Hi there, I am currently working on a project that involves climate model data stored in a NetCDF file. I am currently trying to calculate "weighted" spatial annual "global" averages for precipitation. I need to do this for each of the 95 years of global precipitation data that I have. The idea would be to somehow apply weights to each grid cell by using the cosine of its latitude (which means latitude grid cells at the equator would have a weight of 1 (i.e. the cosine of 0 degrees is 1), and the poles would have a value of 1 (as the cosine of 90 is 1)). Then, I would be in a position to calculate annual weighted averages based on averaging each grid cell. I have an idea how to do this conceptually, but I am not sure where to begin writing a script in R to apply the weights across all grid cells and then average these for each of the 95 years. I would greatly appreciate any help with this, or any resources that may be helpful!!! At the very least, I have opened the .nc file and read-in the NetCDF variables, as shown below: ncfname<-"MaxPrecCCCMACanESM2rcp45.nc" Prec<-raster(ncfname) print(Prec) Model<-nc_open(ncfname) get<-ncvar_get(Model,"onedaymax")longitude<-ncvar_get(Model, "lon") latitude<-ncvar_get(Model, "lat") Year<-ncvar_get(Model, "Year")
Also, if it helps, here is what the .nc file contains: 3 variables (excluding dimension variables): double onedaymax[lon,lat,time] (Contiguous storage) units: mm/day double fivedaymax[lon,lat,time] (Contiguous storage) units: mm/day short Year[time] (Contiguous storage) 3 dimensions: time Size:95 lat Size:64 units: degree North lon Size:128 units: degree East Again, any assistance would be extremely valuable with this! I look forward to your response! [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.