July 2007 ETM Chase REU Cruise

17 July 2007
Low tide: 10:30 AM
High tide: 5:00 PM


Activity Location Time
1 Plan DoSE Monday 15:00/Tuesday 06:00
2 Arrive Astoria Tuesday 08:30-09:00
3 Freshwater Sample
4 casts
near Tongue Point 10:00-11:00
4 Seawater Sample
4 casts
near red26 (TBD Tuesday morning) 13:30? (need an estimate of travel time. This is traveling against the tide)
5 Intrusion and ETM
wait for salt wedge/ETM
near bridge (TBD Tuesday morning) 14:30-17:00



I. Lydie and Pete: (a) Obtain three samples from "fresh" water (0 psu) near the surface and (b) three samples from "salty" water (>30 psu) near the surface, and (c) one sample in the "ETM peak", defined below.

II. Suzanna and Kira: (a) Obtain a series of samples crossing the ETM (the maximum turbidity while in the salt wedge). Samples near the bottom are essential, but (b) a "depth profile" (5-9 samples obtained with the air pump between 10-19 m depth at the same time and place) is preferred. Also (c) obtain one sample from "fresh" water halfway down the water column, and (d) one from "salty" water halfway down the water column.

III. Joseph and Solomon: (a) Take several casts near the forward edge of the salinity intrusion (the 2 psu isosurface). (b) Preferred: Obtain a series of casts starting with bottom salinity < 0.5 psu and ending with bottom salinity > 4 psu, such that the 2 psu isosurface can be inferred via interpolation.

IV. Bill and Nick: Qualitatively assess the task-specific utility of products and auxiliary information included in the cruise dashboard. (Under heavy development.)


1. (06:00 July 17) Select a starting location of the salt intrusion and wedge crossing based on DB16 7-day forecast under a conservative estimate of the forward edge of the salinity intrusion (i.e. slightly upstream from 1 psu bottom salinity, given the flood tide).

1a. (06:30) Leave DoSE.
1b. (08:30) Arrive at Tongue Point.

2. (09:30) Leave port and immediately take a fresh water sample for Goal Ia.

3. Collect saltwater sample
Key product: Individual Cast Profile
Sail to Red26 and take a cast.
- If bottom salinity < 30 psu, continue to take casts until bottom salinity > 30 psu.
- If/When bottom salinity > 30 psu, take a sample.

4. Salinity intrusion and ETM crossing.
Key product: Individual Cast Profile
Key product: Cast Profile Timeseries
- (Qualitatively or quantitatively assess model skill -- Joseph. Key product: Model/Data comparisons.)

a. Sail to selected starting location and take a cast.
- If bottom salinity > 1 psu, sail upstream 1 km and take another cast. Continue until bottom salinity < 1 psu.
- If bottom salinity < 1 psu, remain on station.
b. Continue taking casts at least every 10 minutes, as the salinity intrusion (2 psu isosurface) and then the salt wedge (containing the ETM) flow past boat. If three consecutive casts do not show significant increases in salinity, sail downstream 0.5 km.
c. Continue until either turbidity has increased and then decreased and bottom salinity > 20 psu, or until bottom salinity > 25 psu.

5. Return to port.