SUMMERLAND KEY, Fla. -- NASA and NOAA scientists have begun studying
options for a new hurricane-wind-measuring satellite the White House does not believe is
needed yet, according to interviews with the National Oceanic and Atmospheric
Administration (NOAA), NASA and White House officials.
NASA's
Quick Scatterometer, or QuikScat, satellite bounces radar signals off the ocean to
measure the roughness of the surface. Software processes those readings into
estimates of wind speed and direction. Though it was conceived by NASA as a research
spacecraft, U.S. hurricane forecasters have come to rely on QuikScat to measure the size of a developing
storm's wind field, and in some cases to locate its center of circulation.
U.S.
forecasters are nervous because the eight-year-old QuikScat satellite now is operating on a backup downlink transmitter, and
the administration of U.S. President George W. Bush has no plans to develop a backup
or replacement for it.
National
Hurricane Center Director Bill Proenza has said in a
series of recent speeches and interviews that QuikScat could fail at any time, and he has
called forcefully for a replacement plan.
Bush's science adviser, John Marburger,
who is the director of the White House Office of Science and Technology Policy,
told Space News June 5 he stood by
the administration's position on QuikScat.
The health
of QuikScat is "nowhere near as shaky" as Proenza's comments imply, he said. "We don't see this as a
kind of urgent situation ... I don't know whether it's because the director of the
National Hurricane Center is new and wasn't aware of the situation ... when he
made the comments that triggered this whole flurry of interest," Marburger said. Proenza became
director of the center in January.
Marburger
also noted that the National Research Council's draft report, "Earth Science
and Applications from Space: National Imperatives for the Next Decade and Beyond,"
better known as the Decadal
Survey, does not
reflect Proenza's sense of urgency. That review,
which is still in preliminary form, calls for launching a QuikScat successor between 2013 and 2016.
"This
expression of concern came more or less out of the blue for us," Marburger said.
Hurricane
forecasters disagree with the White House position. Though it cannot detect a
hurricane's highest winds or see through heavy rain, "QuikScat really is the only source of data
that can give you the wind speed and direction over the entire circulation of a
cylone," said forecaster Richard Knabb.
Members of Congress from Louisiana and Florida
introduced earmark legislation May 29 that would authorize $375 million for
NASA to "design and launch" a replacement for QuikScat. Almost simultaneously, NASA's Jet Propulsion Laboratory (JPL) and NOAA
officials agreed on a new teaming arrangement under which JPL would build a
successor to QuikScat for NOAA should money be allocated
through one or both of the agencies, said Ernesto Rodriguez, the project
scientist for ocean wind measurements at JPL.
The
arrangement would represent "a new way of doing business," Rodriguez added. As
a NASA field center, JPL generally builds research instruments for NASA and university
scientists. U.S. weather forecasters sometimes test readings from those instruments,
which was how hurricane forecasters came to rely on QuikScat.
If the new
arrangement holds, it would mark the first time JPL has built an operational
satellite or instrument for NOAA, said Paul Chang, the team lead for ocean wind
work at NOAA's Center for Satellite Applications and
Research in Camp Springs, Md.
Exactly
what a QuikScat replacement might look like and
what it would cost are the subjects of an initial study that
will be paid for this year by NOAA's internal discretionary
funds, Chang said. The estimated cost of the study is
$500,000 to $1 million.
The choice
is to either build a backup satellite quickly to provide a "QuikScat-like capability," or build a more
powerful successor called the Extended Ocean Vector Winds Mission (XOVWM),
Chang said.
Hurricane
forecasters believe the study will confirm that the wisest choice would be to
go directly to the XOVWM mission. "That is the option that the hurricane center
prefers," said Knabb, the hurricane forecaster.
Officials
from JPL and NOAA said it will be difficult if not impossible to dust off the QuikScat blueprint and rebuild the
satellite.
QuikScat was built in the 1990s with 1980s
technology, Rodriguez said. "A lot of that stuff is no longer around,"
Rodriguez said, noting that building a more advanced QuikScat might not cost much more.
However,
even with an earmark, Chang said the earliest such a satellite could be ready
would be 2012. "The urgency is we need to at least start down the path of planning
something," Chang said.
NOAA
spokesman Anson Franklin said the agency's staff would study the QuikScat options with open minds. "We're not
in a position to draw any conclusions about the technology available," Anson
said. As for the proposed congressional earmark, Franklin said: "We appreciate
the congressional interest in [QuikScat] and we have talked to these
members who have proposed this legislation."
Knabb
said forecasters like the XOVWM concept because it would
overcome the major shortcomings of QuikScat, which is that QuikScat's Ku-band radar signals are scattered
by rain. QuikScat data is nevertheless useful because
rainfall in hurricanes and other storms tends to be localized.
Forecasters
would like to measure wind speed and direction throughout storms, said Chang. QuikScat's radar also cannot sense wind speeds
above 90 miles per hour, the equivalent of a minimal hurricane. The new
satellite would add longer wavelength, lower frequency C-band signals to
penetrate the rain and measure winds as high as 180 miles per hour.
The new
satellite also would show more detail for mapping winds closer to the coast, Rodriguez
said. If QuikScat died suddenly, U.S. hurricane
forecasters would not be left without coverage.
Under an
agreement with European weather managers, U.S. forecasters soon will receive
wind maps from the new Advanced Scatterometer
instrument on Europe's first MetOp polar-orbiting
weather satellite launched last October. The European instrument would not be a
perfect replacement for QuikScat, however. It provides less coverage
and its data is not as detailed is that from QuikScat, said Chang.