Southwest US monsoon convection: GOES-15 vs GOES-16

July 12th, 2018 |

GOES-15 Visible (0.63 µm, left) and GOES-16 Visible (0.64 µm, right) images [click to play MP4 animation]

GOES-15 Visible (0.63 µm, left) and GOES-16 “Red” Visible (0.64 µm, right) images [click to play MP4 animation]

GOES-15 (GOES-West) Visible (0.63 µm) and GOES-16 (GOES-East) “Red” Visible (0.64 µm) images — displayed in the native projection of each satellite, and centered on Las Vegas, Nevada — are shown above, depicting the development of deep convection across parts of the Desert Southwest on 12 July 2018. While the GOES-15 satellite was in Rapid Scan Operations mode (providing 2 extra images nearly every hour, at :11 and :41), a GOES-16 Mesoscale Sector was providing images at 1-minute intervals. Numerous flash flood watches, warnings and advisories were issued by NWS Las Vegas during the course of the day as some of the storms produced heavy rainfall (with as much as 0.75 inch at Cal Nev Ari and 0.61 inch at Needles, California KEED).

Note that the GOES-15 Visible images do not appear as bright as those from GOES-16 — prior to the GOES-R Series of satellites, the performance of visible detectors degraded over time, leading to imagery that appeared more dim as the Imager instrument aged. Visible detectors on the new ABI instrument benefit from on-orbit calibration to remedy this type of degradation.

The corresponding GOES-15 Infrared Window (10.7 µm) and GOES-16 “Clean” Infrared Window (10.3 µm) images (below) revealed cloud-top infrared brightness temperatures around -70ºC (black enhancement) associated with some the stronger thunderstorms; this was the tropopause temperature at an altitude of 16.7 km / 48,300 feet on 00 UTC Las Vegas rawinsonde data. The improvement in spatial resolution from 4 km (at sub-satellite point) with GOES-15 to 2 km with GOES-16 is very apparent — even though the satellite viewing angle is about 10 degrees higher for GOES-16 than it is for GOES-15.

GOES-15 Infrared Window (10.7 µm, left) and GOES-16 "Clean" Infrared Window (10.3 µm, right) images [click to play MP4 animation]

GOES-15 Infrared Window (10.7 µm, left) and GOES-16 “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

Higher spatial resolution Infrared Window images from Terra/Aqua MODIS and Suomi NPP VIIRS (below) revealed a cloud-top infrared brightness temperature as cold as -79ºC in far northwestern Arizona on the 2017 UTC VIIRS image.

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

Infrared Window images from Terra/Aqua MODIS (11.0 µm) and Suomi NPP VIIRS (11.45 µm) [click to enlarge]

In addition to heavy rainfall, some thunderstorm winds created areas of blowing sand:

The GOES-16 Total Precipitable Water derived product (below) showed that rich moisture was present across the Desert Southwest, fueling the development of the widespread convection. TPW values in the 1.0 to 2.0 inch range were seen over southeastern California, southwestern Arizona and far southern Nevada.

GOES-16 Total Precipitable Water derived product [click to play MP4 animation]

GOES-16 Total Precipitable Water derived product [click to play MP4 animation]

A 4-km resolution Terra/Aqua MODIS Total Precipitable Water product (below) indicated values in the 40-55 mm or 1.6-2.2 inch range.

Terra/Aqua MODIS Total Precipitable Water product [click to enlarge]

Terra/Aqua MODIS Total Precipitable Water product [click to enlarge]

Stereoscopic views of Convection using GOES-16 and GOES-17

July 12th, 2018 |

GOES-16 (Left) and GOES-17 (Right) Visible (0.64 ) imagery, 1202-1907 UTC on 11 July 2018 (Click to play mp4 animation)

GOES-17 is currently in the test position at 89.5º W Longitude, and GOES-16 is at the GOES-East location at 75.2º W Longitude. This close spacing longitudinally means that stereoscopic three-dimensional views of visible imagery can be produced. The mp4 animation above (Click here for an animated gif) shows convection over the Tennessee River valley from 1202 through 1907 UTC on 11 July 2018 (with some gaps in time when GOES-17 data were not received).

To view the animation in three dimensions, cross your eyes so that three separate images are present.  Focus on the image in the middle.

Added, courtesy of Rick Kohrs, SSEC: When you create a Stretched ‘True Color’ image from the first 3 Channels on GOES-16/GOES-17, you can also see the curvature of the Earth in the stereoscopic view!

Stretched CIMSS Natural True Color imagery, combining Bands 1-3 on GOES-16 and GOES-17, 1400 UTC on 12 July 2018 (Click to enlarge)

GOES-17 imagery in this blog post is preliminary and non-operational.

Hurricane Chris accelerates away from the United States

July 11th, 2018 |

GOES-16 ABI Band 2 (“Red Visible”) Visible (0.64 µm) Imagery, 1852-2117 UTC on 11 July 2018 (Click to animate)

Hurricane Chris is accelerating away from the United States (although it will likely pass very close to Cape Race, Newfoundland Canada). Visible Imagery (GOES-16 ABI Band 2, “Red Visible”, at 0.64 µm), above, from late afternoon on 11 July shows a well-developed storm with a pronounced eye.

Before Sunrise on 11 July 2018, both NOAA-20 and JAXA’s Global Change Observation Mission (GCOM) Satellite overflew the storm at slightly different times.  The VIIRS (Visible Infrared Imaging Radiometer Suite) instrument NOAA-20 samples in the visible and infrared part of the electromagnetic spectrum whereas the AMSR2 Instrument (Advanced Microwave Scanning Radiometer 2) on GCOM samples in the microwave.  Because microwave energy can penetrate clouds, it can be used to estimate rainfall, and the toggle below steps through the Infrared (11.45 µm) and Day Night Band Visible (0.70 µm) from VIIRS (at 0645 UTC) as well as the Convective Precipitation and Surface Rain rate from AMSR2 (at 0618 UTC). 

Lunar illumination is absent  in the Day Night band visible imagery, but Earth glow nevertheless illuminates the eye of the storm;  in addition, two lightning streaks are visible north and east of the center.  Surface Rain and Convective Rain rates show the heaviest rains near the storm center, as expected (NOAA-20 VIIRS and GCOM AMSR2 imagery courtesy William Straka, CIMSS).

VIIRS Infrared (11.45 µm) and Visible (0.70 µm) Day Night Band Visible Imagery, 0645 UTC on 11 July 2018, and GCOM AMSR2 Convective Precipitation and Surface Rain Rate estimates at 0618 UTC on 11 July (Click to enlarge)

Natural gas explosion and fire in Sun Prairie, Wisconsin

July 10th, 2018 |

GOES-16 Shortwave Infrared (3.9 µm) image and Fire Temperature derived product [click to play animation]

GOES-16 Shortwave Infrared (3.9 µm) imagery and Fire Temperature derived product [click to play animation | MP4]

An explosion triggered by a damaged natural gas main in Sun Prairie, Wisconsin occurred around 0005 UTC / 7:05 pm CDT on 10 July 2018 (media story). Layered cloudiness was passing over the region at the time of the initial explosion, but once the clouds cleared a thermal signature (blue pixel) was seen from 0247 to 0342 UTC on the GOES-16 (GOES-East) Fire Temperature product (above) as the fire burned into the nighttime hours. The maximum Fire Temperature value was 537.6 K at 0332 UTC / 10:32 pm CDT.

A thermal anomaly or “hot spot” (dark black pixels) was apparent on 1-km resolution Terra MODIS Shortwave Infrared (3.74 µm) imagery (below) at 0338 UTC / 10:38 pm CDT. The maximum infrared brightness temperature on the MODIS image was 335.4 K.

Terra MODIS Shortwave Infrared (3.74 µm) image, with plots of surface observations in yellow [click to enlarge]

Terra MODIS Shortwave Infrared (3.74 µm) image, with plots of surface observations in yellow [click to enlarge]

A very subtle thermal anomaly (darker gray pixels) was still evident after 07 UTC / 2 am CDT on Suomi NPP and Aqua MODIS Shortwave Infrared images (below).

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS Shortwave Infrared images [click to enlarge]

Terra MODIS, Suomi NPP VIIRS and Aqua MODIS Shortwave Infrared images [click to enlarge]