Delphi Survey
 
deltamanuscript.4june2013.text.docx
 Fundamental Information
 

 


 

 
HISTORICAL TRENDS
 
Figures from, "The Vermont Climate Assessment" by Galford, G., Carlson, S., Ford, S.,
Hoogenboom, A., Nash, J., Palchak, E., Pears, S., Underwood, K. Baker, D. 2014
 
Climate Paper Galford, G., Hadnott, B, et. al In Prep.
Data retrieved from NOAA's Applied Climate Information System
 







 
FUTURE PROJECTIONS

Climate Change Projections in the Lake Champlain Basin Region

 

Figures from, “IMPACTS OF PROJECTED CLIMATE CHANGE OVER THE LAKE CHAMPLAIN BASIN IN VERMONT" by Justin Guilbert, Brian Beckage, Jonathan M. Winter, Radley M. Horton, and Arne Bomblies.  2014

Under review at the American Meteorological Society's Journal of Applied Meteorology and Climatology.

 

Fig. 1 Study region including northern Vermont and southern Quebec, with Lake Champlain and the Champlain Valley bordering the western edge of the study region and the Green Mountains across the eastern portion of the study region. Eighth degree grid boxes are included to show the resolution of the Bias-Correction Constructed Analogues data.

Fig. 2 Historic trends in A) temperature and B) precipitation from weather stations across the study region aggregated to yearly averages. The dotted black lines indicate the number of weather stations that are reporting temperature or precipitation values. We selected 1958 and 1941 as the beginning of the historical period for temperature and precipitation, respectively, because these were the first years with 15 or more weather stations reporting temperature or precipitation. The solid black line is the linear regression line showing the increase in temperature from 1958 to 2012, with the slope indicating an increase of 0.19 degrees Celsius per decade and 0.12 mm per day per decade. Each weather station was weighted equally with no attention to spatial or topographical distributions.

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Fig. 3 Projected increases in A) mean temperature and B) the 0.05 and 0.95 quantiles for 2040-2069 and 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period and 3 GCMs. The 0.05 quantile is representative of the coldest days of a month and the 0.95 quantile is representative of the warmest days of a month. The furthest right column shows the average annual temperature change for mean, and 0.05 and 0.95 quantiles. The summer months, June through August, are projected to generally warm less than months in other seasons.

 

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Fig. 4 Projected increases in A) mean and B) the 0.95 and 0.99 quantiles of daily precipitation for 2040-2069 and 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period and 3 GCMs. Precipitation delta factors above 1.0 indicate that the intensity of a precipitation event is expected to increase. There is large uncertainty in the precipitation projections: Precipitation change for July in the period 2070-2099, for example, varies from a ~25% increase to a ~22% decrease in daily rainfall.  The choice of GCM often has a greater influence than the climate scenario, for example, in October where both the minimum and maximum change in mean precipitation occurs in the same scenario run by two different GCMs. The two quantiles shown are representative of the upper tail of a daily precipitation distribution.  Nearly all delta factors averaged across the year show an increase in large (0.95) daily precipitation events for both future periods while all delta factors averaged across the year for the largest (0.99) daily precipitation events are above 1.0.

 

Fig. 5 The projected number of freezing days per month for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. Freezing days were defined as days with an average temperature below 0o C.  The number of mid-winter, December through February, thaws in the study area will increase as the number of freezing days decreases.

Fig. 6 The projected monthly snowfall for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. Monthly snowfall shows a decreasing trend with time across the three emissions scenarios. All months show decreases in snowfall for both time periods and all scenarios.  By late century, a 42 percent decrease in January snowfall is projected in comparison to the observational period.

 

Fig. 7 The projected number of ‘hot’ days above 90 degrees F for 2040-2069 and 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period.  The number of hot days per year increases by 18.6 and 31.9 days by 2040-2069 and 2070-2099 with increases in July accounting for 7.3 and 11.2 days per year respectively.

 

 

Fig. 8 The projected growing season length for 2040-2069 and 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period.  The growing season length increases by 23.4 and 32.5 days by 2040-2069 and 2070-2099 under RCP 4.5 and by 32.8 and 53.6 days under RCP 8.5.

 

 

Fig. 9. Projected moisture balance for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. Projected future moisture balance usually brackets historic moisture balance indicating uncertainty in moisture balance projections.

 

 

                                        

Fig. 10.  Projected days with maple syrup production for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. Days with maple syrup production are projected to shift from 2 distinct peaks in fall and spring towards one peak in mid-winter. The number of days suitable for maple syrup production is expected to decrease by 7.3 and 11.5 days per year by mid- and late century.

Fig. 11 Projected heat index for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. In degree days the annual heat index is expected to increase by over 600 and 1100 degree days by mid- and late century respectively.

Fig. 12. Projected heating and cooling requirements for A) 2040-2069 and B) 2070-2099 for RCP 4.5 and 8.5 compared to the 1970-1999 base period. The degree days of cooling are expected to increase by 12.7 and 40.0 while the degree days of heating are projected to decrease by 987 and 1409 by mid- and late century respectively.