earth_surf {marelac} | R Documentation |
Computes the surface of 1d by 1dg grid cells as a function of latitude.
Based on data that give the surface distance per 1 dg change in lat/lon from http://en.wikipedia.org/wiki/Latitude
earth_surf(lat = 0, lon = 0)
lat |
latitude (-90 - +90). |
lon |
longitude - not used. |
Surface of the grid cell, in m2.
Karline Soetaert <k.soetaert@nioo.knaw.nl>
earth_surf(seq(0,90,by=15)) SURF <- outer(X=Bathymetry$x, Y=Bathymetry$y, FUN <- function(X,Y) earth_surf(Y,X)) sum(SURF) #is: 510,072,000 km2 # the surface of the Oceans, m2 sum(SURF*(Bathymetry$z<0)) # is: 3.58e14 # the volume of the Oceans, m3 - sum(SURF*Bathymetry$z*(Bathymetry$z<0)) # is: 1.34e+18 # the surface area at several depths SurfDepth <- vector() dseq <- seq(-7500,-250,by=250) for (i in 2:length(dseq)) { ii <- which (Bathymetry$z>dseq[i-1]&Bathymetry$z<=dseq[i]) SurfDepth[i-1]<-sum(SURF[ii]) } plot(dseq[-1],SurfDepth, xlab="depth, m", log="y", ylab = "m2", main = "Surface at ocean depths")