M(date_index,variable_index,sonic_index)

Variable index have the following options:

1   Datenum
2   um
3   vm
4   wm
5   tm
6   wdm
7   wind_speedm_3D
8   uu
9   uv
10   uw
11    vv
12    vw
13    ww
14    ut
15    vt
16    wt
17    tt
18    uuu
19    uuv
20    uuw
21    uut
22    uvv
23    uvw
24    uvt
25    uww
26    uwt
27    utt
28    vvv
29    vvw
30    vvt
31    www
32    wwt
33    wtt
34    ttt
35    uuuu
36    vvvv
37    wwww
38    tttt
39    u_star
40    L_Okukhov