Cluster analysis of tropical cyclone activity in the Atlantic and the Pacific

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Cluster analysis of tropical cyclone activity in
the Atlantic and the Pacific

• Suzana J. Camargo
• Lamont-Doherty Earth Observatory
• Columbia University

Meteorological Research Institute, Tsukuba,
Japan, February 17, 2009.
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Tropical Cyclone Tracks, ENSO and MJO

• Importance different track types have higher
  incidence on some years or when the MJO is active
  and make landfall in different regions.
• Identify different track types, their seasonality
  and relation with large-scale circulation, ENSO
  and MJO.
• New clustering technique used Mixture of
  polynomial regression models (curves) to fit the
  geographical shape of the trajectories.

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Clustering Technique

• Developed by S.J. Gaffney and P. Smyth
• - S.J. Gaffney (2004), Ph.D. thesis, UC Irvine.
• Mixture of polynomial regression models (curves)
  to fit the geographical shape of the
  trajectories.
• Fitting by maximizing the likelihood of the
  parameters.
• Rigorous probabilistic context for clustering
• Accommodate easily tropical cyclone tracks of
  different lengths.
• Applied to extra-tropical Atlantic Cyclones
• Gaffney, Robertson, Smyth, Camargo and Ghil,
  Climate Dynamics (2007)

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Western North Pacific Tropical Cyclones Cluster
AnalysisResults
Camargo, Robertson, Gaffney, Smyth and Ghil,
Cluster Analysis of Typhoon Tracks, Part I
Part II, Journal of Climate (2007).
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Number of clusters
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Mean Regression Trajectories
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Mean Regression Trajectories

• Appropriate number of clusters appears to be
  seven.
• Quantitative and subjective analysis.
• Two main trajectory-types straight-movers and
  recurvers.
• Additional clusters detailed differences in
  shape among these types.

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TRACKS TROPICAL CYCLONES Western North Pacific
1983-2002
20 TCs
TRACKS
22 TCs
13 TCs
17 TCs
MEAN REGRESSION TRAJECTORIES
8 TCs
13 TCs
Most TCs TY 3-5
8 TCs
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Distribution of TC angles of movement
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Number of TCs per Cluster
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Lifetime
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First PositionDensity
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NTC per month
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Cluster A
TRACK DENSITY
FIRST POSITION DENSITY
NTC ANNUAL CYCLE
Landfall 63
Regression Trajectory

• 67 reach typhoon intensity

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Cluster B
TRACK DENSITY
FIRST POSITION DENSITY
NTC ANNUAL CYCLE
Landfall 61
Regression Trajectory
50 only reach TS intensity.
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Cluster C
TRACK DENSITY
FIRST POSITION DENSITY
NTC ANNUAL CYCLE
Landfall 7
Regression Trajectory

• 70 reach typhoon intensity

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Tracks El Niño years
Tracks La Niña years
Cluster A
Cluster E
Cluster G
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ENSO Relationship
NTC- Number of Tropical Cyclones
ACE Accumulated Cyclone Energy
Total ACE has a relationship with ENSO (Camargo
Sobel, 2005).
Total NTC per year is not significantly correlated
with ENSO.
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MJO and clusters
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Eastern North PacificTropical CyclonesCluster
Analysis Results
Camargo, Robertson, Barnston and Ghil, Geochem.
Geophys. Geosys, 2008.
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Eastern North Pacific Tracks and Mean
Regression Trajectories
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MJO and ENP tropical cyclones
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North AtlanticTropical CyclonesCluster Analysis
Results
Kossin, Camargo and Emanuel, 2009, in preparation
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Atlantic clusters tracks
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Track Density per cluster
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SST Anomalies
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Atlantic Meridional Mode
Kossin and Vimont, BAMS 2008
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Vertical Shear
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AMM x ENSO
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GPI PI Composites by cluster
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MJO modulation
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Summary Tracks modulation

• New clustering technique applied to North Pacific
  and North Atlantic TC tracks.
• Clusters with different properties genesis and
  track regions, intensity, timing.
• Clusters strongly related to ENSO, AMM
  (Atlantic) and MJO are identified greater
  predictability on seasonal sub-seasonal time
  scales.