Article on our Advanced Baseline Imager for GOES-R I helped write.

1. Satellite imaging
by Randall Bass and Laura Jairam
ImprovIng
resolutIon
New capabilities in satellite imaging
A new imaging sensor promises huge improvements in meteorological
satellite-imaging information and products
hen Explorer 7 was launched in The ABI will provide significant advancements polar orbiting sensors. Like previous GOES
W 1959 by Verner Suomi and
colleagues at the University of
over the current fleet of GOES satellite
instruments in several key areas, including the
satellites, the ABI will image clouds and
weather systems, monitor water vapor at
Wisconsin, it marked the first successful introduction of new spectral channels from three levels, and estimate sea-surface
meteorological instrument on board an geostationary orbit and a remarkable temperatures, total column ozone, wind
orbiting spacecraft and the age of space- improvement in spatial and temporal resolution speed, and rainfall rates.
based meteorology was born. Finally over current GOES imagery. With the addition of the 0.47 micron
humans were able to see weather from above The spectral characteristics of ABI visible channel, the 0.865-2.25 micron NIR
the atmosphere instead of from within it. combine visible, Near IR, and IR channels channels, and the 8.5 and 10.35 micron IR
When TIROS-1 was launched in 1960, we spanning the range of 0.5-13.3 microns channels, ABI will greatly enhance the
were able to view the Earth and its weather (Table 1). The advantages of ABI’s channel monitoring of vegetative growth, the
systems as a whole for the first time, design are multifold. Heritage GOES identification of fire hot spots and volcanic
changing our perception of the Earth to an channels, highlighted in Table 1, will eruptions, the discrimination of snow and
integrated, inseparable system of land, continue long-standing data sets and ice, and the prediction of hurricane
ocean, and atmosphere. The Applications support traditional GOES imagery products. intensities. The ABI will also be capable of
Technology Satellite was launched into In addition, several new channels will onboard calibration, meaning more reliable
geostationary orbit in 1966, and time provide novel science benefits, as well as data and more accurate forecasting. Overall,
domain images of weather patterns became measurements complimentary to current ABI’s channel characteristics represent the
a reality. The Geostationary Operational combined knowledge of several decades of
Satellite (GOES) program began in 1975 and satellite research and engineering and will
heralded the beginning of operational continue the GOES satellite programs’ more
geostationary satellite imagery that than 30 year trend of advancement in Earth
continues to this day. monitoring and atmospheric remote sensing.
Over time, satellite meteorology has ABI’s spectral advancements will be
become routine. Images of storm systems further augmented by improvements in both
and hurricanes taken from space flash spatial and temporal resolution over the
across the local news broadcasts on a daily current GOES satellite capabilities. The
basis. Today’s younger meteorologists have current GOES imager has a ground
never known a time without weather resolution of approximately 1km for visible
satellite data to help prepare a forecast. But images, and 4km in all other bands. ABI
real-time pictures of weather systems and image resolution will be twice as fine at
weekend forecasts are not the only use of 100% ground coverage with a 0.5km grid
meteorological satellite (METSAT) imagery. for visible images, a 1-2km grid for its Near
The demand for more and more information IR channels, and 2km for MWIR and LWIR
on clouds, water vapor and other bands (Table 1).
atmospheric constituents is increasing as the The current GOES Imager performs full
understanding of our complex atmosphere disk, CONUS, and mesoscale imaging
grows. This growing demand is driving the functions. However, the operational scan
trend toward better, more elaborate weather system can only actively task one of the
satellites. Toward this end, ITT Corporation functions at a time, therefore each image
is building the newest imaging sensor, the must be scheduled for collection in a serial
Advanced Baseline Imager (ABI), for fashion. For example, the current GOES
integration on the next-generation GOES imager takes roughly 26 minutes to collect a
series, GOES-R and GOES-S. full Earth image, which are typically
Simulation, derived from NASA MODIS data, scheduled once every three hours to collect
ABI characteristics showing how ABI clearly captures the over-shooting CONUS and regional images more regularly.
The meteorological community awaits the (cold) cloud tops, while the GOES Imager does The rapid-scan mesoscale function can image
not (Courtesy of CIMSS at the University of
upcoming launch of the GOES-R satellite with a regional area every minute, but at the
Wisconsin-Madison
the ABI on board, currently scheduled for 2015. expense of losing all METSAT coverage for
112 • ME TEOROLOGICAL TEChnOLOGy InTERn ATIOn A L nOVEMBER 2010

2. Satellite imaging
Hurricane
application
Hurricanes have always been of interest to provide insight to better hurricane intensity
maritime and coastal communities. Better estimation. The Hurricane Intensity
hurricane track and intensity prediction are Estimate product has been developed to
a priority for tropical meteorologists. generate hurricane central pressure data
Hurricanes such as Andrew, Mitch and and maximum sustained winds in near real
Katrina have demonstrated both the time. An intensity estimate analysis and an
potential destruction of these storms and intensity trend of the storm will be created
the difficulty in accurately predicting their using this product.
strength and path. The National Hurricane Center will utilize
Although hurricane detection products this information to make more accurate
the rest of the hemisphere. In normal mode, are well established using current GOES forecasts and advanced warnings. Data
the current GOES imager collects imagers, details about the eye of the storm from ABI not only helps forecasters warn
approximately four CONUS images per hour. are underdeveloped. Temporal and spatial the public of impending disasters, it will
In contrast, the new ABI sensor will be able enhancements in the ABI will allow give meteorologists and climatologists
to take a full Earth image in just five minutes. scientists to monitor storm-eye insight into atmospheric conditions that
Furthermore, ABI has a flexible scan mode development in a similar way to watching cause these storms. Finally, ABI data may
where one full Earth disk, three CONUS every frame of a movie in high definition help answer questions on whether climate
images, and 30 mesoscale (aka regional scale, rather than every 10th frame in standard change has an effect on the number and
approximately 1,000 x 1,000km) snapshots definition (below). This capability should intensity of hurricanes in the ocean basins.
are collected every 15 minutes. ABI’s ability to
focus on regional atmospheric phenomena
with a 30-second refresh rate, while still Simulated images of the
monitoring weather on a hemispheric scale, is 16 ABI bands for
Hurricane Katrina. These
truly an exciting advancement for images were simulated
meteorologists. This feature will greatly aid via a combination of high
efforts to comprehensively track weather spatial-resolution
systems affecting North America (see figures numerical model runs
left). It is estimated that ABI will provide 48 and advanced ‘forward’
radiative transfer models
times the amount of data available from the (Courtesy of CIMSS at
current GOES Imager. the University of
Wisconsin-Madison)
ABI products
ABI will enable more accurate nowcasting
and short-term forecasting than current
METSAT data can provide, based solely on
its finer spatial, spectral, and temporal
resolution. The enhanced resolution and
additional channels on ABI will also offer
new opportunities for remote sensing.
The list of potential applications entices
meteorologists, land-use planners and the
casual weather enthusiast. Supercell
detection, fire detection and characterization,
upper-level sulfuric acid detection, air-quality
analysis, vegetation monitoring, cloud-top
phase/particle-size data, rainfall-rate
detection, and hurricane-intensity estimation,
to name a few, are new and enhanced developed many new cloud products. ABI’s monitors convective developments, and along
products. They can be divided into three higher spatial- and temporal-resolution data with the cloud-top temperature and cloud-top
categories: weather and atmospheric allows forecasters to closely monitor the pressure products, will provide information
monitoring products, climate monitoring, development of clouds in all weather for satellite-derived wind monitoring. Cloud
and hazard detection. There are far too many situations. It will be used in conjunction with optical depth, cloud-particle size distribution,
individual products to describe here, but a radiative transfer model to generate cloud- cloud liquid water and cloud-ice water
several of significance are highlighted. type and cloud top-phase products. These products round out the cloud-application
The improved detection of clouds will products will classify the various types of suite. In addition to improving aircraft safety,
benefit the weather community, as well as clouds. The phase (ice, water or mixed) of a these products will also provide vital
climatologists and the aviation community. A cloud can impact aircraft icing conditions, and information for climate research.
GOES-R Cloud Application Team has been therefore plays a key role in aviation routing Many people around the world are
created and its members have already and planning. The cloud top-height product affected by flooding each year, particularly
ME TEOROLOGICAL TEChnOLOGy InTER n ATIOn AL nOVEMBER 2010 • 113

3. Satellite imaging
Table 1: Channel Characteristics of the Advanced Baseline Imager
ABI Channels Spectral Spatial
Band Ch. Center Width IFOV Imagery Use Heritage Instruments
Wavelength (µm) FWHM (µm) at nadir (km)
VIS 1 0.47 0.04 1 Daytime aerosol over land, vegetative MODIS*
health, coastal mapping
2 0.64 0.1 0.5 Daytime clouds, fog, insolation, winds Current GOES Imager
and Sounder
NIR 3 0.865 0.039 1 Daytime vegetation, burn scar, VIIRS**, AVHRR†
aerosol over water, winds
4 1.378 0.015 2 Daytime cirrus clouds VIIRS, MODIS
5 1.61 0.06 1 Daytime cloud-top phase and particle size, VIIRS, AVHRR
snow and cloud discrimination
6 2.25 0.05 2 Daytime land properties, cloud particle size, VIIRS, MODIS
vegetation, snow, hot-spot identification
MWIR 7 3.9 0.2 2 Surface, clouds, nighttime fog, winds, Current GOES Imager
fire/hot-spot, volcanic eruption/ash, snow/ice
detection, urban heat islands
8 6.185 0.83 2 High-level atmospheric water vapor, winds, rainfall Current GOES Imager
9 6.95 0.4 2 Mid-level atmospheric water vapor, winds, rainfall Current GOES Sounder
10 7.34 0.2 2 Lower-level water vapor, winds, upper-level Spectrally modified
sulfuric acid (SO2 ) current GOES Sounder
11 8.5 0.4 2 Total water for stability, cloud phase, dust, MODIS Airborne
SO2 aerosols Simulator (MAS)
LWIR 12 9.61 0.38 2 Total ozone, turbulence, winds Spectrally modified
current GOES Sounder
13 10.35 0.5 2 Hurricane intensity, surface moisture, cloud particle size MAS
14 11.2 0.8 2 Detection of hazardous weather conditions, Sea Surface Current GOES Sounder
Temp (SST), clouds, rainfall rates
15 12.3 1 2 Total water, ash, dust, SST, cloud particle size Current GOES Sounder
16 13.3 0.6 2 Air temp, cloud heights and amounts, Current GOES Imager
tropopause delineation and Sounder
*MODerate Resolution Imaging Spectroradiometer (MODIS)
** Visible and Infrared Imager and Radiometer Suite (VIIRS)
† Advanced Very High Resolution Radiometer (AVHRR)
in low-lying regions like the Gulf of Mexico result, improved forecasts and advanced
and the south-eastern coastlines of the USA. warning systems will allow forecasters and
Three new products have been designed for the public to take more preventative
anticipated ABI data: rainfall rate, rainfall measures when faced with weather
potential, and probability of rainfall. These phenomena. This short list of products is
precipitation-estimation products are only a small preview of the benefits that the
expected to reduce economic and human ABI suite will offer the weather community
costs associated with flooding events. and the general public. A prototype model of
Rainfall rate is designed to retrieve cloud the ABI is currently undergoing thermal-
phases and particle sizes from the new vacuum testing at ITT’s Rochester, NY
SWIR and MWIR bands on ABI. It will use a facility. This prototype model was built with
statistical model that will account for the specific design requirements of the
natural variation between, and within, actual flight model for GOES-R, which is
regions rather than assuming one regional currently in production and on track for a
base model. The improved 2km spatial Prototype model of ABI
successful integration and, most
resolution will enable better accuracy in the importantly, a successful launch in 2015. z
calculation of rainfall rates. The rainfall
potential product will extrapolate Baseline Imager on the GOES series will be Randall Bass is a senior meteorologist with ITT
information from the rainfall rate to aid in an excellent asset to meteorologists and Geospatial Systems, Herndon, Virginia and Laura
forecasting areas of heaviest rain and flood climatologists around the world. Its spectral, Jairam is a senior image scientist with ITT Geospatial
potential, with up to three hours of warning. spatial, and temporal advancements will Systems in Herndon. Cooperation came from Rachel
The rainfall probability product is a three provide more accurate measurements of Fitzhugh, an image scientist with ITT Geospatial
hour forecast, predicting the geographical cloud properties, convective development, Systems, Rochester, and Marie Knappenberger, a
areas where rain is expected. The Advance rainfall rates and hurricane intensities. As a geoscientist in Rochester, New York
114 • ME TEOROLOGICAL TEChnOLOGy InTERn ATIOn A L nOVEMBER 2010