how can I average monthly Windspeed (Ws) data from 1945-2010. The data loaded into a struct, with 2 fields (data.t and data.ws)

This is the data struct

filename: 'g4.areaAvgTimeSeries.GLDAS_NOAH025_M_2_0_Wind_f_inst.19480201-20181231.6W_49N_3W_50N.csv'

t: [1×755 double]

Ws: [1×755 double]

function data=load_giovanni_data2(filename)

%fuction to load wind speed data from giovanni

%input is filename of data file

%output is the date/time and speed from the data file

data.filename = filename;

fid = fopen(filename);

for I= 1:10

templ=fgetl(fid);

end

j=1;

while ischar(templ)

temp=textscan(templ,'%s %f', 'Delimiter',',');

data.t(j)=datenum(cell2mat (temp{1}) );

data.Ws(j) = temp{2};

templ=fgetl(fid);

j=j+1;

end

fclose(fid);

[Akira Agata]

Looking at your data (extracted from attached windspeed.fig file), it seems to be a monthly data. You need to average it yearly or quarterly ? In addition, if possible, I would recommend uploading your original CSV file.

[samuel pearson]

I need to average it yearly from this data

Answer 1

[Akira Agata]

Thank you for sharing your original CSV file.

By using readtable and retime functions, you can do this task more easily! Following is an simple example.

fileName = 'g4.areaAvgTimeSeries.GLDAS_NOAH025_M_2_0_Wind_f_inst.19480201-20181231.6W_49N_3W_50N.csv';

% Read from CSV file
T = readtable(fileName,'HeaderLines',8);
T.Properties.VariableNames = {'Time','WindSpeed'};

% Convert to timetable and apply retime()
TT = table2timetable(T);
TT = retime(TT,'yearly','mean');

The result is:

>> TT

TT =

63×1 timetable

Time WindSpeed

___________________ _________

1948-01-01 00:00:00 6.8213

1949-01-01 00:00:00 6.2222

1950-01-01 00:00:00 7.0241

1951-01-01 00:00:00 6.7801

...

[samuel pearson]

Thank you very much!