Larry Goddard/Pat Caldwell's Oahu Surf Observations

These are visual observations made in "Hawaii Scale",
which is one-half peak face, trough-to-crest height on the
shoreward side of the wave at time of maximum cresting.

Format:
yyyy mm dd nshor wshor almo dh  winw  wspd wdir nsd ssd
2000  1  1    8    4    1    2    3    2   17   15  999
2000  1  2    5    2    1    2    2    2   17   15  999
2000  1  3    4    2    1    2    2    2   17   15  999
                                                                                  
yyyy: year, mm: month, dd: day
nshor (mostly Sunset until > 15 Hawaii scale (Hs), then 
         Waimea reports are used)
wshor (Makaha) low quality, use with caution
almo (Ala Moana) south shore
dh (Diamond Head) 
winw (Windward Oahu (east side) index) use with caution
wspd (wind speed in beaufort for open waters)
wdir (wind direction, coded 1=N 2=NNE 3=NE, etc ... 16=NNW
      17:calm, 18:mixed)
nsd (north shore wave direction as above)
ssd (south shore direction)
                                                                                  
missing data flag 999
                                                                                  
Background/Explanation:
Data are recorded in Hawaii scale, which has been shown
with photographic evidence to be half the trough-to-crest
height at the moment of maximum cresting for the highest
portion of the shoreward wave front, with a 20% margin
of error (Caldwell and Aucan, 2007).  

Important references:

Caldwell, P.C., 2005.  The Validity of North Shore Oahu, Hawaiian Islands,
Surf Observations. Journal of Coastal Research, 21(6),pp. 1127-1138.

Caldwell, P.C. and J.P. Aucan, 2007. An Empirical Method for Estimating Surf
Heights from Deep Water Significant Wave Heights and Peak Periods in Coastal
Zones with Narrow Shelves, Steep Bottom Slopes, and High Refraction. Journal
of Coastal Research, 23(6). 

This dataset includes daily estimates of surf size at
the various sides of Oahu, Hawaii.  Since it is visually
acquired, readings were only made during daylight hours.  
The data represent the upper end of the reported range for
the highest report for any given day.  For instance, if the 
surf report was 4-6 in the AM and 2-4 in the PM, 6 would be 
recorded.  The height nominally represents the average of the
highest 10% (H1/10) waves, which are the common though less
frequent higher sets with such groups arriving roughly 8-15
minutes apart.   

Mr. Larry Goddard provided the database for the North Shore
from 1968-9/1987 and the south shore (Ala Moana) from
1972-7/1987.  Many observations were his own, but he
also received help from reputable surfers such as
Randy Rarick, Peter Cole, Bernie Baker, and Lt. Benson.

Mr. Caldwell began a digital archive of surf observations,
coincidently, when Mr. Goddard moved to the mainland
and discontinued his set.  The Caldwell set from 1987
onward considers the  primary source as the Oahu lifeguard 
and the Surf News Network reports, unless more reliable 
information was provided via a network of surfing friends.  
The data quality should be higher starting in 1999 due to 
the availability of Internet cameras at key surf locations. 

For the North Shore, Sunset Beach is the primary 
observation spot when the surf is below 15 Hs.  Sometimes 
for a straight north to northeast swell, Laniakea is used 
if available since it could be bigger than Sunset.  Once 
the surf is 15 Hs or higher, Waimea Bay is the typical 
observation point.  

For North Shore climatology, note AUCAN paper below.

To translate from Hawaii scale to trough-to-crest for heights
greater than 15 Hs, zones of high refraction on outer reefs
are double Hawaii scale within a 20% margin of error.  Heights
at Waimea are roughly 1.5 times Hawaii scale.

The wave direction data began in 1990 based on personal 
knowledge of Mr. Patrick Caldwell, who has studied the weather
maps daily in preparation of surf forecasts. 
Another technique used was noting the swell sizes
on the various sides of the island.  For instance,
if Makaha is 8',  Sunset is 10', and N.Beach is 2',
then the direction is obviously dominated by NW 
component. Since 12/2001, a directional buoy near Waimea,
Oahu has improved the wave direction information.

For the Windward Surf Index, reports from North Beach 
on the Kaneohe Marine Corp Base Hawaii were used until 
1995 when it was discontinued by the Oahu lifeguard 
reporting system. Since then, Makapuu has been the primary 
reporting site, although Mr. Caldwell lives in Kailua Hawaii 
and has been able to fine tune the estimates personally.
The windward index includes both trade wind energy
as well as any long period swell from North Pacific
sources.  Due to potential for large gradients in
size along the windward coast during the arrival
of long period energy, especially if the direction
requires refraction around Kahuku Point, the Windward
Surf Index is of low quality.  However, by correlating
the wind to the waves and using only trade events,
the data are likely of reasonable quality.  For understanding
wind wave energy, see 

Aucan, J., 2006. Directional Wave Climatology for the Hawaiian Islands from
Buoy Data and the Influence of ENSO on Extreme Wave Events from Model
Hindcast. 9th International Workshop on Wave Hindcasting and Forecasting.
JCOMM Technical Report No. 34 / WMO-TD. No. 1368.

Wind data are an estimate of ballpark open ocean
speeds, independent of island influence.  Usually,
the Bellows or Kahuku anemometers are used during
trade wind events.


For a south shore surf climatology, see

Caldwell, P.C., 2007.  Spectral Density Composites for Aid in South Swell
Forecasts for Oahu, Hawaii.  10th International Workshop on Wave Hindcasting
and Forecasting, Turtle Bay, Oahu, Nov. 11-16, 2007.

A new climatology has been made and is available at
http://ilikai.soest.hawaii.edu/HILO/climo/oahu_surf_climatlogy.html

For other surf research, see:
http://ilikai.soest.hawaii.edu/HILO/SurfResearch.html
