bichengdong / typhoontrack2gridpoint

This script is developed to translate Typhoon track data, with information on maximum wind speed and typhoon center, into wind speed at a grid point location. for the Priority indexing model this will be at the center of municipalities

Typhoon wind hazard estimation

This tool was developed to prepare input for typhoon damage prediction model. The tool is written in R, it uses WILLOUGHBY et al. methedology to calculate windspeed at any gridpoint location in the Phillipiness area of Responsiblity(PAR), based on a typhoon track data. The script reused some codes from stormwindmodel R package. Stormwindmodel was developed to estimate windspeed at a grid location.

The script is available under the GPL license

Localized windspeed

This script is developed to calculate localized wind speed and exposure duration from a typhoon track data with information on maximum wind speed and typhoon center. This tool can be used to calculate wind speed at any grid point location in the Philippines Responsibility Area (PAR). In Addition to maximum wind speed the tool will also calculate duration of exposure to a wind speed above a certain threshold.

Typhoon Track data

Typhoon forecast data from National Met agencies come in different format, the following example shows a typhoon warning bulletin issued by PAGASA for the Philippines responsibility area.

The relevant information on typhoon is extracted form the text document

The typhoon track data is not sufficient information to estimate the possible impact of typhoon. A wind severity map, which will show the magnitude of wind at different locations is needed as an input for impact based forecasting models. For 510 typhoon model we need data at each grid location (municipality centers) and this tool can be used to calculate wind speed at municipality centers.

In addition to typhoon track data , we need to provide information on grid locations for which we want to extract windspeed Grid point location is provided in the following format

• gridid,glat,glon
• PH012801000,18.453,120.910
• PH012802000,18.267,120.610
• PH012803000,17.906,120.500
• PH012804000,18.490,120.750
• PH012805000,18.038,120.580
• PH012807000,18.219,120.860
• PH012808000,18.011,120.500 ...

where: gridid- municipality pcode, glat is latitude, glon is longitude with the two inputs, Track data and grid points, the code will produce output similar to the table shown below In the table above
Vmax_gust maximum wind speed Vmax_sust maximum sustaind speed dist_track minimum distance from typhoon track dist_track minimum distance from typhoon track gust_dur total duration of exposure for gust wind gust_dur total duration of exposure for gust wind above 30mph gust_dur total duration of exposure for gust wind above 30mph

duration of exposure for gust wind above 30mph	Distance from typhoon track and wind speed

sust_dur total duration of exposure for sustained wind

Wind severty mapping

Then we can create a severity map from the calculated gridpoint windspeed data

Referances

This tool is based on the the work of "Willoughby, HE, RWR Darling, and ME Rahn. 2006. Parametric Representation of the Primary Hurricane Vortex. Part II: A New Family of Sectionally Continuous Profiles.” Monthly Weather Review 134 (4): 1102–20.