Research ArticleCLIMATOLOGY

Estimation of the maximum annual number of North Atlantic tropical cyclones using climate models

See allHide authors and affiliations

Science Advances  22 Aug 2018:
Vol. 4, no. 8, eaat6509
DOI: 10.1126/sciadv.aat6509
  • Fig. 1 Interannual variability of North Atlantic TCs.

    Interannual observed TC numbers using all TCs (black dotted), long-lived TCs (>2.0 days; black solid), and tracks used by Landsea et al. (3) (gray solid). Red dashed lines indicate the period of comparison with the reanalysis-derived GPIs.

  • Fig. 2 Variability in annual numbers of North Atlantic TCs calculated in reanalysis and model data.

    Histograms of normalized variance-scaled GPIs calculated on a 5° × 5° grid for the EC-Earth model (yellow), the CSIRO model (red), NCEP-2 reanalyses (blue), and ERA-Interim reanalyses (green) for (A) the Emanuel and Nolan index (EN) (27), (B) the Tippett index (TIP) (29), and (C) the Bruyère et al. index (CGI) (28). Arrows show 2005 GPI values (actual and unbinned) for the reanalyses and observed number of TCs (black).

  • Fig. 3 Interannual variability of North Atlantic TCs.

    Interannual observed TC numbers (from IBTrACS, black line) and variance-scaled genesis indices calculated in ERA-Interim (dashed lines) and NCEP-2 reanalyses (solid lines). Values in parentheses indicate interannual correlations (r2) between GPIs and IBTrACS.

  • Fig. 4 Number of Atlantic TCs simulated by the MRI model.

    The number of directly simulated TCs in the MRI model for (A) the ensemble member m050 and (B) each ensemble member forced by 2005 SSTs. The mean TC occurrence for each is shown by the horizontal dashed lines.

  • Table 1 Frequency of when the observed number of TCs in 2005 is exceeded.

    The percentage of years the modeled GPIs exceed the observed 2005 number of 28.0 and the calculated 2005 reanalysis GPIs over the entire North Atlantic basin. Values in parentheses include an internal variability of two TCs in the model-calculated GPIs. The number of years of simulation is included for each model.

    Dataset for
    comparison
    GPIModel
    CSIRO
    (5000 years)
    EC-Earth
    (1000 years)
    MRI (m050)
    (61 years)
    Observed
    (all TCs)
    EN0% (0.4%)0% (0.5%)0% (0%)
    TIP<0.05% (0.4%)0.1% (1.1%)0% (1.6%)
    CGI0% (0.6%)0% (0.5%)0% (0%)
    ERAEN1.9% (9.0%)2.4% (9.2%)4.9% (9.8%)
    TIP1.0% (6.0%)1.9% (6.9%)1.6% (8.2%)
    CGI3.7% (11.1 %)4.7% (13.5%)4.9% (14.8%)
    NCEPEN0.9% (5.8%)0.9% (6.5%)0% (6.6%)
    TIP1.1% (6.3%)2.0% (7.0%)1.6% (8.2%)
    CGI2.0% (8.4%)2.2% (9.2%)1.6% (9.8%)

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/8/eaat6509/DC1

    Fig. S1. Annual variability in North Atlantic TCs.

    Fig. S2. As in fig. S1 but scaled to long-lived TCs.

    Fig. S3. Interannual variability of modeled GPIs.

    Fig. S4. As in fig. S3 but scaled to long-lived TCs.

    Fig. S5. As in Fig. 1 but scaled to long-lived TCs.

    Fig. S6. As in Fig. 3 but for long-lived TCs.

    Fig. S7. As in Fig. 4 but for long-lived TCs (>2.0 days).

    Fig. S8. Distribution of mean-scaled numbers of North Atlantic TCs calculated in reanalysis and model data.

    Fig. S9. As in fig. S8 but scaled to long-lived TCs.

    Table S1. As in Table 1 but for long-lived TCs only.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Annual variability in North Atlantic TCs.
    • Fig. S2. As in fig. S1 but scaled to long-lived TCs.
    • Fig. S3. Interannual variability of modeled GPIs.
    • Fig. S4. As in fig. S3 but scaled to long-lived TCs.
    • Fig. S5. As in Fig. 1 but scaled to long-lived TCs.
    • Fig. S6. As in Fig. 3 but for long-lived TCs.
    • Fig. S7. As in Fig. 4 but for long-lived TCs (>2.0 days).
    • Fig. S8. Distribution of mean-scaled numbers of North Atlantic TCs calculated in reanalysis and model data.
    • Fig. S9. As in fig. S8 but scaled to long-lived TCs.
    • Table S1. As in Table 1 but for long-lived TCs only.

    Download PDF

    Files in this Data Supplement:

Navigate This Article