Station 44008 (LLNR 827) - NANTUCKET 54 NM Southeast of Nantucket Image indicating link to RSS feed of recent meteorological observations for station 44008

Nantucket Shoals LB "N"


Conditions at 44008 as of
(7:40 pm EST on 12/12/2025)
0040 GMT on 12/13/2025:
     

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

5-day plot - Wind Direction Wind Direction (WDIR): W ( 280 deg true )
5-day plot - Wind Speed Wind Speed (WSPD): 23.3 kts
5-day plot - Wind Gust Wind Gust (GST): 31.1 kts
5-day plot - Atmospheric Pressure Atmospheric Pressure (PRES):30.00 in
5-day plot - Air Temperature Air Temperature (ATMP): 39.9 °F
5-day plot - Water Temperature Water Temperature (WTMP): 48.9 °F
5-day plot - Dew Point Dew Point (DEWP): 31.6 °F
5-day plot - Wind Chill Wind Chill (CHILL): 28.9 °F
5-day plot - Wind Speed at 10 Meters Wind Speed at 10 meters (WSPD10M): 27.2 kts
5-day plot - Wind Speed at 20 Meters Wind Speed at 20 meters (WSPD20M): 27.2 kts
5-day plot -  Wind Speed, Wind Gust and Atmospheric Pressure Combined plot of Wind Speed, Gust, and Air Pressure
Supplemental Measurements
Lowest 1-minute Pressure
Time (EST)Pressure
7:36 pm29.98 in
Highest 1-minute Wind Speed
Time (EST)5-day plot - 1-Minute Wind Speed WSPD 5-day plot - 1-Minute Wind Direction WDIR
7:36 pm 29.1 kts W ( 280 deg true )
Previous observations
TIME
(EST)
5-day plot - Wind Direction
WDIR
 
5-day plot - Wind Speed
WSPD
kts
5-day plot - Wind Gust
GST
kts
5-day plot - Wave Height
WVHT
ft
5-day plot - Dominant Wave Period
DPD
sec
5-day plot - Average Wave Period
APD
sec
5-day plot - Mean Wave Direction
MWD
 
5-day plot - Atmospheric Pressure
PRES
in
5-day plot - Pressure Tendency
PTDY
in
5-day plot - Air Temperature
ATMP
°F
5-day plot - Water Temperature
WTMP
°F
5-day plot - Dew Point
DEWP
°F
5-day plot - Salinity
SAL
psu
5-day plot - Visibility
VIS
nmi
5-day plot - Tide (above MLLW)
TIDE
ft
2025-12-12 07:30 pmWNW 25.3 31.1----29.99- 39.9 48.7 31.3---
2025-12-12 07:20 pmWNW 23.3 29.1 10.5 86.0 W30.00- 39.9 48.7 31.8---
2025-12-12 07:10 pm W 23.3 29.1 10.5-6.0 W30.00- 39.7 48.7 31.5---
2025-12-12 07:00 pmWNW 25.3 31.1----30.00+0.07 39.6- 30.9---
2025-12-12 06:50 pmWNW 25.3 31.1 9.2 75.6WNW29.99- 39.6 48.7 31.1---
2025-12-12 06:40 pm W 25.3 33.0----29.98- 39.6 48.7 31.3---
2025-12-12 06:20 pmWNW 25.3 31.1 10.2 85.9 W29.98- 39.4 48.7 31.1---
2025-12-12 06:10 pm W 25.3 31.1 10.2-5.9 W29.97- 39.2 48.7 31.1---
2025-12-12 06:00 pmWNW 25.3 31.1----29.97+0.06 39.4- 31.5---
2025-12-12 05:50 pm W 25.3 31.1 10.8 86.0 W29.96- 39.2 48.7 30.9---
2025-12-12 05:40 pm W 25.3 31.1----29.96- 39.0 48.7 31.1---
2025-12-12 05:30 pm W 23.3 29.1----29.96- 39.2 48.6 31.6---
2025-12-12 05:20 pm W 25.3 31.1 9.8 86.0 W29.95- 38.7 48.6 30.2---
2025-12-12 05:10 pm W 25.3 31.1 9.8-6.0 W29.94- 38.7 48.6 30.2---
2025-12-12 05:00 pm W 25.3 31.1----29.94+0.06 38.7 48.7 30.7---
2025-12-12 04:50 pm W 23.3 31.1 9.5 85.9 W29.94- 38.7 48.6 30.9---
2025-12-12 04:40 pm W 25.3 29.1 9.5-5.9 W29.94- 38.5 48.6 30.6---
2025-12-12 04:30 pm W 25.3 31.1----29.93- 38.3 48.6 30.4---
2025-12-12 04:20 pm W 25.3 29.1 9.2 85.7 W29.93- 38.3- 30.9---
2025-12-12 04:10 pm W 25.3 29.1 9.2-5.7 W29.93- 38.3 48.4 30.7---
2025-12-12 04:00 pm W 25.3 31.1----29.93+0.05 38.1 48.4 30.4---
2025-12-12 03:50 pm W 25.3 29.1 9.2 86.0 W29.92- 38.3 48.4 30.4---
2025-12-12 03:40 pm W 25.3 31.1----29.92- 38.1 48.4 30.4---
2025-12-12 03:30 pm W 25.3 29.1----29.91- 38.1 48.4 30.6---
2025-12-12 03:20 pm W 25.3 31.1 10.5 86.2 W29.91- 37.9 48.2 30.0---
2025-12-12 03:10 pm W 25.3 31.1----29.91- 37.9 48.2 30.0---
2025-12-12 03:00 pm W 25.3 31.1----29.90+0.03 37.8- 30.2---
2025-12-12 02:50 pm W 25.3 33.0 9.8 86.2 W29.90- 37.6 48.2 30.0---
2025-12-12 02:40 pm W 23.3 29.1----29.89- 37.6 48.0 29.5---
2025-12-12 02:30 pm W 23.3 29.1----29.90- 37.2- 29.1---
2025-12-12 02:20 pm W 23.3 31.1 9.8 96.1WSW29.89- 37.8 48.6 30.2---
2025-12-12 02:10 pm W 25.3 31.1 9.8-6.1WSW29.88- 37.2 48.6 29.1---
2025-12-12 02:00 pm W 23.3 31.1----29.88+0.00 37.0 48.6 29.3---
2025-12-12 01:50 pm W 25.3 31.1 9.8 86.1 W29.89- 36.7 48.7 28.6---
2025-12-12 01:40 pm W 25.3 31.1----29.88- 36.9 48.6 28.9---
2025-12-12 01:30 pm W 23.3 31.1----29.88- 36.9 48.6 29.3---
2025-12-12 01:20 pm W 25.3 29.1 10.2 96.2WSW29.88- 36.5 48.7 28.2---
2025-12-12 01:10 pm W 23.3 31.1 10.2-6.2WSW29.88- 36.1 48.7 27.7---
2025-12-12 01:00 pm W 25.3 31.1----29.88-0.02 36.1 48.6 27.7---
2025-12-12 12:50 pm W 25.3 33.0 10.8 86.4 W29.87- 36.3 48.6 27.9---
2025-12-12 12:40 pmWNW 25.3 31.1----29.87- 36.1 48.6 27.1---
2025-12-12 12:30 pmWNW 25.3 31.1----29.87- 36.0 48.6 27.1---
2025-12-12 12:20 pm W 25.3 31.1 10.2 96.2WSW29.87- 36.0 48.6 27.1---
2025-12-12 12:10 pm W 23.3 31.1 10.2-6.2WSW29.87- 36.1 48.7 26.8---
2025-12-12 12:00 pm W 25.3 31.1----29.87+0.00 35.8 48.7 27.1---
2025-12-12 11:50 am W 23.3 29.1 10.8 96.3WSW29.88- 35.6 48.7 26.8---
2025-12-12 11:40 amWNW 25.3 31.1----29.88- 35.8 48.7 27.5---
2025-12-12 11:30 amWNW 25.3 31.1----29.88- 35.4 48.7 27.1---
2025-12-12 11:20 amWNW 25.3 33.0 12.1 86.6 W29.88- 35.4 48.7 25.9---
2025-12-12 11:10 amWNW 25.3 33.0 12.1-6.6 W29.88- 35.6 48.7 26.6---
2025-12-12 11:00 amWNW 25.3 31.1----29.88+0.03 35.4 48.7 27.5---
2025-12-12 10:50 amWNW 25.3 31.1 10.8 96.4WSW29.89- 35.4 48.7 26.6---
2025-12-12 10:40 amWNW 25.3 33.0----29.89- 35.2 48.7 26.1---
2025-12-12 10:30 amWNW 25.3 33.0----29.89- 35.1 48.7 26.1---
2025-12-12 10:20 amWNW 27.2 33.0 11.2 96.4 W29.89- 35.1 48.7 26.4---
2025-12-12 10:10 amWNW 25.3 33.0 11.2-6.4 W29.89- 35.2- 27.1---
2025-12-12 10:00 amWNW 25.3 35.0----29.89+0.06 34.9 48.6 25.5---
2025-12-12 09:50 amWNW 27.2 35.0 10.8 86.3 W29.89- 35.1 48.6 25.9---
2025-12-12 09:40 amWNW 27.2 35.0----29.89- 35.1 48.6 26.1---
2025-12-12 09:30 amWNW 27.2 33.0----29.88- 35.1 48.6 25.9---
2025-12-12 09:20 amWNW 25.3 31.1 12.1 96.5WSW29.88- 35.2 48.7 27.0---
2025-12-12 09:10 amWNW 25.3 31.1 12.1-6.5WSW29.88- 35.2 48.7 27.1---
2025-12-12 09:00 amWNW 25.3 35.0----29.88+0.06 34.9 48.6 27.7---
2025-12-12 08:50 amWNW 27.2 35.0 11.5 96.4 W29.87- 35.1 48.6 26.4---
2025-12-12 08:40 amWNW 25.3 33.0----29.87- 35.2 48.6 26.6---
2025-12-12 08:30 amWNW 25.3 31.1----29.87- 35.1 48.6 27.1---
2025-12-12 08:20 amWNW 25.3 33.0 12.5 96.6 W29.86- 35.2- 25.5---
2025-12-12 08:10 amWNW 27.2 33.0 12.5-6.6 W29.86- 35.1 48.6 25.9---
2025-12-12 08:00 amWNW 25.3 35.0----29.86+0.07 35.1 48.6 25.3---
2025-12-12 07:50 amWNW 27.2 35.0 11.5 96.3 W29.86- 35.2 48.6 25.0---
2025-12-12 07:40 amWNW 27.2 33.0----29.85- 35.1 48.6 25.5---
2025-12-12 07:30 amWNW 27.2 33.0----29.85- 35.4 48.6 25.5---
2025-12-12 07:20 amWNW 27.2 35.0 11.8 96.3 W29.85- 35.4 48.6 25.3---
2025-12-12 07:10 am W 25.3 35.0 11.8-6.3 W29.84- 35.2 48.6 25.0---
2025-12-12 07:00 am W 25.3 33.0----29.84+0.08 35.4 48.6 26.1---
2025-12-12 06:50 amWNW 27.2 33.0 12.5 96.7 W29.83- 35.2 48.6 25.2---
2025-12-12 06:40 amWNW 27.2 33.0----29.83- 34.9 48.7 25.3---
2025-12-12 06:30 amWNW 25.3 33.0----29.82- 35.1- 25.7---
2025-12-12 06:20 amWNW 27.2 35.0 12.8 96.6 W29.82- 35.1 48.9 25.5---
2025-12-12 06:10 amWNW 27.2 33.0----29.82- 34.7 48.9 26.8---
2025-12-12 06:00 amWNW 25.3 36.9----29.81+0.07 34.7 48.9 27.3---
2025-12-12 05:50 amWNW 25.3 33.0 12.5 86.5WNW29.81- 34.5 49.1 27.7---
2025-12-12 05:40 amWNW 27.2 33.0----29.80- 35.2 48.9 26.8---
2025-12-12 05:30 amWNW 27.2 33.0----29.80- 35.4 49.1 26.6---
2025-12-12 05:20 am W 25.3 33.0 13.1 106.9 W29.79- 34.9 48.9 27.0---
2025-12-12 05:10 am W 27.2 35.0 13.1-6.9 W29.79- 35.2 49.1 28.0---
2025-12-12 05:00 amWNW 27.2 33.0----29.78+0.06 35.1 49.1 27.3---
2025-12-12 04:50 amWNW 27.2 35.0 15.1 97.1 W29.78- 35.4 49.1 27.3---
2025-12-12 04:40 amWNW 29.1 38.9----29.78- 34.9- 27.5---
2025-12-12 04:30 amWNW 29.1 36.9----29.78- 35.4 49.1 27.0---
2025-12-12 04:20 amWNW 29.1 36.9 15.1 96.9 W29.77- 36.0 49.1 25.5---
2025-12-12 04:10 am W 29.1 36.9 15.1-6.9 W29.77- 36.5 49.1 25.7---
2025-12-12 04:00 am W 31.1 36.9----29.76+0.05 36.5- 24.3---
2025-12-12 03:50 am W 29.1 36.9 15.1 97.0 W29.76- 36.9 49.1 26.2---
2025-12-12 03:40 am W 31.1 40.8----29.75- 36.5 49.1 26.2---
2025-12-12 03:30 am W 31.1 40.8----29.75- 36.5 49.1 25.9---
2025-12-12 03:20 am W 31.1 38.9 15.7 97.1 W29.75- 36.7 49.1 25.7---
2025-12-12 03:10 am W 31.1 38.9 15.7-7.1 W29.75- 37.0 49.1 26.2---
2025-12-12 03:00 am W 29.1 38.9----29.74+0.05 36.1 49.1 27.0---
2025-12-12 02:50 am W 33.0 42.7 14.1 97.0 W29.75- 37.2- 27.1---
2025-12-12 02:40 amWNW 31.1 38.9----29.74- 37.2 49.1 26.2---
2025-12-12 02:30 am W 29.1 38.9----29.73- 37.4 49.1 26.2---
2025-12-12 02:20 am W 29.1 38.9 14.4 97.1 W29.73- 36.5 49.1 28.2---
2025-12-12 02:10 am W 31.1 38.9 14.4-7.1 W29.73- 37.6 49.1 27.5---
2025-12-12 02:00 am W 29.1 35.0----29.73+0.03 36.9 49.1 27.0---
2025-12-12 01:50 amWNW 29.1 36.9 14.8 97.3 W29.73- 36.3 49.1 28.8---
2025-12-12 01:40 amWNW 29.1 38.9 14.8-7.3 W29.73- 35.8 49.1 28.6---
2025-12-12 01:30 am W 31.1 38.9----29.73- 36.3 49.1 27.9---
2025-12-12 01:20 am W 31.1 38.9 15.1 97.2 W29.72- 36.5 49.1 26.2---
2025-12-12 01:10 am W 29.1 36.9----29.71- 36.7 48.9 26.6---
2025-12-12 01:00 amWNW 27.2 36.9----29.71+0.00 36.7- 27.7---
2025-12-12 12:50 amWNW 31.1 40.8 14.1 97.1 W29.71- 37.2 48.7 27.0---
2025-12-12 12:40 am W 29.1 38.9----29.70- 37.2 48.7 26.2---
2025-12-12 12:30 am W 27.2 38.9----29.70- 37.2 48.7 26.2---
2025-12-12 12:20 am W 29.1 36.9 14.4 97.1 W29.71- 37.4 48.7 25.2---
2025-12-12 12:10 am W 29.1 36.9 14.4-7.1 W29.70- 37.6 48.7 26.1---
2025-12-12 12:00 am W 29.1 35.0----29.70+0.00 37.6 48.7 26.2---
2025-12-11 11:50 pmWNW 27.2 35.0 12.5 96.8WSW29.70- 37.4 48.6 26.6---
2025-12-11 11:40 pm W 29.1 36.9 12.5-6.8WSW29.70- 36.9 48.6 26.8---
2025-12-11 11:30 pmWNW 31.1 36.9----29.70- 36.3 48.6 27.7---
2025-12-11 11:20 pmWNW 29.1 38.9 14.1 97.0WSW29.70- 36.3 48.6 28.2---
2025-12-11 11:10 pmWNW 29.1 36.9 14.1-7.0WSW29.70- 36.9- 28.2---
2025-12-11 11:00 pmWNW 31.1 38.9----29.70+0.00 37.9 48.6 27.0---
2025-12-11 10:50 pmWNW 31.1 38.9 12.5 96.8WSW29.70- 37.4 48.6 27.9---
2025-12-11 10:40 pmWNW 29.1 38.9 12.5-6.8WSW29.69- 37.6 48.6 27.3---
2025-12-11 10:30 pmWNW 29.1 36.9----29.70- 37.8 48.6 27.0---
2025-12-11 10:20 pmWNW 29.1 36.9 12.1 96.9WSW29.70- 37.6 48.6 26.8---
2025-12-11 10:10 pmWNW 27.2 36.9----29.70- 37.8 48.6 28.6---
2025-12-11 10:00 pmWNW 29.1 38.9----29.70+0.04 37.4 48.6 28.0---
2025-12-11 09:50 pmWNW 31.1 40.8 13.5 97.0WSW29.70- 38.1 48.6 26.8---
2025-12-11 09:40 pmWNW 31.1 36.9----29.70- 38.1 48.6 25.9---
2025-12-11 09:30 pmWNW 31.1 36.9----29.70- 38.3 48.6 25.2---
2025-12-11 09:20 pmWNW 29.1 38.9 13.8 97.2WSW29.69- 38.1- 25.7---
2025-12-11 09:10 pmWNW 29.1 36.9----29.70- 38.5 48.6 26.6---
2025-12-11 09:00 pmWNW 29.1 38.9----29.69+0.05 37.9 48.6 26.1---
2025-12-11 08:50 pmWNW 29.1 35.0 14.4 97.2WSW29.70- 38.1 48.6 27.5---
2025-12-11 08:40 pmWNW 29.1 36.9----29.70- 38.3 48.6 26.8---
2025-12-11 08:30 pmWNW 29.1 36.9----29.69- 38.5 48.6 27.0---
2025-12-11 08:20 pmWNW 29.1 35.0 13.5 107.0 SW29.69- 38.3 48.7 26.2---
2025-12-11 08:10 pmWNW 31.1 38.9 13.5-7.0 SW29.69- 38.7 48.7 25.0---
2025-12-11 08:00 pmWNW 27.2 40.8----29.69+0.08 38.7 48.7 25.2---
2025-12-11 07:50 pmWNW 25.3 35.0 12.8 96.9WSW29.68- 38.5 48.7 25.5---

Wave Summary
for 44008 as of
(7:10 pm EST on 12/12/2025)
0010 GMT on 12/13/2025:

These wave data are displayed in rounded times.

     

Click on the graph icon in the table below to see a time series plot of the last five days of that observation.

5-day plot - Significant Wave Height Significant Wave Height (WVHT): 10.5 ft
5-day plot - Swell Height Swell Height (SwH): 0.0 ft
5-day plot - Wind Wave Height Wind Wave Height (WWH): 10.5 ft
5-day plot - Wind Wave Period Wind Wave Period (WWP): 8.3 sec
5-day plot - Wind Wave Direction Wind Wave Direction (WWD): W
5-day plot - Wave Steepness Wave Steepness (STEEPNESS): STEEP
5-day plot - Average Wave Period Average Wave Period (APD): 6.0 sec
Previous observations
TIME
(EST)
5-day plot - Wave Height
WVHT
ft
5-day plot - Swell Height
SwH
ft
5-day plot - Swell Period
SwP
sec
5-day plot - Swell Direction
SwD
 
5-day plot - Wind Wave Height
WWH
ft
5-day plot - Wind Wave Period
WWP
sec
5-day plot - Wind Wave Direction
WWD
 
5-day plot - Wave Steepness
STEEPNESS
 
5-day plot - Average Wave Period
APD
sec
2025-12-12 06:40 pm 9.2 0.0-- 9.2 6.7 WNWVERY_STEEP 5.6
2025-12-12 06:10 pm 10.2 0.0-- 10.2 8.3 W STEEP 5.9
2025-12-12 05:40 pm 10.8 0.0-- 10.8 8.3 W STEEP 6.0
2025-12-12 05:10 pm 9.8 0.0-- 9.8 8.3 W STEEP 6.0
2025-12-12 04:40 pm 9.5 0.0-- 9.5 8.3 W STEEP 5.9
2025-12-12 04:10 pm 9.2 3.6 9.1WSW 8.5 7.7 W STEEP 5.7
2025-12-12 03:40 pm 9.2 0.0-- 9.2 8.3 W STEEP 6.0
2025-12-12 03:10 pm 10.5 0.0-- 10.5 8.3 W STEEP 6.2
2025-12-12 02:40 pm 9.8 6.2 8.3 W 7.9 5.0 W STEEP 6.2
2025-12-12 02:10 pm 9.8 4.6 9.1WSW 8.9 7.1 W STEEP 6.1
2025-12-12 01:40 pm 9.8 0.0-- 9.8 8.3 W STEEP 6.1
2025-12-12 01:10 pm 10.2 0.0-- 10.2 9.1 WSW STEEP 6.2
2025-12-12 12:40 pm 10.8 0.0-- 10.8 7.7 W STEEP 6.4
2025-12-12 12:10 pm 10.2 5.2 9.1WSW 8.5 7.1 W STEEP 6.2
2025-12-12 11:40 am 10.8 5.9 9.1WSW 8.9 7.7 W STEEP 6.3
2025-12-12 11:10 am 12.1 6.2 10.0WSW 10.2 8.3 W STEEP 6.6
2025-12-12 10:40 am 10.8 6.2 9.1WSW 8.5 7.1 W STEEP 6.4
2025-12-12 10:10 am 11.2 0.0-- 11.2 9.1 W STEEP 6.4
2025-12-12 09:40 am 10.8 5.2 10.0WSW 9.5 8.3 W STEEP 6.3
2025-12-12 09:10 am 12.1 0.0-- 12.1 9.1 WSW STEEP 6.5
2025-12-12 08:40 am 11.5 6.6 9.1 W 9.2 7.7 WNW STEEP 6.4
2025-12-12 08:10 am 12.5 7.5 9.1 W 9.8 6.2 WNW STEEP 6.6
2025-12-12 07:40 am 11.5 7.2 9.1 W 8.9 7.7 WNW STEEP 6.3
2025-12-12 07:10 am 11.8 6.6 9.1 W 9.5 7.7 WNW STEEP 6.3
2025-12-12 06:40 am 12.5 7.9 9.1 W 9.8 4.8 WNW STEEP 6.7
2025-12-12 06:10 am 12.8 7.9 9.1 W 9.8 6.7 WNW STEEP 6.6
2025-12-12 05:40 am 12.5 7.2 9.1 W 10.2 7.7 WNWVERY_STEEP 6.5
2025-12-12 05:10 am 13.1 3.3 17.4NNW 12.8 10.0 W AVERAGE 6.9
2025-12-12 04:40 am 15.1 0.0-- 15.1 9.1 W STEEP 7.1
2025-12-12 04:10 am 15.1 0.0-- 15.1 9.1 W STEEP 6.9
2025-12-12 03:40 am 15.1 0.0-- 15.1 9.1 W STEEP 7.0
2025-12-12 03:10 am 15.7 1.0 17.4 N 15.7 9.1 W STEEP 7.1
2025-12-12 02:40 am 14.1 9.5 9.1 W 10.5 5.3 WNW STEEP 7.0
2025-12-12 02:10 am 14.4 5.2 13.8 NW 13.5 9.1 W STEEP 7.1
2025-12-12 01:40 am 14.8 0.0-- 14.8 9.1 W STEEP 7.3
2025-12-12 01:10 am 15.1 0.7 16.0 NE 15.1 9.1 W STEEP 7.2
2025-12-12 12:40 am 14.1 5.9 14.8WNW 12.8 9.1 W STEEP 7.1
2025-12-12 12:10 am 14.4 4.6 19.0 N 13.8 9.1 W STEEP 7.1
2025-12-11 11:40 pm 12.5 2.3 16.0WNW 12.1 9.1 WSW STEEP 6.8
2025-12-11 11:10 pm 14.1 0.0-- 14.1 9.1 WSW STEEP 7.0
2025-12-11 10:40 pm 12.5 8.9 9.1WSW 8.9 7.1 W STEEP 6.8
2025-12-11 10:10 pm 12.1 0.0-- 12.1 9.1 WSW STEEP 6.9
2025-12-11 09:40 pm 13.5 0.0-- 13.5 9.1 WSW STEEP 7.0
2025-12-11 09:10 pm 13.8 0.0-- 13.8 9.1 WSW STEEP 7.2
2025-12-11 08:40 pm 14.4 0.0-- 14.4 9.1 WSW STEEP 7.2
2025-12-11 08:10 pm 13.5 9.5 10.0 SW 9.2 6.7 W STEEP 7.0

Plot icon Plot of wave energy versus frequency (and period)