creating time series on specific coordinates rainfall using .nc

I downloaded the global-scale rainfall data from 2017 to 2021 from the climate.copernicus portal (climate.copernicus). The system downloaded an .nc file for each year.

I would first of all like to be able to merge these files if possible, or at a later date be able to plot the time series of rainfall from 2017 to 2021 on a single graph. Another important step is that I would like to be able to have the time series of a specific point with the following coordinates 58.491573, 25.778418; or alternatively use a rectangle where I can have the time series considering the centroid of the polygon. how can I do?

But at the end, I wasn't able to create one plot with data on x-axis and rainfall data on y-axis considenring specific coordinates.

For now I have this script that allows me to open the file and understand the internal variables.

ncfile = ('GPCC_total_precipitation_mon_0.5x0.5_global_2017_v2020.0.nc');

% To get information about the nc file

ncinfo(ncfile)

% to display nc file

ncdisp(ncfile)

Here there is output

Format:
           netcdf4
Dimensions:
           time = 12    (UNLIMITED)
           lon  = 720
           lat  = 360
Variables:
    time
           Size:       12x1
           Dimensions: time
           Datatype:   double
           Attributes:
                       standard_name = 'time'
                       units         = 'hours since 1891-1-1 00:00:00'
                       calendar      = 'proleptic_gregorian'
                       axis          = 'T'
    lon 
           Size:       720x1
           Dimensions: lon
           Datatype:   double
           Attributes:
                       standard_name = 'longitude'
                       long_name     = 'longitude'
                       units         = 'degrees_east'
                       axis          = 'X'
    lat 
           Size:       360x1
           Dimensions: lat
           Datatype:   double
           Attributes:
                       standard_name = 'latitude'
                       long_name     = 'latitude'
                       units         = 'degrees_north'
                       axis          = 'Y'
    pr  
           Size:       720x360x12
           Dimensions: lon,lat,time
           Datatype:   single
           Attributes:
                       standard_name = 'lwe_precipitation_rate'
                       long_name     = 'total monthly precipitation'
                       units         = 'mm/month'
                       code          = 20
                       _FillValue    = 3.000000060858434e+33
                       missing_value = 3.000000060858434e+33
                       institution   = 'DWD'

Then I split the data considering the Variables using this code

% to read a vriable 'var' exisiting in nc file

long = ncread(ncfile,'lon');

latt = ncread(ncfile,'lat');

time = ncread(ncfile,'time');

pr = ncread(ncfile, 'pr'); %rainfall data

Answer 1

[Cris LaPierre]

Look at the size info to figure out the dimensions of pr

• First dimension is longitude
• Second dimension is latitute
• Third dimension is time

So if I wanted to extract all the pr values for a specific longitude and latitude, I would first figure out which row corresponds to the longitude of interest, and which column corresponds to the latitude of interest. Assuming the lon/lat coordinate exactly matches the data sample grid, that might look like this:

lon = 8.491573;
lat = 25.778418;
indx = long==lon;
indy = latt==lat;

prData = pr(indx,indy,:);
plot(time,prData)

Since you have multiple files, the first step might be to use fileDatastore to load all the data first, and then work on the data. You can write a custom function that can load the data from a single file, and use that as the ReadFcn for you fileDatastore.