GOES-15 replaces GOES-11 as the operational GOES-West satellite

December 6th, 2011 |

At 15:46 UTC on 06 December 2011, GOES-15 replaced GOES-11 as the operational GOES-West satellite. GOES-11 (launched in 2000, and operational since 2006) was one of the older GOES-I/J/K/L/M series of satellites (GOES-8/9/10/11/12), while GOES-15 (launched in 2010; Post Launch Test) is one of the newer GOES-N/O/P series of satellites (GOES-13/14/15) — so there are some important differences that users of the new GOES-15 imagery should be aware of:

  1. Improved water vapor channel (Imager channel 3)
  2. Slightly different visible channel (Imager chanel 1)
  3. 13.3 µm IR (Imager channel 6) replaces the 12.0 µm  IR (Imager channel 5)
  4. Improved Image Navigation and Registration (INR)
  5. Shorter image outages during Spring and Fall season “eclipse periods”
  6. Less noise on many of the Sounder channels
GOES-11 vs GOES-15 Imager water vapor channel data as the source for GOES-West

GOES-11 vs GOES-15 Imager water vapor channel data as the source for GOES-West

The improvement made to the GOES-15 Imager instrument water vapor channel is likely the most important change that operational users will notice. In the sequence of AWIPS images above, the first 3 images are using the 8-km resolution GOES-11 6.7 µm channel as the source for GOES-West water vapor imagery, while the final 3 images use the 4-km resolution GOES-15 6.5 µm channel. Note the change to slightly warmer/drier water vapor brightness temperatures (brighter yellow color enhancement) after the changeover to GOES-15 — this in part due to the fact that the spectral response function of the 4-km resolution water vapor channel on GOES-12 and beyond is much wider than that of the 8-km resolution water vapor channel on GOES-8 through GOES-11. In addition, notice that the north-south “seam” joining the GOES-West and GOES-East water vapor channel images disappears, since the characteristics of the water vapor channels are now identical on those two satellites.

In the sequence of AWIPS images below, the first 2 images are using the GOES-11 Sounder instrument 6.5 µm channel as the source for GOES-West water vapor imagery, while the final 2 images use the GOES-15 Sounder 6.5 µm channel. Note the improvement in noise seen in the Sounder instrument water vapor images after the changeover to GOES-15. Since the 3 GOES Sounder water vapor channels are a component of the GOES Sounder Total Precipitable Water derived product imagery, the quality of that product should also improve.

GOES-11 vs GOES-15 Sounder 6.5 µm water vapor channel data as the source for GOES-West

GOES-11 vs GOES-15 Sounder 6.5 µm water vapor channel data as the source for GOES-West

In terms of the visible imagery, a comparison using GOES-11 (the first 3 images) vs GOES-15 (the final set of 3 images) Imager visible channel data is seen below (during a test on 29 November). Immediately obvious is the fact that the GOES-15 visible channel imagery appears “brighter” than the GOES-11 visible channel imagery — this is due to the fact that the performance of the GOES visible detectors degrades over time. The 0.63 µm visible channel on GOES-15 is also slightly different than the 0.65 µm visible channel on GOES-11, as is discussed in the “GOES-13 is now the operational GOES-East satellite” blog post. GOES-15 is similar to GOES-13, since it is part of the GOES-N/O/P series of spacecraft.

Using GOES-11 vs GOES-15 as the source for GOES-West visible channel images

Using GOES-11 vs GOES-15 as the source for GOES-West visible channel images

One of the benefits of GOES-15 is improved Image Navigation and Registration (INR), which leads to less image-to-image “wobble” when viewing an animation. The improved GOES-15 INR is quite evident when compared to GOES-11 for this blowing dust case on 27 November (below; click image to play animation).

GOES-11 0.65 µm and GOES-15 0.63 µm visible images (click image to play animation)

GOES-11 0.65 µm and GOES-15 0.63 µm visible images (click image to play animation)

A comparison of the GOES-15 0.63 µm visible channel, the 10.7 µm “IR window” channel, and the 13.3 µm “CO2 absorption” IR channel (below) shows that high cloud features will show up with more clarity on the 13.3 µm images — by examining the weighting function of the 13.3 µm IR channel, it can be seen that this CO2 absorption channel samples radiation from a much deeper, much higher altitude than the standard 10.7 µm IR window channel.

GOES-15 0.63 µm visible channel, 10.7 µm IR channel, and 13.3 µm IR channel images

GOES-15 0.63 µm visible channel, 10.7 µm IR channel, and 13.3 µm IR channel images

The 13.3 µm “CO2 absorption” IR channel is also used for the creation of derived products such as Cloud Top Pressure. An example of a combined GOES-15 (GOES-West) + GOES-13 (GOES-East) Cloud Top Pressure product is shown below (courtesy of Tony Schreiner, CIMSS).

GOES-15 + GOES-13 Cloud Top Pressure product

GOES-15 + GOES-13 Cloud Top Pressure product

An example of the value of having larger batteries onboard the GOES-13/14/15 spacecraft during eclipse periods can be seen below, as Hurricane Ike was making landfall along the Texas coast in September of 2008. During the approximately 3 hour image outage from GOES-12 during the eclipse period (when the satellite was in the Earth’s shadow, and the solar panels could not generate the power necessary to operate the GOES imager and GOES sounder instrument packages), GOES-13 IR images continued to be available — and these GOES-13 images showed a strong spiral band that was in the process of intensifying and moving inland along the far northeastern Texas and far southwestern Louisiana coastlines.

GOES-12 vs GOES-13 IR images (Hurricane Ike making landfall)

GOES-12 vs GOES-13 IR images (Hurricane Ike making landfall)

Additional information can be found on the VISIT training lesson “GOES-15 Becomes GOES-West“.

HISTORICAL NOTE: GOES-15 became GOES-West on the 45th anniversary of the launch of ATS-1 on 06 December 1966. ATS-1 was the first meteorological satellite to provide geostationary images — an example of an early ATS-1 visible image is seen below, and QuickTime movies are available which show animations of some of the early ATS-1 images.

ATS-1 visible image (11 December 1966)

ATS-1 visible image (11 December 1966)

GOES-13 is now the operational GOES-East satellite

April 14th, 2010 |
GOES-12 0.65 µm vs GOES-13 0.63 µm visible images

GOES-12 0.65 µm vs GOES-13 0.63 µm visible images

As of 18:34 UTC on 14 April 2010, GOES-13 (launched May 2006, with a Post Launch Test in December 2006) replaced GOES-12 (launched July 2001) as the operational GOES-East satellite  — for more information, see the NOAA NESDIS Satellite Services Division. A sequence of AWIPS images (above) shows the last three GOES-12 visible images followed by the first three GOES-13 visible images centered over the Upper Midwest region of the US during the satellite transition period. Both the GOES-12 and the GOES-13 visible images are enhanced using the “Linear” AWIPS enhancement (see below for more details).

Note that areas of dense vegetation (for example, over river valleys, and also across much of southern Indiana) appear slightly darker on the GOES-13 visible channel images. This is due to the fact that the visible channel on the newer GOES series — GOES-13 and beyond — is a narrower channel (centered at 0.63 µm, vs 0.65 µm for the older GOES satellites) that misses the “brighter” portion of the grass/vegetation spectrum (green plot) that begins to increase rapidly at wavelengths higher than about 0.7 µm (below). You will also notice that the cloud features appear slightly brighter in the last three GOES-13 images — this is due to the fact that the GOES visible detector performance tends to degrade over time, so the visible images from the much  older GOES-12 satellite appear slightly “washed out” in comparison.

GOES-12 vs GOES-13 visible channel spectral response function plots

GOES-12 vs GOES-13 visible channel spectral response function plots

Note to AWIPS users: because of the different characteristics of the GOES-13 visible channel, it is suggested that you change the default GOES visible image enhancement from “ZA” to “Linear” — as seen in a GOES-13 visible image comparison with those 2 enhancements (below), the GOES-13 imagery can appear too dark with the default “ZA” enhancement.

GOES-13 visible image: "ZA" enhancement vs "Linear" enhancement

GOES-13 visible image: “ZA” enhancement vs “Linear” enhancement

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GOES-12 vs GOES-13 Sounder 4.5 µm shortwave IR images

GOES-12 vs GOES-13 Sounder 4.5 µm shortwave IR images

There are also significant improvements in the quality of the GOES-13 Sounder data, due to the fact that GOES-12 had been experiencing filter wheel problems for quite some time. AWIPS comparisons of the last GOES-12 and the first GOES-13 Sounder 4.5 µm shortwave IR images (above) and 6.5 µm water vapor channel images (below) clearly demonstrate the dramatic reduction in noise — in these Sounder composite images, the western portion of the image is GOES-11 (GOES-West) data, while the eastern portion of the image is either GOES-12 or GOES-13 (GOES-East) data. In particular, the 6.5 µm water vapor image is “cleaner” on GOES-13 as a result of “colder” detectors on the newer spacecraft design, which more effectively radiate to space.

GOES-12 vs GOES-13 Sounder 6.5 µm water vapor channel images

GOES-12 vs GOES-13 Sounder 6.5 µm water vapor channel images

Blended Total Precipitable Water products

March 9th, 2009 |
Blended Total Precipitable Water (AWIPS menu)

Blended Total Precipitable Water (AWIPS menu)

Beginning on 09 March 2009, two new Blended Total Precipitable Water (TPW) products were made available to NWS forecast offices who have installed AWIPS Operational Build 9 (OB9) — a Blended TPW product (above; Animated GIF), and a Percent of Normal TPW product (below; Animated GIF).

Percent of Normal TPW (AWIPS menu)

Percent of Normal TPW (AWIPS menu)

The Blended TPW products incorporate data from a number of polar-orbiting and geostationary satellite platforms. Over water, the algorithm currently uses data from:

  • the SSM/I instrument (on the DMSP F13 satellite)
  • the AMSU instrument (on the NOAA-15, NOAA-16, NOAA-17, NOAA-18, and MetOp-A satellites)

and over land, the algorithm uses data from:

  • the  GOES Sounder instrument (on the GOES-11 and GOES-12 satellites)
  • ground-based Global Positioning System (GPS-MET) receivers

On AWIPS, the Blended TPW product is generated using the latest data source available for each pixel; it is  then  mapped to a Mercator projection with a spatial resolution of 16 km at the Equator. The products are available in AWIPS on a varying schedule, but in general there will be 1 or 2 Blended TPW images per hour.

The Percent of Normal TPW  (or “Blended TPW Anomaly”) product (below) compares the current Blended TPW values to the mean values derived during the 1988-1999 time period (using a climatology of SSM/I TPW over oceans, and a mix of rawinsonde and TOVS sounding TPW over land). Note that while the raw TPW Anomaly product is capable of calculating  values in excess of 200%, on AWIPS all of the TPW Anomaly values  greater than 200% are simply colored yellow (and displayed as “> 201” using AWIPS cursor sampling).

Blended TPW Percent of Normal (TPW Anomaly)

Percent of Normal TPW (TPW Anomaly)

A 4-panel comparison of Blended, GOES Sounder, DMSP SSM/I, and POES AMSU TPW products (below, using a different CIMSS TPW enhancement) demonstrates some of the advantages of the blended TPW product, namely (1) no gaps between the individual swaths of polar-orbiting satellite data over water, and (2) the availability of TPW data in areas of dense cloud cover (over both land and water).

Comparison on Blended, GOES Sounder, DMSP SSM/I, and POES AMSU TPW products

Comparison of Blended, GOES Sounder, SSM/I, and AMSU TPW products

A comparison of AWIPS cursor sampling of the Blended, GOES Sounder, DMSP SSM/I, and POES AMSU TPW products (below) shows that in general, the TPW value for any given location should agree to within a few millimeters (or within several hundredths to perhaps one tenth of an inch).

Comparison of Blended, GOES sounder, SSM/I, and AMSU TPW products

Comparison of Blended, GOES sounder, SSM/I, and AMSU TPW products

However, at times there may be some disagreement between TPW values at any particular point (below), due to temporal differences of the data as displayed in AWIPS. In other words, the time displayed in the AWIPS product label may not necessarily apply to all portions of the displayed image.

Comparison of Blended, GOES sounder, SSM/I, and AMSU TPW products

Comparison of Blended, GOES sounder, SSM/I, and AMSU TPW products

The images below show the coverage of the Blended TPW product when displayed in AWIPS at the Northern Hemisphere, Pacific Mercator, North America, Pacific Satellite, and CONUS scales.

Blended TPW product (displayed on the Northern Hemisphere scale)

Blended TPW product (displayed on the Northern Hemisphere scale)

Blended TPW product (displayed on the Pacific Mercator scale)

Blended TPW product (displayed on the Pacific Mercator scale)

Blended TPW product (displayed on the North America scale)

Blended TPW product (displayed on the North America scale)

Blended TPW product (displayed on the Pacific Satellite scale)

Blended TPW product (displayed on the Pacific Satellite scale)

Blended TPW product (displayed on the CONUS scale)

Blended TPW product (displayed on the CONUS scale)

The Blended TPW and TPW Anomaly products were developed at the Cooperative Institute for Research in the Atmosphere (CIRA), and over the past few years they have been transitioned from research into NESDIS operations.

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References and related websites:

  • Kidder, S.Q. and A.S. Jones, 2007: A blended satellite Total Precipitable Water product for operational forecasting.
  • Ferraro et al., 2005: NOAA Operational Hydrological Products Derived From the Advanced Microwave Sounding Unit. IEEE Trans. Geosci. Remote Sens., 43, 1036-1049.
  • Alishouse, J.C., S. Snyder, J. Vongsathorn, and R.R. Ferraro, 1990: Determination of oceanic total precipitable water from the SSM/I. IEEE Trans. Geo. Rem. Sens., Vol. 28, 811-816.
  • Smith et al., 2007: Short-Range Forecast Impact from Assimilation of GPS-IPW Observations into the Rapid Update Cycle. Mon. Wea. Rev., 135, 2914-2930.
  • Schmit et al., 2002: Validation and use of GOES Sounder moisture information. Wea. Forecasting, 17, 139-154.

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updated 20 March 2009 –

MTSAT High Density Winds

January 1st, 2009 |
MTSAT High Density Winds (AWIPS menu)

MTSAT High Density Winds (AWIPS menu)

Beginning in October 2008,  “high density winds” (also known as Atmospheric Motion Vectors, or AMVs) derived from the Japanese geostationary  Multi-functional Transport Satellite (MTSAT-1R, which is positioned over the Equator at 140º East longitude) were added to the NOAAPORT Satellite Broadcast Network (SBN). National Weather Service forecast offices localized as West CONUS sites (or OCONUS offices in the Alaska Region and the Pacific Region) that have installed AWIPS Operational Build 9.0 or higher will be able to access these new MTSAT satellite winds products from the AWIPS menu (above).
TECHNICAL IMPLEMENTATION NOTICE 08-61
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
317 PM EDT FRI AUG 1 2008 

SUBJECT:  NESDIS HIGH DENSITY GEOSTATIONARY WINDS TO BE
          ADDED TO SBN/NOAAPORT: EFFECTIVE OCTOBER 15 2008 

EFFECTIVE WEDNESDAY OCTOBER 15 2008...BEGINNING AT APPROXIMATELY
1500 COORDINATED UNIVERSAL TIME /UTC/...THE NATIONAL
ENVIRONMENTAL SATELLITE...DATA...AND INFORMATION SERVICE /NESDIS/
AND NWS START DISSEMINATING HIGH DENSITY GEOSTATIONARY /MTSAT/
WIND PRODUCTS VIA SBN/NOAAPORT.

THE MTSAT WINDS /FROM THE JAPANESE SATELLITE/ WILL AUGMENT THE
CURRENT GOES EAST AND WEST HIGH DENSITY WINDS OVER SPARSE DATA
REGIONS...MOST BENEFITING THE ALASKA AND PACIFIC REGIONS AND THE
AVIATION WEATHER CENTER /AWC/.
Coverage of MTSAT vs GOES High Density Winds

Coverage of MTSAT High Density Winds vs GOES High Density Winds

A comparison of the areal coverage of the MTSAT vs the GOES high density winds is shown on the Pacific Mercator scale  (above) and Northern Hemisphere scale (below). The MTSAT high density winds will be available north of the Equator every 3 hours (at 02, 05, 08, 11, 14, 17, 20, and 23 UTC), and south of the Equator every 6 hours (at 00, 06, 12, and 18 UTC).

Coverage of MTSAT vs GOES High Density Winds

Coverage of MTSAT High Density Winds vs GOES High Density Winds

With the AWIPS cursor sampling function activated, the user will be able to display the valid time, the type of satellite imagery used to derive a particular AMV (Visible, InfraRed, shortwave InfraRed, or Water Vapor), the pressure of the height assignment for that AMV, and the direction/speed of that AMV (below). The wind vectors can be color-coded according to pressure layers (as shown below), or by AMV type (IR, Water Vapor, Visible, or 3.9 µm shortwave IR). Targets are tracked on three consecutive satellite images in order to calculate the direction and speed of each AMV.

MTSAT High Density Winds

MTSAT High Density Winds

These MTSAT winds available on AWIPS should be very similar to those derived using GOES data, since NESDIS is using the same AMV software (which was developed at CIMSS) for both satellites. For more details about the derivation and application of satellite-derived atmospheric motion vector products, see the SHyMet GOES High Density Winds lesson.

Reference:

Velden, C.S. et al., 2005: Recent Innovations in Deriving Winds from Meteorological Satellites. Bull. Amer. Meteor. Soc., 86, 205-223

– Updated 29 January 2009