19881988

Station ALOHA (~4750m deep)Station ALOHA (~4750m deep)

25 years of HOT25 years of HOT

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

Station ALOHA (~4750m deep)Station ALOHA (~4750m deep)

25 years of HOT25 years of HOT NSFNOAASt t f H ii

NSFNOAASt t f H iiState of Hawaii (UH/SOEST)State of Hawaii (UH/SOEST)

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

Mahalo nui loa to countless folks for their contributions to

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

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

folks for their contributions to the successes of HOT and Station ALOHA

Quantifying the Surface R. Weller (WHOI)

y gFreshwater Flux at Station ALOHA

Roger Lukas*, Fernando Santiago‐Mandujano*, Albert Plueddemann+, Robert Weller+ Fred Duennebier*Robert Weller+, Fred Duennebier*, 

Bruce Howe** U. Hawaii at Manoa + Woods Hole Oceanographic Institution

Ocean Sciences Meeting 2014

The ocean and the hydrological cycleThe ocean and the hydrological cycle

Tradewinds – Harvesting Water and Heat From the Ocean

NOAA/OAR Ocean Reference Stations

D ti t th lDonating to the warm pool

Precious RainsPrecious Rains

Hawaii’s tenuous water resources

∫(E-P)dt∫(E-P)dt

WHOTS Rainfall and Evaporation

Sean Whelan (WHOI)

Rainfall –

Has small space-time scalesp

Not well-observed from space

Poorly represented in NWP model-reanalyses

WHOTS and the hydrological cycleWHOTS and the hydrological cycle

Winter Storms Interact with ITCZWinter Storms Interact with ITCZ

WHOTS and the hydrological cycleWHOTS 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 LayerWHOTS Buoy Mixed Layer

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

Multiple data sources d hand error characteristics

December 5th, 2012 Rainfall Event,Molokai NexRad

Station ALOHA

Molokai NexRAD

HOT Cruise 248h b dShipboard Rain Gauges

WHOTS-9 Buoy data

q prate

wind speedspeed

wind direction

SSTSurface salinity

SST

Rainfall Rates from NexRADRainfall Rates from NexRAD

December 5th, 2012 Rainfall EventDecember 5th, 2012 Rainfall Event

Hydrophone soundHydrophone sound

b f i tbefore rainstorm

during rainstorm

Spectrogram for Dec 5th 2012Spectrogram for Dec 5 2012db re

frequency

201µ Pascal

eque cy(kHz) 15

10

4728 m5

minutes from 08:500 15012060

ALOHA Cabled ObservatoryObservatory

17.5 KHz

10.5 KHz

4728 m

4 KHz

rainfall wind

4 KHz

rate speed

10 5 KHz

rainfallrate

windspeed

10.5 KHz

17.5 KHz

rainfall windrainfallrate speed

TRMM rain radar

mm/hr max

min

TRMM Satellite Rainfall EstimatesTRMM Satellite Rainfall Estimates

5-day accumulation estimatesy

Numerical Weather Predictiond l f ll fModel Rainfall for Station ALOHA

120

WHOTS-980

ECMWF40

0

SummarySummary

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

• Time‐space variability of rainfall challenges freshwater budgetsfreshwater budgets

• Bridging scales is crucial for satellite ground‐hi d ifi i f NWP d litruthing, 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)• Related posters by Nystuen et al. (UW/APL); Poster by Monk et al. (BIOS); Poster by Yang et al. (UW)