1) The document analyzes seasonal forecasts for global wind energy availability in autumn. 2) It identifies several key regions where wind resource is both abundant and highly variable between years, making them most suitable for seasonal wind forecasting. 3) The forecasts are evaluated against past data and found to have the highest skill in predicting wind resource variability, magnitude, and uncertainty in certain regions like Patagonia, parts of Africa, Asia, and Australia.

1. Climate Forecasting Unit
AUTUMN
Seasonal Forecasts for
Global Wind Energy
Melanie Davis, Francisco Doblas-Reyes, Fabian Lienert

2. Climate Forecasting Unit
Fig. W1.3.1: Autumn 10m wind resource (speed, m/s) availability from 1981-2011 (ERA-Interim)
m/s
Stage A: Wind Resource Assessment
Wind energy potential: Where is it the windiest?
Darker red regions of this map show where global 10m wind resource (speed, m/s) is highest in autumn, and
lighter yellow regions where it is lowest.
N.b. This information is based on reanalysis* data (ERA-Interim) not direct observations.
* Reanalysis information comes from an objective combination of observations and numerical models that simulate one or more aspects of the Earth system, to
generate a synthesised estimate of the state of the climate system and how it changes over time.
AUTUMN Wind Forecasts
(September + October + November)

3. Climate Forecasting Unit
Fig. W1.3.2: Autumn 10m wind resource inter-annual variability from 1981-2011 (ERA-Interim)
m/s
Stage A: Wind Resource Assessment
Wind energy volatility: Where does the wind vary the greatest?
Darker red regions of this map show where global 10m wind resource varies the most from one year to the
next in autumn, and lighter yellow regions where it varies the least.
N.b. This information is based on reanalysis* data (ERA-Interim) not direct observations.
AUTUMN Wind Forecasts
(September + October + November)

4. Climate Forecasting Unit
Europe
Autumn 10m wind resource availability Autumn 10m wind resource inter-annual variability
m/s
Areas of
interest: Patagonia/
Chile
Central
Sahara/
Sahel/S.W.
Ethiopia
W.India/
W.China/
Afghanistan/
Pakistan/
Tajikistan
N. Australia/
Tasmania/
Pacific Isles
S.America Africa Asia Australia
N.Mexico/
S.Greenland
N.America
UK/
Baltic Sea
Stage A: Wind Resource Assessment
Where is wind resource potential and variability (volatility) highest?
By comparing both the autumn 10m global wind resource availability and inter-annual variability, it can be
seen that there are several key areas (listed above) where wind resource is both abundant and highly variable.
These regions are most vulnerable to wind resource variability over climate timescales, and are therefore of
greatest interest for seasonal forecasting in autumn.
AUTUMN Wind Forecasts
(September + October + November)

5. Climate Forecasting Unit
Fig. W2.3.1: Autumn 10m wind resource ensemble mean correlation
(ECMWF S4, 1 month forecast lead time, once a year from 1981-2010)
time
windspeed
forecast
+ 1.0
obs. forecast
- 1.0
forecast
example 1
forecast
- 1.0
example 2
example 3
Stage B: Wind Forecast Skill Assessment
1St
validation of the climate forecast system:
The skill of a climate forecast system, to predict global wind resource variability in autumn 1 month ahead, is
partially shown in this map. Skill is assessed by comparing the mean of a autumn wind forecast, made every
year since 1981, to the reanalysis “observations” over the same period. If they follow the same variability over
time, the skill is positive. This is the case even if their magnitudes are different (see example 1 and 2).
Perfect
Forecast
Same as
Climatology
Worse
than
Clima-
tology
AUTUMN Wind Forecasts
(September + October + November)
Can the wind forecast mean tell us about the
wind resource variability at a specific time?

6. Climate Forecasting Unit
Fig. W2.3.1: Autumn 10m wind resource ensemble mean correlation
(ECMWF S4, 1 month forecast lead time, once a year from 1981-2010)
Stage B: Wind Forecast Skill Assessment
1St
validation of the climate forecast system:
Dark red regions of the map show where the climate forecast system demonstrates the highest skill in autumn
seasonal forecasting, with a forecast issued 1 month in advance. White regions show where there is no
available forecast skill, and blue regions where the climate forecast system performs worse than a random
prediction. A skill of 1 corresponds to a climate forecast that can perfectly represent the past “observations”.
Perfect
Forecast
Same as
Climatology
Worse
than
Clima-
tology
AUTUMN Wind Forecasts
(September + October + November)
Can the wind forecast mean tell us about the
wind resource variability at a specific time?

7. Climate Forecasting Unit
Fig. W2.3.2: Autumn 10m wind resource CR probability skill score
(ECMWF S4, 1 month forecast lead time, once a year from 1981-2010)
time
windspeed
forecast
+ 1.0
obs. forecast
- 1.0
forecast
example 1
forecast
- 1.0
example 2
example 3
Stage B: Wind Forecast Skill Assessment
2nd
validation of the climate forecast system:
The skill of a climate forecast system, to predict global wind resource variability in autumn 1 month ahead, is
fully shown in this map. Here, skill is assessed by comparing the full distribution (not just the mean value as in
the previous map) of an autumn wind forecast, made every year since 1981, to the “observations” over the
same period. If they follow the same magnitude of variability over time, the skill is positive (example 2).
Perfect
Forecast
Same as
Climatology
Worse
than
Clima-
tology
AUTUMN Wind Forecasts
(September + October + November)
Can the wind forecast distribution tell us about
the magnitude of the wind resource variability,
and its uncertainty at a specific time?

8. Climate Forecasting Unit
Fig. W2.3.2: Autumn 10m wind resource CR probability skill score
(ECMWF S4, 1 month forecast lead time, once a year from 1981-2010)
Stage B: Wind Forecast Skill Assessment
2nd
validation of the climate forecast system:
Dark red regions of the map show where the climate forecast system demonstrates the highest skill in autumn
seasonal forecasting, with a forecast issued 1 month in advance. White regions show where there is no
available forecast skill, and blue regions where the climate forecast system performs worse than a random
prediction. A skill of 1 corresponds to a climate forecast that can perfectly represent the past “observations”.
Perfect
Forecast
Same as
Climatology
Worse
than
Clima-
tology
AUTUMN Wind Forecasts
(September + October + November)
Can the wind forecast distribution tell us about
the magnitude of the wind resource variability,
and its uncertainty at a specific time?

9. Climate Forecasting Unit
Europe
Areas of
interest:
N.E.Coast/
Paraguay/
E.Bolivia
Indonesia/
S.China/
Hong Kong/
Taiwan
C.E.Australia/
Pacific Isles
S.America Africa
Asia
Australia
Caribbean
N.America
UK/Baltic/
S.Atlantic
Autumn 10m wind resource variability
magnitude, and its uncertainty forecast skill
Autumn 10m wind resource variability
forecast skill
Wind resource variability
forecast skill only
Both wind resource variability and magnitude forecast skill
Stage B: Wind Forecast Skill Assessment Where is wind forecast skill highest?
By comparing both the autumn 10m global wind resource forecast skill assessments, it can be seen that there
are several key areas (listed above) where wind resource forecasts are skilful in assessing its variability,
magnitude and uncertainty. These regions show the greatest potential for the use of operational autumn wind
forecasts, and are therefore of greatest interest to seasonal wind forecasting in autumn.
AUTUMN Wind Forecasts
(September + October + November)
Kenya-
Somalia
Coast

10. Climate Forecasting Unit
Stage B: Wind Forecast Skill Assessment
Magnitude and uncertaintlyforecast skillVariability forecast skill
m/sm/sm/s
SPRING Wind Forecasts
These four maps compare the seasonal autumn 10m wind resource global forecast skill maps (bottom)
alongside the autumn 10m global wind resource availability and inter-annual variability maps (top). It can be
seen that there are several key areas (highlighted above) where the forecast skill is high in both its variability,
magnitude and uncertainty, and the wind resource is both abundant and highly variable. These regions
demonstrate where autumn seasonal wind forecasts have the greatest value and potential for operational use.
EuropeAreas of
Interest:
(Forecast skill)
N.E.Coast/
Paraguay/
E.Bolivia
Indonesia/
S.China/
Hong Kong/
Taiwan
S.America Africa Asia Australia
Caribbean
N.America
UK/Baltic Sea/
S.Atlantic
Europe S.America Africa Asia AustraliaN.America
Patagonia/
Chile
Central
Sahara/
Sahel/S.W.
Ethiopia
W.India/
W.China/
Afghanistan/
Pakistan/
Tajikistan
N.Australia/
Tasmania/
Pacific Isles
N.Mexico/
S.Greenland
UK/
Baltic Sea
Areas of
Interest:
(Resources)
Where is wind resource potential and volatility highest?
Wind resource inter-annual variabilityWind resource availability
Stage A: Wind Resource Assessment
Variability forecast skill
Where is wind forecast skill highest?
AUTUMN Wind Forecasts
(September + October + November)
E.Australia/
Pacific Isles
Kenya-
Somalia
Coast

11. Climate Forecasting Unit
%
Europe
MexicoUK/Baltic Sea
Areas of Interest Identified:
(Resources and Forecast Skill)
W.
Australia
Pacific Isles
Fig. W3.3.1: Probabilistic forecast of (future) autumn 2011,10m wind resource most likely tercile
(ECMWF S4, 1 month forecast lead time)
Stage C: Operational Wind Forecast
This operational wind forecast shows the probability of global 10m wind resource to be higher (red), lower
(blue) or normal (white) over the forthcoming autumn season, compared to their mean value over the past 30
years. As the forecast season is autumn 2011, this is an example of wind forecast information that could have
been available for use within a decision making process in August 2011.
AUTUMN Wind Forecasts
(September + October + November)

12. Climate Forecasting Unit
%
Stage C: Operational Wind Forecast
The key areas of highest interest are shown, identified in the stages A and B of the forecast methodology.
These regions demonstrate where autumn seasonal 10m wind forecasts have the greatest value and potential
for operational use. The areas that are blanked out either have lower forecast skill in autumn (Stage B) and/or
lower wind resource availability and inter-annual variability (Stage A).
Fig. W3.3.1: Probabilistic forecast of (future) autumn 2011,10m wind resource most likely tercile
(ECMWF S4, 1 month forecast lead time)
AUTUMN Wind Forecasts
(September + October + November)
Europe
MexicoUK/Baltic Sea
Areas of Interest Identified:
(Resources and Forecast Skill)
W.
Australia
Pacific Isles

13. Climate Forecasting Unit
%
Stage C: Operational Wind Forecast
This does not mean that the blanked out areas are not useful, only that the operational wind forecast for these
regions should be used within a decision making process with due awareness to their corresponding
limitations. The primary limitations to a climate forecast are either the forecast skill and/or the low risk of
variability in the wind resource for a given region. See the “caveats” webpage for further limitations.
Fig. W3.3.1: Probabilistic forecast of (future) autumn 2011,10m wind resource most likely tercile
(ECMWF S4, 1 month forecast lead time)
AUTUMN Wind Forecasts
(September + October + November)
Europe
MexicoUK/Baltic Sea
Areas of Interest Identified:
(Resources and Forecast Skill)
W.
Australia
Pacific Isles

14. Climate Forecasting Unit
The research leading to these results has received funding
from the European Union Seventh Framework Programme
(FP7/2007-2013) under the following projects:
CLIM-RUN, www.clim-run.eu (GA n° 265192)
EUPORIAS, www.euporias.eu (GA n° 308291)
SPECS, www.specs-fp7.eu (GA n° 308378)