Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

grenada by ajizai

VIEWS: 284 PAGES: 27

									                  Hurricane Hazard Data
                           for
              Caribbean Coastal Construction

                            Project Overview


Funded by the Caribbean Regional Program of the US Agency for International Development.
        Executed by the Organization of American States, in conjunction with the
                 Engineering Institute of the University of the West Indies.

              System Design and Analysis by Watson Technical Consulting.

                 Hurricane Hazard Information for
                 Caribbean Coastal Construction     1
                  Introduction


Project Goals

Storm Hazard Assessment Methodology

Statistical Methodology

Data Bases

On-line Data Access System




   Hurricane Hazard Information for
   Caribbean Coastal Construction     2
                             Project Goals
To create an easy to use on-line resource to allow planners and
coastal engineers to access basic hurricane hazard data in a format
conducive for use in the design process.

Hazards reported are wind, wave, and storm surge, for 10, 25,
50, and 100 year return periods. Return period data is
characterized at maximum likelihood (MLE), 75%, 90%, and 95%
projection limits.

Two Web Sites to be established:
     Primary: University of the West Indies
     Backup: Old Dominion University


               Hurricane Hazard Information for
               Caribbean Coastal Construction     3
                 Storm Impacts at the Coast
Three phenomena output: Wind, Waves, and Storm Surge.
Storm surge outputs include of wave setup, wind setup, pressure setup,
and astronomical tide.

                                                   Wind
       Wave Run up

                                                            Still Water Level at Shoreline
                                                                        Wave Crest/TWL
                                               Wave Setup                 Wind Setup
                                                                                  Pressure Setup
                                                                               Astronomical Tide

                                                                                        Mean
                                                                                        Low
                                                                                        Water




                Hurricane Hazard Information for
                Caribbean Coastal Construction     4
                  Methodology Overview

Simulate every Atlantic storm since 1886 (1851) with the TAOS
hazard modeling system to generate the wind, wave, and storm
surge at every grid cell in the study area.

At each point, compute weibull distribution for each phenomena.

Simulate return period events to test interactions.

Compute desired return period and projection limit results.




              Hurricane Hazard Information for
              Caribbean Coastal Construction     5
 The Arbiter Of Storms (TAOS) hazard model
Modular, 4D composite model platform with user selectable modules:
         12 Wind Models
         3 Boundary Layer Models
         3 Storm Surge Models
         5 Wave Models
         2 Rainfall/Runoff Models
- 1,620 basic combinations
- with damage functions, over
  10,000 possible outcomes for
  a single event!

Scalable, from single processor through supercomputer MPI or
PVM systems such as the WTCI earthdome system.

TSAP Statistics System with plug in modules for various distributions,
either desktop of batch run capability.

              Hurricane Hazard Information for
              Caribbean Coastal Construction     6
             Storm Hazard Model Modules

Key TAOS/mpi Modules:

    •Wind Field                               •Damage
                                                 Structure Damage
    •Water Flow (Storm Surge)                    Coastal Erosion
                                                 Vegetation Damage
    •Waves
                                              •GIS/Mapping Interface
    •Tides (UTex CSR Model)                       GrADS Meteorology package
                                                  ArcInfo and ArcView
    •Rainfall and runoff                          Mapinfo
                                                  GRASS
Storm components are interactive and can have feedbacks: for
example, changes to land cover cause changes to wind speeds, etc.


               Hurricane Hazard Information for
               Caribbean Coastal Construction     7
   Input Data Bases for Simulations


•Digital Elevation Model (topography and bathymetry)
         Allows proper flow of water to be computed
         for storm surge, waves, and inland flooding

•Land Cover/Land Use (land and underwater)
       Friction effects on both air and water to compute
       correct wind speeds and flow rates
       Debris generation

•Historical Storm Characteristics for Statistical Analysis
 and validation




        Hurricane Hazard Information for
        Caribbean Coastal Construction     8
                       Model Physics: Wind
 Module Used: Standard Project Hurricane (SPH)
 Source: NOAA Technical Report NWS 23

Basic wind field characteristics:
        Asymmetric wind field
        Radius of Maximum Winds
        Storm motion
        Central and Far Field Pressure

Terrain effects:
         The wind at a point depends on
         what is upwind of the point, as
         much as 10 miles.

Note storm centered grid system.

                 Hurricane Hazard Information for
                 Caribbean Coastal Construction     9
                                                                                                                                           c
                                                                                                                                        KBOS




                                                                                                                        KLGA     KISP
                                                                                                              KEW R
                                                                                                                       c          c
                                                                                                                      c cc
                                                                                                                         KN YC




                                                                                                                                        Wind Model Validation Example
                                                                                                     KPH L
                                                                                                          c
                                                                                                              KAC Y
                                                                                                                c



                                                                                        KN HK      KSBY
                                                                                          c         c

                                                                           KR IC
                                                                               c
                                                                                   KF AFKLF I
                                                                                        c c KN TU
                                                                                           cc
                                                                                              c
                                                                                       KN GU
                                                                                           KEC G
                                                                                               c


                                                                  KGSB
                                                                   c        KEW N
                                                                               c KN KT
                                                                         KN CA     c
                                                                           c       c   KMH X
                                                                  KILM
                                                  KF LO
                                                    c               c




                                         KIGC
                                              c
                                              c KC HS
                             KN BC
                               c

                                                                                                   Correlation: 0.9222
                 KSAV
                     c


                KSSI
                 c
        KJAX
  KN ZC     c
        c
KGN V
  c
KOC F                KD AB
  c                      c
              KSF B
            KOR L c
                 c            KC OF
                KOR L
                               c
                               c KML B
                                   KF PR
                                     c


                                         LKW F 1
                                                          MYG F
                                              c             c
                                KF XE
                              ABAN 6 c
                                          c
                               KT MB
                                     c
                                                                         MYN N
                                                                           c




                                                                                                                                               Comparison of observed and computed peak
 Figure 7: Locations of ASOS Sites reporting Floyd Winds
                                                                                                                                               winds for Hurricane Floyd (1999)
                                                                                                Hurricane Hazard Information for
                                                                                                Caribbean Coastal Construction                        10
            Model Physics: Storm Surge

Modules, vertical coordinates (3D vs. 4D), horizontal resolutions
depends on underlying data bases

Low Res (> 600 meter grids): vertically integrated equations
      Source Equations: Harris

High Res (< 600 meter grids): 5 vertical layers
      Source Equations: Watson, based on Mellor

Tides: University of Texas CSR Tide Model



             Hurricane Hazard Information for
             Caribbean Coastal Construction     11
                      Comparisons with Tide Gauges
                                                                1.6

                                              St. Augustine     1.4

                                                                1.2

                                                                1.0

                                                                0.8

                                                                0.6

                                                                0.4

                                                                0.2

                                                               -0.0

                                                               -0.2

                                                               -0.4
                                                                      0   10   20   30   40   50    60    70   80   90 100 110 120

                                                                                                   time


                                                                1.6

                                                                1.4

                                                                1.2

                                                                1.0

                                                                0.8

                                                                0.6

                                                                0.4



                                               Trident Pier     0.2

                                                               -0.0

                                                               -0.2

                                                               -0.4
Solid Line: Modeled    Hurricane Hazard Information for               0   10   20   30   40   50    60    70   80   90 100 110 120
Dots: Observed         Caribbean Coastal Construction     12                                       time
               Peak Surge Observations (Marilyn, 1995)
 Storm      Source   Location   Type      Observed Modeled %error  Error (m)
 Marilyn 95 USGS     SC 1       OB             0.98    1.00  2.50%       0.02
                     SC 2       OB             2.65    2.50  5.75%       0.15
                     SC 3       OB             2.90    2.50 13.68%       0.40
                     SC 4       OB             1.77    1.50 15.17%       0.27
                     SC 5       OB             1.52    1.50  1.60%       0.02
                     SC 6       OB             1.52    1.50  1.60%       0.02
                     SC 7       OB             1.89    1.75  7.42%       0.14
                     SC 8       OB             1.43    1.75 22.13%       0.32
                     SC 9       OB             2.04    2.00  2.09%       0.04
                     SC 10      OB             1.98    2.00  0.92%       0.02
                                                                                                                       Marilyn Storm Surge             y = 0.6741x + 0.567
                     SC 11      OB             1.59    1.80 13.54%       0.21                                                                              R2 = 0.9003

                     SC 12      OB             1.83    1.80  1.60%       0.03              3.50

                     SC 13      OB             2.59    2.20 15.11%       0.39
                     SC 14      OB             3.57    2.80 21.50%       0.77              3.00
                     SC 15      OB             2.90    2.50 13.68%       0.40
                     ST 1       OB             2.01    2.00  0.61%       0.01
                     ST 2       OB             2.16    2.00  7.61%       0.16              2.50

                     ST 3       OB             2.16    2.20  1.63%       0.04
                     ST 4       OB             2.32    2.20  5.05%       0.12              2.00




                                                                                Computed
                     ST 5       OB             2.26    2.20  2.49%       0.06

                                                                                           1.50
                                                           Average:      0.18

                                                                                           1.00




Observed peak water levels from                                                            0.50




post storm surveys on St. Croix                                                            0.00
                                                                                               0.00   0.50   1.00   1.50         2.00        2.50   3.00          3.50       4.00
                                                                                                                               Observed


and St. Thomas by the USACE

                                       Hurricane Hazard Information for
                                       Caribbean Coastal Construction                        13
                 Model Physics: Waves


NOAA Wavewatch III Model (deep and transitional water)
     Source: Tolman, modularized and modified for
            moving grid

WTC inshore model (shallow water)
      Sources: Lyons, Watson

Again, physics used depends on resolution.




            Hurricane Hazard Information for
            Caribbean Coastal Construction     14
                              Wave Validation




Comparison of operational (real time) wave forecast
and NOAA buoy reports


                   Hurricane Hazard Information for
                   Caribbean Coastal Construction     15
                        Validation Summary


Tests against detailed data from over 30 storms worldwide.

Performance summary (90% limits)
       Peak Wind (350 observations): +/- 5 knots
       Peak Wave (185 observations): +/- 0.8 meters (deep water Hs)
       Peak Storm Surge (1500 observations): +/- 0.3 meters

Model uncertainty is included in the projection limit calculations.




                Hurricane Hazard Information for
                Caribbean Coastal Construction     16
                    Statistical Terminology

MLE: Maximum Likelihood Estimate. The ‘best guess’ at a value. This
      is NOT the same as the 50% estimate.

Projection Limit: For a given projection limit, the value which should
        not be exceeded more than 1-(limit) of observations.

Example: 100 year, 75% projection limit.
      For a large number of 100 year periods, 75% of them will fall
      at or below this value. Only 25% should be greater.
      OR, for a large number of sites over a 100 year period, 75%
      of the sites will see less than this value; 25% would be expected
      to exceed it.




                Hurricane Hazard Information for
                Caribbean Coastal Construction     17
                       Statistical Analysis

Once storm runs are completed, outputs are analyzed to produce
return period data sets.



Single Site Example:
  Four Seasons Hotel, Nevis




               Hurricane Hazard Information for
               Caribbean Coastal Construction     18
                        Single Site Analysis: Wind
Raw text output of TSAP program:
  BASIC TC WIND STATISTICS REPORT FOR Nevis                 2 PARAMETER WEIBULL ESTIMATE OF RETURN TIMES

          1220 EVENTS EXAMINED                             ALPHA     1.333316, BETA 35.105717
   FROM        1850 TO        1999                         SDA      0.21 SDB     4.40, CORREL:         0.871427

   NOTES:                                                  CHI**2 13.486692
      RAW DATA IS IN FILE YRMAX.DAT                        K-S   0.046980, K-S PROB         0.995793
      CAT 0 = TROPICAL STORM
                                                             5   YEAR   WIND    50KTS   (EMP:   52KTS)
   EVENTS BY CATEGORY                                       10   YEAR   WIND    65KTS   (EMP:   70KTS)
  SAFFIR/SIMPSON CATEGORY   0:   48                         25   YEAR   WIND    84KTS   (EMP:   79KTS)
  SAFFIR/SIMPSON CATEGORY   1:    9                         50   YEAR   WIND    97KTS   (EMP:   89KTS)
  SAFFIR/SIMPSON CATEGORY   2:    4                        100   YEAR   WIND   110KTS   (EMP:   91KTS)
  SAFFIR/SIMPSON CATEGORY   3:    1
  SAFFIR/SIMPSON CATEGORY   4:    1                         MLE BASED WIND RETURN TIMES
  SAFFIR/SIMPSON CATEGORY   5:    0                        WIND SPD       PROB     RETURN PD
                                                             50KTS        0.2014      5.0 YRS
   ------------------------------------------------          64KTS        0.1078      9.3 YRS
   EMPIRICAL ESTIMATE OF RETURN PERIODS                     100KTS        0.0176     56.7 YRS
  SAFFIR/SIMPSON CATEGORY 0:      2.5 YEARS     0.396       ------------------------------------------------
  SAFFIR/SIMPSON CATEGORY 1:      8.3 YEARS     0.121       PROJECTION LIMIT CONFIDENCE LEVELS
  SAFFIR/SIMPSON CATEGORY 2:     24.8 YEARS     0.040
  SAFFIR/SIMPSON CATEGORY 3:     74.5 YEARS     0.013       YEAR           50%     75%        90%      95%      99%
  SAFFIR/SIMPSON CATEGORY 4:    149.0 YEARS     0.007       10YR:         66.4    69.0      71.4     73.2     76.8
  SAFFIR/SIMPSON CATEGORY 5: Infinit YEARS      0.000       25YR:         85.3    89.3      93.5     96.9    108.8
                                                            50YR:         98.5   104.1     110.8    116.7    132.7
                                                           100YR:        110.7   118.9     128.7    136.8    157.3




                        Hurricane Hazard Information for
                        Caribbean Coastal Construction     19
Single Site Statistics: Nevis Wind




                                          Graphic output of
                                          weibull fit for winds
                                          at Four Seasons, Nevis




  Hurricane Hazard Information for
  Caribbean Coastal Construction     20
           Statistical Methodology Validation

Used data from 1886-1987 to make a 10 year forecast.

Validated wind forecast against 10,600 land sites in the Atlantic Hurricane
basin using the 10 year period 1988 - 1997.


        Percentage of sites below prediction limit:

                Predicted                          Observed
                50%                                53%
                75%                                75%
                90%                                90%
                95%                                94%
                99%                                97%



                Hurricane Hazard Information for
                Caribbean Coastal Construction     21
    The Caribbean Hazard Data Web Server

Interactive, web based system using open source/public domain software.



                                                      Temporary URL:
                                                      http://weather.methaz.com/cdcm/

                                                      Permanent URL:
                                                      UWI: ??
                                                      ODU: http://cdcm.cee.odu.edu/

                                                      Primary site will provide for
                                                      mailing lists to discuss coastal
                                                      engineering and design problems,
                                                      techniques, etc.


              Hurricane Hazard Information for
              Caribbean Coastal Construction     22
                  On-line Documentation
• Notes on wind, wave, and storm surge model outputs
• Validation and uncertainty
• Terminology
• Building Code Notes




              Hurricane Hazard Information for
              Caribbean Coastal Construction     23
                              Available Data Bases
Regional 30 arc second (nominal 926 meters)
As part of the Caribbean Disaster Mitigation Project (CDMP), a regional storm risk atlas was
developed. The return period was based on an analysis of hurricanes from 1886 to 1998, with storm
hazard model runs conducted using a regional 30 arc second (nominal 926 meter) grid. It covers the
Eastern Caribbean from Puerto Rico through Trinidad and Tobago.


6 arc second (182 meter) Kitts/Nevis/Antigua/Barbuda
This data set was developed for the Post Georges Disaster Mitigation Project. It covers the islands
of St. Kitts, Nevis, Barbuda, and Antigua. The return period analysis was based on data from 1851
through 1999. The storm hazard model runs were made at a resolution of 6 arc seconds (182 meter grid).
Only MLE data available for this area.

Hurricane Track Data Base
This is a version of the 1851-2000 storm track data set created by from the US National Hurricane
Center.




                        Hurricane Hazard Information for
                        Caribbean Coastal Construction     24
                            Data Set Access
• User may select return period and projection limit
• Choice of background maps
• Point and click report generation




                 Hurricane Hazard Information for
                 Caribbean Coastal Construction     25
                                        Report Format


                                        Site Map and Data Location




                                        Site information




                                        Hazard Data




Hurricane Hazard Information for
Caribbean Coastal Construction     26
                               Summary



• On-line hurricane hazard data for the Eastern Caribbean
• 10, 25, 50, 100 year return period data bases
• MLE, 75%, 90%, and 95% projection limits for regional data set
• R&D site available at http://weather.methaz.com/cdcm/
• Final data sets and user interface by end of September 2001
• Final web sites at UWI and ODU by end of 2001




             Hurricane Hazard Information for
             Caribbean Coastal Construction     27

								
To top