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| Figure - Extended periods of drought can lead to other hazards including wild fires. |
Photos and images provided by Dr. Jeffrey Basara.
The U.S. heat wave of June 2012 saw 2,284 record-breaking temperatures. In October, the New York Times reported that the worst drought in 50 years is currently gripping the Corn Belt from Nebraska to Illinois, driving up food prices. Texas wildfires ravage that state in 2011 and 2012. Oklahoma is presently experiencing exceptional drought.
How do these events compare to the climatic events of the Dust Bowl during the Great Depression years when a heat wave gripped the country in 1936 and impacted Texas, Oklahoma, Kansas, Arkansas, Missouri, Iowa, Colorado, and New Mexico causing crops to fail?
This and other questions
are of interest to hydrologist/ hydrometeorologist Jeffrey Basara, Director of
Research for the Oklahoma Climatological Survey and Associate Professor in
the School of Meteorology at the University of Oklahoma. In his work, Dr.
Basara looks at real time data for the Great Plains and Oklahoma, in
particular. While meteorologists primarily look at atmospheric conditions,
hydrologists examine the complex interactions of water between the surface and
the atmosphere and how the processes relate to weather and climate.
SHAN: What attracted you to
the field of hydrology?
JEFF: It was not my first
choice. My education was in meteorology. When I was a graduate student working
for Ken Crawford, Director of the Oklahoma Climatalogical Survey, we were
installing soil moisture sensors into the Oklahoma Mesonetwork. I was asked to
attend an American Meteorological Society Hydrology Conference in Long Beach,
California in 1997, and it seemed as if the entire symposium was focused on how
soil moisture effects climate. Everything was about modeling. Every
presentation. They didn’t have a
way to validate the results, which we did because of our network of sensing
stations.
It was then that I realized
how fortunate I was to have this opportunity to work in hydrology. Ken Crawford
was my Master and Ph.D. advisor and he said to me, “You will be an expert in
your field.” He was right. He has a legacy of providing opportunities to young
researchers that turn into great careers.
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| Flux Tower Figure - Instrumentation deployed near Marena, Oklahoma, used to collect observations of soil, vegetation, and atmospheric conditions valuable in land-atmosphere interactions and drought research. |
SHAN: How have deliberate
man-made changes improved weather and climate in some regions – as for
example, the building of man-made lakes?
JEFF: There is little doubt
that a reservoir can effect soil moisture and weather. However, there are
other examples. The winter wheat belt in Oklahoma creates a mesoscale
atmospheric phenomena. It effects moisture content in the boundary layer and
actually makes the weather cooler and more moist during the spring. One of my
favorite thunderstorm/atmospheric events occurs along the wheat belt. We
actually know squall lines form in the winter wheat belt area, which then
impacts precipitation for the whole region.
There are other examples
that have the opposite effect. The urban area of Oklahoma City shows a
man-made heat element – an urban heat island. It is hotter and dryer than the
surrounding areas. This doesn’t just effect the urban area itself, but also
produces a warmer, dryer impact downstream.
We are using the
Mesonetwork for studying land-atmosphere interactions, feedback mechanisms
that can impact moisture above and below ground. These measurements from the
Mesonetwork are not only important for understanding the real-time weather,
but also showing climate impacts. When you think about hydrological events –
none are more devastating than drought and now we have data like never
before.
One topic we are now
studying is called “flash drought,” the rapid onset of drought in certain
areas. In 2005-2006, and then again in 2010-2011, it was dry in the spring,
summer and through the winter - over three seasons. But there are times when
drought occurs in a very rapid way, in a matter of weeks, and that is called
flash drought.
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In 2011, we came out of
that drought with a very wet fall and winter season that took us completely
out of the exceptional drought category. In fact, most of Oklahoma was
removed from drought classification of any kind. But then we had a warm
spring with limited rain and within 45-60 days during the summer, we were in
exceptional drought again. What had taken months before – we experienced in
6-8 weeks.
Using the network sensors,
we were able to see in May that a flash drought might be occurring.
Monitoring the weather and soil moisture, the soil moisture was telling an
interesting story. We had real time data information, where as in the past it
was nearly impossible to predict. We were able to alert people that needed to
know, like farmers and producers.
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SHAN: What are the present
areas of your greatest concern and focus with regards to weather and climate?
JEFF: The biggest concern
is drought and its impacts. The Southern Great Plains, which is comprised of
Nebraska, Kansas, Oklahoma, and Texas, is an area of drought concern. The
precipitation is never normal. It’s more like a pendulum that swings back and
forth between periods of drought and above normal precipitation (pluvials).
There are reasons for this – storm tracks, ocean currents, and
land-atmosphere patterns – that develop and persist.
In this region there are
also large urban areas with a growing population base – Oklahoma City,
Dallas, Austin and San Antonio. How is that population going to deal with the
increasing challenges of water resources? When we get into periods of drought
there are socio-economic impacts that are a big concern.
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I recently flew into Dallas
and had the opportunity to see that the reservoirs are not at capacity. Water
resources are becoming stressed due to human demand and natural drought. Another
issue is the overall water budget. What changes have we seen? Evaporation,
transpiration, storage changes of water have occurred. The Ogallala Aquifer
(an underground water reservoir that spreads from Texas to Nebraska) is being
depleted. It has been treated like a fossil resource, like oil, with no
regulation for drilling and pumping. By some estimates, it is at 20% of its
original capacity. Lakes that once existed have completely vanished in the
region.
There is another reserve of
water, the Arbuckle/Simpson reservoir, that has strong regulatory controls.
It’s being used with a more conservatory fashion. But places, like Dallas and
other populated areas, would like to get their hands on this water.
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| Figure - Land-atmosphere interactions played an important role in the redevelopment of Tropical Storm Erin over central Oklahoma and excessive rainfall during August 2007. |
SHAN: What are some of the
socio-economic benefits that come from improved hydrological models?
JEFF: Mark Twain once said,
“Whiskey is for drinking and water is for fighting.”
Water is becoming a
contentious issue. Better models, including soil moisture, are going to be
critical in helping us address all the needs of the region. The Oklahoma
Mesonetwork is providing a half million observations per day real time and an
archive of approximately 5 billion. That is a lot of data. Along with models,
this gives us a much better handle on water resources and how to address what
we’re seeing now in the Southern Great Plains.
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For more information
contact the Oklahoma Climatological Survey: http://climate.ok.gov/
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Shän Boggs worked
with Dr. Kenneth Crawford and others during the early development of the
Oklahoma Mesonetwork. She is a writer and editor, and now lives in California.
Her interests include science, technology, the environment, health, multimedia, and art.
