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Land-surface Atmosphere Research
My research philosophy can be summarized best as:
- tackle a variety of interesting problems,
- use whatever tools are relevant to address the problem at hand, and
- learn new tools, as needed.
The overarching theme of my research has been the interaction between the land surface and the
atmosphere. My primary tools in this endeavor are computer simulation models of the land
surface and the atmosphere. My major research area is in physical meteorology and climatology,
specifically the fluxes of energy and mass between the surface and the atmospheric boundary
layer. Much of my research has focused on radiative fluxes between vegetated surfaces and the
atmosphere, but I have also conducted NASA-funded modeling and field studies investigating
energy exchanges over the Greenland ice sheet and their impact on the amount and extent of
surface melting. I am currently involved in several research projects concerning land surfaceatmosphere
interactions in the Nebraska Sand Hills. One of these is investigating how the Sand
Hills' unique soil properties affect generation of warm-season mesoscale precipitation over the
Sand Hills and surrounding plains. Our findings show that the Sand Hills have a complex set of
effects on the atmosphere — in some cases acting to inhibit convective precipitation while in
others acting to enhance convection and precipitation generation in the region. These
investigations originally were part of a large, multi-investigator NSF grant to study the Sand
Hills as a complex ecosystem. This team of researchers included ecologists, physicists,
geologists, hydrologists and meteorologists.
Paleoclimate Modeling
Shortly after the Meteorology/Climatology Program was merged with the Geology Department
to form the Department of Geosciences in 1997, one of my geologist colleagues, Dave Loope,
poked his head into my office and asked, “Can we model the climate of the Jurassic?” My
answer was, “It can be done, but I’ve never done anything like that.” Thus, I embarked on a
completely new research track – paleoclimate modeling. For me, this meant learning a
completely new modeling system, along with developing new datasets to provide the appropriate
boundary conditions needed for the Jurassic environment. Along with another colleague, Bob
Oglesby, we are using the National Center for Atmospheric Research (NCAR) Community
Climate Simulation Model (CCSM) to simulate the climate of 200 million years ago as part of
our research into the environment that led to development of vast eolian formations in what is
now the southwestern United States. We were successful in obtaining NSF funding for the early
stages of this research and are seeking additional funding to continue our investigations. When
we first started this project, I had some difficulty fitting it into my overall theme of land surfaceatmosphere
interactions until I realized that it was just a matter of scale. A primary control on
the atmospheric circulation is the global distribution of land and ocean and, as the assemblage of
the continents into Pangea during the Jurassic represents a significantly different land/ocean
configuration than today, land surface-atmosphere interactions – at a global scale – is the major
focus of our research.
My collaboration with Loope and Oglesby has led to other paleoclimate investigations into the
causes of past periods of extreme aridity in central North America which led, for example, to
reactivation of dunes in parts of the Sand Hills. While large-scale changes in atmospheric
circulation seem to be primarily responsible for initiating the dry conditions, we are currently
seeking funding from NSF to conduct high-resolution modeling to investigate the role of local
and regional feedbacks in exacerbating and sustaining these droughts.
Regional Climate Modeling
As basic climate science research has made it increasingly clear that human-induced climate
change is occurring, more scientists are focusing on understanding the impacts of climate
change. A fundamental aspect of this shift in focus is the need for accurate and precise climate
predictions and information at local and regional scales – a capability yet to be developed. A
second fundamental need is to make this information available in an understandable and
accessible format to the stakeholders and policy-makers who must develop and implement
strategies for adapting to climate change. Together with colleagues in Computer Science and
Engineering (Swanson, Goddard, Ramamurthy), the School of Natural Resources (Hayes,
Istanbullouglu) and other University of Nebraska campuses (Larsen, Bishop, Shambaugh-Miller)
and with support from Oak Ridge National Laboratory and the National Center for Atmospheric
Research, Bob Oglesby and I have proposed to establish the Nebraska Center for Regional
Climate Modeling (NCRCM). This center’s long-term goal is to fill a major gap in climate
change research capability at the regional, national, and international levels: the need for
accurate and precise information on climate change at local and regional scales that will enable
the accurate forecasting needed for informed decision-making about adaptation to and mitigation
of climate change. This center will focus resources on further developing two existing clusters of
expertise – climate modeling and decision support systems – and increasing ancillary expertise in
hydrologic and land-cover modeling, water law and public policy, and rural health.
The NCRCM will develop the capability to downscale the predictions of global climate models
to predictions at the regional level, such as the Great Plains, the Northeastern U.S., or the
Himalayas, use these results to determine likely impacts of climate change on the region, and
develop decision support systems that deliver climate change information to policy-makers and
stakeholders in an understandable, easily-accessible format.