% of Land Area

1
Ongoing Studies of Urban Effects on the Water
Cycle at UGA Ms. Chandana Mitra
(Presenting)-Representing Dr. Marshall Shepherds
Research Group (Lauren Hand, Willis Shem, Michael
Carter, Yan Zhou) University of Georgia,
Atmospheric Sciences/Geography Dept.
43 of Land Area Dominated by Agriculture
of Land Area Built-up 3 - 6
2
Urbanization Affects the Water Cycle Change

• Is the Water Cycle Accelerating?
• Precipitation Can be a Beacon for Climate Change
  or Accelerating Water Cycle
• Is urbanization contributing?

Dr. Shepherds Group at UGA is primarily funded
by NASA and DTRA, through the University of
Utah Regions under study Atlanta, Houston,
Oklahoma City, Kolkata in India, S. Korean urban
areas, Pearl River Delta and East China urban
areas
3
Urban Influences on Rainfall
Previous research (see Shepherd 2006, Shepherd
2005 for reviews) has indicated that
urban-induced changes in natural precipitation
may likely be due to one or a combination of
factors
1) Atmospheric destabilization through the
enhanced thermal mixing due to low-level heating
(i.e., Urban Heat Island (UHI))
2) Increased turbulence and mechanical mixing due
to increased aerodynamic roughness created by
tall buildings
3) Modified microphysical and dynamic processes
caused by the addition of aerosols from
automobiles and industry 4) Bifurcation of
pre-existing precipitating systems by physical or
thermodynamic processes.
4
Quantifying Causes of Atlanta Urban Rainfall
Anomalies
Shem and Shepherd (2007), Goal Use WRF to
investigate physical mechanisms linking
Urbanization and Rainfall around Atlanta (e.g.
Shepherd et Al 2003, Dixon and Mote (2003), Diem
and Mote (2005)
1994
2005
No City
Green-No City, Purple-1994, Orange2005
5
Regional Mesoscale Simulations for
Houston Shepherd (2005), Shepherd and Burian
(2003)
(Shepherd et al. 2005)
Case study of recent observation findings
indicating urban-caused anomalies in lightning
(Orville et al. 2001) and rainfall (Shepherd
2005, Shepherd and Burian (2003)
6
Future Urban Land Use and Precipitation
Current 2025

• Projected Houston growth using UrbSim planning
  model
• Insert new urban land in MM5/NOAH
• Run simulation using 2001 Case Study
  meteorological conditions

7
Heavy Rainfall Downwind of OKC? Researcher
Lauren Hand
Average 24-Hr. Accumulation of Heavy-Extremely
Heavy Rainfall during the Warm Season (in inches)
Objective Prototyping a methodology to examine
Multiple Cities worldwide using NASA
Precipitation data
8
Urbanization and Rainfall Pre-Monsoon and
Kolkata. Researcher Chandana Mitra
9
Urbanization and Rainfall
Pre-Monsoon and Kolkata
10
How NSF May Advance Urban-Rainfall Studies

• By providing new observing systems to monitor and
  track anthropogenic and natural aerosols, land
  cover/land use changes, cloud microphysics, and
  precipitation processes
• By funding research that couples use of
  synergistic datasets from NASA, USGS, NSF and
  industry (e.g. Landsat, MODIS, Cloudsat,
  TRMM,Ikonos)
• Long-term measurements needed to detect trends in
  precipitation caused by human activity (in-situ
  and remote sensing)
• More basic funding on physical processes related
  to urban-induced rainfall
• A well-posed campaign to replicate METROMEX (e.g.
  HEAT or others) with current observational/modelin
  g capabilities
• Coupled physical-social model systems (see
  figure)
• Continued support for programs like the Dynamics
  of Coupled Human-Natural Systems

(From Shepherd et al. 2006)
11
Future Direction at UGA on Urban-Water Cycle
Studies

• Satellite and ground-based observations to
  quantify global urban-rainfall relationships
• Improved regional modeling to quantify physical
  mechanism that cause urban-rainfall variability
• Advancing knowledge of Aerosol-Urban LULC effects
  on radiative and microphysics processes using the
  emerging synergistic observations like (MODIS,
  TRMM, CALIPSO, CLoudSat) and modeling systems
• Should urban land use/aerosols be represented in
  GCMs
• Defining the urban hydrologic footprint and
  feedbacks to broader climate change processes
• Mitigation Strategies (e.g.albedo/vegetation
  modification, smart urban planning, etc.) and
  effects on climate system

12
The Urban Climate System Dr. J. Marshall Shepherd
and Dr. Thomas Mote GEOG 8120
The Anthropocene
humans have become a geologic agent comparable
to erosion and eruptions it seems appropriate to
emphasize the central role of mankind in geology
and ecology by proposing to use the term
'anthropocene' for the current geological epoch."
Paul J. Crutzen