1. EPIC 2001: 10N, 95W TAO Buoy, Brown, New Horizon Cruise-avg C-band radar rain rate O(10) differences over 150 km 146 km Study of upper ocean budgets of heat and salt Weakly stratified pycnocline Measurements focused ~20 m and below Cruise averaged rain rate from (P-E) and evaporation rate agreed with ship mounted rain gauges

2. EPIC Rain Comparisons: Rainfall rate, rr(mm h -1 ), and cumulative rain, CR (m) Optical Rain Gauge Brown Optical Rain Gauge New Horizon C-Band Radar – 10 km avg Brown Cumulative rainfall from ship a factor of 2 larger than rain radar averaged over 10 km Precipitation rates from rain radar average over 100 km radius was 1/3 of ship averages Rain rate inferred from freshwater budget Agreed with ship measurements Differed from rain radar by factor of 2 (10 km avg) or 3 (100 km avg)

3. Sea Snake, SeaSoar, and MMP(profiler) Time Series Sea Snake Sea Soar MMP RESIDUAL PATCHES Frequency of occurrence of large SSS excursions from sea snake much greater than SeaSoar or MMP TEMPORAL VARIABILITY Cruise dS/dt from sea snake significantly greater than that from shallowest SeaSoar/MMP measurement

4. Ship-based Measurement Consideration Characterize SSS variability: near-surface to 100 m Surface forcing functions Characterize spatial and temporal variability Underway salinity and temperature profiling: 4-6 kts Skin SST via IR radiometer Pumped sea snake: 10 cm Towed SSP (Surface Salinity Profiler) 10 cm to 1 or 2 m Through hull TSG – Thompson (Brown): 2 m, 3 m, 5 m Scanfish/towed CTD/MVP: 10-150+ m

5. Ship-base measurements (continued) Surface fluxes Direct covariance Downwelling/upwelling SW/LW radiation Precipitation Spatial scales: Rain radar Point rain accumulation: disdrometers, capacitance Surface wave field: Ship-based radar New Doppler radar being developed at APL-UW WAMOS Mapping thermal patches: ship & balloon IR cameras

6. Interagency Interest: ONR Physical Oceanography – Scott Harper Near-surface salinity/DYNAMO Waveglider innovations Air-sea fluxes Near-surface T/S profiles FLIP Air-Sea Fluxes Detailed near-surface T/S: 0-10+ m Dissipation? Platform for NSF proposals?

7. FLIP: Floating Instrument Platform San Diego to 10N 125W: 1440 nmi (10 day transit at 6 knts) 35 day duration without underway replenishment Replenish (food and fuel) from research vessel Tug considerations

8. SPURS2: Autonomous Platform Considerations Persistence and collectively large footprint Capture seasonality of precipitation cycle Measure impact of episodic and patchy rain events Processes controlling evolution of near-surface salinity Waveglider near surface measurements Air-sea fluxes: spatial variability (validate w/ mooring) Pumped stinger sampling: SSS/SST 0-1m Passive Acoustics: Rain rate and wind speed Platforms: Argo, Seaglider, MLF Central mooring

9. Autonomous Platforms: Lagrangian Component Tandem platforms Wave- or seaglider following Mixed-layer float Or follow patch of fresh water EPIC hypothesis: Heavy rain with anticyclonic eddy Follow eddy/low SSS patch identified by mooring Seaglider – turbulence Waveglider – SSS profile and air-sea fluxes EPIC (3-week average) SSH TRMM