5/7/07 ETM Chase Practice Cruise: Cruise Report
June 5, 2007
Ship: R/V Forerunner
Captain: Gene Bock
Scientific crew: Michael Wilkin (Chief technician), Lydie Herfort (Chief scientist), Bill Howe, and Sergey Frolov
Documents: Original Cruise Plan and Cast log as recorded on board
Loading time: 8:00 am local time
Start time: 8:45 am local time
Last cast: 16:11 pm local time
Bottom = 1 m from bottom, except for Stations 15-28 where bottom is river bed.
First location determined in the morning of 5 June 2007, using model DB 16.
Coordinates of first location = -123 x 46.8’, 46 x 12.78’ (-123.78, 6.213), at 9:00 am PST.
According to the model this should be 0 PSU surface & 5 PSU bottom. Unfortunately, this site was determined in PST time and not local time (which incorporate saving day). So, 9:00 am PST = 10:00 am local time.
Internet connection failed at 8:58 am and 1:00 pm local time and at several other times.
From station 1 to 2, speed of the boat = 6 nots
Initial cast was too salty at the bottom (13 PSU) so we sailed to a new location 1 km upriver in the channel to -123.46.8, 46.13.16.
Need to ask for Cruise Planner to give data in all lat./long. units. (degrees, decimal, minutes).
Problem with seeing the OBS data from CMOP website! 11:10 am (local time) Charles says that this is now fixed and was related with problems with O2 sensor.
St 4 cast 1, rather good layer of salt wedge while for casts 2 & 3, are extremely thin layers of salt wedge (about 1 m).
St 5 cast 1, which is more westward, is again a thicker layer of salt wedge.
St 7 cast 1, very large layer of salt wedge at 2 PSU (about 15 m at 2 PSU).
St 8 cast 1, the boat drifted quite a lot so take much care for analysis of this cast, for example the bottom depth varied form 18-30 m whist doing this CTD cast.
After station 9 cast 1, we decided that instead of trying to get to a site which would be 0 PSU throughout the water column, it would be more interesting to sail seawards and sample the incoming high salinity (perhaps 20 PSU).
Station 11, cast 1, we measured at the edge of the south channel (water depth = 8.7 m) because there were several large ships in the channel itself at this location.
Stations 19 & 20, high salinity intrusion at the very bottom.
This cruise highlighted the need to clarify the difference between the residual salt from the previous tide and the new salt wedge with coming in with the new flood tide.
Need to define clearly what is a salt wedge, for example station 13 cast 1, this is the salty water (8.5 PSU) coming in although the surface water is about 2 PSU.
From Stations 15 until the last one, we actually touched the river bed, so the bottom value is not as for the rest 1 m from river bed but true river bed value.
Values depths given by ADCP and CTD are not the same values with the ADCP giving a depth about 4 m shallower that that of the CTD.
Products Required for August
Some requirements for the cruise mapper application emerged:
- Display gridlines on the map showing rough lat/lon coordinates
- Allow distance calculations using the map by clicking on two diferent points
- Allow users to type in arbitrary lat/lon coordinates and have those positions appear no the map
- Lat/lon coordinates should be in degrees and decimal minutes (or allow choice of units)
- Allow time zone to be changed
- We could not get profile information to display. Waypoints were created properly, but no profile popped up. could have been due to browser settings
- The ship's current position and past trajectory should be a selectable layer.
Bill will write down a set of "Cruise activities" based on the cruise plan for August and based on conversations with the chief scientists. For each activity, we will identify the critical products required to support it. These products will then become the on-ship requirements for the August cruise. Any products not on this list may or may not be available for August in order to reduce scope.