Using different TC databases - source formats

There are a wide variety of formats of tropical cyclone track databases available, both observational and model generated (e.g. we have used tropical cyclone-like vortices derived from regional and global climate models). To introduce users to the model, we include the format for the International Best Tracks Archive for Climate Stewardship (IBTrACS-WMO format). The default action for TCRM is to download the current version (v03r05 at August 2014) and use this to calibrate the model.

Required fields

As a bare minimum, TCRM requires data on the date/time, longitude, latitude, central pressure of each cyclone observation. It also requires a field that indicates each unique TC event in the database. This can be a tcserialno - a unique string for each event; a TC num which is an integer value for each event in a season; or an indicator field, which is set to 1 for the first observation of a new TC, and 0 otherwise.

For individual scenario modelling, an additional field containing the radius to maximum winds (rmax) must be included.

Database format

The first few lines of the IBTrACS database are shown below.

IBTrACS WMO: International Best Tracks Archive for Climate Stewardship -- WMO DATA ONLY -- Version: v03r05
Serial_Num,Season,Num,Basin,Sub_basin,Name,ISO_time,Nature,Latitude,Longitude,Wind(WMO),Pres(WMO),Center,Wind(WMO) Percentile,Pres(WMO) Percentile,Track_type
N/A,Year,#,BB,BB,N/A,YYYY-MM-DD HH:MM:SS,N/A,deg_north,deg_east,kt,mb,N/A,%,%,N/A
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-11 06:00:00, NR, -8.60,  79.80,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-12 06:00:00, NR, -9.00,  78.90,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-13 06:00:00, NR,-10.40,  73.20,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-14 06:00:00, NR,-12.80,  69.90,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-15 06:00:00, NR,-13.90,  68.90,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-16 06:00:00, NR,-15.30,  67.70,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-17 06:00:00, NR,-16.50,  67.00,  0.0,    0.0,reunion,-100.000,-100.000,main
1848011S09080,1848,02, SI, MM,XXXX848003,1848-01-18 06:00:00, NR,-18.00,  67.40,  0.0,    0.0,reunion,-100.000,-100.000,main

Setting the configuration options

The columns arrangement can be determined from looking at the second line of the database: Serial_Num,Season,Num,Basin,Sub_basin,Name,ISO_time,Nature,Latitude,Longitude,Wind(WMO),Pres(WMO),Center,Wind(WMO) Percentile,Pres(WMO) Percentile,Track_type. The important variables required for TCRM are the Serial_Num, ISO_time, Latitude, Longitude and Pres(WMO) columns. All other variables can be ignored. Based on this, the Columns option can be set as:

Columns = tcserialno,season,num,skip,skip,skip,date,skip,lat,lon,skip,pressure

Notice that there are only 12 columns specified, but the database contains 15 columns. The last three columns are not used, so since they are not specified, they are automatically ignored.

The data are comma-delimited, so the FieldDelimiter option is set to a comma – it does not need to be wrapped in quotes.

FieldDelimiter = ,

The first three lines are metadata and information that describe the data (version, column names, units). These lines are ignored when the NumberOfHeadingLines option is set to 3.

NumberOfHeadingLines = 3

The format of the date field needs to be specified in the configuration file. Format specification is controlled by Python’s standard datetime module.

DateFormat = %Y-%m-%d %H:%M:%S

The remaining three options – PressureUnits, LengthUnits and SpeedUnits – set the units of the pressure values, any length units and the speed units (of motion of the storms). Notice that the third line in the database indicates the wind speed is in units of kt (knots) - this refers to the observed maximum wind speed. The SpeedUnits option controls the units for the forward motion speed of storms - a field that is not included in the IBTrACS database.

PressureUnits = hPa
LengthUnits = km
SpeedUnits = kmh

The full section for using IBTrACS is shown below.

[IBTRACS]
; Input data file settings
URL = ftp://eclipse.ncdc.noaa.gov/pub/ibtracs/v03r05/wmo/csv/Allstorms.ibtracs_wmo.v03r05.csv.gz
Path = input
Filename = Allstorms.ibtracs_wmo.v03r05.csv
NumberOfHeadingLines = 3
Columns = tcserialno,season,num,skip,skip,skip,date,skip,lat,lon,skip,pressure
FieldDelimiter = ,
DateFormat = %Y-%m-%d %H:%M:%S
PressureUnits = hPa
LengthUnits = km
SpeedUnits = kph