Developing a Cold Temperature Risk Assessment Kristen Gore, Adrienne Wootten, and Ryan Boyles Carolinas and Virginia Climate Conference October 20, 2009 Wilmington, NC

Motivation Spring freezes can potentially eliminate an entire year’s worth of cropsSpring freezes can potentially eliminate an entire year’s worth of crops –Severe damage can have impacts for several years to fruit crops Some crops are more vulnerable then othersSome crops are more vulnerable then others Risk of freeze damage depends onRisk of freeze damage depends on –Plant develop prior to freeze –Timing, duration of freeze

The NC Department of Agriculture and Consumer Services Estimated Crop Losses to a total of $112 million dollars in North Carolina

Methods The Probability of a freeze is determined usingThe Probability of a freeze is determined using –Station –Time Span (at least 30yrs) –Date of Interest –Temperature Threshold (depends on the crop)

Statistical Information Probability of the Low Temperature Falling below the threshold for a given dateProbability of the Low Temperature Falling below the threshold for a given date Low Temperature Frequency DistributionLow Temperature Frequency Distribution Climatological Probability TrendClimatological Probability Trend Yearly Growing Degree Day (GDD) TrendYearly Growing Degree Day (GDD) Trend Climatological GDD TrendClimatological GDD Trend

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In the Future Finish DevelopmentFinish Development Develop map-based risk productsDevelop map-based risk products –Location, crop specific Look at risk as influenced by ENSO, Arctic OscillationLook at risk as influenced by ENSO, Arctic Oscillation