Changes of frost in North Carolina State in recent years

1. Changes of frost in North Carolina State in recent years • Student Author - Anonymous • MEA593 Final Project • 05/09/2013

2. Motivation • Frost is the solid deposition of water vapor from humid air • Temperature extremes • Early frost can be detrimental to crops or reduce future crop yields especially when the development is delayed • Many plants can be damaged or killed by frost • Easter Freeze 2007 event

3. Date • 1982 ~ 2012, North Carolina State • Data - use a temp threshold of 32 F for frost • Station data: USHCN (United States Historical Climatology Network), 29 stations in NC • NARR data (North American Regional Reanalysis): 3-hourly air temp at 2m data, eight times/day, 0600 time level is chosen • Monthly mean PNA index from Climate Prediction Center

4. Hypotheses • Under global warming, my hypotheses would be: • Number of frost days: • Date of last spring frost: EARLIER • Date of first fall frost: LATER • Length of frost-free season: (frost-free season means the period between the last spring and first fall frost, also called growing season)

5. Results-Changes of frost days

6. Results-Changes of dates of last spring frost

7. Results-Changes of dates of first fall frost

8. Results-Changes of lengths of frost-free season

9. Results-From station data • NC has three distinct regions: the Appalachian Mountains, the Piedmont and Coastal Plains • 29 stations located in NC, 3 of them are chosen and they come from three regions, respectively

10. Stations from distinct regions

11. Relationship with SLP • Pacific/North American Pattern (PNA) index is measurement of the strength of the PNA pattern • PNA pattern: dominant mode of low-frequency climate variability in the northern hemisphere’s extra-tropical regions • Average from November through March, difficult to detect during summer

12. During the negative phase of PNA, warmer than average conditions persist over the south-central and southeastern U.S. and anomalously high pressures are centered Meehl et al.(2004) : more frost days when high pressure dominates on the monthly time scales r=0.32 Image from www.docweather.com

13. Projection for twenty-first century • Using fully coupled global climate model • Annual changes of frost days for 20 year average 2080-2099 minus the twentieth century reference period 1961-1990 Meehl et al (2004)

14. Future changes of frost days with … With nighttime minimum temperatures With sea level Pressure Anomalous northwesterly geostrophic flow over eastern North America, advecting anomalously cooler air into eastern and southeastern North America, bring more frost days the largest increase of nighttime minimum temperatures occur where there are fewer decreases in frost days

15. Mitigation & Adaptation • Agriculture not only suffers from the impacts of climate change, it is also responsible for 31% of global warming with land use change • Mitigation and adaptation must be equally considered in association with agriculture • “Climate-Smart Agriculture”: “sustainably increases productivity, resilience (adaptation), reduces/removes greenhouse gases (mitigation) while enhancing the achievement of national food security and development goals”

16. Mitigation • Mitigation means from the point of agriculture to reduce the releases of greenhouse gases and slow down the global warming to some extent • Mitigation GHGs in agricultural soils • Mitigation of CO2, N2O, CH4 through sequestration in agriculture • Innovative technology and advanced research

17. Adaptation • Adaptation here is referred as the agricultural policies and practices that can reduce the vulnerability of biological systems to climate change impacts

19. Government and research organizations need provide frost related information to practicers accurately and timely • Crop suitability studies: cryophilous plants and crops, heliophilous plants • Vulnerable species identification • Cost benefit analysis and investigation of invasive flora should be taken into account in the first place • The balance related to the agriculture in the national market and international trade should be taken into consideration when designing and planning the options and implementations • Monitor, evaluate, compile • The results of these assessments are used to increase effectiveness of implementations and improve the awareness, resulting in a nonmalignant cyclic process

20. Uncertainty • A combinations of factors influencing the changes of frost days in North Carolina State • Models which produce projections • Adaptation aligned with regional impacts • Cross-disciplinary collaboration

21. Conclusion • Frost days has changed under global warming, from the number of frost days, dates of last spring and first fall frost and the determined length of frost-free season from observations • Frost days will continue to change from the projections for future • PNA index can be used to predict the changes of frost days • Mitigation and adaptation should be considered equally in association with agriculture

22. References • Lindkvist L, Gustavsson T, Bogren J (2000) A frost assessment method for mountainous areas. Agricultural and Forest Meteorology, 102, 51-67. • Easterling DR (2002) Recent changes in frost days and the frost-free season in the United States. American Meteorological Society 83: 1327-1332. • Meehl GA, Tebaldi C, Nychka D (2004) Changes in frost days in simulations of twenty-first century climate. Climate Dynamics 23: 495-511. • Augspurger, Carol K (2013) Reconstructing patterns of temperature, phenology, and frost damage over 124 years: Spring damage risk is increasing. Ecology 94(1): 41-50. • Cuxart J, Guijarro JA (2010) Observed trends in frost and hours of cold in Majorca. International Journal of Climatology 30: 2358-2364. • Ohkubo S, Iwata Y, Hirota T (2012) Influence of snow-cover and soil-frost variations on continuously monitored CO2 flux from agricultural land. Agricultural and Forest Meteorology 165: 25-34. • IPCC. 2007. Climate Change 2007: Synthesis Report. Contributions of Working Groups I, Ii, and Iiito the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. • Darren Swanson, Jim Hiley, Henry David Venema, Richard Grosshans, 2009. Indicators of Adaptive Capacity to Climate Change for Agriculture in the Prairie Region of Canada.

23. Thank you!