45 – 10:41 UTC period. An AWIPS 1-km resolution Suomi NPP VIIRS 3.74 µm shortwave IR image was available at 09:24 UTC (during the GOES-15 INR anomaly) — a comparison of this VIIRS image with the closest available GOES-15 shortwave IR image (below) demonstrates the value of higher spatial resolution VIIRS data to aid in a more accurate determination of the actual fire size and location.

Suomi NPP VIIRS 3.74 µm and GOES-15 3.9 µm shortwave IR images

Hot spots associated with the ongoing Rim Fire — so far the 3rd-largest fire on record in California — can also be seen about 100 miles to the east-southeast.

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

1-km resolution GOES-13 0.63 µm visible channel images (above; click image to play animation) revealed a pronounced convective burst associated with Tropical Depression #7, which was centered just southeast of Puerto Rico late in the day on 04 September 2013. On the final visible image before darkness, a pair of small but distinct overshooting tops could be seen, which actually signalled the beginning of another convective burst.

The corresponding 4-km resolution GOES-13 10.7 µm IR channel images (below; click image to play animation) showed that there were a series 3 well-defined convective bursts (2 more followed after darkness), each exhibiting areas with cloud-top IR brightness temperatures of -80º C or colder (violet color enhancement). On the final image in the animation (at 02:45 UTC), the coldest IR brightness temperature was -86º C This was about the time that Tropical Depression #7 was upgraded to Tropical Storm Gabrielle.

GOES-13 10.7 µm IR channel images (click image to play animation)

A 1-km resolution POES AVHRR 12.0 µm IR image at 01:16 UTC (below) showed one overshooting top that exhibited an IR brightness temperature of -90º C (dark violet enhancement).

POES AVHRR 12.0 µm IR image

Two GOES-13 IR images at 03:45 UTC on 05 September from the CIMSS Tropical Cyclones site (below) showed that (1) Gabrielle was in an environment characterized by a light amount (around 10 knots) of deep layer (200-850 hPa) wind shear, and (2) a well-defined low-level cyclonic circulation was difficult to distinguish with the ASCAT surface scatterometer winds at that time.

GOES-13 IR image with deep layer wind shear analysis

GOES-13 10.7 µm IR image with ASCAT surface scatterometer winds

===== 05 September Update =====

DMSP-17 SSMIS 85 GHz microwave brightness temperature

On the morning of 05 September, a DMSP-17 SSMIS 85 GHz microwave brightness temperature image at 10:42 UTC (above) and GOES-13 10.7 µm IR images (below) suggested that the mid-level circulation center of of Gabrielle was reforming well to to the east of the original fix location low-level circulation center. Around the time of the end of the IR image animation, Gabrielle was downgraded to a Tropical Depression.

GOES-13 10.7 µm IR images

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Google Maps terrain, with Landsat-8 0.45 µm visible channel and 2.29 µm shortwave IR channel images

Google Maps terrain along with 30-meter resolution Lansdat-8 0.45 µm visible channel and 2.29 µm shortwave IR channel images of the Rim Fire in California at 18:42 UTC on 31 August 2013 are shown above. While there were some scattered clouds in the satellite scene, a great deal of optically-thick smoke could be seen in the visible image (along with some new smoke plumes from a cluster of active fires). On the shortwave IR image, the active fire “hot spots” appear as bright white features around the perimeter of the fire burn scar. These Landsat-8 images are displayed using the SSEC Web Map Server.

As of 31 August, the Rim Fire had burned 222,777 acres, making it the 4th largest fire on record for the state of California; the fire was estimated to be 45% contained at that time. The corresponding 31 August Landsat-8 false-color Red/Green/Blue (RGB) image — created using Bands 7/5/3 — shows the large areal extent of the fire burn scar (darker red colors), along with the active fires along the perimeter (brighter pink colors).

Google Maps terrain, with Landsat-8 false-color Red/Green/Blue (RGB) false-color image

Credits: original RGB image created by Sam Batzli, SSEC; RGB image converted for WMS display by Russ Dengel, SSEC.

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