How can I obtain time seris data from ECMWF netcdf file

Hello all,

I am trying to get time series data from daily ECMWF netcdf file at exact location. I want to do that for multiple files located in a folder and write to results on excel sheet. My code and error are given below.

Thanks!

clc
clear all
folder='C:/Users/kullanici/Documents/MATLAB/PBL-Daily-1200-2017';
filetype='*.nc'; 
f=fullfile(folder,filetype);
d=dir(f);
LT=41.25;LG=21.25;
for i=1:numel(d);
blh(i)=ncread([fullfile(folder,d(i).name)],'blh');
lon(i)=ncread([fullfile(folder,d(i).name)],'longitude');
lat(i)=ncread([fullfile(folder,d(i).name)],'latitude');
time1(i)=ncread([fullfile(folder,d(i).name)],'time');
end
for i=1:numel(d);
time(i)=double(time1);
[TEMP,a2]=min(abs(lon(i)-LG));
[TEMP,a1]=min(abs(lat(i)-LT));
blh_ist(i)=blh(a2,a1,:);
BLH(i)=blh_ist(:);
AA(i)=datestr(time(i)./24+datenum('1900-01-01 0:0:0'));
AA(i)=datenum(AA(i));
AA(i)=datenum(AA(i));
yy(i)=year(AA(i));mm(i)=month(AA(i));dd(i)=day(AA(i));hh(i)=hour(AA(i));
date1(i)=[yy mm dd hh];
end
for i=1:numel(d);
filename='PBL_12.xlsx';
sheet = 1;
xlswrite(filename,date1(i),sheet,'A2')
xlswrite(filename,BLH(i),sheet,'E2')
end

ERROR: Subscripted assignment dimension mismatch.

Error in PBL (line 9)

blh(i)=ncread([fullfile(folder,d(i).name)],'blh');

Answer 1

[KSSV]

YOur data read shoule be a matrix or array..you cannot store them like the way you did. YOu shoule do as below:

clc
clear all
folder='C:/Users/kullanici/Documents/MATLAB/PBL-Daily-1200-2017';
filetype='*.nc';
f=fullfile(folder,filetype);
d=dir(f);
LT=41.25;LG=21.25;
N = numel(d) ;
blh = cell(N,1) ;
lon = cell(N,1) ;
lat = cell(N,1) ;
time1 = cell(N,1) ;
for i=1:N
    blh{i}=ncread([fullfile(folder,d(i).name)],'blh');
    lon{i}=ncread([fullfile(folder,d(i).name)],'longitude');
    lat{i}=ncread([fullfile(folder,d(i).name)],'latitude');
    time1{i}=ncread([fullfile(folder,d(i).name)],'time');
end

If all the variables in each file has same dimensions..you can save them into a matrix. As I am not aware of the dimensions, I have stored them into a cell.

Answer 2

[sujan ghimire]

I have below information from NetCDF file, how can i covert to CSV or XLS for specific Lat long.

ei.oper.an.sfc.regn128sc.hcc_188.201107.ghimire463266.nc

Format:

64bit

Global Attributes:

creation_date = 'Sat Dec 19 05:45:16 MST 2020'

NCL_Version = '6.6.2'

system = 'Linux casper34 3.10.0-1127.18.2.el7.x86_64 #1 SMP Sun Jul 26 15:27:06 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux'

Conventions = 'None'

grib_source = 'ei.oper.an.sfc.regn128sc.hcc_188.201107.ghimire463266.grb'

title = 'NCL: convert-GRIB-to-netCDF'

Dimensions:

initial_time0_hours = 124 (UNLIMITED)

g4_lat_1 = 256

g4_lon_2 = 512

ncl_strlen_0 = 18

Variables:

HCC_GDS4_SFC

Size: 512x256x124

Dimensions: g4_lon_2,g4_lat_1,initial_time0_hours

Datatype: single

Attributes:

forecast_time_units = 'hours'

forecast_time = 0

parameter_number = 188

parameter_table_version = 128

gds_grid_type = 4

level_indicator = 1

_FillValue = 1.000000020040877e+20

units = '(0 - 1)'

long_name = 'High cloud cover'

center = 'European Center for Medium-Range Weather Forecasts (RSMC)'

initial_time0_hours

Size: 124x1

Dimensions: initial_time0_hours

Datatype: double

Attributes:

units = 'hours since 1800-01-01 00:00'

long_name = 'initial time'

initial_time0_encoded

Size: 124x1

Dimensions: initial_time0_hours

Datatype: double

Attributes:

units = 'yyyymmddhh.hh_frac'

long_name = 'initial time encoded as double'

g4_lat_1

Size: 256x1

Dimensions: g4_lat_1

Datatype: single

Attributes:

La1 = 89.463

Lo1 = 0

La2 = -89.463

Lo2 = 359.297

Di = 0.70313

N = 128

units = 'degrees_north'

GridType = 'Gaussian Latitude/Longitude Grid'

long_name = 'latitude'

g4_lon_2

Size: 512x1

Dimensions: g4_lon_2

Datatype: single

Attributes:

La1 = 89.463

Lo1 = 0

La2 = -89.463

Lo2 = 359.297

Di = 0.70313

N = 128

units = 'degrees_east'

GridType = 'Gaussian Latitude/Longitude Grid'

long_name = 'longitude'

initial_time0

Size: 18x124

Dimensions: ncl_strlen_0,initial_time0_hours

Datatype: char

Attributes:

NCL_converted_from_type = 'string'

units = 'mm/dd/yyyy (hh:mm)'

long_name = 'Initial time of first record'

Variable names are:

HCC_GDS4_SFC

initial_time0_hours

initial_time0_encoded

g4_lat_1

g4_lon_2

initial_time0