Development of a Tropical Cyclone Rain Forecasting Tool Frank

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					   Development of a Tropical Cyclone Rain
            Forecasting Tool
                             Frank D. Marks
          NOAA/AOML, Hurricane Research Division, Miami, FL 33149



     QPE Techniques in TCs
      • TRMM and gauges
     QPF Techniques in TCs
      • R-CLIPER
      • 2002 Storms
      • Where do we go from here?


               Support from NOAA JHT and NASA TRMM and CAMEX
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             QPE techniques in TCs:
DATA:
 TMI R estimates for 245 storms (December
  1997-2000), globally, yielding 2121 events, from
  TD to CAT5 (Lonfat et al 2003).
                1998-2000 TMI events by Intensity
                Storm IntensityEvents %
                TD/TS          1361     64
                Category 1-2    548     26
                Category 3-5    212     10
                Total          2121
   560,000 hourly gauge estimates in 46 US
    landfalling hurricanes (1948-2000) (DeMaria
    2003)
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                    QPF techniques in TCs:
    Develop R-CLIPER from gauge and TMI climatology for
     operational and model QPF comparisons.
    Project R-climatology along NHC forecast track.




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                      R-CLIPER
   Radial distribution of R for gauge and TMI climatology
    consistent.
   TMI peak R increases with intensity: 3 mm h-1 TD/TS;
    7.2 mm h-1 CAT 1-2; 12.5 mm h-1 CAT 3-5.
   TMI peak R radius decreases with storm intensity.




2/10/03   F.Marks                  5
                        R-CLIPER Cases
7.7”
                                               15.9”
                            4.8”




                                            color
                                        contours         Position
                                       denote Rtotal        and
       4.1”                 8.6”         (inches,        intensity
                                         peak at        from best
                                          landfall     track (6 h)
                                           listed)


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                         R-CLIPER Cases
                                          Danny 97
   R-CLIPER underestimates
    area of Rtotal by factor of 2
                                                       % of gauges
    using CDF.
       PMM R-CLIPER/Gauge Rtotal
                          90%       90%

                     Andrew 92
               50%
                                                  01
                                          Allison50%

                                                        % of area
      20%




                     Floyd 99
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                    QPF in Landfalling TCs
         For  2002 season ran 584 forecasts in 32
           storms in the ATL, EPAC, and CPAC for both
           the gauge and TRMM R-CLIPER.
                                                                                            summary
                                                           100
                                                                             ATL
                                                                             EPAC
                                                            80               CPAC
Atlantic                 14   255
                                    Number of Fore casts
East Pacific             15   281                           60


Central Pacific          3    48                            40

Total                    32   584
                                                            20



                                                             0
                                                                 1   2   3     4    5   6   7     8      9   10 11 12 13 14 15
                                                                                                Stor m

    2/10/03    F.Marks                                                   8
               QPF in Landfalling TCs

                Gauge
                 TRMM




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      Where do we go from here?
   R-CLIPER ran operationally in 2002 at NHC.
   Provides benchmark for evaluation of other QPF
    techniques.
   Develop data products for hurricane specialists.
   Compare R-CLIPER forecasts to models and 6-
    h average rainfall amounts on HPC 1°X1° grid.
   Work with HPC to provide track guidance after
    landfall.




2/10/03   F.Marks             10
     Comparison with
                                            Rogers et al 2002
        Models
   RCLIPER Rmax along
    track, with a probability
    of heavy rain right or left
    of track.
   RCLIPER Rmax
    increases when storm
    slows or turns.
   Model shows symmetry
    and asymmetry.
                                  RCLIPER
               QPF in Landfalling TCs
ISSUES:
 Are we providing our users what they need?
  Different users have different needs.
 How do we develop an evaluation/validation
  system for high-resolution QPF product?
 How will it be used operationally (probabilistic)?
NEEDS:
 New products developed for forecasters and
  hydrologists.
 New display products to convey uncertainty to
  forecaster and others.

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