17.12. The JONH Data Record - JONSWAP Spectrum 

      2   5  7   11         21       31       41       51       61
    - --- -- ---- ---------- -------- -------- -------- -------- --------
   |X|   |  |JONH|XXXXXXXXXX|        |        |        |        |        |
    - --- -- ---- ---------- -------- -------- -------- -------- --------
       |  |   |                 |        |         |       |        |
       |  |   |                 |        |         |       |        |
       |  |   |                 |        |         |       | (5)Peak Frequency (F10.0)
       |  |   |                 |        |         |       |
       |  |   |                 |        |         |       |
       |  |   |                 |        |         |       |_(4)Significant Wave Height Hs(F10.0)
       |  |   |                 |        |         |
       |  |   |                 |        |         |_(3)Gamma(F10.0)
       |  |   |                 |        |
       |  |   |                 |        |_(2)Finish Frequency(F10.0)
       |  |   |                 |
       |  |   |                 |_(1)Start Frequency(F10.0)
       |  |   |
       |  |   |_Compulsory Data Record Keyword(A4)
       |  |
       |  |_Optional User Identifier(A2)
       |
       |_Compulsory END on last data record in data category(A3)

This data record also defines a JONSWAP spectrum. The only difference from the JONS data record is that significant wave height Hs is used instead of the parameter Alpha.