Steven B. Feldstein
Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania, U.S.A.
Presented at Tel Aviv University, Department of Zoology, Tel Aviv, Israel on May 12, 2010
Atmospheric teleconnections, bird Atmospheric teleconnections, bird migration, and implications for migration, and implications for
probabilistic forecasts of bird strikesprobabilistic forecasts of bird strikes
PREDICTABILITY
Three time scales associated with atmospheric predictability
Deterministic Predictability (Weather) (Useful 3-5 day numerical model forecasts) Numerous studies show a linkage between weather, i.e., storms, precipitation, fronts, etc., and bird migration. Van Belle et al. (2007) 3-day forecast of bird
migration intensity.
Extended-Range Predictability (1 week to 1 month timescale) Predictability mostly poor (because of chaos), except perhaps when teleconnction patterns are excited. Linkage to bird migration associated with storms that accompany teleconnection patterns (Elkins (2008).
Monthly and Seasonal Predictability (Climate, > 1month, average of weather) (Closely linked to seasonal cycle and boundary forcing) (Useful ensemble forecasts.) Linkage between El Nino/Southern Oscillation and bird migration (Hameed et al. 2009).
El Nino/Southern Oscillation and Bird Migration at Attu, Alaska
From 1980-2000, each year, about 100 birders visited Attu, Island to add Asian bird species to the North American bird lists Island, Alaska
to add Asian birds to their North American bird
Common Sandpiper Long-toed Stint Rustic Bunting
AIPD = Asian Individuals Per Day (North American species excluded from total) (Hameed et al. 2009)
QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and a
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El Nino/Southern Oscillation
ENSO, storms, and bird migration
ENSO affects
bird migration
through its
influence on the
latitude of the
jet and the
storms that follow
the jet, i.e. ENSO
alters the
environment
through which
storms propagate.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
The dominant Northern Hemisphere teleconnection patterns
North Atlantic Oscillation Pacific/North American pattern
Teleconnections evolve on a 7-10 day time scale (longer than weather time scale).
They alter storm path and storm intensity.Climate Prediction Center
Siberian Vagrants and the PNA Siberian Vagrants and the PNA Teleconnection PatternTeleconnection Pattern
Records of all observations (locations and dates in California) of Dusky Warbler, White Wagtail, Red-throated Pipit and other Siberian vagrants
Composite PNA index
Dusky Warbler (PNA=- 0.42, n=15, p<0.1)
White Wagtail (PNA=-0.26, n=22, p<0.02)
Red-throated Pipit (PNA=-0.38, n=79, p<0.01)
(Steven Feldstein, Peter Pyle, Steve Mlodinow, Richard Erickson, Jim Tietz)
Anomalous wind vectors associated with Dusky Warbler records in CaliforniaAnomalous wind vectors associated with Dusky Warbler records in California
Lag 0 DaysLag -1 Days
Lag -2 DaysLag -3 Days
Nearctic Vagrants and the North Atlantic OscillationNearctic Vagrants and the North Atlantic Oscillation
(Elkins 2008, British Birds)
Circumglobal Teleconnection Pattern
Time-averaged
V over
persistent event
(lag -6 to lag +9 days)
Correlation with EOF1 =0.83 Correlation with EOF1 =-0.72
Wave packets associated with SL precip
300
wet dry
EOF1
300-hPa geopotential height evolution - Middle Eastern precipitation
Feldstein and Dayan (2008)
-6 days -4 days -2 days
0 days +2 days +4 days
+5 days +7days +9 days
Composite
analysisEvolution of
300-hPa height
field determines
the wind, T,
T, P, P, and
rainfall,
variables which
influence bird
migration.
Wave packet
first seen over
NE Pacific.
Wave field
persists for 2
weeks. This
slow evolution
may allow for
a 7-day
weather
forecast for
Israel?
Israeli Migrants and the Circumglobal Teleconnection Israeli Migrants and the Circumglobal Teleconnection Pattern (CTP)?Pattern (CTP)?
QUESTIONS: Does the CTP influence bird migration over Israel?
Can the CTP be used to forecast the bird migration intensity or bird strike frequency with a
1-7 day lead time (fall season)? Beyond 3-4 days, is a forecast of bird migration
intensity with a probabilistic model based upon the CTP better than that based upon a deterministic linear regression model (e.g., Van Belle et al. 2007)?
16 North Pacific sea level pressure cluster patterns16 North Pacific sea level pressure cluster patterns
Example of
cluster
analysis
Tropical Convection Associated with Tropical Convection Associated with the Madden-Julian Oscillation (MJO)the Madden-Julian Oscillation (MJO)
Phase 1
Phase 2
Phase 3Phase 4
Phase 5
Phase 6
Phase 7
Phase 8
Time between Phases ~ 6 days
180 ۫° 60 ۫°W20 ۫°E
Dominant intraseaonal oscillation in the tropics
MJO cycle: 30-60 days
Shading OLR
Time between phases ~ 6 days
From Wheeler and Hendon (2004)
From Wheeler and Hendon (2004)
Frequency of occurrence for each cluster pattern and MJO phaseFrequency of occurrence for each cluster pattern and MJO phase
1-7 day Forecast of Anomalous Bird Migration intensity in Israel1-7 day Forecast of Anomalous Bird Migration intensity in Israel
Phase Number = location in Israel
Pattern Number = cluster pattern
Lag = 1 to 7 days (Feldstein
and Dayan 2008)
Color denotes anomalous
bird migration intensity
determined from composites of
the daily bird migration intensity
for each pattern number
Cluster analysis with 300-hPa meridional wind (1-7 day variability (CTP) dominated by the upper tropospheric flow and it
also determines the lower tropospheric flow where birds are observed)
(Cluster patterns represent slowly-evolving component of flow, small number of patterns with large spatial scales)
Analysis performed at separate locations (airports, radar stations, etc.) in Israel
Analysis can be performed separately for soaring (raptors) and powered flight (shorebirds) migrants
Conditional probabilities based on the accumulation of migrants during previous days (bad weather)
1-7 Day Probabilistic Bird Migration Intensity Forecast
Seasonal Forecast of Anomalous Bird Migration Seasonal Forecast of Anomalous Bird Migration Intensity in IsraelIntensity in Israel
mean is the anomalous seasonal meridional wind
is cluster pattern c
is the frequency of cluster pattern c
Obtain forecast of seasonal mean meridional wind
Determine the cluster pattern which has the largest projection onto
Estimate seasonal mean bird migration intensity (above average, average, below
average) in terms of the most frequently occurring cluster pattern.
Combined Probabilistic/Deterministic Bird Combined Probabilistic/Deterministic Bird Migration Intensity ForecastMigration Intensity Forecast
FF = (w1F1 + w2F2)/(w1 + w2)
F1 = probabilistic forecast based on cluster patterns
F2 = linear regression forecast based on deterministic
weather forecast model (e. g., Van Belle et al. 2007).
W = P(B|A) A= forecasted bird migration intensity
B= observed bird migration intensity
Presumably Presumably F1 (F2 ) forecast is better for longer (shorter) lead times.
Bayesian forecast also possible using multimodel ensemble approach
Bird migration related to (a) weather, (b) teleconnections (PNA, NAO),
and (c) climate (ENSO)
Forecast of bird migration intensity based upon cluster analysis of the 300-hPa
meridional wind
Using weights, can combine probabilistic forecast with deterministic linear regression
forecast
The technique can be extended to seasonal bird migration intensity forecasts.
ConclusionsConclusions