Description of NDBC wave spectra

The Wave Processing Module (WPM) Spectrum
Band	Center Frequency of Band (Hz)	Bandwidth (Hz)
1	0.020¹	0.010
2	0.0325	0.005
3	0.0375	0.005
4	0.0425	0.005
5	0.0475	0.005
6	0.0525	0.005
7	0.0575	0.005
8	0.0625	0.005
9	0.0675	0.005
10	0.0725	0.005
11	0.0775	0.005
12	0.0825	0.005
13	0.0875	0.005
14	0.0925	0.005
15	0.1000	0.010
16	0.1100	0.010
17	0.1200	0.010
18	0.1300	0.010
19	0.1400	0.010
20	0.1500	0.010
21	0.1600	0.010
22	0.1700	0.010
23	0.1800	0.010
24	0.1900	0.010
25	0.2000	0.010
26	0.2100	0.010
27	0.2200	0.010
28	0.2300	0.010
29	0.2400	0.010
30	0.2500	0.010
31	0.2600	0.010
32	0.2700	0.010
33	0.2800	0.010
34	0.2900	0.010
35	0.3000	0.010
36	0.3100	0.010
37	0.3200	0.010
38	0.3300	0.010
39	0.3400	0.010
40	0.3500	0.010
41	0.3650	0.020
42	0.3850	0.020
43	0.4050	0.020
44	0.4250	0.020
45	0.4450	0.020
46	0.4650	0.020
47	0.4850	0.020

WPM spectrum is described in the WMO FM 65-XI WAVOB code as:

13/// 13254 15003 26/// 21005 21004 07/// 33655 32004

NDBC does not include the 0.02 Hz frequency in the FM 65 WAVEOB code. The FM 65 only contains 46 bands 2 through 47 listed in the table.

See: http://www.ndbc.noaa.gov/decode.shtml for information on the FM 65 WAVEOB code.

The (Directional) Wave Analyzer (DWA or WA) Spectra
WA Band	DWA Band	Center Frequency of Band (Hz)	Bandwidth (Hz)
1	1	0.03	0.01
2	2	0.04	0.01
3	3	0.05	0.01
4	4	0.06	0.01
5	5	0.07	0.01
6	6	0.08	0.01
7	7	0.09	0.01
8	8	0.10	0.01
9	9	0.11	0.01
10	10	0.12	0.01
11	11	0.13	0.01
12	12	0.14	0.01
13	13	0.15	0.01
14	14	0.16	0.01
15	15	0.17	0.01
16	16	0.18	0.01
17	17	0.19	0.01
18	18	0.20	0.01
19	19	0.21	0.01
20	20	0.22	0.01
21	21	0.23	0.01
22	22	0.24	0.01
23	23	0.25	0.01
24	24	0.26	0.01
25	25	0.27	0.01
26	26	0.28	0.01
27	27	0.29	0.01
28	28	0.30	0.01
29	29	0.31	0.01
30	30	0.32	0.01
31	31	0.33	0.01
32	32	0.34	0.01
33	33	0.35	0.01
N/A	34	0.36	0.01
N/A	35	0.37	0.01
N/A	36	0.38	0.01
N/A	37	0.39	0.01
N/A	38²	0.40	0.01

The (D)WA spectrum is described in the FM 65-XI WAVOB code as:

33/// 13004 11004

See: http://www.ndbc.noaa.gov/decode.shtml for information on the FM 65 WAVEOB code. The FM 65 WAVOB code only provides the first 33 frequency bands.

¹ 0.02 Hz is a noise band and not used in the calculations for WVHT, DPD, or APD.
² For nondirectional spectrum. The directional spectrum stops at 0.35 Hz, Band 33.

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Page last modified: February 6, 2008

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