The WHOI Hawaii Ocean Time-series Station (WHOTS) Roger Lukas, Robert Weller and Albert Plueddemann Station ALOHA is an element of NOAAs Ocean Reference Stations part of the OceanSITES & JCOMM OPS international network leverages long record and context from HOT (e.g. carbon cycle and salinity/hydrological cycle) near-surface measurements in real-time facilitating ALOHA Mauna Loa ALOHA/HOT pH pCO 2 trends, ENSO and annual cycle resolved by HOT from PMEL ocean carbon website effects of eddies and storms are not resolved by HOT but are resolved by WHOTS (NOAA&NSF) pCO 2 air pCO 2 water NOAA/PMEL MAPCO 2 SIO & NOAA/ESRL UH & SIO & OSU & UW & UM & WHOI & NSF & NOAA WHOTS surface buoy (real-time) wind, T, RH Radiation (short, long, up/down) Rainfall Near-surface ocean T, S pCO 2 air and water; pH (PMEL) soon: fluorescence in water (Laney/WHOI) future: wave spectrum Mooring (delayed mode) u, T, C, S, P [0-155 m] near-bottom microcat to be added(~4750 m) dissolved oxygen is a goal 4750 m T S focus on salinity and hydrological cycle sea surface Koko Head ALOHA z potential density (kg m -3 ) Local and Remotely-Forced Salinity Trends and Variations HOT WHOTS fully-resolved temporal sampling historical hydrographic profiles within 200 km of ALOHA (note gaps) HOT cruises present decadal variations long-term trend (disrupted ) Gunter Seckel Bureau of Commercial Fisheries Honolulu Laboratory Salinity plays an important role in stability of upper ocean on interannual and decadal time scales, with effects on mixing and productivity (Corno et al., 2007; Bidigare et al., 2009) HOT mixed layer temperature, salinity and density (top) and anomalies (bottom). [Note inverted temperature scale] WHOTS (incl. air-sea fluxes) poor ocean forcing data Can we understand and close the upper ocean salt budget? Evaporation: Comparison of WHOTS with ECMWF-Interim important biases in mean and variance of ECMWF analyzed evaporation WHOTS decorrelation scale for evaporation large relative to reanalysis grid scale not spatial mismatch daily averages r2r2 Precipitation: WHOTS net evaporative regime under core of Trade Winds Sean Whelan (WHOI) Rainfall Has small space-time scales Not well-observed from space Poorly represented in NWP model-reanalyses Trend removed from net cumulative P-E (the freshwater needed to balance must arrive from higher latitudes directly via surface currents, or be entrained into the mixed layer at ALOHA after transport in the upper pycnocline) WHOTS mixed layer salinity compared to WHOTS freshwater fluxes S(t) has some correspondence with local freshwater flux anomalies comparison of MLD from WHOTS mooring (colored lines) with estimates from high-resolution CTD profiles during HOT and WHOTS cruises Price-Weller-Pinkel mixed layer model forced with WHOTS air-sea fluxes WHOTS mooring mixed layer depth Need to bring in 3-D advective contributions interannual variations of eddies enhanced shear vertical mixing lateral eddy transports?? rotation of currents due to eddies WHOTS Sustained, collaborative, interdisciplinary science Air-sea fluxes, ocean-truthing atmospheric reanalyses, forcing and benchmarking ocean models Creating a high-resolution surface and upper ocean climatology including atmospheric forcing and carbon variables Facilitating research on eddies and ecosystem dynamics Impacts as part of a global observational network Assessing ocean changes (incl. C) and enabling climate predictions Atmosphere and ocean modeling Ocean Reference Stations Institutions & agencies needed to sustain infrastructure Sustained multi-institutional collaboration (WHOI, UH/SOEST, PMEL) Collaborative funding, NOAA, NSF and SOEST OceanSITES data management (setting metadata standards) WHOTS met/fluxes and subsurface incl. V though mid-2011 Thank You! WHOTS data are available viaftp://ftp.ifremer.fr/ifremer/oceansites/ ftp://data.ndbc.noaa.gov/data/oceansites/ Salinity Trends on Isopycnals Freshening ( m) Max /decade large! The freshening signal is very robust on isopycnal surfaces, filtering out noise from internal waves Smaller signal, but correlated with O 2 and nutrients Large upper pycnocline decadal variation since 2007 has disrupted mid-pycnocline trend 20-Year Long Thermohaline ALOHA Warming over much of upper ocean (x m!) Peak warming m (S max ), not at surface Cooling below 700 m Salinity increasing in upper 200 m Freshening in the thermocline (z)S(z) 0.4 C/decade 0.16/decade m density ; density Stratification in upper ocean! deeper mixing productivity Salinity trends on Isopycnals water on heavier isopycnals comes from farther away (psu/50 yrs) 24 25 Durack and Wijffels (2010) 27.5 Salinity Trends on Neutral Surfaces Durack and Wijffels (2010) zonally averaged salinity trends (psu/ ) 70 S70 N Subduction of ML salinity anomalies + anomalous subduction Analysis of Argo float data Sasaki et al. (2010, GRL); see also Ren and Riser (2010, (Deep-Sea Research II Suginohara memorial issue) Evolution of a fresh/cold anomaly Updated and adapted from Dore et al. (2009, Proc Natl Acad Sci USA 106:12235 ) pH of surface ocean ALOHA pH trend vs depth Annual, interannual, decadal and longer term changes in surface forcing, mixing, and advection Local and remote physics are crucial, not just pCO 2, temperature and biology pH DIC This point was made in the paper Maximum not in surface layer Integrated net heat flux (T*MLD) Clearly, cold and salty water must be transported into the surface layer at ALOHA by some combination of horizontal advection, upwelling, and vertical mixing to provide a mean balance how much do they contribute to interannual decadal variations?