DOI: 10.25919/shdk-7p29
title: WHACS: Wave Hindcast for the Australian Climate Service

description: WHACS, the Wave Hindcast for the Australian Climate Service, is an ocean wave hindcast running from 1979 to the present* (2023 at the time of publication). 
WHACS is designed to replace the CAWCR Wave Hindcast (Durrant, Hemer, Smith, Trenham & Greenslade (2019) http://hdl.handle.net/102.100.100/137152). 
A manuscript describing this dataset is in preparation.

WHACS data was generated using the WAVEWATCH III v6.07 wave model using ST6 physics, forced with ERA5 hourly winds and daily sea ice. The model was run on a spherical multi-cell (SMC) grid with a base resolution of 0.25 degrees in the polar regions and 0.125 degrees the non-polar global ocean, and a higher resolution of ~7km in the coastal zone globally.

The dataset comprises 4 components (3 only in this publication): the full SMC grid data; regridded data at 1/8deg globally; regridded data at 1/16deg in the Australian region, and spectral outputs (not in this dataset).
The model produced spectral wave output at 11224 points: 286 buoys; 370 points on a global 10-degree grid; 10055 points from the coastal SMC grid in the Australian, New Zealand, Indian and Pacific Islands and the Maritime Continent regions; an additional 80 points around NZ; and 443 points that define the SCHISM-WWMIII based Coupled Coastal Hazard Prediction System (CCHaPS) hindcast. 

Further information will be provided in an accompanying paper which will be linked to this metadata record in due course. 

N.B. December 1978 was run as a "model spin-up" month, data should be reliable from January 1979.

SMC parameters: longitude; latitude; time; uwnd; vwnd (Eastward and Northward wind); hs (significant wave height); t01(mean period T01); t02 (mean wave period T02); t0m1 (mean period T0m1); fp (peak wave frequency); dir (mean wave direction); spr (directional spread); dp (peak direction); phs0; phs1; phs2; phs3 (significant wave height partitions); ptp0; ptp1; ptp2; ptp3 (peak period partitions); pdir0; pdir1; pdir2; pdir3 (mean wave direction partitions); pspr0; pspr1; pspr2; pspr3 (wave directional spreading partitions); pdp0; pdp1; pdp2; pdp3 (peak wave direction partitions); pqp0; pqp1; pqp2; pqp3 (wave peakedness partitions); ppe0; ppe1; ppe2; ppe3 (wave peak enhancement factor partitions); CgE (wave energy flux). 

Regridded parameters: longitude; latitude; time; hs (significant wave height); uwnd; vwnd (Eastward and Northward wind); t01(mean period T01); t02 (mean wave period T02); t0m1 (mean period T0m1); fp (peak wave frequency); dir (mean wave direction); dp (peak direction); phs0; phs1; phs2 (significant wave height partitions); ptp0; ptp1; ptp2 (peak period partitions); pdir0; pdir1; pdir2 (mean wave direction partitions); CgE (wave energy flux). 

Some corrections were made to the data during post-processing: 
- CgE took negative values in sea ice regions and due to numerical overflow in some cases. These values were reset to NaN or brought within range by changing the datatype from int16 to uint16. 
- fp took negative values sometimes due to a known bug in this version of WW3 (https://github.com/NOAA-EMC/WW3/pull/741)
- Negative values of pqp* variables were reset to the maximum allowed, however such values would be considered nonphysical (https://github.com/NOAA-EMC/WW3/issues/210), If using the partitioned Goda's peakedness parameter variables, please do so with caution.


Not included in this collection:
Spectral wave parameters: time; station; longitude; latitude; frequency; frequency1; frequency2 (centre, upper and lower bands); direction; efth (sea surface wave directional variance spectral density); dth (depth); wnd; wnddir (wind speed and direction 10m above surface); curr; currdir (sea water speed and direction).