Using polar-orbiting satellite data to help fill in gaps during a GOES-13 outage

September 24th, 2012 |
GOES, POES AVHRR, MODIS, and Suomi NPP VIIRS IR images (click to play animation)

GOES, POES AVHRR, MODIS, and Suomi NPP VIIRS IR images (click to play animation)

The GOES-13 (GOES-East) satellite suffered anomalies that forced it to be placed into standby mode late in the day (at 21:22 UTC) on 23 September 2012 (NOAA NESDIS notification message). The GOES-15 (GOES-West) satellite was then placed into Full Disk scan mode, supplying images to cover as much of the eastern US and adjacent offshore waters as possible at 30-minute intervals.

During the GOES-13 outage, satellite imagery viewed in AWIPS on the “CONUS” scale did not display the complete full disk scan information from GOES-15, resulting in large areas with no data over the southeastern and eastern US (note: the full GOES-15 scan sector is available when viewed on the AWIPS “North America” scale, but the data resolution is degraded due to the very large satellite viewing angle). However, during this period there were a handful of overpasses from a number of polar-orbiting satellites, allowing imagery from the POES AVHRR, MODIS, and Suomi NPP VIIRS instruments to help fill in some of the gaps on the GOES imagery. Examples of these polar-orbiting IR images interjected among the available GOES-15 IR images are shown above. During the 21-hour GOES-East outage period, there were a total of 25 polar-orbiting passes (15 POES AVHRR, 7 MODIS, and 3 Suomi NPP VIIRS) available to offer high spatial resolution data over areas with poor quality GOES-15 data coverage.

CIMSS is able to provide POES AVHRR, MODIS, and Suomi NPP VIIRS imagery in AWIPS format to NWS forecast offices (via Unidata LDM subscription) to serve as an additional source of satellite imagery that could prove to be useful during such geostationary satellite outages.

While the GOES-13 outage persists, real-time GOES-14 imagery can be viewed using the SSEC Geostationary Image Browser.

UPDATE: As of 17:45 UTC on 24 September, GOES-14 replaced GOES-13 as the operational GOES-East satellite (NOAA/NESDIS notification message). After the 18:31 UTC image (below), there was complete coverage of the CONUS from GOES-14 (as viewed using all AWIPS scales).

GOES-14 10.7 µm IR image

GOES-14 10.7 µm IR image

In the early morning, before GOES-14 took over as the operational GOES-East satellite, it captured a beautiful sequence of 0.63 µm visible channel images (below; click image to play animation) showing river valley fog across parts of Kentucky, West Virginia, and adjacent states. Also evident early in the animation across the far southern portion of the images is the hazy signature of smoke aloft, transported from the large fires that have been burning in the Pacific Northwest states.

GOES-14 0.63 µm visible channel images (click image to play animation)

GOES-14 0.63 µm visible channel images (click image to play animation)

Satellite Views of Unusual Pre-dawn Temperature Rise

September 24th, 2012 |
METARS over south-central Wisconsin

METARS over south-central Wisconsin

The animation above shows three hours of METAR plots, with the first one — 0900 UTC — overlaying a MODIS Infrared image. Note how the temperature at Madison (KMSN) in the center of the image rises from 34 with calm winds at 0900 UTC to 37 with light southwest winds at 1000 UTC to 47 at 1100 UTC.

MODIS Estimates of Lake Surface Temperature

MODIS Estimates of Lake Surface Temperature

Madison’s Truax airport is northeast of Lake Mendota, a lake with a surface area of approximately 40 square miles. MODIS SSTs esimates, above, show surface temperatures near 60 degrees Fahrenheit, in agreement with in situ observations (Click here for real-time observations). Land surface temperature estimates, below, show that most of the Wisconsin is near freezing, although a pocket of low 20s (Fahrenheit) exists in northeast Dane County. The elevated terrain of the Military Ridge in Iowa County shows up nicely as somewhat warmer. (Click here for a toggle between Land Surface Temperature and Topography). Land-surface temperatures over Lake Mendota (yellow) are in the low 60s. Both land-surface and lake-surface temperature estimates are warmer than the 11-µm brightness temperature because those algorithms consider more than just the 11-µm brightness temperature.

MODIS Estimates of Land Surface Temperature

MODIS Estimates of Land Surface Temperature

The southwest winds that developed in the early morning hours were able to move warmer lake-modified air to the observating station at the airport, resulting in the dramatic temperature rise. The National Weather Service in Sullivan also noted this temperature rise. GOES-West imagery in that plot (GOES-West is used because GOES-East at the time had shut down due to an anomaly) suggests that the airport warmth was sub-pixel scale.