1988

Station ALOHA (~4750m deep)

Hawaii Ocean Time-series (HOT)October 1988 - present (260 cruises; ~10/yr)

25 years of HOT

Station ALOHA (~4750m deep)

Hawaii Ocean Time-series (HOT)October 1988 - present (260 cruises; ~10/yr)

Mahalo nui loa to countless folks for their contributions to the successes of HOT and Station ALOHA

25 years of HOT NSFNOAAState of Hawaii (UH/SOEST)

Quantifying the Surface Freshwater Flux at Station ALOHA

Roger Lukas*, Fernando Santiago-Mandujano*, Albert Plueddemann+, Robert

Weller+, Fred Duennebier*, Bruce Howe*

* U. Hawaii at Manoa + Woods Hole Oceanographic Institution

Ocean Sciences Meeting 2014

R. Weller (WHOI)

The ocean and the hydrological cycle

Tradewinds – Harvesting Water and Heat From the Ocean

NOAA/OAR Ocean Reference Stations

Donating to the warm pool

Precious Rains

Hawaii’s tenuous water resources

∫(E-P)dt

WHOTS Rainfall and Evaporation

Sean Whelan (WHOI)

Rainfall –

Has small space-time scales

Not well-observed from space

Poorly represented in NWP model-reanalyses

WHOTS and the hydrological cycle

Winter Storms Interact with ITCZ

WHOTS and the hydrological cycle

How stable and reliable are the trends estimated from limited observations?

Observations limited in duration and spatial extent; exponential rainfall distributions in space and time

WHOTS Buoy Mixed Layer

See poster #2463 by McCoy et al., this session

Multiple data sources and error characteristics

December 5th, 2012 Rainfall EventMolokai NexRad

Station ALOHA

Molokai NexRAD

HOT Cruise 248Shipboard Rain Gauges

q prate

wind speed

wind direction

Surface salinity

SST

WHOTS-9 Buoy data

Rainfall Rates from NexRAD

December 5th, 2012 Rainfall Event

Hydrophone sound

before rainstorm

during rainstorm

minutes from 08:50

Spectrogram for Dec 5th 2012

frequency(kHz) 15

20

5

10

0 15012060

db re 1µ Pascal

4728 m

ALOHA Cabled Observatory

4728 m

17.5 KHz

10.5 KHz

4 KHz

4 KHz

10.5 KHz

rainfallrate

rainfallrate

windspeed

windspeed

17.5 KHz

rainfallrate

windspeed

mm/hr max

min

TRMM rain radar

TRMM Satellite Rainfall Estimates

5-day accumulation estimates

Numerical Weather PredictionModel Rainfall for Station ALOHA

ECMWF

WHOTS-9

120

80

0

40

Summary

• Measured rainfall in situ much larger than satellite, comparable to NexRAD weather radar

• Time-space variability of rainfall challenges freshwater budgets

• Bridging scales is crucial for satellite ground-truthing, and verification of NWP and climate models

• Related posters by Nystuen et al. (UW/APL); Poster by Monk et al. (BIOS); Poster by Yang et al. (UW)