This document is not subject to the controls of the
International Traffic in Arms Regulations (ITAR) or the Export
Administration Regulations (EAR). 2015 NOAA Satellite Conference 27
April 1 May, 2015, Greenbelt Marriott, Greenbelt, MD Synopsis: This
poster discusses the key weather observation performance objectives
for the Canadian Polar Communication and Weather (PCW) mission and
how they drive the design and operation of a PCW imager. The
decreasing ice in the Arctic is leading to more personnel, ships,
and operations, resulting in a greater need for more accurate,
timely weather predictions. The US, Japanese, Korean, and European
meteorological agencies are all upgrading their geostationary
weather imagers to provide much more frequent Full Disk Earth
images (every 5 to 10 minutes). Arctic weather observation,
however, is still limited to a few passes a day from low Earth
orbit (LEO) satellites, many of which are well beyond their
intended operational life. The PCW mission concept is to provide
Arctic weather observations with the same temporal fidelity and
spectral resolution as equatorial and mid-latitude weather and
similar spatial resolution. Key performance objectives drive the
design and operation of a PCW imager. Key mission decisions include
number of satellites, orbit (LEO vs. HEO; Molniya, TAP, Tundra),
coverage, image collection interval, types of images (Full Disk,
storm watch, etc.), spectral bands, spatial resolution, etc. Exelis
Advanced Baseline Imager (ABI) will fly on GOES-R East, GOES-R
West, GEO-KOMPSAT-2A (Korea), and is flying on Himawari (Japan),
and providing these missions the additional capability for
interleaved mesoscales delivering storm observations every 30 to 60
seconds. ABIs operational flexibility also makes it an ideal
solution for the PCW mission. 1. Arctic Deserves Same Quality of
Weather Predictions as CONUS Geostationary weather satellites have
continuous coverage of their region of the Earth, providing high
temporal resolution and the ability to monitor rapidly evolving
severe weather events. The U.S., Japanese, Korean, and European
weather agencies are all making significant upgrades to their
geostationary weather imagers, enabling Full Disk Earth images
every 10 minutes instead of every 30 minutes. The U.S., Japanese,
and Korean imagers will also have the capability to interleave
storm watch collections every 30-60 seconds. However, due to the
curvature of the Earth none of these missions provide adequate
spatial resolution above 60 latitude. Hence, the Arctic must rely
on data from low Earth orbiting (LEO) weather satellites. At the
same time, the decreasing ice in the Arctic is leading to a need
for more accurate weather forecasting. There is an increase in
commercial shipping, commercial operations, and permanent
residents. The decreasing ice is also causing more severe weather
and greater variability in the weather. (Figure 1) 2. LEO Imagers
Have Many Limitations Much of the Arctics satellite weather data
comes from LEO satellites. They provide useful data but have
critical limitations. LEO data is collected one swath at a time
with an orbital period of ~100 minutes. There is no ability to
obtain persistent images, which means evolving weather cannot be
observed in the way that it can with a geostationary imager. The
long time gaps between observations means much of the Arctic
weather products come from numerical weather models rather than
directly from images. However, the images used to initialize and
drive the models consist of pixels collected over a wide span of
time (aging pixels), impacting the accuracy of these models. VIIRS,
the next generation LEO imager, lacks the water vapor bands used
for winds a critical product for Arctic weather. 6. PCW Designed
for Persistent Arctic Coverage The 100% coverage region for PCW is
shown in blue in Figure 2. PCW will provide continuous coverage of
the entire Arctic region, filling the gap left by the geostationary
imagers. Continuous coverage is provided for all parts of the earth
above 60N latitude, which includes most of Canada, Alaska, Iceland,
Greenland, etc. With ABI-class imagers on PCW, Full Disk Earth
images, including the Arctic, can be collected every 10 minutes and
storm watch images can be collected every minute. There is a
distinct trend over the last couple of decades of warmer
temperatures in the Arctic. This leads to less ice and greater
weather and environmental uncertainty. The frequency and intensity
of Arctic cyclones is increasing (1900 storms between 2000 and
2010). Shipping traffic and human habitation is also increasing as
the ice melts. 4. Orbit Choice Balances Resolution and Lifetime The
Tundra orbit is a moderately eccentric orbit, as shown in Figure 3.
Apogee is ~20% higher than a geostationary orbit and perigee is
~20% lower. The orbital period is twenty-four hours. Two satellites
are used, orbiting twelve hours apart. There is a significant
difference in the radiation environments between the Molniya, TAP,
and Tundra orbits, leading to very different expected mission
lifetimes of the imager. Shown in Table 1 are the estimated
lifetimes of the ABI payload in all three orbits. As can be seen,
the better resolution Molniya orbit comes at a cost three times
that of the Tundra orbit mission. Tundra provides significant
lifetime improvement (3x Molniya) and a very significant life cycle
cost advantage over the other two orbits. Mission optimization:
Tundra is best providing significantly lower 15 year life cycle
cost while still meeting Arctic needs and the added benefit of
significant Antarctica coverage. 5. PCW Imagery Will Improve Arctic
Weather Knowledge and Forecasts ABI provides sixteen channels
selected for weather data products (listed in Table 2). They
include the water vapor channels used for assessing winds as well
as channels for identifying fires and tracking volcanic ash. ABI
has the flexibility to swap out certain channels to meet specific
mission needs (Table 3). Although located at a much higher orbit
than the LEO constellation, the resolution of an ABI on PCW is
comparable and offers the advantage of being uniform (no distortion
caused by abrupt resolution changes). The resolution is compatible
with the current numerical weather models. The resolution is also
as good as or better than that obtained for CONUS imagery from
GOES-R because the area of interest is directly beneath the
satellite (see Figure 4). The ability to collect an entire image
within 10 minutes will significantly improve knowledge of current
Arctic weather. It will also improve the models by eliminating the
aging pixels issue. One minute updates for severe weather events
will provide one hundred times the temporal fidelity of current LEO
imagers. Like a LEO instrument, PCW will provide coverage for the
entire globe. Unlike a LEO instrument, it can provide persistent
coverage of the Arctic. Figure 2 shows the global coverage for PCW
when flying in a 90 Tundra orbit. The blue region is 24 hours of
coverage per day and every spot on the earth is observed for more
than 4 hours per day. Antarctica is observed for more than 8 hours
per day. PCW will also provide significant coverage in the Indian
Ocean region which will be of particular importance with the
planned retirement of Meteosat 7 in 2016. Wavelength (m)GSD (km)
Main Applications 0.471.1Surface, clouds, aerosols 0.640.5Wind,
clouds, ice mapping 0.871.1Wind, aerosols, vegetation 1.382.0Cirrus
detection 1.611.1Snow-cloud distinction, ice cover 2.252.0Aerosol,
smoke, cloud phase 3.92.3Fog, fire detection, ice/cloud separation,
wind 6.1852.3Wind, high level humidity 6.952.3Wind, mid level
humidity 7.342.3Wind, low level humidity,SO 2 8.52.3Total water,
cloud phase 9.612.3Total ozone 10.352.0Cloud, surface, cirrus
11.22.0Cloud, Sea Surface Temperature (SST), ash 12.32.0Ash, SST
13.32.0Cloud height Figure 4: Resolution of Arctic images from PCW
will be similar to CONUS images from GOES-R Table 2: ABI spectral
channels selected for weather data products Nadir GSD at PCW
reference altitude (apogee 3 hours) Arctic Weather Every 10
Minutes: Exelis ABI on PCW Dr. Paul Griffith and Sue Wirth Exelis
Geospatial Systems Figure 2: ABI on PCW provides 24/7 coverage of
Arctic with updated images every 10 minutes 3. Maximize Quality and
Quantity of Weather Data Products at Minimum Cost and Risk Identify
the fundamental mission objective, which is to produce high quality
weather data products. Success is defined as mission-level
optimization rather than optimizing the mission elements (payload,
satellite, ground). The key parameters for obtaining high quality
weather data products are: Spatial resolution, Coverage both area
and repetition interval (i.e. temporal resolution), Spectral bands,
SNR, and Radiometric Accuracy A key mission parameter derived from
these data product parameters is orbit. Credit: United States Navy
CONUS Arctic GEO HEO True-color composite (Band 1 (blue), Band 2
(green), Band 3 (red)) from Japan Meteorological Agency website
http://www.jma.go.jp/jma/jma-
eng/satellite/news/himawari89/20141218_himawari8_first_images.htmlhttp://www.jma.go.jp/jma/jma-
eng/satellite/news/himawari89/20141218_himawari8_first_images.html
FPMFPA Resolution (km) Center wavelength (m) ABIAHIAMIPCW VNIR
A04710.47 A0640.50.64 A08610.8650.51 0.865 A13821.3781.611.3781.61
A16111.610.865 1.05 A22522.25 1.612.25 MWIR A39023.9 A61826.185
A69526.95 A73427.34 A85028.5 LWIR A96129.61 A1035210.35 A1120211.2
A1230212.3 A1330213.3 Color Key: Not in ABI Different FPA Figure 3:
HEO orbit options (Molniya, TAP, and Tundra) shown relative to
geostationary altitude for reference Table 3: Spectral channels for
ABI, AHI, AMI, and PCW Table 1: Comparison of HEO Orbits Figure 1:
Sea routes expanding due to reduction in ice Hours