[ncl-talk] EOF Reconstruction of mode 2 larger than mode 1

[蘇容瑩]

Hello all,

I input omega data(time, lev, lat, lon) and do EOF for every grid
point to get characteristic vertical structure of omega.

I used eofunc to get 3 modes of eigenvectors.

However, I met a problem, when I reconstructed mode 1(w1) and mode 2 (w2).

I tested 3 grid points and compared reconstructed omega and original omega.

grid 1 : 0N, 150E in western Pacific

grid 2 : 10N, 120W in eastern Pacific

grid 3 : 10S, 110W in eastern Pacific cold tongue

Result in grid 1 & 2 match my intuition. w1 >w2

However, result in grid 3 against my intuition. w2>w1

After examining data, I found ts_mean of mode 2 larger then mode 1 so
that w2 larger than w1.

I attached my code for EOF reconstruction below.

Is there anything wrong with my conceptions or coding process?

Thanks for help!



    do mode = 0, 2

        w_re = new((/nSeason,klev,nlat,mlon/),float,msg_val)
        w_re = 0.
        dimName = (/"time", "plev", "lat", "lon"/)
        do dim = 0, 3
          w_re!dim = dimName(dim)
          if (dim .ne. 0) then
            w_re&$dimName(dim)$ = w_eof&$dimName(dim)$
          end if
        end do
        do i = 0, nlat-1
          do j = 0, mlon-1
            do time = 0, nSeason-1
              if (num(ismissing(w_eof(mode,:,i,j))) .le. 5) then
                w_re(time,:,i,j) =
w_eof(mode,:,i,j)*(w_ts(mode,time,i,j) + w_ts_mean(mode,i,j))
              end if
            end do
          end do
        end do



-- 

-------------------
Rung-Ying, Su
Department of Atmospheric Sciences
National Central University (http://www.ncu.edu.tw/)
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