MetFns (version 2.0)

pop.index2: Calculation of population index based on average distance from the limiting magnitude

Description

Calculates and plots population index of a meteor shower for a given magnitude data, specified period of days, minimum and maximum bin size, and number of meteors.

Usage

pop.index2(data,year,month.beg,month.end=month.beg,day.beg,day.end=day.beg,
time.beg=0,time.end=2359,shw,k1=0.01,k2=1,num,add.plot=FALSE,xlim1=NULL,
xlim2=NULL,xinc=NULL,ylim1=NULL,ylim2=NULL,yinc=NULL)

Arguments

data

data frame consisting of visual meteor magnitude data.

year

numeric vector of length 4 specifying year.

month.beg

numeric vector specifying the beginning month.

month.end

numeric vector specifying the ending month. By default, month.end is set to be equal to month.beg.

day.beg

numeric vector specifying the beginning day.

day.end

numeric vector specifying the ending day. By default, day.end is set to be equal to day.beg.

time.beg

numeric vector (0-2359) specifying lower boundary of time in hours and minutes, corresponding to day.beg. By default, time.beg is set to be equal to 0.

time.end

numeric vector(0-2359) specifying upper boundary of time in hours and minutes, corresponding to day.end. By default, time.end is set to be equal to 2359.

shw

character string consisting of three capital letters which represent meteor shower code.

k1

numeric vector specifying minimum bin size, in degrees of solar longitude. By default, it is equal to 0.01.

k2

numeric vector specifying maximum bin size, in degrees of solar longitude. By default, it is equal to 1.

num

numeric vector specifying total number of meteors per interval.

add.plot

logical vector. If TRUE, the population index is plotted.

xlim1

numeric vector specifying minimum value on x-axis.

xlim2

numeric vector specifying maximum value on x-axis.

xinc

numeric vector specifying increment between labels on x-axis.

ylim1

numeric vector specifying minimum value on y-axis.

ylim2

numeric vector specifying maximum value on y-axis.

yinc

numeric vector specifying increment between labels on y-axis.

Value

• Data frame containing following vectors [object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

code

xinc,yinc

emph

65%

Details

Adaptive-bin size algorithm is used. It tries to maintain a used-defined optimum meteor number per bin. For the case that not enough meteors are available, a maximum bin size is used. Average distance from the limiting magnitude, as difference between the limiting magnitude and average meteor magnitude, is calculated for each observing time interval. Final average distance from the limiting magnitude is calculated as a weighted average of all individual average distances, where number of meteors in each observing interval represents weights. Conversion of average distance from limiting magnitude to population index is done using natural spline interpolation spline of table values popind. Error margins of population index are calculated using bivariate Krige interpolation krigeInterp of table values popind.err

References

Arlt, R. (2003). Bulletin 19 of the International Leonid Watch: Population index study of the 2002 Leonid meteors. WGN, Journal of the IMO,31:3, 77-87.

See Also

pop.index,zhr

Examples

## calculate population index for observations of 1997 Perseids, time period 
## 10th August 19h to 13th August 7h, radiant elevation higher than 20 degrees, 
## total correction smaller than 5
## First select 1997 Perseids, 28th July to 16th August, radiant elevation 
## higher than 20 degrees
## data(magn97)
## magn<-filter(magn97,year=1997,month.beg=7,month.end=8,day.beg=28,day.end=16,
## shw="PER",h.low=20)
## pop.index2(magn,year=1997,month.beg=8,day.beg=10,day.end=13,time.beg=1900,
## time.end=700,shw="PER",num=300)

## make graphic of population index
##x-axis limits: min(sollong)=138.27, max(sollong)=140.51
##y-axis limits: min(pop.index-sigma.r)=1.59,max(pop.index+sigma.r)=2.79
## pop.index2(magn,year=1997,month.beg=8,day.beg=10,day.end=13,time.beg=1900,
## time.end=700,shw="PER",num=300,
## add.plot=TRUE,xlim1=138.2,xlim2=140.6,xinc=0.1,ylim1=1.5,ylim2=2.8,yinc=0.1)