Transcript Winkler Scale - Department of Plant Sciences

Using Satellite &
Ground Data to
Examine Climate
Change & Premium
Wine Production in
California
Arnold J. Bloom
Dept. of Plant Sciences
U. of California at Davis
[email protected]
Drinking Bacchus
Reni, Guido c.1623
1947 Chateau Cheval Blanc Vinfolio
San Francisco, July 2006
$33,781.25
2005 Charles Shaw Merlot
“Two-buck Chuck”
Trader Joe’s
$1.99
“Premium wine grapes are produced
almost exclusively in a narrow climatic
range characterized by a lack of both
extreme heat and extreme cold.”
Sacramento
Valley
Napa
Valley
Napa Valley Petit Verdot grapes = $5,409 per ton
San
Francisco
San
Joaquin
Valley
San Joaquin Valley red grapes = $270 per ton
Salinas
Valley
20-fold difference in price
Los
Angeles
Imperial
Valley
Anticipated changes in global average temperatures under different emission
scenarios according various computer models
A2
A 1B
4
2
B1
A 1T
B2
A 1B
A2
A 1FI
Temperature change (°C)
6
0
1960 1980 2000 2020 2040 2060 2080 2100
Year
Stott et al. 2006, IPCC 2007
Current and anticipated percentages of suitable years for premium winegrape production in various locations in the United States according to
computer models
2005
2100
0
25
50
Suitable years (%)
75
100
M. A. White et al. (2006) PNAS 103:11217-11222
Observed changes in global average temperatures with respect to the average from
1951 to 1980
Global Land−Ocean Temperature Index
Temperature Anomaly (°C)
.6
Annual Mean
5−year Running Mean
.4
.2
.0
−.2
−.4
1880
1900
1920
1940
1960
1980
2000
Hansen et al. 2006 PNAS 103:14288-14293
Ft. Bragg
Colfax
Davis
Napa
Winkler Scale
• Technique for classifying the climate of
wine growing regions.
• Developed at UC Davis by A. J.
Winkler and M. Amerine 1944.
• Sum of degree days over 10°C from
April 1 until October 31.
= Σmax [(avg. daily temp. – 10), 0]
Winkler Scale
• Regions I (1,111 – 1,390 growing-degree days) and II
(1,391 – 1,670 growing-degree days) generally produce the
best dry table wines with light to medium body and good
balance.
• Region III (1,671 – 1,950 growing-degree days) produces
full-bodied dry and sweet wines.
• Region IV (1,951 – 2,220 growing-degree days) is best for
fortified wines, with table wines being inferior.
• Region V (2,220 – 2,499 growing-degree days) is best for
table grapes and makes low-quality table wines.
Winkler et al. 1974
General Viticulture,
2nd Ed., UC Press
Growing degree days (°C)
2000
1000
Ground Stations
1-y avg.
Ocean
Napa
Davis
Foothills
0
1880
1900
1920
1940
1960
Year
1980
2000
2020
Ft. Bragg
0
Colfax
III
NapaDavis
V
III
Winkler Scale
• Regions I (1,111 – 1,390 growing-degree days) and II
(1,391 – 1,670 growing-degree days) generally produce the
best dry table wines with light to medium body and good
balance.
• Region III (1,671 – 1,950 growing-degree days) produces
full-bodied dry and sweet wines.
• Region IV (1,951 – 2,220 growing-degree days) is best for
fortified wines, with table wines being inferior.
• Region V (2,220 – 2,499 growing-degree days) is best for
table grapes and makes low-quality table wines.
Conclusions
• Satellite data
– Spatial resolution too low
– Time scale too short
– White et al. (2008)
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1025&context=nasapub
• Ground data
– Year-to-year variation obscures trends
– Running averages show trends
– Climate change is shifting premium grape
growing areas