strange difference btw area avg. and zonally avg.

Hi all,

I was not able to find why there occurred a difference between area averaged
value of a certain region and average value of zonally averaged values of
that region?

I have an array t2max(time,lat,lon) with dimension sizes ntime=248 (3-hour
maximum values in a month), nlat=52, nlon = 148.

In the first step, I calculated the area averaged value for each time
according to certain latitude and longitude values. By applying do loop to
this 1-d array with 248 elements and selecting the maximum value of each
day, I got daily area averaged values and finally I got monthly area
averaged value by averaging the daily values.

In the second step, I tried to determine the maximum value over all time at
each lat/lon grid point in the t2max (time,lat,lon) array by using dim_max
function. I got an array with 2-d (52,148) after this step and with the aid
of dim_avg_Wrap function, I finally got an array consisting of zonally
averaged values for the same region with a dimension size of 52.

The problem is that when I average these 52 values, the result is not same
as in the first step. Actually both of them must be same. Isn't it?

Any comment will be appreciated. Thanks a lot!

Deniz

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