SCERP Meeting Dec 2006

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Investigation of Dust Emission Hotspots in
Chihuahuan Desert Playa Basins Principal
Investigators Thomas E. Gill, UTEP
Miguel Dominguez
Acosta, UACJ Graduate Student Researchers Nancy
I. Rivera Rivera
Adriana E. Perez

Alfredo Ruiz
Sonny Emmert
Sabrina
Canalda
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THE PROBLEM

• Windblown desert dust- primarily from natural
  sources near the US/Mexico border in the
  Chihuahuan Desert region of Chihuahua, Texas, and
  New Mexico- creates intense plumes of particulate
  matter (primarily coarse but also fine particles)

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THE PROBLEM

• This dust may advect in from the desert to
  populated areas such as El Paso/ Cd. Juarez, Las
  Cruces, Palomas/ Columbus, and other cities.

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Image from TCEQ Chelsea Street Webcam, El Paso
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El Paso Hourly max over 1200 µg/m3
San Antonio- spike to 900 µg/m3 LRGV- gt 600µg/m3
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Long-distance transport
receptor
source
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All The Way to Canada
Dirty Bomb ???
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In contrast to urban fugitive dust in Chihuahuan
Desert border cities, which has been investigated
in a number of projects, these desert dust storms
have been very poorly described and understood.
Their sources and transport patterns were only
very crudely known, the specific atmospheric and
land-surface conditions that cause them poorly
understood, and the composition and
characteristics of these aerosols and their
emitting source materials had not been analyzed.
The motivation of this project was to begin to
better understand these natural dust events.
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Where Does It Come From?
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Whats There Where It Comes From?
Prospero et al. (Global sources of atmospheric
soil dust, Reviews of Geophysics 40, 2002)
stated, This, in fact, very well describes
the source area of an April 2001 dust event
previously studied by the PI and the major
sources of dust on a global basis are known to be
dry lake beds recently wet in the geological
past, especially where they are associated with
large sand deposits.
In Mexico, there is a substantial but variably
active (dust) source just south of the U.S.-
Mexico border where there is an extensive system
of playas and aeolian, lacustrine and alluvial
sediments. There is a second center of activity
farther to the southeast also in the Basin and
Range portion of Mexico.
Image from PACES, UTEP
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The Culprit!!! (???)
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Remote sensing wizardry was applied to a huge
database of satellite imagery to detect the
actual source points of large dust plumes.
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Source Locations for Dust Plume
Outbreaks (Nancy Rivera, UTEP M.S. Thesis
defended 11/2006)
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RESULTS YES, PLAYAS ARE IMPORTANT but its not
that cut and dried.
Lake Palomas- clay playa
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White Sands (Lake Lucero/ Lake Otero)- saline
playa
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About half the dust sources do turn out to be
associated with playas (dry lakes). Especially
important turns out to be the EDGES of playas-
where there is an interface between loose sands
and fine clay and silt particles which become
dust.
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Desert shrublands/ rangelands not associated with
playas are also an important contributor-
especially areas with coppice dunes and lots of
sand.
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Agricultural lands, especially in Casas Grandes
River valley (Chih.) are a small but persistent
source of dust lands are fallow in windy winter
season
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NEXT STEP visit many of these dust source sites
(ground truthing) and characterize their
geology/land use, sediment and soil
characteristics, and collect samples for
additional analysis of sedimentology and
chemistry.
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Passive blowing dust and sand sampling traps were
deployed at several sites and are being monitored
regularly.
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The remoteness of these sites and the infrequency
of individual dust events generally precluded
active aerosol sampling. However, an opportunity
did arise to collect aerosol samples at two sites
near the White Sands sources in 2005 thanks to a
collaboration with White Sands Missile
Range and two other universities.
(These data still being analyzed)
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Field reconnaissance revealed some surprises. A
few anthropogenically dis-turbed sites were also
discovered (cattle corrals, and this site
precisely at a dust source point in the middle of
nowhere anyone know what was going on here?)
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PARTICLE SIZE DISTRIBUTION OF DUST-EMITTING
SOILS Measured via laser diffraction
White Sands, saline gypsum playa soil red line
shows particle size distribution when wet, green
line shows when dry.
Notice
the double peak (sand and 10µm) in dry White
Sands surface soil.
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PARTICLE SIZE DISTRIBUTION OF DUST-EMITTING
SOILS Measured via laser diffraction
Agricultural soil. Notice the long tail of very
fine particles as small as 2 µm.
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PARTICLE SIZE DISTRIBUTION OF DUST-EMITTING
SOILS Measured via laser diffraction
Near shore of paleo-lake Palomas in Chihuahua.
Sequence of three samples moving from the playa
surface (green) to sand sheet away from the shore
(blue). Notice the playa surface clay (particles
submicron to a few microns) and fine particles as
small as 1µm, and the three distinct populations
of particles clay, silt (10- 20 µm) and sand
(100- 200 µm).
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PARTICLE SIZE DISTRIBUTION OF DUST-EMITTING SOILS
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Wind erosion process requires both coarse
particles (100 µm) for saltation motion close to
the ground that sandblasts and kicks fine
dust particles into the atmosphere
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PARTICLE SIZE DISTRIBUTION OF DUST-EMITTING SOILS
The environment on and near the edge of many
playas (dry lake beds) is perfect for windblown
dust emission due to the presence of sand
(provides the energy and work of saltation and
sandblasting) and silt and clay (get blasted off
into the atmosphere as dust aerosols).
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As sand moves downwind towards the Samalayuca
dunes, it initially (blue) contains a tail of
fine particles (even as fine as submicron), and
as the sand bounces downwind towards the
Samalayuca dunes (red) the fine material
disappears where did it go? It turned to dust
and blew out! Natural winnowing process
cleans the sand and results in these dust events.
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Electron microscopic analysis of particles
recovered from individual dust events reveals
aggregates (clumps) of much finer particles.
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X-ray spectrometric elemental analysis of dust
source materials may be usable to gain chemical
signatures of individual source types and
assess the possibility of health impacts.
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Metals such as lead, zinc and arsenic have been
detected in individual dust-source soil samples.
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Implications
Additional Findings- As well as helping us work
towards answering some questions, this study has
helped provoke some new ones as well.
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Implications
Additional Findings
The relatively random distribution of source
points from event to event- even within
pre-ferred areas- suggests to us that the actual
initiation spots of dust events may be controlled
to a large degree by small-scale meteorolo-gical
fluctuations (relatively chaotic), as opposed to
land surface or geological factors (relatively
predictable).
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Implications
Many of the source points are on the downwind
side of mountain ranges, suggesting the possible
role of topography- enhanced wind flows in
provoking dust emission in the future we hope to
be able to model this and investigate this
possibility further.
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JOURNAL ARTICLE SUBMITTED Lee, J.A., T.E. Gill,
K.R. Mulligan, M.A. Dominguez, and A.E. Perez, in
review. Land use/land cover and point sources of
the 15 December 2003 dust storm in southwestern
North America. Submitted to Geomorphology.
CONFERENCE PROCEEDINGS Rivera Rivera, N.I.,
M.P. Bleiweiss, J.L. Hand, and T.E. Gill, 2006.
Characterization of dust storms' sources in
southwestern U. S and northwestern Mexico using
remote sensing imagery. Preprints of the 14th
Conference on Satellite Meteorology and
Oceanography, American Meteorological Society,
January 2006, Atlanta, GA, P3.9, 17
pp. Novlan, D.J., M. Hardiman, and T.E. Gill,
2007. A synoptic climatology of blowing dust
events in El Paso, Texas from 1932-2005.
Preprints of the 16th Conference on Applied
Climatology, American Meteorological Society,
January 2007, San Antonio, TX , J3.12, 13
pp. ABSTRACTS OF CONFERENCE PRESENTATIONS Cahill
, C.F., Y. Yee, T.E. Gill, A. Ruiz, S.P. Emmert,
T.A. Cahill, F. Wilson, and E. Ellison, 2005.
Springtime dust aerosols at White Sands Missile
Range, New Mexico. EOS (Transactions, American
Geophysical Union) 86 (52 supp.) P22B-
02. Rivera Rivera, N.I., T.E. Gill, M.P.
Bleiweiss, J.L. Hand, M.A. Dominguez, A. Ruiz,
A.E. Perez, S.P. Emmert, J.A. Lee, and K.R.
Mulligan, 2005. Detection and preliminary
assessment of source areas of the 15 December
2003 dust storm in the Chihuahuan Desert,
southwestern North America. EOS (Transactions,
American Geophysical Union) 86 (52 supp.)
H51C-0389. Emmert, S.P., and T.E. Gill, 2006.
Source apportionment and composition of
precipitation and wet deposition in the Paso Del
Norte airshed. Abstracts of the Eighth
Conference on Atmospheric Chemistry, American
Meteorological Society Annual Meeting, Atlanta,
GA, January 2006, Abstract J5.2. Canalda, S.M.,
T.E. Gill, and S.P. Emmert, 2006. Long-range
transport of particles from regional dust storms
originating in the Chihuahuan Desert. Program
and Abstracts, New Mexico Geological Society 2006
Spring Meeting, Socorro, April 2006, p.
10. Dominguez, M.A., T.E. Gill, and R. Schmidt,
2006. The Lake Palomas - Samalayuca dune corridor
system, Chihuahua, Mexico. In Nickling, W.G.,
S. Turner, J.A. Gillies and M. Puddister,
editors, Program and Abstracts of the Sixth
International Conference on Aeolian Research,
Guelph, Canada, July 2006, p. 80. Rivera Rivera,
N.I., T.E. Gill, M.P. Bleiweiss, and J.L. Hand,
2006. Detection and characterization of dust
source areas in the Chihuahuan Desert,
southwestern North America, through remote
sensing. In Nickling, W.G., S. Turner, J.A.
Gillies and M. Puddister, editors, Program and
Abstracts of the Sixth International Conference
on Aeolian Research, Guelph, Canada, July 2006,
p. 140. Lee, J.A., T.E. Gill, K.R. Mulligan,
M.A. Dominguez, A.E. Perez, and A. Ruiz, 2006.
Land use/land cover and point sources of the 15
December 2003 dust storm in southwestern North
America. In Nickling, W.G., S. Turner, J.A.
Gillies and M. Puddister, editors, Program and
Abstracts of the Sixth International Conference
on Aeolian Research, Guelph, Canada, July 2006,
p. 142. Gill, T.E., R.J. Vet, P.E. Biscaye, M.P.
Bleiweiss, and M. Shaw, 2006. Recurrent
transcontinental dust transport from southwestern
North America to Canada. In Nickling, W.G., S.
Turner, J.A. Gillies and M. Puddister, editors,
Program and Abstracts of the Sixth International
Conference on Aeolian Research, Guelph, Canada,
July 2006, p. 150. Project- Related Professional
Meetings, Conferences, Symposia, Workshops
Attended American Geophysical Union Annual Fall
Meeting, San Francisco, CA, December
2005. American Meteorological Society Annual
Meeting, Atlanta, GA, January 2006 UTEP
Geological Sciences Colloquium, March 2006 Sixth
International Conference on Aeolian Research,
Guelph, Ontario, Canada, July 2006. National Park
Service, Chihuahuan Desert Inventory Monitoring
Network (CHDN) Vital Signs Prioritization
Workshop, El Paso, TX, August 2006
Undergraduate Research Students Canalda,
Sabrina (Senior, Geology)- 2005/06. Graduate
Thesis Completed Rivera Rivera, Nancy I.,
December 2006 (M.S., Environmental Science,
UTEP), Detection and Characterization of Dust
Source Areas in the Chihuahuan Desert,
Southwestern North America. 4 Additional
Graduate Students Supported and/or Perfoming
Thesis/Dissertation Research Related To This
Project. 6 Or More Journal Articles In
Development (should be submitted in 2007) Related
To The Findings Of This Project. 2 Additional
Proposals Submitted To Date (1 Funded) Related To
This Project More To Come
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HAY PREGUNTAS?