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History of this Initiative
Exploratory Team, The University of Arizona, July-August 2007
The following is a chronological listing of all exchanged emails. This should
give readers a good idea on how this initiative is shaping up and how it got
started:
From: Jonathan Overpeck
Date: May 24, 2007 10:50:03 PM MST
To: Alfredo Huete
Cc: Rob Kursinski , shuttle@hwr.arizona.edu, xubin@gogo.atmo.arizona.edu, comrie@arizona.edu, smarsh@Ag.arizona.edu, Barbara Morehouse , "Jeffrey C. Silvertooth" , Steve Archer , david@atmos.washington.edu, Travis Huxman , david.adelman@law.arizona.edu, Joaquin Ruiz , Drake@lpl.arizona.edu, Teresac@email.arizona.edu, Barbara Morehouse , gmgarfin@u.arizona.edu, chuck@Ag.arizona.edu, "Stephen R. Yool"
Subject: Re: two related ideas for immediate TRIF seed funding
Hi Alfredo, Stuart and friends: This sounds great. With this email, Teresa will know that she should be ready to use TRIF TER funds to pay 1-2 months of Kamel's time, plus cover travel expenses if you need to invite a key person or two to help brainstorm or build alliances. The one caveat is that all the funds need to be spent by Dec 07, so I advise moving fast. There may be other reasons for moving fast too...
Again, many thanks. Peck
Hello Jonathan,
Stuart Marsh and I discussed this and we're very willing to collaborate on this arid lands mission effort with Rob Kursinski. We've also identified a potential postdoc, Dr. Kamel Didan, who has been involved intimately with EOS satellite missions, and who could devote a month or more to putting together a white paper and integrating knowledge from the atmosphere, climate, hydrology, and ecology expertise present on campus and the state of Arizona. Let us know how we can proceed and help in this effort,
Sincerely,
Alfredo Huete
On May 19, 2007, at 10:34 AM, Jonathan Overpeck wrote:
hi Rob and friends... Great thoughts, thanks. Although it's too late to think about this for decision packages, and I sense after talking with Joaquin and Mike Drake yesterday not appropriate for decision packages, I do think we need to aggressively pursue a comprehensive in situ (for sure) and remotely-sensed (hopefully, if it makes sense) regional observation infrastructure for the Southwest (including Mexico) which is key for many things - e.g., figuring out/predicting the monsoon, hydromet, land-surface and ecosystem dynamics etc.
Mike Drake (who sees Rob as a key LPL rep) thinks UA could lead efforts for an arid systems satellite for regional science. It would likely be a global mission, but focused on arid systems, and including North America/AZ. He knew all about the regional satellite initiative and players coming out of CA. We agreed that we ought to get serious about:
1) identifying what in situ and remotely-sensed measurements are currently available?
2) what measurements are needed and why? We ought to think big - this is our chance.
3) what technology is needed - both in situ and space-based? For the latter, Mike expressed willingness to focus proven LPL expertise on the initial brainstorming of instrument and mission needs
Although the LPL instrument guys will apparently be swamped through the first half of summer pulling off another huge space mission, I'd like to offer the group on this email (and any others you think would be a help - working fast here) support for a senior grad, post-doc or other capable person to help all involved create a UA white paper on #1-3 above by sometime in the Fall 07 semester. The purpose of this email is to see if there is support for this, and to get it going. Rob is an ideal leader/co-leader, but he's also going to be a dad again soon, so perhaps one or two of you could agree to co-lead with him? Stuart? Alfredo? If you'd like to take ISPE up on an offer of personnel funds (and even travel funds if there are a couple key people we ought to get on campus to help brainstorm), please organize a little and get a plan to me by email in the next couple weeks - after that, I have to escape to remote Tibet for NSF-funded monsoon work.
As added incentive, I can report that we're likely to have partners in other regional states who could help push this both within our states and at the federal level. With the on-going drought, and climate-change projections for the region, this is doable.
Best/thanks, Peck
Hi Peck,
Sorry for the long e-mail but I have been thinking about your TRIF money and I wanted to mention 2 closely related seed efforts for immediate consideration for your TRIF $. They involve measurements of water vapor fluxes and particularly moisture convergence and divergence in the North American Southwest.
Last month's Southwestern Dust Bowl article in SCIENCE indicated that the IPCC climate models predict the North American Southwest will dry out over the next few decades due largely to a reduction in wintertime precipitation. Their initial discussion was in terms of precipitation minus evaporation across the region. Their analysis of the model predictions was done in terms of convergence/divergence of precipitable water fluxes across the region. As you know I have doubts particularly about the summertime portion of this prediction but this is a VERY important issue particularly as Arizona is the fastest growing state in the nation.
I have been advocating that we develop a observational network to directly measure water vapor fluxes across the Southwest region in order to determine and understand the moisture convergence and divergence across the region both in terms of short term fluxes to aid weather forecasts and energy usage and agriculture and long term to determine climatic variability and trends.
Our ability to do this at present is remarkably poor. During the NAME field campaign where we had many additional measurements, our ability was still remarkably poor. For example, one day we had unexpected increase in Precipitable water (PW) in the Tucson are that led to thunderstorms in the area and I asked the various NAME participants where the moisture came from because it was unclear to me. The answer was that it was unclear to everyone. The measurements were simply inadequate.
While one might think satellite observations could do the trick, they can't measure winds and their water vapor measurement capability is limited. IR and visible satellite observations cannot penetrate the frequent cloudiness associated with precipitation. Microwave satellite observations of water vapor are not useful over land in general because of surface emissivity variations.
To attack this problem, the best way to measure water vapor fluxes in our region is via a series of co-located wind profiler and a microwave water vapor profiler (microwave to penetrate through clouds). (Note that we already have precipitation radars covering the state although there are issues with topography.) The water vapor profiler has limited vertical resolution but I think the bigger problem is these instruments are expensive costing about $100K apiece and we need co-located wind profilers and water vapor profilers at a lot of locations to cover for instance water vapor fluxes across the Arizona border.
To get a sense of the number of instruments required, the perimeter of Arizona is approximately 2800 km. if we placed a water vapor flux measurement system every 100 km around the perimeter, we would need 28 such systems. We might need them even closer because the water vapor may decorrelate over shorter distances especially over topography (correlation scales shorten during the monsoon season due to the convection). At $200K a pop, the necessary instrumentation to cover the Arizona border with 100 km resolution would cost ~$6M and I don;t know the installation, monitoring and maintenance costs.
ALTERNATIVE INSTRUMENTATION USING GPS: My suggestion is that we use groups of 3 or 4 GPS receivers to estimate the PWV fluxes. Each GPS receiver estimates PWV at high time resolution. We would then perform lead-lag cross correlations between the PWV estimates. The peak lead-lag correlation delay would yield the motion of the PWV and therefore the PWV flux. I know this approach is feasible because a graduate student working at JPL several years ago was able to use the dense network of GPS receivers in Southern California to estimate water vapor weighted winds. He really didn't know what to do with these winds but to me, the utility in our area is to use the water weighted winds combined with the PWV to provide the PWV flux and convergence.
Also I note that there is actually more information available because each GPS receiver measures many lines of sight through the atmosphere, each of which can be used in determining the motion of the water vapor.
While such a system certainly does not provide the vertical information of a wind profiler and passive vertical sounder, the advantage of such a system is 3 receivers would cost about $10K or 20 times less than a wind profiler and passive water vapor microwave sounder, dramatically reducing the cost of a large network. Such networks could be deployed in the US and in Mexico.
Data Assimilation: The GPS PWV data would also be assimilated into regional models to generate analyses of the water vapor and fluxes that would potentially be quite accurate but that depends on the model accuracy which is an unknown quantity. I want a system that can generate estimate without relying on models that can then also be assimilated into the Numerical Weather prediction (NWP) systems that will hopefully provide even better estimates if the models are good enough.
PROPOSAL CONCEPT
I am proposing two endeavors related to this idea
IDEA ONE
ACCURACY ASSESSMENT: The key question to be addressed immediately is the accuracy to which PWV fluxes can be estimated via this GPS cross-correlation technique. To evaluate the performance and feasibility of such an approach, I propose that we use a high resolution model output and simulate the GPS observations and assess them against the actual water vapor fluxes and flux convergence in the model.
The modeling study would use the existing high resolution forecasts produced by the WRF model, currently run by Mike Leuthold in ATMO. The steps would involve the following.
A post doc or graduate student would
A. analyze the WRF output estimating the actual PWV fluxes using the wind and water vapor profiles in the model
B. This researcher would also estimate the PWV that would be measured by GPS
C. He/she would then calculate the lead-lag cross correlations between nearby PWV estimates to estimate the PWV flux as would be estimated using GPS PWV measurements (Different spacings of receivers would be considered and would different meteorological conditions)
D. He/she would determine the accuracy of the GPS PWV flux estimates for different conditions by comparing them against the actual water vapor fluxes in the model
SECOND IDEA
ACTUAL MEASUREMENTS: The second concept is to actually purchase a few GPS receivers and surface meteorological stations and put them out in the Walnut Gulch area where there is much other water related instrumentation to determine water vapor fluxes and convergence in the area and use these together with the existing observations of precipitation, evaporation and soil moisture to determine whether or not we can close the water budget in this area. There is some urgency because I just discovered today that Ken Cummins will be installing three sets of instrumentation shortly to measure surface moisture in the area during this summer's monsoon.
The applications of such an observational network are numerous and I can't forsee all of them by any means but I can say that the payoff woud include being able for the first time to determine the atmospheric moisture convergence and divergence in the Arizona region for short and long term applications to determine amount of moisture converging into the area during precipitation events and evaporative loss of water in the intervals between precipitation events to constrain and hopefully allow us to close the water vapor budget within the region enclosed by the network(s) and in particular to determine whether there is a long term drying of the region as predicted by models. These observations would also obviously be closely coupled to soil moisture variations and trends.
This would lead to follow-on proposals to NOAA in particular as well as the state of Arizona and possibly Mexico assuming they can be made interested to develop such an observational network and analysis system for our region.
Let me know what you think as soon as you can.
Thanks,
Rob
--
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795
http://www.geo.arizona.edu/
http://www.ispe.arizona.edu/
Alfredo R. Huete
Department of Soil, Water and Environmental Science
429 Shantz Bldg. #38
University of Arizona
Tucson, AZ 85721-0038
tel: 520-621-3228
fax: 520-621-1647
mobile: 520-241-0958
http://tbrs.arizona.edu
http://www.gidp.arizona.edu/program_descriptions/remotesensing.php
--
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795
http://www.geo.arizona.edu/
http://www.ispe.arizona.edu/
From: Jonathan Overpeck
Date: May 24, 2007 11:03:11 PM MST
To: Xubin Zeng
Cc: Alfredo Huete , smarsh@ag.arizona.edu, comrie@arizona.edu, Joaquin Ruiz , Drake@lpl.arizona.edu
Subject: Re: California regional climate change initiative
JUST FOR UA FOLKS - thanks Xubin. Here's that other reason for moving fast on our own UA assessment that Alfredo and Stuart have volunteered to help coordinate. Seems like two models:
1) regional sat mission funded by states (UA clearly not the lead, but could get useful data)
or
2) global mission focused on arid/semi-arid regions (UA could lead, relevant beyond our fair state/region, which could mean more science for the buck)
I leave it to those who know more to figure out how to play these - do both? One or the other? Mike Drake might have some sage input - he's cc'd too.
best, and thanks again, peck
Hi Andrew,
I have come back from attending the California Council on Science and
Technology (CCST) Meeting from 8am-2:30pm today with a focus on Regional
Climate Change.
Here is a brief summary:
(a) after presenting the regional satellite idea, CCST is NOT ready to
present it to the governor and legislature;
(b) after various presentations and discussions (including 60+ bills in
the CA legislature), CCST is ready to push for regional climate change
through the governor and legislature; the time for it is right
(c) CCST will present a short white paper (action plan) to the Governor
(who likes action rather than another feasibility study), requesting
to be asked to do a rapid but careful study and action plan on the
observational network strategy (satellite, airborne platform, surface-based).
This report and the overall regional climate change report will be
in the hands of the Governor by early July
(d) the strategy is to ask and allow the governor to give an announcement
or remarks on this new initiative during the coming national governors'
association meeting on 7/23/07. CCST will also work with the state
legislature on various climate-related bills
(e) CCST also recognizes and values the joint action by Arizona if possible
(and other states in the future). Charles Kennel told Patrick that
he will be happy to come to Arizona to help us push. He also told me that
we should, if possible, email him AZ action plan so that it will be
included in their white paper. this will benefit mutually.
(f) observational network is a crucial part of this initiative, but other
parts (e.g., modeling, education, partnership, economic benefits ...) are
also important.
What we need to do in AZ:
(a) Janet Napolitano is still the chair of the national governors'
associateion. It would be in her (and AZ') best interest to give a few
remarks or make an announcement on regional climate change for AZ after
Arnold gives his announcement on CA initiative. therefore time is right
for us.
(b) time is very short, and Patrick is thinking about possible meeting
with you (and possibly Robert Shelton) Friday or Monday to develop
the AZ action plan; e.g.,
1) prepare a short white paper;
2) meet with governor or her rep through the ABOR connection (Patrick
knows more)
3) emphasize the partnership between CA and AZ
4) request to be asked for a rapid and careful action plan by early
July, and get small amount of money for this study (Patrick has
an idea on how to get it)
5) hope the governor (and possibly the legislature) will take some
actions following the action (e.g., during the governors' association
meeting; ...)
I am leaving this Saturday for France to help organize international effort
in developing global land surface energy and water flux datasets. I will
be back next Saturday, and will be available to assist you at that time
if needed.
-------------
To make sure I didn't waste your travel support, here is what I did while
in CA:
During the discussion period, I raised two points that were well received:
(a) future climate change over western U.S. has many similarities and is
quite different from central and eastern U.S. (as shown in one of the
presentations). Therefore it is better for western states to work together
both in terms of the networking of surface observational network in
individual states and in pushing for federal (NASA and NOAA) actions
(on remote sensing);
(b) western governors' association was succsssful in pushing for the
congressional act and federal support for national drought monitoring
I talked with Charles Kennel (the leader of this Regional Climate
Change, former NASA AA on earth science and former director of Scripps)
on the way to the airport. I also talked with Patrick (Burkhart)
at the airport about AZ action.
best
xubin
Dr. Xubin Zeng, Professor Email: xubin@atmo.arizona.edu
Department of Atmospheric Sciences Phone: (520) 621-4782
1118 E. 4th St., P.O. Box 210081 Fax: (520) 621-6833
The University of Arizona, Tucson, AZ 85721, USA
http://www.atmo.arizona.edu/personalpages/zeng/zeng.html
--
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795
http://www.geo.arizona.edu/
http://www.ispe.arizona.edu/
On May 19, 2007, at 10:34 AM, Jonathan Overpeck wrote:
hi Rob and friends... Great thoughts, thanks. Although it's too late to think about this for decision packages, and I sense after talking with Joaquin and Mike Drake yesterday not appropriate for decision packages, I do think we need to aggressively pursue a comprehensive in situ (for sure) and remotely-sensed (hopefully, if it makes sense) regional observation infrastructure for the Southwest (including Mexico) which is key for many things - e.g., figuring out/predicting the monsoon, hydromet, land-surface and ecosystem dynamics etc.
Mike Drake (who sees Rob as a key LPL rep) thinks UA could lead efforts for an arid systems satellite for regional science. It would likely be a global mission, but focused on arid systems, and including North America/AZ. He knew all about the regional satellite initiative and players coming out of CA. We agreed that we ought to get serious about:
1) identifying what in situ and remotely-sensed measurements are currently available?
2) what measurements are needed and why? We ought to think big - this is our chance.
3) what technology is needed - both in situ and space-based? For the latter, Mike expressed willingness to focus proven LPL expertise on the initial brainstorming of instrument and mission needs
Although the LPL instrument guys will apparently be swamped through the first half of summer pulling off another huge space mission, I'd like to offer the group on this email (and any others you think would be a help - working fast here) support for a senior grad, post-doc or other capable person to help all involved create a UA white paper on #1-3 above by sometime in the Fall 07 semester. The purpose of this email is to see if there is support for this, and to get it going. Rob is an ideal leader/co-leader, but he's also going to be a dad again soon, so perhaps one or two of you could agree to co-lead with him? Stuart? Alfredo? If you'd like to take ISPE up on an offer of personnel funds (and even travel funds if there are a couple key people we ought to get on campus to help brainstorm), please organize a little and get a plan to me by email in the next couple weeks - after that, I have to escape to remote Tibet for NSF-funded monsoon work.
As added incentive, I can report that we're likely to have partners in other regional states who could help push this both within our states and at the federal level. With the on-going drought, and climate-change projections for the region, this is doable.
Best/thanks, Peck
Hi Peck,
Sorry for the long e-mail but I have been thinking about your TRIF money and I wanted to mention 2 closely related seed efforts for immediate consideration for your TRIF $. They involve measurements of water vapor fluxes and particularly moisture convergence and divergence in the North American Southwest.
Last month's Southwestern Dust Bowl article in SCIENCE indicated that the IPCC climate models predict the North American Southwest will dry out over the next few decades due largely to a reduction in wintertime precipitation. Their initial discussion was in terms of precipitation minus evaporation across the region. Their analysis of the model predictions was done in terms of convergence/divergence of precipitable water fluxes across the region. As you know I have doubts particularly about the summertime portion of this prediction but this is a VERY important issue particularly as Arizona is the fastest growing state in the nation.
I have been advocating that we develop a observational network to directly measure water vapor fluxes across the Southwest region in order to determine and understand the moisture convergence and divergence across the region both in terms of short term fluxes to aid weather forecasts and energy usage and agriculture and long term to determine climatic variability and trends.
Our ability to do this at present is remarkably poor. During the NAME field campaign where we had many additional measurements, our ability was still remarkably poor. For example, one day we had unexpected increase in Precipitable water (PW) in the Tucson are that led to thunderstorms in the area and I asked the various NAME participants where the moisture came from because it was unclear to me. The answer was that it was unclear to everyone. The measurements were simply inadequate.
While one might think satellite observations could do the trick, they can't measure winds and their water vapor measurement capability is limited. IR and visible satellite observations cannot penetrate the frequent cloudiness associated with precipitation. Microwave satellite observations of water vapor are not useful over land in general because of surface emissivity variations.
To attack this problem, the best way to measure water vapor fluxes in our region is via a series of co-located wind profiler and a microwave water vapor profiler (microwave to penetrate through clouds). (Note that we already have precipitation radars covering the state although there are issues with topography.) The water vapor profiler has limited vertical resolution but I think the bigger problem is these instruments are expensive costing about $100K apiece and we need co-located wind profilers and water vapor profilers at a lot of locations to cover for instance water vapor fluxes across the Arizona border.
To get a sense of the number of instruments required, the perimeter of Arizona is approximately 2800 km. if we placed a water vapor flux measurement system every 100 km around the perimeter, we would need 28 such systems. We might need them even closer because the water vapor may decorrelate over shorter distances especially over topography (correlation scales shorten during the monsoon season due to the convection). At $200K a pop, the necessary instrumentation to cover the Arizona border with 100 km resolution would cost ~$6M and I don;t know the installation, monitoring and maintenance costs.
ALTERNATIVE INSTRUMENTATION USING GPS: My suggestion is that we use groups of 3 or 4 GPS receivers to estimate the PWV fluxes. Each GPS receiver estimates PWV at high time resolution. We would then perform lead-lag cross correlations between the PWV estimates. The peak lead-lag correlation delay would yield the motion of the PWV and therefore the PWV flux. I know this approach is feasible because a graduate student working at JPL several years ago was able to use the dense network of GPS receivers in Southern California to estimate water vapor weighted winds. He really didn't know what to do with these winds but to me, the utility in our area is to use the water weighted winds combined with the PWV to provide the PWV flux and convergence.
Also I note that there is actually more information available because each GPS receiver measures many lines of sight through the atmosphere, each of which can be used in determining the motion of the water vapor.
While such a system certainly does not provide the vertical information of a wind profiler and passive vertical sounder, the advantage of such a system is 3 receivers would cost about $10K or 20 times less than a wind profiler and passive water vapor microwave sounder, dramatically reducing the cost of a large network. Such networks could be deployed in the US and in Mexico.
Data Assimilation: The GPS PWV data would also be assimilated into regional models to generate analyses of the water vapor and fluxes that would potentially be quite accurate but that depends on the model accuracy which is an unknown quantity. I want a system that can generate estimate without relying on models that can then also be assimilated into the Numerical Weather prediction (NWP) systems that will hopefully provide even better estimates if the models are good enough.
PROPOSAL CONCEPT
I am proposing two endeavors related to this idea
IDEA ONE
ACCURACY ASSESSMENT: The key question to be addressed immediately is the accuracy to which PWV fluxes can be estimated via this GPS cross-correlation technique. To evaluate the performance and feasibility of such an approach, I propose that we use a high resolution model output and simulate the GPS observations and assess them against the actual water vapor fluxes and flux convergence in the model.
The modeling study would use the existing high resolution forecasts produced by the WRF model, currently run by Mike Leuthold in ATMO. The steps would involve the following.
A post doc or graduate student would
A. analyze the WRF output estimating the actual PWV fluxes using the wind and water vapor profiles in the model
B. This researcher would also estimate the PWV that would be measured by GPS
C. He/she would then calculate the lead-lag cross correlations between nearby PWV estimates to estimate the PWV flux as would be estimated using GPS PWV measurements (Different spacings of receivers would be considered and would different meteorological conditions)
D. He/she would determine the accuracy of the GPS PWV flux estimates for different conditions by comparing them against the actual water vapor fluxes in the model
SECOND IDEA
ACTUAL MEASUREMENTS: The second concept is to actually purchase a few GPS receivers and surface meteorological stations and put them out in the Walnut Gulch area where there is much other water related instrumentation to determine water vapor fluxes and convergence in the area and use these together with the existing observations of precipitation, evaporation and soil moisture to determine whether or not we can close the water budget in this area. There is some urgency because I just discovered today that Ken Cummins will be installing three sets of instrumentation shortly to measure surface moisture in the area during this summer's monsoon.
The applications of such an observational network are numerous and I can't forsee all of them by any means but I can say that the payoff woud include being able for the first time to determine the atmospheric moisture convergence and divergence in the Arizona region for short and long term applications to determine amount of moisture converging into the area during precipitation events and evaporative loss of water in the intervals between precipitation events to constrain and hopefully allow us to close the water vapor budget within the region enclosed by the network(s) and in particular to determine whether there is a long term drying of the region as predicted by models. These observations would also obviously be closely coupled to soil moisture variations and trends.
This would lead to follow-on proposals to NOAA in particular as well as the state of Arizona and possibly Mexico assuming they can be made interested to develop such an observational network and analysis system for our region.
Let me know what you think as soon as you can.
Thanks,
Rob
--
Jonathan T. Overpeck
Director, Institute for the Study of Planet Earth
Professor, Department of Geosciences
Professor, Department of Atmospheric Sciences
Mail and Fedex Address:
Institute for the Study of Planet Earth
715 N. Park Ave. 2nd Floor
University of Arizona
Tucson, AZ 85721
direct tel: +1 520 622-9065
fax: +1 520 792-8795
http://www.geo.arizona.edu/
http://www.ispe.arizona.edu/
Alfredo R. Huete
Department of Soil, Water and Environmental Science
429 Shantz Bldg. #38
University of Arizona
Tucson, AZ 85721-0038
tel: 520-621-3228
fax: 520-621-1647
mobile: 520-241-0958
http://tbrs.arizona.edu
http://www.gidp.arizona.edu/program_descriptions/remotesensing.php
Stuart E. Marsh, Ph.D.
Professor and Chair Arid Lands Resource Sciences
Professor Geography and Regional Development
Director Arizona Remote Sensing Center
The University of Arizona
Office of Arid Lands Studies
Arizona Remote Sensing Center
1955 E. Sixth Street
Tucson, AZ 85719
email: smarsh@ag.arizona.edu
Phone:520 621-8574 Fax:520 621-3816
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