Impacts of climate anomalies on
water resources in the Carolinas
Dan Tufford, Greg Carbone, Jim Hussey, Kirstin Dow
University of South Carolina
Climate Prediction Application Science Workshop
Chapel Hill, NC
06 March 2008
Evaluating ENSO Impacts in the
Carolinas
Stakeholders’ perceptions
of ENSO impacts
Discerning and
communicating
variability of ENSO
expression
Regional assessment
• North and South Carolina
• COOP and USGS
– 1950 – 2004
• Monthly total precipitation and streamflow
• Assign ENSO phase by month (CPC)
– Cool (La Niña), neutral, warm (El Niño)
• Assign AMO phase by year
– Warm – 1950-1963, 1995-2004
– Cool – 1964-1994
• Each month assigned to a season
– Winter = DJF, Spring = MAM, etc.
• SAS Proc GENMOD
– Gamma distribution
– Significance at p ≤ .05
ENSO and AMO analysis
Winter
Spring
ENSO phase AMO both AMO cool AMO warm Coastal effect
W/C
W/N
N/C
W/C
W/N
N/C
Summer W/C
W/N
N/C
Autumn
W/C
W/N
N/C
Winter – AMO n/a
Precipitation
Stream flow
Winter – AMO cool
Precipitation
Stream flow
Winter – AMO warm
Precipitation
Stream flow
ENSO and AMO analysis
• Winter – warm AMO, both precipitation
and streamflow
– El Niño > Neutral > La Niña
ENSO and AMO analysis
• Winter – warm AMO, both precipitation and
streamflow
– El Niño > Neutral > La Niña
• Spring – similar relationships
– Not as strong as winter
• Summer – significant precipitation only
– Both El Niño, La Niña > Neutral when AMO cool
– Both El Niño, La Niña < Neutral when AMO warm
• Autumn – both precipitation and streamflow
– Greater regional differences – interior v coastal
– Differences between precipitation and streamflow
Influence of tropical storms
Dams R Us
• Analysis of only
unregulated stations
does not significantly
alter the interpretation of
the results.
• Suggests actual inflow
to reservoirs impacts
their operations as much
or more than weather.
Uses of these results/methods
• Hydrologic modeling
– Effect of interannual and multidecadal phase
– Both short- and long-term scenarios
• Value of subregional analysis for water
management and planning
– Climate driven interannual weather patterns do vary
over the study area
• Provides another perspective of the impacts of
land use change
• Streamflow is more important than precipitation
for some sectors
– Analysis may provide a basis for seasonal
differentiation among these sources of water
Regional drought implications
• Prior knowledge that La
Niña is associated with dry
winter conditions in the
southeast
• These results show this
effect is associated with
the warm phase AMO
• Providing AMO and ENSO
phases with monitor
reports and seasonal
forecasts would make
them more information rich
Drought implications example
• Telephone surveys of
horticultural industry in
NC/SC
• “If drought continues
residential planting will be
minimal due to watering
restrictions”
• Planting decisions are
made months in advance
– Influenced by an indirect
effect
• Some do their own
monitoring to stay abreast
of local conditions
Additional acknowledgements
• Jinyoung Rhee, PhD – USC Geography
• Graduate students
– Kirsten Lackstrom, Richard Murphy, Sara Yorty
• Undergraduate students
– Lauren Felker, Grandon Wilson