[R] problem with Zenith angle calculation

[Alemu Tadesse]

Dea R users,

In the package insol
I was trying to calculate sunzenith angle. I am using two different date
formats as shown below and both give me different results. Comapring the
results from NOAA website the one below is correct.

xx<-JD(ISOdate(2010,10,1,11))
sv=sunvector(xx,lat,lon,tmz)
zenith=sunpos(sv)
azimuth<-zenith[1,1]
zenith<-zenith[1,2]
zenith
[1] 40.18603
However, the one below is not correct. I have several datetimes and either
I have to use loop to separate year, month, day hour to use the one above.
when I try insert a vector of year, month, day, hour   the formula above
doesn't work. I wish I know how to do it for several dates correctly using
the one below.


x<-JD(as.POSIXct("2010-10-01 11:00:00",tz="",format="%Y-%m-%d %H:%M:%S"))
sv=sunvector(x,lat,lon,tmz)
zenith=sunpos(sv)
azimuth<-zenith[1,1]
zenith<-zenith[1,2]
 zenith
[1] 77.79948

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