The wind is a dynamic element of the global climate system. In order to assess wind resources and the risks posed by infrequent but exceptional events accurately, it is critical to understand the wind’s temporal variability and spatial structure, as well as the physical mechanisms that influence its behavior.

1. THE
WIND
A
DROUGHT
IN

2. Photograph: the russians are here

3. 0
10,000
20,000
30,000
40,000
1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
U.S. installed wind energy capacity (megawa s)
Source: Office of Energy efficiency and Renewable Energy

5. Photograph: LakeBarcro VA

7. Photograph: canoe too

8. Photograph: GKS

10. STEP ONE
Examine regional or global wind atlases

12. STEP TWO
Collect detailed on-site measurements

14. STEP THREE
Use long-term climate records to
estimate past changes in the wind

15. possible wind farm

16. possible wind farm
climate station

17. possible wind farm
climate station
long wind record

18. possible wind farm
climate station
long wind record
probability distribution
function

19. STEP FOUR
Use the
probability distribution function
to estimate future wind conditions

20. strong windsweak winds
rare
frequent
probability distribution function

21. strong windsweak winds
rare
frequent
probability distribution function

22. strong windsweak winds
rare
frequent
probability distribution function

23. strong windsweak winds
rare
frequent
probability distribution function

24. strong windsweak winds
rare
frequent
probability distribution function

25. strong windsweak winds
rare
frequent
probability distribution function

27. stationary
independent and identically distributed
ASSUMPTIONS

28. W I N D S O F C H A N G E

29. stationarity is the idea that natural systems fluctuate
within an unchanging envelope of variability.
Source: Milly et al., Science, 2008

30. Trends in near-surface wind speeds, 1973 to 2005
faster
slower
Source: Prior et al., Journal of Geophysical Research, 2009

31. global ‘stilling’

32. Robert Gramlich, policy director at the American
Wind Energy Association, said the idea of reduced
winds was new to him.
He wants to see verification from other studies
before he worries too much about it.
Seth Borenstein, Associated Press
“
”

34. Using anemometer observations from approximately 160
sites, daily surfaces of [wind speed] have been interpolated
for the Australian continent for 1975–2006. The results
showed reductions in [wind speed] over some 88% of the
continent.
“
” McVicar et al., Geophysical Research Le ers, 2008

36. From 1969 to 2000, the annual mean wind speed over
China has decreased steadily by 28%, and the prevalence
of windy days (daily mean wind speed > 5 m/s) has
decreased by 58%.
“
” Xu et al., Journal of Geophysical Research, 2006

38. During the period analyzed, the homogenized near-
surface wind speed series show significant decreases
throughout western Canada and most parts of southern
Canada (except the Maritimes)...
“
”
Wan et al., Journal of Climate, 2010

39. Source: Vautard et al., Nature Geoscience, 2010
Trends in near-surface wind speed, 1979 to 2008

40. As wind electricity production is much more efficient at
stronger winds, a continuation of such trends would lead
to a major loss of wind power production.
“
”
Vautard et al., Nature Geoscience, 2010

42. A D R O U G H T I N T H E W I N D

43. independent and identically distributed

44. strong windsweak winds
rare
frequent

46. “add[s] significantly to the uncertainty
in predicting the energy output of a
wind farm at a particular location
during its projected lifetime.
INTERANNUAL VARIABILITY
”

47. “...not well understood.
INTERANNUAL VARIABILITY
”

48. Our analysis of wind speed measurements from 1996–2001
at five tall-tower sites in Minnesota showed that there can
be substantial interannual variability in mean annual wind
speed and wind power...
“
”
Klink et al., Physical Geography, 2003

49. We speculate that interannual variability in mean annual wind
speed primarily is due to variations in the large-scale
atmospheric circulation, including its effects on cyclonic activity.
“
”
Klink et al., Physical Geography, 2003

52. Photograph: canoe too

53. mean annual wind speed
@ 10 m

54. Mean winter wind speed, southern Canadian Prairies
Source: St. George and Wolfe, GRL, 2009

55. SST and geopotential height anomalies during low-wind winters
Source: St. George and Wolfe, GRL, 2009

56. Source: St. George and Wolfe, GRL, 2009
less likely
more likely
strong windsweak winds

57. Source: St. George and Wolfe, GRL, 2009
less likely
more likely
strong windsweak winds

60. [The next strong El Niño] ... may also test the
ability of Prairie wind farms to maintain
expected energy outputs during a prolonged
interval of unusually weak winds.
“
”Geophysical Research Le ers
December 2009

61. Sea-surface temperature anomalies during the 2009-2010 winter

62. ...our wind resources in the quarter were down
approximately 30 percent, compared to what we would
see in a normal year. As a result, expected production
from our wind facilities was lower by roughly 200
gigawa hours.
Stephen Snyder
President and Chief Executive Officer
April 27, 2010
“
”

63. -10 -5 0 +5 +10

64. A F U T U R E F O R O L D W I N D S
Photograph: fieldsbh

65. WHY THE PAST
MATTERShow tree rings and environmental history help us make
better decisions about water, climate and the future

66. Unlike many “hard sciences”, history cannot
lend itself to experimentation.
“
”
Nassim Taleb, Fooled By Randomness

67. But somehow, overall, history is potent enough
to deliver, on time, in the medium or long run,
most of the possible scenarios, and to
eventually bury the bad guy.
“
”
Nassim Taleb, Fooled By Randomness

69. Photograph: GKS

70. THE
WIND
A
DROUGHT
IN