Correspondence of February 18-19
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From: Kenneth Jezek
My suggestion for a background mission is to include image and
interferometric mappings of large portions the Antarctic Continent
within the McMurdo Station Mask. Working with ASF and any others
interested, I can probably come up with an acquisition plan that might
be excecuted annually.
Ken
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From: Ron Kwok
All,
I agree with Ken. The background mission should focus on Antarctica
and Southern Ocean especially the Ross Sea - areas within the McMurdo
mask.
The background mission should be planned once and the acquisition
requests submitted to CSA on a routine basis, much like that the of
procedures followed for the Arctic snapshot.
We should not wait on this opportunity to collect data.
I suggest we implement a plan ASAP so that we can monitor the fall-winter
transition of the areas around McMurdo.
I volunteer to help with the coverage planning.
Ron
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From: harry@apl.washington.edu
ASF User Working Group:
During our last teleconference (Feb 4) we discussed possible
background missions for Radarsat, to take advantage of the unused
U.S. allocation during each 24-day cycle. The background mission
would be restricted to in-mask acquisitions, i.e. ASF and/or McMurdo.
I am posting your comments on our web site. Go to:
http://psc.apl.washington.edu/ASFUWG
and select "Notes on a Radarsat Background Mission".
In my notes from the telecon of Feb 4 (also posted on the web site)
I suggested that ideas for the background mission be sent to Jim
Conner at ASF (james@sitka.images.alaska.edu). I also indicated
a certain urgency to this issue, since unused allocation means
data that will never be collected. Jim sent out a notice to all
users via the User Bulletin of Feb 10. I don't know what kind of
response he got. Jim and Verne are travelling this week but will
presumably be back in the office next week.
I think the background mission should include acquisitions of the
Ross Sea and Southern Ocean, via the McMurdo station. The Arctic
has its Snapshot and RGPS, and the Antarctic continent has its
mapping mission. The Southern Ocean would seem to be the logical
choice for enhanced coverage.
Greta Reynolds has provided some numbers on the amount of unused
allocation per cycle -- see the web site referenced above.
Ron Kwok has volunteered to help with planning the background
coverage. I would like to see some concrete proposals and numbers
by the next telecon (Thursday March 4), such as:
* Projected number of minutes available in upcoming cycles;
* Preferred beam modes;
* Potential coverage of Ross Sea (or whatever) with the beams
and minutes available.
Greta, Ron, are you willing to work up some possible scenarios?
I'm hoping that we'll have enough information and feedback to
discuss at the next telecon that we can come to a decision and
move ahead with DARs for the background mission.
-Harry
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From: Kenneth Jezek
I am alittle confused as to what is going on here. There seems to be a
defacto decision to acquire acquistions over the Ross Sea as the one and
only background mission because other regions of interest are 'getting
their share'. I really object to this approach and would like to reopen
this discussion on March 4.
Ken
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From: Sivaprasad Gogineni
Folks
If we have unused capacity for RADARSAT I would like to pole the community
through discipline program managers for any projects and prioritise these
based on the input.
Prasad
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From: Howard Zebker
I too have a bit of concern of narowing down the scope of the background
Radarsat mission so quickly. There are many parts of the world where
the availability of existing spaceborne is limited. Especially in regions
where there hasn't been extended ERS coverage, it would make sense to
see if we could use Radarsat capability. The issue here is whether we can use
the tape recorders on the satellite to downlink data in Alaska regardless
of where it was acquired. I don't know the answer to this question.
But if we could get data over many places on Earth, I'd think that much
of the Pacific Rim (including Hawaii, South America, and the southwest
Pacific) would be prime candidates. The region is tectonically active
and important, and has not had as much ERS coverage because of the poor
quality of the ground stations.
Japan is another possibility. Although solid Earth doesn't rate too
highly these days, there is important science to be done.
As with Ron, I'd be happy to plan acquisitions.
Cheers,
Howard
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From: mrd@sundog.jpl.nasa.gov (Mark R. Drinkwater)
Ken and colleagues
as one of the ADRO sea-ice investigators,
I can assure you that most who participated for the
last 3 years in trying to study Antarctic sea ice have
suffered from the fact that Radarsat acquisitions have not
met their expectations viz. spatio-temporal coverage. None
are satisfied, and I could offer many reasons why
I believe that to be the case. But, despite limited
geographic regions of interest, it is criminal that we
remain without a single continuous seasonal dataset
anywhere in the McMurdo mask - or anywhere in the Southern
Hemisphere ice cover for that matter. I have tried in vain
to tailor acquisitions to meet this basic need. Others
have tried too. Here is the first opportunity to meet this
need (properly) with ASF's direct planning support - at
least (at first) from the perspective of a seasonal ice
advance perspective.
On balance, since McMurdo begun operation we have mapped
all of the continent and obtained tandem data over most of
the continental ice (albeit with ERS-1/2) with 100km scenes.
Based on these experiences, clearly more is required.
However, I am concerned that the interest surrounding
the RAMP and interferometric potential do not override
the most basic requirements laid out in the original
ASF Science Plan. Almost ten years later, we still did
not meet most of them. I implore that we move in a
direction necessary to start addressing and meeting the
(obviously) recently relegated requirements of the sea-ice
SAR scientific user community.
Mark.
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From: Sivaprasad Gogineni
Folks:
Before you all get carried away with collecting data as a background
mission, you should factor in the costs associated with data transfer and
processing. If the data processing can be accomplished within the existing
resources and there are no additional costs associated with acquisition and
transfer of data we can definetely consider a project or projects.
Otherwise we should look at the science value of the project or projects
before proceeding with acquisition plans.
I feel that we are resources (fudning to process, analyze and synthesize)
limited than data limited at this stage.
Prasad
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From: harry@apl.washington.edu
Dear All,
Ken wrote:
-----------------
I am alittle confused as to what is going on here. There seems to be a
defacto decision to acquire acquistions over the Ross Sea as the one and
only background mission because other regions of interest are 'getting
their share'. I really object to this approach and would like to reopen
this discussion on March 4.
-----------------
Don't worry, I'm not trying to railroad any decisions through ASF
via the UWG. We are only an advisory group. I expect that Verne
will have to make a final decision about what (if any) background
mission to implement. I am confident that he will weigh all the
factors and do what is best for the most users. I certainly do
want to have a discussion about this during the telecon of March 4.
I want it to be an informed discussion, with specific numbers and
ideas. I'm not ordering anyone to come up with a plan for imaging
the Ross Sea; obviously that's beyond my authority and I wouldn't
do it anyway. I was trying to generate some action so that this
issue does not languish for several telecon-cycles. Apparently
I succeeded in generating some feedback - thank you Prasad, Mark,
Howard, Ken.
Howard raised the issue of using the Radarsat tape recorder and
downlinking the data at ASF. I thought we had considered that idea
and had been told that it was unworkable. I thought the tape
recorder was a scarce and closely-guarded resource and that CSA
has not qualified ASF for tape recorder downlink. The whole
recorder has to be dumped at once, and so the receiving station
becomes responsible for shipping all the data to the various users
who requested it. Could someone at ASF please confirm or deny
what I've just said and set us straight? Thanks.
Prasad said he "would like to poll the community through discipline
program managers for any projects and prioritize these based on the
input." Prasad, by all means please contact program managers and
get input from them and their funded researchers. We'd like to
hear about it.
Prasad also raised the issue of cost. Verne, what is the marginal
cost of acquiring X more minutes of direct-downlink data at ASF or
McMurdo? I think that's the only consideration. Even if the
resources for processing and analyzing that data are not available
for several more years, at least we have the data. If we don't
take advantage of the unused allocation now, it's gone forever.
If acquisition is cheap, the data should be acquired; processing
and analysis can always wait.
-Harry
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From: Sivaprasad Gogineni
Harry:
Before anyone goes on advocating one project or another I would like to see
a clear statement on what data will be used for and what science we are
going to accomplish with these data. Have we looked at the scientific
utility of SAR data for sea ice studies in Antarctica? There are several
projects supported under ADRO on sea ice in the Southern ocean. I have not
seen any results to justify collecting more data.
I would like to remind everyone that all data acquisition projects have to
be approved by HQ program scientist!!!
Prasad
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From: Ben Holt
The idea was to come with some reasonable background mission options,
do some planning, and to see how things stack up against each other and
within the available allocation. Clearly Ken, Mark, and Howard are doing
that.
The question was posed to the UWG and we can make some recommendation
to Verne and Prasad to implement, based on these options. My guess
is that a reasonable plan can be worked out to accomodate several
of these options.
Prasad's suggestion below is somewhat baffling to me though. ASF
is still lacking an assessment of the selected Antarctic AO proposals
as to Radarsat requirements. There are numerous short proposals
for data requests that are still on the table to ASF. As indicated
by the UWG discussion so far, there are current investigators
who have additional ideas for useful data. Isn't it pushing things
a little bit at this point to 'poll the discipline managers'
for additional requirements? If there actually are new requirements
from them out there, how come we dont already know about them? How do
we balance them against a current suite of requirements/requests that
still not fully understood?? I guess we will see what the
other disciplines have in mind and figure it out from there.
Ben
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From: Greta Reynolds
Harry-
The planners have provided some suggestions on areas to cover
with the background mission based on already planned coverage.
This would alleviate potential internal conflicts. Coupled with
a consensus of the UWG on the most scientifically interesting
geographic regions would hopefully provide a good sense
background mission. We can provide SPA files that show areas
of already planned coverage for the ASF and MGS masks if
you would like to post them on the web-site for review prior
to the discussion at the telecon. There may be a consideration
of confidentiality of areas requested, so I'll let you folks
think about posting the planned coverage.
To respond to one of the questions raised in the recent flurry of
mail messages......
"Howard raised the issue of using the Radarsat tape recorder and
downlinking the data at ASF. I thought we had considered that idea
and had been told that it was unworkable. I thought the tape
recorder was a scarce and closely-guarded resource and that CSA
has not qualified ASF for tape recorder downlink. The whole
recorder has to be dumped at once, and so the receiving station
becomes responsible for shipping all the data to the various users
who requested it. Could someone at ASF please confirm or deny
what I've just said and set us straight? Thanks."
The US government allocation for tape recorder time is 114
minutes of the total 1519 minutes per 24 day cycle. The recorder
time is closely protected, and User Services provides feedback to
the planning group for actual submissions. It is true that the entire
recorder is dumped at once, and by policy the stations authorized
for OBR downlink are Prince Albert and Gatineau. There are
occassions in which OBR downlinks are scheduled at ASF, purely
for tape recorder management, and CSA mission planning con-
siderations. If data on the OBR is destined for a non-US governement
user, ASF is requested to provide the data to RSI. If US government
requested data are downlinked at the Canadian facilities we
acquire the data from them. There are distinct budget considerations
for any data acquired at stations other than ASF or MGS or for
recorded data, which led to the background mission in the ASF
or MGS mask only.
Greta
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From: Sivaprasad Gogineni
Ben:
What is so confusing about asking other program managers if they have any
requirements for RADARSAT data? Ernie Paylor and Peter contacted me
sometime back about dumping RADARSAT data at Hawaii ground station. If we
work out an agreement with CSA to collect real time data with the Hawaii
ground station, folks in natural hazards and oceans area may be interested
in using radar data both for scientific research and operational
applications.
Until recently we have restricted ASF from placing orders for 100% of the
capacity because we did not want another fiasco with over subscription. I
believe that this restriction has been lifted recently. Darryl can confirm
or deny this.
Prasad
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From: Ben Holt
Prasad,
Well quite honestly the message you have been giving us/ASF for
the last couple of years is to take care of what is on your plate
first. Finally we have done most of that, with the interferometry
bunch still to be satisfied with reasonable products and as I pointed out
the unknowns about the Antarctic AO folks as well as current request
for background suggestions. I have long believed
that ASF should be 'expanding the customer base', and I guess now you have
confirmed that you think its time to do it too. Ben
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From: Sivaprasad Gogineni
Ben:
If we have taken care of the existing users, we should expand ASF
activity to support research projects. I get two different messages: one
from the users in private that they
are not happy about what they got so far and need more to accomplish
their research; and other from ASF that says that all users' have got all
the data they need.
Prasad
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From: mrd@sundog.jpl.nasa.gov (Mark R. Drinkwater)
Folks
On reflection, I would more prefer to see a
small quick user survey to go out to ADRO users
of the last 3 years to see how they could
be helped by new additional data takes which
address either missing data, holes in
their coverage, or a lack of uncalibrated
ScanSAR products in their regions of interest.
If the charge is that these users have not
made a suitable justifiable case for instance
for a particular background mission tailored to meet
their collective science requirements then
they should at least be given the opportunity
to respond stating why not. Particular
attention should be paid to what about the data,
data quality, acquisition planning, or other
factors have led to them not meeting their
own expectations viz. their ADRO projects.
I suspect that this should have been done a
long time ago to satify NASA where the money
would be best directed.
We are perhaps getting way too far ahead of
ourselves in continually planning for new future
users/or data uses, without first addressing why
existing NASA-funded studies have not borne fruits.
Mark.
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From: Craig Lingle
Prasad & Verne et al.,
Ron Kwok and I, and also Ron and Ken Jezek, have discussed acquiring SAR
data over the West Antarctic ice sheet (WAIS), during both ascending and
descending orbits, as a component of the proposed "background mission."
(Ascending/descending will make these data useful for INSAR measurement of
surface velocities on the relatively slow-moving inland ice sheet).
We also suggest there is no reason to view this as the "inland ice sheet
users" versus the "sea ice users" (the bloods vs. the krips, as it were),
since the fraction of WAIS north of lat. 79 S is a relatively small patch
of real estate. Acquisition swaths extending over WAIS could begin well
out over the sea ice.
We also suggest it would be counterproductive to get tied up with
proposals, project descriptions, and all that. Since this will be a
"background mission," we should simply go ahead and do it and make the data
available to any who wish to make use of it.
Regards-
Craig
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From: "Earnest D. Paylor, II"
Colleagues,
I would really like to see list of the original ADRO program requests,
as well as the other "approved" NASA users who have requested RADARSAT
data, compared to the data delivered from ASF. I stand with Prasad in
that many of my PI's tell me of their disappointment that they have
been unsuccessful in obtaining RADARSAT data and have basically given
up on the system. There is a disconnect somewhere which definitely
needs to be fixed before any thought is given to expanding the user
base.......
Earnie
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From: "Vanessa L. Griffin"
Prasad:
I agree with your assessment. Increasingly, we are having to commit more
and more resources to "obtain" our "free" RADARSAT allocated data from
foreign ground stations. The "bill" for this data purchase is approaching
$1M per year. Most of the suggestions I have seen for the background
collection would involve use of the tape recorder or a foreign ground
station. A decision to collect this data, and incur the ancillary costs
must be carefully thought through. Based on our previous discussions, I
believe you have the lead here.
This said, let me be clear that I fully support the desire to use more of
our allocation -- and in so doing, maximizing the science return on the
resources we have committed at ASF.
Vanessa
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From: Keith Raney
Greetings, everyone.
It is terrific to see so much useful interest and traffic on this topic!
From my perspective, if there is a significant unused fraction of our
data access, then that is a mighty poor argument in favor of "the
critical role of SAR in Earth system science"! Therefore, it would seem
to be essential to design a background mission that (1) is affordable,
(2) uses the available data allotment wisely, and (3) pays due respect
to the relevance if not criticality of SAR data to Earth system science!
The mandate seems clear. All that remains is to agree on a means to
design such a mission.
Keith
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