Physical Properties and Physical Properties and Forcings in an Estuarine Forcings in an Estuarine

SystemSystem

2013 PICES Summer School2013 PICES Summer SchoolGroup 4Group 4

Matthew, Daniel, Jingsong, Matthew, Daniel, Jingsong, Chorong, Joocheul, Morgaine, Chorong, Joocheul, Morgaine,

Polina, AmyPolina, Amy

Topic: Physical Topic: Physical OceanographyOceanography

Question:Question:

Describe the time dependence in Describe the time dependence in physical properties (temperature, physical properties (temperature, salinity, dissolved oxygen) and salinity, dissolved oxygen) and explain what forces these.explain what forces these.

Yaquina Bay: 2 Sites, 1.5 Yaquina Bay: 2 Sites, 1.5 DaysDays

Mooring w/ CTD

CTD casts

MooringMooring

Winds – upwelling favorableWinds – upwelling favorable

Y14 Sample TimesY14 Sample Times

(m)

Aug. 20 Aug. 21

Δh = 5cm

Δh = 46cm

Y14Y14

TrendsTrends

Day 1: Day 1: – well-mixed throughoutwell-mixed throughout

Day 2: Day 2: – well-mixed below 3mwell-mixed below 3m– lower T, higher S, lower DO (rel. to day lower T, higher S, lower DO (rel. to day

1)1)

No apparent tidal influence in CTD No apparent tidal influence in CTD cast data at Y14 stationcast data at Y14 station– sampling on opposite sides of tidal peak sampling on opposite sides of tidal peak

(not at extremes)(not at extremes)– Day 2: 2Day 2: 2ndnd sample in the slack tide sample in the slack tide

HypothesesHypotheses

1: Well-mixed water column due to 1: Well-mixed water column due to low summertime river flow relative to low summertime river flow relative to tide flow.tide flow.

2: Day 2 had more upwelled ocean 2: Day 2 had more upwelled ocean water at Y14.water at Y14.– stronger tide, wind from the Nstronger tide, wind from the N– T decreased, S increased, DO decreasedT decreased, S increased, DO decreased

Vertical velocity differencesVertical velocity differencesare smallare small

Potential issuesPotential issues

Non-verticality of castNon-verticality of cast– drift of boat during samplingdrift of boat during sampling– strong currents strong currents CTD line angled CTD line angled

Non-shared datumNon-shared datum– depth relative to surfacedepth relative to surface– up to 0.5m change in depth (flood vs. up to 0.5m change in depth (flood vs.

ebb)ebb)

ConclusionsConclusions

Upwelled water is identifiable at both Upwelled water is identifiable at both stations on Day 2stations on Day 2

River water is not a strong influence: River water is not a strong influence: low flow rates low flow rates strong mixing strong mixing well-mixed water column (no salt well-mixed water column (no salt wedge) wedge)

CTD sampling must be better spaced CTD sampling must be better spaced along tidal cycle to make conclusions along tidal cycle to make conclusions about effects of the tide with only about effects of the tide with only discrete samplingdiscrete sampling

Thank youThank you

GRACIAS!!!!GRACIAS!!!! GAMSAHAMNIDA!!!!GAMSAHAMNIDA!!!! ARIGATOU!!!!ARIGATOU!!!! DANKE SCHOEN!!!!DANKE SCHOEN!!!! CHEERS MATES!!!CHEERS MATES!!! SHYE SHYE!SHYE SHYE! SPACIBO!!!SPACIBO!!!

Backup SlidesBackup Slides

Day 1: Flood tideDay 1: Flood tide

Day 1: Ebb tideDay 1: Ebb tide

Day 2: Flood tideDay 2: Flood tide

Day 2: Ebb tideDay 2: Ebb tide

Tidal cycles in flow-through Tidal cycles in flow-through

Temperature decrease & salinity Temperature decrease & salinity increase as flood tide comes inincrease as flood tide comes in

Temperature & salinity relatively Temperature & salinity relatively constant for samples around max constant for samples around max tide pointtide point

Group1Group1

Group2

Group3