Bremerhaven - Northern North Sea - Bremerhaven

05.09. - 17.09.1998

The EU project PROVESS aims at a better understanding of PROcesses of Vertical Exchange in Shelf Seas. An important aspect within the large variety of relevant mechanisms is the autumnal breakdown of the stratification as it occurs in large parts of the Northern North Sea between September and December. It involves heat loss to the atmosphere, wind mixing, exchanges across and deepening of the thermocline, and overturning in the surface mixed layer.

A specific experiment has been designed to study these processes in detail including biological consequences such as mixing of nutrient-rich deeper water into the photic zone creating favourable conditions for phytoplankton blooms in autumn.

The study area has been chosen in the Northern North Sea where tidal currents are weak, and water depths in the order of 100 m are large enough to clearly separate the surface mixed layer and the bottom boundary layer. Excluding effects by Atlantic inflows and by the Norwegian Costal Current a site centered at 59°20'N, 1°E has been selected for the experiment.

In view of the rather long period and the event-like character of transitions from stratified to mixed conditions the observations involve 4 ships from September to November and an array of 18 moorings for that time. This cruise report deals with the first expedition in this series with the general goal to provide the initial conditions prior to or during the onset of the cooling phase and stormy wind season.

The scientific aims of the cruise were

- to assess the hydrographic conditions in the study area by means of CTD-surveys including the distributions of chlorophyll-fluorescence and turbidity.

- to perform biological and chemical sampling for phytoplankton, photosynthetic pigments, particulate organic matter and dissolved oxygen.

- to observe temporal changes of the stratification and of the nutrient situation during the first phase of the autumnal changes of the summer stratification.

- to study the turbulence regimes in the water column above, across and beneath the thermocline to derive turbulence parameters for modelling of the vertical mixing processes.

A further major task for this expedition was the deployment of numerous moorings to measure time series of meteorological, hydrographical and chemical quantities. The moorings will be recovered at the end of the experiment in November.

RV "Valdivia" left the port of Bremerhaven on September 5, 1998, about midday. Mooring work began in the early morning of September 7, and continued for 4 days during daylight hours. The nights in between were used for the planned CTD work on a box with sides of about 50 km around the main site. Except for one day of a bit rough conditions work was accompanied by moderate winds and wave heights.

In the late afternoon of September 10 the ship anchored on a water depth of about 100 m in the vicinity (1.5 km) of the central mooring array. Regular CTD-casts and turbulence measurements were carried out every 1.5 hours until September 14, about midday.

A second CTD survey followed, this time on two sections perpendicular to each other with the center at the main site. Making use of the favourable weather conditions on the next morning the survey was interrupted to recover moorings C and F. The last CTD station was perfomed on September 15 at midnight.

"Valdivia" arrived back in Bremerhaven on September 17 in the early afternoon, one day earlier than planned.

4. Work achieved

4.1 Moorings (J. Humphery)

A total of nineteen mooring-packages were deployed from the "Valdivia" during the above cruise. They included surface buoys, single-point (pop-up) sub-surface moorings and benthic landers (bed-frames) in waters which are generally a little over 100 m deep. A heavily-instrumented site centred close to 59° 20'N, 1° 00'E is complimented by secondary sites extending up to 40 km North and East. Unless stated otherwise, all the moorings are due for recovery in early November by RRS "Challenger".

Moorings E and F were deployed to measure near-surface currents, with two Inter Ocean S4 electromagnetic current meters suspended at 4m and 10m below the surface on each. Mooring E was a J-rig (so called because of the shape which the mooring takes up in the water); the current-meters should have enough endurance to last until November. Mooring F is an eta-rig (so called because it takes the shape of the Greek letter eta when in the water); this mooring is thought to have a better dynamic performance than the J-rig, but history has shown that it does not survive very well. It has been recovered at the end of the "Valdivia" cruise and carries two high-capacity Inter Ocean S4 current meters working in fast mode.

Mooring G carries a 2.6m toroidal buoy which supports a meteorological package supplied by NIOZ, Texel, Netherlands.

Mooring H is a Waverider buoy measuring heave only: the signal is processed into spectra which are transmitted to the ARGOS satellite system together with position-information.

Mooring I is a 1.9m toroid carrying a flourometer, a transmissometer and a nitrate analyser at a nominal depth of 1m to provide environmental data. Another fluorometer, supplied by NIOZ, Texel, Netherlands, is carried at a depth of about 14m.

Sub-surface mooring strings:

These moorings were of standard pop-up form with spherical sub-surface floats and 0.5 tonne chain anchors. In-line buoyancy (glass spheres) was fitted to protect the instruments and releases from trawling activity where necessary.

Moorings J1 and J2 are, respectively, midwater and near-bed environmental moorings, carrying fluorometers, current meters, transmissometers and nutrient analysers. J1 carries its array (with a standard nitrate analyser) at about 50 m (ie, in mid-water), and J2 carries its array at about 10m above the bed. J2 carries a double nutrient package: as well as a standard nitrate system, it also carries a prototype silicate analyser.

Mooring K was not deployed because a faulty SUV6 data logger could not be repaired in time for the cruise.

Moorings L, R and S all carried thermistor strings and miniature temperature loggers to investigate the breakdown of the thermocline with the approach of winter. Additionally, mooring L carried an INFLUX current meter for the Alfred Wegener Institute, Bremerhaven; this device combined a current meter with fluorometer and backscatter sensors.

Seabed landers (bed-frames):

Wherever possible, seabed frames were used to house recording instruments: these are less susceptible to trawling-damage. They included acoustic doppler current profilers (at 150kHz and 1.2MHz), bottom-pressure recorders (BPRs) and the STABLE system. Submersible ARGOS beacons are fitted to the frames where possible.

Moorings A and U carried an RDI 150kHz broadband ADCP and pressure recorder on each frame (POL instruments). Moorings B and C carried RDI 1.2MHz (short-range) Workhorse ADCPs: that on mooring B is owned by UWB, is sampling slowly and will be recovered in November, while the POL instrument on mooring C is sampling quickly and has been recovered at the end of the "Valdivia" cruise.

Mooring D is the large benthic instrument called STABLE (Sediment Transport And Boundary Layer Equipment). This carries flow-sensors to measure turbulent and mean current strengths and directions, pressure recorders, acoustic backscatter sediment profilers, compass, pitch, roll and temperature sensors. Additionally, a new fast (8Hz) temperature and conductivity system is being used; the frame also carries three simple sediment traps.

Mooring V carries an RDI 150kHz narrow-band ADCP (RVS instrument).

Moorings X and Y are small frames which carry pressure recorders for water-depth and tidal signals. They are at the extreme ends of the experimental array, respectively at 40 km East and North of the main site.

4.2.1 CTD and optical equipment

The basic instrument carrier to measure stratification and optical quantities in the water column was a Seabird Mini Rosette water sampler with 12 bottles, 2.5 litres each. This unit was modified to carry a Seabird 911 plus CTD, an optical instrument with sensors for the fluorescence of chlorophyll and yellow substance together with a sensor for Mie backscattering of light. The outputs of the optical sensors used the analogue channels of the CTD for digitizing and data transmission. Additionally a self-contained PAR instrument was fitted to the rosette frame.

Seabird CTD

The sensors of the 911 plus unit had been calibrated at the factory prior to the cruise. As we have several years of experience with the sensors we are confident to rely on the calibration without further checks by water sampling.

The accuracies specified are

conductivity: ± 0.003 mS/cm pressure: ±0.35 dbar

temperature: ± 0.002°C

Optical sensors

The following 3 optical sensors are integrated in one housing. The unit is manufactured by Dr. Haardt, Optik Mikroelektronik, and the sensors have the following specifications within the ranges selected for this cruise:

Light source: 2 Xenon flash tubes

Filters for the detection of

This self-contained instrument is manufactured by Ingenieurbüro Marcel Kruse. It has a cosine diffusor and records radiation in a range of 400 - 700 nm using a diode array. Depending on light intensities integration time ranges between 15 ms to 16 s for one spectrum. Storage capacity is 90 spectra. Programming and readout is done by a laptop computer.

References

- Seabird Electronics INC., 1808, 136th Place NE, Bellevue, WA98005, USA. CTD system, Operating and Instruction Manual

- Dr. Haardt Optik Mikroelektronik, Alter Kieler Weg 19, 24245 Kleinbarkau, Germany. Back Scat Fluorometer Model 1302 Chla/Yell/Aut 2R/Mo, Instruction Manual

- Ingenieurbüro Marcel Kruse, Informationstechnik, Am Walde 12, 27616 Stubben,
Germany. Instrument pamphlet

4.2.2 Hydrographic surveys

The purpose of two CTD surveys was to assess the hydrographic situation at the beginning of the Northern Experiment. The first was done on sections forming a box of 76 x 51 km around the central position at 59°20'N, 001°00'E. Station spacing was about 5 km in the order of the tidal excursion in the area. As this work was carried out during the nights in between mooring laying, the interruptions have to be considered when assessing the respective sections.

The second survey formed a cross with its centre at the main site of the moorings. The positions and times of the CTD stations are listed in chapter 7. It also contains the series of profiles measured at the anchor station.

The ship anchored at 59°19.2'N, 001°02.1'E on a water depth of 98 m for studying the temporal evolution of the thermocline and its microstructure.

At regular intervals of 1.5 hours one CTD cast and a series of 8 turbulence profiles were obtained. Biological and chemical samples were collected from time to time, and PAR spectra were also measured. Occasionally the CTD was placed in the thermocline to record internal waves.

4.3.1 Microstructure measurements with the MICSOS-probe (H. Baumert, J. Post)

Introduction

Vertical exchanges are controlled principally by the turbulence characteristics of the water column with three regions of special significance in the surface mixed layer, the pycnocline and the benthic boundary layer. For that reason one of the main targets of PROVESS is the determination of turbulence properties by means of innovative measurements at two locations in the North Sea. During the first cruise of the Northern North Sea Experimentî (PROVESS N-1) these measurements were made with the MICSOS- or MST-Probe.

The MICSOS Profiler

The MICSOS Profiler is a free sinking or rising multi-parameter probe equipped with high resolution microstructure (temperature) and turbulence (current shear) sensors and precision CTD sensors. To control disturbing vibrations of the profiler itself, an internal vibration sensor is incorporated. The turbulence is measured by an aerofoil-shaped shear probe with a time constant of 4 ms. The high resolution temperature probe is based on a thermocouple with a time constant of about 5 ms. Data resolution of all sensors is 16 bits. The sampling rate of the profiler is 1 kHz. The data are transmitted via a fast link to a computer on the mother ship. The descent rate of the profiler can be adjusted by removable weights.

The MICSOS-System consists of a profiler, a special neutrally-buoyant cable, a data and power supply interface and a logger. The system is completed by a data evaluation software package.

Field Work

During the VALDIVIA Cruise No. 174 the MICSOS profiler was used to collect data about the microscale water stratification and turbulence characteristics around the main pycnocline.

For that reason a series of about 50 sets of vertical profiles, each consisting of 8 casts, and therefore in toto about 400 casts, were measured from about ten meters below the sea surface down to a water depth of 80 to 90 meters. The uppermost ten meters cannot be evaluated due to the strong influence of the ship on the hydrodynamic fields of interest. The measurements were carried out while the ship was anchoring on a permanent position in the centre of the target area (59( 20` N and 001( 00` E) within a water depth of about 100 meters. The main pycnocline was in a water depth of about 40 meters. When starting with the microstructure measurements the pycnocline was sharp. During the period of observations it changed it`s shape slightly with frequently occurring stair cases.

The MICSOS measurements were made between Thursday 10th at 16:00 UTC (18:00 local time) and Monday 14th of September 1998 at 13:00 UTC. The sets of profiles were made at 90 minute-intervals. Each set of casts took about 45 minutes. One cast produced about 4.2 MBytes of data so that for the whole MICSOS campaign about 2.5 Giga-Bytes of data were recorded. At the beginning of each set of microstructure measurements, a vertical CTD-profile was acquired with a SEABIRD probe, and so the MICSOS-CTD and SEABIRD data could be compared and correlated. Furthermore, the SEABIRD probe was used to carry out longer-term measurements (time series) at the centre of the pycnocline (at about 41 metres) to gain information on internal waves.

The series of MICSOS turbulence measurements was successful. At first glance it can be stated that:

- a valuable set of microstructure and turbulence data have been collected;
- the dynamic evolution of the pycnocline was recorded, and
- the CTD time series sometimes revealed the occurrence of internal waves.

5. Biological and chemical sampling (P. Tett)

Rosette bottles were used to take water samples for phytoplankton, photosynthetic pigments, particulate organic matter (POM), dissolved oxygen (DO) and dissolved nutrients. The 'main site' refers to samples taken at 59°19'-20'N, 01°01'-02'E, close to the moorings I, J1 and J2, which were equipped with fluorometers and nutrient analysers. The aims of this work were: (1) to obtain data for the calibration of these moored instruments, especially the fluorometers; and (2) to commence a time-series of biological observations at this study site.

Methods & Results

(1) Phytoplankton. Samples of about 200 ml were preserved with acid Lugol's iodine for microscopic analysis at Napier University.

date (Sep. 98)	CTD stn-event	depth(s), m	notes
7	1-15	6	SML at 59°20N, 1°42'E
9	49-69	5	SML at main site
10	73-94	30	DCM at main site
11	76-120	30	DCM at main site
13	76-206	6, 35	SML & DCM at main site
15	99-266	7, 35	SML & DCM at main site

(2) Photosynthetic pigments. About 2 litres were filtered through 47 mm GF/F filters, which were then extracted overnight in buffered 90% acetone. Optical densities were measured against a 90% acetone blank in a Shimadzu UV-1202 spectrophotometer using 50 mm pathlength sub-micro cells. Measurements were made at 750, 665, 664, 647, 630, 510 and 480 nm, and, after addition of 2 drops 1N HCl, at 750 and 665 nm. Concentrations of chlorophyll a and pheopigments were calculated by the Lorenzen method, of chlorophylls a, b and c by the Trichromatic equations (with coefficients of Jeffrey & Humphrey, 1975), and of total carotenoids from the o.d. at 510 and 480 nm.

Measurements suffered from high and somewhat variable blanks, and the s.d. of replicate chlorophyll a estimated by the Lorenzen method was too high (0.19 mg m-3) for these values to be considered reliable. The standard deviations of replicate estimates of chlorophyll a by the Trichromatic method (0.05 mg m-3) and of carotenoids (0.06 mg m-3) were acceptable. A summary of results for the main site (all samples between 9 and 15 September) is given below. The s.d. values in the table are a measure of the spread of the observations, and in most cases exceed the measurement error deduced from replicates.

Depth (range), m	chloro-phyll a	mg m-3	carotenoids	mg m-3	no. samples	comments
	mean	s.d.	mean	range
5 - 9	0.48	0.11	0.34	0.22	13	SML, surface fluorometers
28-36	0.76	0.16	0.50	0.09	9	DCM
50-54	0.12	0.06	0.04	0.04	11	50 m fluorometer
90-94	0.07	0.05	-0.02	0.07	11	BBL, 90 m fluorometer

Water samples were fractionated on 14 and 15 September, using 'Nucleopore'-type 5 mm pore-size filters, 47 mm diameter, placed on top of GF/F filters. About two-thirds of pigments in SML samples passed through the 5 mm pores and were retained by the GF/F filter. The proportion was closer to a half in the case of DCM samples.

(3) Particulate Organic Matter. About 1 litre of water was filtered through pre-baked 25 mm GF/F filters, which were then stored over desiccant in darkness for analysis at the Dunstaffnage Marine Laboratory.

date (Sep. 98)	CTD stn-event	depth(s), m	notes
9	53-74	5,50,90	main site
11	76-120	5,30,50,90	main site
13	76-206	6,35,53,93	main site

(4) Dissolved Oxygen. The micro-Winkler method was used. Glass bottles of about 160 ml were filled, via a silicone rubber tube, from the rosette bottles, and the contents fixed in the usual way with solutions of manganous sulphate and alkaline iodide. The contents were later acidified and titrated with a solution of sodium thiosulphate using the method of Bryan et al. with a Dosimat titrator and a photo-optical end-point detector; the thiosulphate was standardised against a known solution of potassium iodate. The standardisation s.e. was 0.4%.

Some problems were encountered with the sample titration end point, and some data were lost as a result of this. These difficulties were due to insufficient dissolution of the precipitate before titration. It was found that addition of 1.1 ml (rather than 1.0 ml as per recipe) of 5M sulphuric acid completely dissolved the precipitate in all cases, and resulted in a satisfactory end point. Disregarding samples which gave a poor end point (and for which data will not be reported), the s.d. of replicate oxygen measurements was 0.7 mM or 0.23% saturation.

date (Sep. 98)	CTD stn-event	depths, m (for good data)	notes
13	76-195	6,36,52,82,97	main site
13	76-213	5,20,31,50,80,97	main site
14	76-231	5,21,36,51,81	main site
14	76-237	58,63,82,87,95	main site
14	76-238	7,11,15,19,22,26,30,35,39,43,46,52	main site
15	99-265	11,23,32,42,52,63,72, 82,93	main site

(5) Dissolved Nutrients. GF/F filtered water was preserved with mercuric chloride for analysis for nitrate and silicate at the Dunstaffnage Marine Laboratory.

date (Sep 98)	CTD stn-event	depths, m	notes
9	53-074	4, 90	main site
15	99-266	93,52,36,7	main site

Discussion of results

Figure 1 shows the relationship between the voltage output of the chlorophyll channel of the 'Dr Haardt' BackScatter-Fluorometer, and water-sample chlorophyll as calculated using the Trichromatic equations.

Although a quadratic equation fitted somewhat better, a linear regression of voltage (V) on chlorophyll concentration (X, in mg m-3) provides a preliminary calibration for this fluorometer:

V = a + b.X ===> X = (V - a)/b

where the coefficients were:

a = 0.05, s.e.= 0.02 Volts
b = 0.64, s.e.= 0.03 Volts (mg chl a m-3)-1

Profiles showed well developed boundary layers and thermocline, as exemplified in Fig 2. for 14 September at the main site.

During the 7 days (September 8-15) of intensive sampling, chlorophyll averaged about 0.5 mg m-3 in the Surface Mixed Layer. Some (but not all) profiles showed a Deep Chlorophyll Maximum in the upper thermocline with concentrations sometimes exceeding 0.75 mg m-3. In the lower thermocline and in the Bottom (or Benthic) Boundary Layer, chlorophyll concentrations did not exceed 0.25 mg m-3. The pigment size fractionation measurements showed that most chlorophyll-containing particles in the SML were less than 5 mm in diameter. This suggests that the phytoplankton here was a Summer association of small cells supported by recycled nitrogen. (Had an Autumn bloom of diatoms already commenced, it is likely that most chlorophyll would have been retained on a 5 mm pore size filter).

The profile of oxygen % saturation in Fig. 2 shows that there has been consumption of oxygen below the SML during the period when the sub-surface water was (as it continues) isolated from the atmosphere. When Apparent Oxygen Utilisation (AOU) was plotted against water temperature, a straight line was obtained (Fig. 3), implying that the oxygen profile was dominated by the effects of physical mixing and boundary exchange. That is, most remineralisation, and concommitant use of oxygen, probably occurred in or on the sea-bed, or in the BBL, rather than in the thermocline.

It may be presumed that the AOU in deep water corresponds to nutrient enrichment: the maximum AOU of 40 mM implies the release in deep water of 4 - 5 mM of nitrate since stratification began. Dissolved silica might also be expected to have increased during this time. Thus, future deepening of the SML will entrain water containing nutrients, including dissolved silica. This may give rise to an Autumn bloom of diatoms if other conditions (especially, mean irradiance in the SML) allow.

Other points

PAR spectra were collected on most days at about (local) noon, from depths of 30, 25, 20, 15, 10, 5 and 2 m. These spectra will be analysed to give spectra of the diffuse attenuation coefficient, for use with numerical simulations of phytoplankton growth.

It is possible that some of the chlorophyll-containing organisms in the pycnocline, were capable of some vertical migration. It will thus be interesting to examine the time-series of CTD-fluorescence profiles made at the anchor station (CTD 76), in order to find midwater peaks in fluorescence and to ascertain if they move vertically according to a diel cycle. Because of variability in pynocline depth due to internal waves, it will be best to plot fluorescence against density: vertical migration will be evidenced by shifts in the position of peaks relative to density.

6. Preliminary results

The stratification found at the Northern Site still exhibits the typical characteristics of summer conditions. This is also true for the phytoplankton association found in the area. From considerations based on oxygen measurements it is concluded that future deepening of the surface mixed layer will entrain water containing nutrients. This is one of the necessary conditions for an autumn bloom of diatoms.

There was a considerable variability of the stratification of temperature and salinity in space as well as in time. The above profiles display the range of shapes of the thermocline found in the area. The causes for the more or less steep gradients are not yet known. They have occured on neighbouring stations 5 km apart or at the same station in the course of time. Based on the large data sets of CTD and turbulence measurements collected on this and the future cruises - and together with the mooring data - it will be an exciting analysis to find the solution.

7. CTD station list

(Table generated by BODC)

Sample CTD profiles at station 54 and 17

File Name	Water depth	Date/Time(UTC)	LAT deg N	LAT min	LON deg E	LON min	Additional information
1_006		07/09/1998 06:00	59	20.50	1	40.40	PAR
1_015		07/09/1998 08:02	59	20.30	1	42.29	PAR, BOTTLES
2_019	102	07/09/1998 11:50	59	19.96	1	25.57	PAR
3_020	114	07/09/1998 12:44	59	17.31	1	39.62
4_021	112	07/09/1998 13:12	59	15.00	1	40.89
5_022	113	07/09/1998 13:37	59	12.49	1	40.07
5_023	113	07/09/1998 12:45	59	12.49	1	40.07
6_024	113	07/09/1998 14:10	59	9.91	1	40.08
6_025	113	07/09/1998 14:18	59	9.91	1	40.09
7_026	113	07/09/1998 14:47	59	7.47	1	40.04
8_027	114	07/09/1998 15:15	59	4.98	1	40.17
9_028	114	07/09/1998 15:47	59	2.48	1	40.14
10_029	114	07/09/1998 16:35	59	0.05	1	40.26
11_030	117	07/09/1998 17:07	59	0.00	1	35.08
14_031	119	07/09/1998 17:36	59	0.05	1	30.22
15_032	123	07/09/1998 18:03	58	59.96	1	25.22
16_033	125	07/09/1998 18:38	59	0.00	1	20.00
17_034	127	07/09/1998 19:09	59	0.00	1	19.11
18_035	121	07/09/1998 19:40	59	0.00	1	10.15
19_036	128	07/09/1998 20:10	59	0.00	1	5.08
20_037	120	07/09/1998 20:40	59	0.00	1	0.14
21_038	130	07/09/1998 21:11	59	0.00	0	55.06
22_039	133	07/09/1998 21:41	59	0.00	0	50.12
23_040	126	07/09/1998 22:14	59	0.00	0	45.07
24_041	127	07/09/1998 22:58	58	59.92	0	40.02
25_042	154	07/09/1998 23:30	58	59.91	0	35.04
26_043	144	08/09/1998 00:05	58	59.93	0	30.03
27_044	152	08/09/1998 00:36	58	59.93	0	25.00
28_045	150	08/09/1998 01:10	58	59.90	0	20.00
29_046	135	08/09/1998 01:42	59	2.52	0	20.11
30_051	104	08/09/1998 09:00	59	19.77	1	0.39	RIG_A
35_054	115	08/09/1998 17:54	59	27.56	0	45.11	RIG_Y
36_055	130	08/09/1998 21:12	59	5.01	0	20.15
37_056	121	08/09/1998 21:44	59	7.56	0	20.32
38_057	136	08/09/1998 22:18	59	10.59	0	20.19
39_058	137	08/09/1998 22:49	59	12.51	0	20.01
40_059	147	08/09/1998 23:20	59	15.02	0	20.05
41_060	135	08/09/1998 23:52	59	17.51	0	20.12
42_061	138	08/09/1998 00:26	59	20.00	0	20.11
43_062	138	08/09/1998 00:58	59	22.52	0	20.12
44_063	138	08/09/1998 01:31	59	25.01	0	20.00
45_064	135	08/09/1998 02:04	59	27.53	0	20.05
46_065	128	08/09/1998 02:35	59	27.47	0	25.03
47_066	126	08/09/1998 03:10	59	27.50	0	30.00
48_067	116	08/09/1998 03:38	59	27.52	0	35.06
49_069		08/09/1998 07:48	59	19.36	1	0.68	BOTTLES, RIG_I
53_074		08/09/1998 18:12	59	19.68	0	59.85	BOTTLES,RIG_J2
54_075	116	08/09/1998 19:45	59	27.68	0	35.32
55_076	118	08/09/1998 20:12	59	27.51	0	40.00
56_077	116	08/09/1998 20:40	59	27.57	0	45.00
57_078	116	08/09/1998 21:05	59	27.50	0	50.00
58_079	112	08/09/1998 21:32	59	27.51	0	55.00
59_080	109	08/09/1998 21:55	59	27.51	1	0.00
60_081	107	08/09/1998 22:25	59	27.51	1	5.12
61_082	105	09/09/1998 22:51	59	27.47	1	10.07
62_083	100	09/09/1998 23:26	59	27.34	1	15.03
63_084	104	09/09/1998 23:51	59	27.39	1	20.02
64_085	108	10/09/1998 00:19	59	27.25	1	25.13
65_086	106	10/09/1998 00:53	59	27.29	1	30.19
66_087	111	10/09/1998 01:18	59	27.48	1	35.03
67_088	116	10/09/1998 01:47	59	27.47	1	40.07
68_089	116	10/09/1998 02:17	59	25.00	1	40.02
69_090	115	10/09/1998 02:49	59	22.50	1	40.02
70_091	114	10/09/1998 03:18	59	20.02	1	39.82
73_094	102	10/09/1998 10:17	59	19.29	1	2.08	BOTTLES,PAR,RIG_J1
76_099		10/09/1998 17:39	59	20.00	1	2.14
76_100		10/09/1998 18:00	59	20.00	1	2.13
76_102		10/09/1998 19:00	59	20.00	1	2.10
76_104		10/09/1998 20:00	59	19.91	1	2.12
76_106		10/09/1998 21:00	59	19.92	1	2.09
76_108		10/09/1998 22:30	59	19.98	1	2.02
76_110		11/09/1998 00:00	59	19.86	1	2.16
76_112		11/09/1998 01:30	59	19.83	1	2.09
76_114		11/09/1998 03:00	59	19.79	1	2.10
76_116		11/09/1998 04:30	59	19.79	1	2.10
76_118		11/09/1998 06:00	59	19.79	1	2.10
76_120		11/09/1998 07:30	59	19.79	1	2.10	BOTTLES
76_122		11/09/1998 09:00	59	19.79	1	2.10
76_123		11/09/1998 09:07	59	19.79	1	2.10	time-serie at 43 m
76_125		11/09/1998 10:32	59	19.79	1	2.10
76_126		11/09/1998 10:41	59	19.79	1	2.10	time-serie at 43 m
76_128		11/09/1998 12:02	59	19.85	1	2.19	PAR
76_129		11/09/1998 12:25	59	19.85	1	2.19	time-serie
76_131		11/09/1998 13:35	59	19.82	1	2.20
76_132		11/09/1998 13:40	59	19.82	1	2.20	time-serie at 44 m
76_134		11/09/1998 15:00	59	19.82	1	2.14
76_136		11/09/1998 16:30	59	19.82	1	2.14
76_138		11/09/1998 18:08	59	19.82	1	2.14
76_140		11/09/1998 19:30	59	19.82	1	12.17
76_142		11/09/1998 21:00	59	19.82	1	12.17
76_144		11/09/1998 22:30	59	19.83	1	2.18
76_146		12/09/1998 00:00	59	19.83	1	2.20
76_148		12/09/1998 01:30	59	19.84	1	2.15
76_150		12/09/1998 03:00	59	19.76	1	2.17
76_152		12/09/1998 04:30	59	19.78	1	2.08
76_154		12/09/1998 06:00	59	19.80	1	2.08
76_156		12/09/1998 07:30	59	19.80	1	2.08
76_157		12/09/1998 07:40	59	19.80	1	2.08	time-serie
76_159		12/09/1998 09:00	59	19.80	1	2.08
76_160		12/09/1998 09:10	59	19.80	1	2.08	time-serie
76_162		12/09/1998 10:30	59	19.80	1	2.08
76_163		12/09/1998 10:40	59	19.80	1	2.08	time-serie
76_165		12/09/1998 12:00	59	19.80	1	2.04	BOTTLES
76_167		12/09/1998 13:30	59	19.79	1	2.06	PAR
76_168		12/09/1998 13:35	59	19.79	1	2.06	time-serie
76_170		12/09/1998 15:00	59	19.78	1	2.03
76_171		12/09/1998 15:10	59	19.78	1	2.03	time-serie
76_173		12/09/1998 16:30	59	19.78	1	2.03
76_174		12/09/1998 16:40	59	19.78	1	2.03	time-serie
76_176		12/09/1998 18:00	59	19.78	1	2.03
76_177		12/09/1998 18:05	59	19.78	1	2.03	time-serie
76_179		12/09/1998 19:30	59	19.78	1	2.03
76_180		12/09/1998 19:35	59	19.78	1	2.03	time-serie
76_182		12/09/1998 21:00	59	19.78	1	2.03
76_183		12/09/1998 21:05	59	19.78	1	2.03	time-serie
76_185		12/09/1998 22:33	59	19.79	1	2.05
76_187		13/09/1998 00:02	59	19.81	1	2.17
76_189		13/09/1998 01:30	59	19.78	1	2.13
76_191		13/09/1998 03:00	59	19.76	1	2.09
76_193		13/09/1998 04:30	59	19.77	1	2.07
76_195		13/09/1998 06:00	59	19.77	1	2.07	BOTTLES
76_197		13/09/1998 07:30	59	19.77	1	2.07
76_198		13/09/1998 07:40	59	19.77	1	2.07	time-serie
76_200		13/09/1998 09:10	59	19.77	1	2.07
76_201		13/09/1998 09:20	59	19.77	1	2.07	time-serie
76_203		13/09/1998 10:30	59	19.79	1	2.07
76_204		13/09/1998 10:40	59	19.79	1	2.07	time-serie
76_206		13/09/1998 12:03	59	19.75	1	2.07	BOTTLES,PAR
76_208		13/09/1998 13:15	59	19.78	1	2.13	PAR
76_209		13/09/1998 13:32	59	19.79	1	2.13
76_211		13/09/1998 15:00	59	19.77	1	2.12
76_213		13/09/1998 16:30	59	19.77	1	2.04	BOTTLES
76_215		13/09/1998 18:00	59	19.77	1	2.04
76_217		13/09/1998 19:30	59	19.77	1	2.04
76_219		13/09/1998 21:00	59	19.77	1	2.04
76_221		13/09/1998 22:30	59	19.77	1	2.04
76_223		14/09/1998 00:00	59	19.81	1	2.08
76_225		14/09/1998 01:30	59	19.77	1	2.13
76_227		14/09/1998 03:00	59	19.77	1	2.14
76_229		14/09/1998 04:30	59	19.76	1	2.08
76_231		14/09/1998 06:10	59	19.76	1	2.08	BOTTLES
76_233		14/09/1998 07:30	59	19.76	1	2.08
76_235		14/09/1998 09:00	59	19.76	1	2.08
76_237		14/09/1998 10:33	59	19.55	1	2.13	BOTTLES
76_238		14/09/1998 10:56	59	19.55	1	2.13	BOTTLES
76_239		14/09/1998 12:00	59	19.50	1	2.16	PAR
76_241		14/09/1998 13:30	59	19.53	1	2.16
76_242		14/09/1998 14:30	59	19.54	1	2.14
77_243		14/09/1998 18:00	59	34.90	1	1.89
78_244		14/09/1998 18:27	59	32.47	1	1.87
79_245		14/09/1998 18:57	59	29.95	1	1.96
80_246		14/09/1998 19:32	59	27.36	1	1.87
81_247		14/09/1998 19:54	59	27.39	1	2.09
82_248		14/09/1998 20:25	59	22.43	1	1.88
83_249		14/09/1998 20:53	59	19.84	1	2.05
84_250		14/09/1998 21:19	59	17.50	1	1.77
85_251		14/09/1998 21:50	59	14.97	1	1.78
86_252		14/09/1998 22:25	59	12.52	1	1.92
87_253		14/09/1998 22:56	59	9.97	1	2.05
88_254		14/09/1998 23:28	59	7.46	1	2.03
89_255		15/09/1998 00:03	59	4.98	1	1.81
90_256		15/09/1998 00:43	59	2.44	1	2.24
91_257		15/09/1998 01:19	59	0.50	1	2.31
92_258		15/09/1998 04:30	59	18.52	0	19.76
93_259		15/09/1998 05:00	59	18.48	0	24.71
94_260		15/09/1998 05:30	59	18.50	0	29.96
95_261		15/09/1998 06:00	59	19.00	0	35.00
99_265		15/09/1998 12:35	59	19.64	1	2.28	BOTTLES
99_266		15/09/1998 12:48	59	19.64	1	2.28	BOTTLES,PR
100_267	161	15/09/1998 15:30	59	18.48	0	35.11
101_268	131	15/09/1998 16:10	59	18.51	0	39.89
102_269	129	15/09/1998 16:40	59	18.44	0	45.04
103_270	125	15/09/1998 17:10	59	18.38	0	49.98
104_271	112	15/09/1998 17:35	59	18.38	0	55.02
105_272	105	15/09/1998 18:00	59	18.47	1	0.00
106_273	97	15/09/1998 18:26	59	18.43	1	5.03
107_274	113	15/09/1998 18:43	59	18.36	1	9.91
108_275	107	15/09/1998 19:15	59	18.39	1	15.07
109_276	108	15/09/1998 19:40	59	18.38	1	20.00
110_277	96	15/09/1998 20:11	59	18.31	1	25.03
111_278	102	15/09/1998 20:34	59	18.50	1	30.02
112_279	109	15/09/1998 20:59	59	18.41	1	35.03
113_280	112	15/09/1998 21:23	59	18.27	1	39.94
114_281	114	15/09/1998 21:52	59	17.47	1	45.00

Last Updated on 15/10/1998
By gmon

8. Participants

Name	Institution	Address
Ballard, Norman Charles G.	Proudman Oceanographic Laboratory	Bidston Observatory, Birkenhead Merseyside, L43 7 RA United Kingdom
Banaszek, Anthony	"	"
Humphery, John Douglas	"	"
Dr. Baumert, Helmut	Hydromod Sci. Cons.	Bahnhofstraße 52 22880 Wedel/Holstein Germany
Boyd, Joyce	Southampton Oceanographic Centre	Empress Dock Southampton SO14 3ZH UK.
Damm, Michael	Alfred-Wegener-Institut	Columbusstraße 27568 Bremerhaven, Germany
Prof. Dr. Krause, Gunther Chief Scientist	"	"
Ohm, Klaus	"	"
Dr. Holtsch, Kurt	Sea and Sun Technology GmbH	Erfurter Str. 2 24610 Trappenkamp Germany
Post, Johannes	Hydromod Service GmbH	Lister Meile 27 30161 Hannover
Dr. Tett, Paul	Napier University Dept. of Biol. Sciences	10 Colinton Road Edinburgh EH10 5DT Scotland, UK.
Wynar, John	RVS, Southampton Oceanographic Centre	European Way Empress Dock Southampton SO14 3ZH UK.