Trends in Spatial and Temporal Variability of Snowfall Totals and Events in Wisconsin, 1974 - 2010
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Transcript of Trends in Spatial and Temporal Variability of Snowfall Totals and Events in Wisconsin, 1974 - 2010
Trends in Spatial and Temporal Variability of
Snowfall Totals and Events in Wisconsin, 1974 - 2010
Presented by: Daryn HardwickGraduate, Geography Department, Saint Cloud State University
Faculty Advisors: Dr. Keith Rice, UWSP Geography Department Eugene Martin, UWSP Geography Department
Introduction
Purposeo To better understand winter climatology for the state of
Wisconsin
Hypothesiso Ha = There has been a decrease in both the amount of
snowfall and individual snowfall events in the state of Wisconsin between 1974 and 2010.
o Ho = There has been no change in the amount of snowfall or individual snowfall events in the state of Wisconsin between 1974 and 2010.
Introduction Economic Benefits
o Winter Tourism - $7.9 billion annuallyo Cold Water Fishing - $2.3 billion/year industryo Snowpack Water Storage saves between $2.3 - 348
billion/year
Economic Costso Snow Removal - $2 billion/yearo Road Closures - $2.5 billion/year
• Lost retail trade, wages, and tax revenueo Damage to Utilities
• $2 billion lost in 1994 snow storm in Mississippio Flooding
• $4.7 billion lost in 1997 Red River flooding in ND and MN
Introduction
The Impact of Snow/Winter Events on Humans:o 23.4 deaths per year causedo 161.7 injuries per year causedo $484 million in damage caused annually
Groundwater Rechargeo Urie (1966) determined about 2/3 of yearly groundwater
recharge contributed by winter precipitation
Literature Review Decline in snow cover extent and duration
o Choi et al. 2010, Davies 1994, Dêry and Brown 2007
Great Lakes studieso Burnett et al. (2003) - increase in snowfall and both the
lee and windward sideso Norton and Bolsenga (2007) – increase in lake-effect
snowfall
Wisconsin snowfallo Kunkel et al. (2009) – slight increase in snowfall
Methodology Data
o National Weather Service Cooperative Observer Program• Precipitation, Snowfall, and Snow Depth• October – April• 1974/75 – 2009/10 seasons• 152 weather stations, 11 out-of-state
Analyseso Station Homogenyo Season Averages and Event Totalso Snowfall/Precipitation Ratioo Regression lines (trends)
Analysis & Results Station Homogeny – having <10% missing data
over the study period (Kunkel et al. 2009)
o 137/152 (90%) determined homogenous for precipitationo 120/152 (79%) determined homogenous for snowfallo 78/152 (51%) determined homogenous for snow deptho Only stations suitable in both precipitation and snowfall
were used in final analysis, 117 stations (77%)
2008-2010 Seasons
Homogenous Stations
Results - Precipitation
Season Average Number of Events
48.73 - 51.5
51.51 - 54.28
54.29 - 57.05
57.06 - 59.83
59.84 - 62.6
62.61 - 65.38
65.39 - 68.16
68.17 - 70.93
70.94 - 73.71
4.935 - 5.319
5.32 - 5.704
5.705 - 6.088
6.089 - 6.472
6.473 - 6.856
6.857 - 7.241
7.242 - 7.625
7.626 - 8.009
8.01 - 8.393 Avg. = 60.1371 days/seasonAvg. = 6.31167 (0.01 in./recorded day)
Results – Precipitation Trends
Avg. Precipitation 1974-2010
Avg. Precipitation 1974-2007
< -0.0175
-0.0175 - -0.0125
-0.0125 - -0.0075
-0.0075 - -0.0025
-0.0025 - 0.0025
0.0025 - 0.0075
0.0075 - 0.01
0.01 - 0.0125
> 0.0125 State Trend = - 0.00112 (0.01 in./recorded day/year)State Trend = 0.01063 (0.01 in./recorded day/year)
Results – Precipitation Trends
Precipitation Events 1974-2010
Precipitation Events 1974-2007
> -0.3
-0.3 - -0.2
-0.2 - -0.1
-0.1 - -0.005
-0.005 - 0.005
0.005 - 0.05
0.05 - 0.1
0.1 - 0.15
> 0.15 Avg. = - 0.02615 days/season/yearAvg. = 0.05314 days/season/year
Results - Snowfall
Season Average Number of Events
1.417 - 1.963
1.964 - 2.508
2.509 - 3.053
3.054 - 3.599
3.6 - 4.144
4.145 - 4.689
4.69 - 5.235
5.236 - 5.78
5.781 - 6.325
17.5 - 21.32
21.33 - 25.13
25.14 - 28.95
28.96 - 32.77
32.78 - 36.59
36.6 - 40.4
40.41 - 44.22
44.23 - 48.04
48.05 - 51.86 Avg. = 26.8694 days/seasonAvg. = 2.30673 (0.1 in./recorded day)
Results – Snowfall Trends
Avg. Snowfall 1974-2010
Avg. Snowfall 1974-2007
< -0.0175
-0.0175 - -0.0125
-0.0125 - -0.0075
-0.0075 - -0.0025
-0.0025 - 0.0025
0.0025 - 0.0075
0.0075 - 0.01
0.01 - 0.0125
> 0.0125 Avg. = - 0.0046 (0.1 in./recorded day/year)Avg. = 0.00151 (0.1 in./recorded day/year)
Results – Snowfall Trends
Snowfall Events 1974-2010
Snowfall Events 1974-2007
> -0.3
-0.3 - -0.2
-0.2 - -0.1
-0.1 - -0.005
-0.005 - 0.005
0.005 - 0.05
0.05 - 0.1
0.1 - 0.15
> 0.15 Avg. = - 0.12792 days/season/yearAvg. = - 0.03975 days/season/year
Snowfall/Precipitation Ratio
Season Average
1.775 - 2.525
2.526 - 3.275
3.276 - 4.025
4.026 - 4.775
4.776 - 5.526
5.527 - 6.276
6.277 - 7.026
7.027 - 7.776
7.777 - 8.527 Avg. = 3.77435
Snowfall/Precipitation Ratio
1974-2010 Trend 1974-2007 Trend
< -0.0175
-0.0175 - -0.0125
-0.0125 - -0.0075
-0.0075 - -0.0025
-0.0025 - 0.0025
0.0025 - 0.0075
0.0075 - 0.0125
0.0125 - 0.0175
> 0.0175 Avg. = - 0.00774 (0.1 in./recorded day/year)Avg. = - 0.00529 (0.1 in./recorded day/year)
Precipitation by Latitude
41 42 43 44 45 46 47 48
-1.5
-1
-0.5
0
0.5
1
Precipitation as Rain Event Trend, 1975-2010
Latitude (degrees)
Tre
nd (
days/s
eason/y
ear)
41 42 43 44 45 46 47 48-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0.1
Precipitation as Rain Trend, 1975-2010
Latitude (degrees)
Tre
nd (
0.0
1 in./
record
ed d
ay/y
ear)
Snowfall by Latitude
41 42 43 44 45 46 47 48-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
Snowfall Events Trend, 1975-2010
Latitude (degrees)
Tre
nd (
days/s
eason/y
ear)
41 42 43 44 45 46 47 48-0.06
-0.04
-0.02
0
0.02
0.04
0.06
0.08
Snowfall Trend , 1975-2010
Latitude (degrees)
Tre
nd (
0.1
in./
record
ed d
ay/y
ear)
Precipitation/Snowfall by Latitude
41 42 43 44 45 46 47 48-0.14
-0.12
-0.1
-0.08
-0.06
-0.04
-0.02
0
0.02
0.04
0.06
Precipitation/Snowfall Ratio Trend, 1975-2010
Latitude (degrees)
Tre
nd (
0.1
in./
record
ed d
ay/y
ear)
Conclusions
Increase in Winter Precipitationo Significant at the ≥ 95% confidence level (p = 0.0001)
Increase in Winter Snowfallo Not significant at the ≥ 95% confidence level (p = 0.3624)
Decrease in Snowfall-to-Precipitation Ratioo Not significant at the ≥ 95% confidence level (p = 0.0526)
Increase in Days with Precipitationo Significant at the ≥ 95% confidence level (p = 0.0365)
Decrease in Days with Snowfallo Significant at the ≥ 95% confidence level (p = 0.0271)
2008-2010 Seasonso Anomaly or new trend?
Conclusions Self Critiques
o Climate data inherently unreliable?o Number of Events in a given seasono Are t-test’s suitable for climatic data?o Is 36 years enough for a climate study?
Future Researcho Investigate above critiqueso Do El Niño or La Niña have an effect?o Spatial and temporal trends in temperatureo Trends in Snow Cover and Snow Deptho Snowfall-to-Precipitation Ratio
References CitedAdams, R., L. Houston, and R. Weiher, 2004: The Value of Snow and Snow Information Services.Report prepared for NOAA's National Operational Hydrological Remote Sensing Center.
Assel, R. A., and D. M. Robertson, 1995: Changes in winter air temperatures near Lake Michigan, 1851-1993, as determined from regional lake-ice records. Limnol. Oceanogr., 40(1), 165-176.
Braham, R. R., and M. J. Dungey, 1984. Quantitative Estimates of the Effect of Lake Michigan on Snowfall. J. Climate and Applied Meteorology, 23, 940- 949.
Burnett A. W., M. E. Kirby, H. T. Mullins, and W. P. Patterson, 2003: Increasing Great Lake- Effect Snowfall during the Twentieth Century: A Regional Response to Global Warming? J. Climate 16,3535-3541.
Choi, G., D.A. Robinson and S. Kang, 2010: Changing Northern Hemisphere snow seasons. Journal of Climate, 23, 5305-5310.
Davies, T. D., 1994. Snow Cover-atmosphere interactions. Intl. Association of Hydrological Sciences, Publ. No. 223, 3-13.
Déry, S. J., and R. D. Brown, 2007. Recent Northern Hemisphere snow cover extent trends and implications for the snow-albedo feedback. Geophys. Research Letters, 34, 1-6.
Kunkel, K.E., M. Palecki, L. Ensor, K.G. Hubbard, D. Robinson, K. Redmond, and D. Easterling, 2009: Trends in 20th Century U.S. snowfall using a quality-controlled data set. J. Atmos. Ocean. Tech., 26, 33-44.
Kunkel, K. E., M. Palecki, K.G. Hubbard, D.Robinson, K. Redmond, and D. Easterling, 2007: Trend identification in 20th Century U.S. snowfall: The Challenges. J. Atmos. Oceanic Technol., 24, 64-73.
Leathers, D. J., and D. A. Robinson, 1993. The Association between Extremes in North American Snow Cover Extent and United States Temperatures. J. of Climate, 6, 1345-1355.
McCabe G. J., Clark M. P., and Serreze M. C., 2001: Trends in Northern Hemisphere surface cyclone frequency and intensity. J. Climate 14, 2763–2768.
NOAA NCDC Climate-Radar Data Inventory, Cooperative Observer Program climate data, Data used: 1974-2010.
NOAA NWS Office of Climate, Water, and Weather Services, Natural Hazard Statistics, 1940- 2009.
NOAA NWS, Summary of Natural Hazard Statistics for 2000 in the United States, 2000, [3 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2001 in the United States, 2001, [3 pp.]
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NOAA NWS, Summary of Natural Hazard Statistics for 2003 in the United States, 2003, [3 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2004 in the United States, 2004, [3 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2005 in the United States, 2005, [3 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2006 in the United States, 2006, [3 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2007 in the United States, 2007, [4 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2008 in the United States, 2008, [6 pp.]
NOAA NWS, Summary of Natural Hazard Statistics for 2009 in the United States, 2009, [4 pp.]
Norton, D. C., and S. J. Bolsenga, 1993. Spatiotemporal Trends in Lake Effect and Continental Snowfall in the Laurentian Great Lakes, 1951-1980. J. of Climate, 6, 1943-1956.
NWS Weather Forecast Office, Cooperative Observer Program, 2009.
Urie, D. H., 1966. Influence of Forest Cover on Snowpack and Ground-Water Recharge. Ground Water, Vol. 4, Issue 1, 5-9.
Wisconsin State Cartographer’s Office, Wisconsin Seasons, 2010.
Wisconsin State Cartographer’s Office, Wisconsin Statistics, 2009.
Daryn HardwickContact: [email protected]