Arabian Sea mixed layer dynamics experiment

91 Pages·2006·3.52 MB·English

Woods Hole Oceanographic Institution WHOI-95-14
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Arabian Sea Mixed Layer Dynamics Experiment
Mooring Deployment Cruise Report
R/V Thomas Thompson Cruise Number 46
1995
14 April- 29 April
DOCUMENT
by
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Woods Hole Oceanographic
Richard A. Trask Instiution
Robert A. Weller
William M. Ostrom
July 1995
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Upper Ocean Processes Group
Woods Hole Oceanographic Institution
Woods Hole, Massachusetts 02543 U.S.A.
UOP Technical Report 95-4
WHOI-95-14
UOP 95-04
Arabian Sea Mixed Layer DYnamics Experiment Mooring DeploYment
Cruise Report
R/V Thomas Thompson Cruise Number 46
14 April- 29 April 1995
by
t'- DOCUfvl¡ENT
Richard P. Trask
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Robert A. Weller L H:UI):: :1\ R~ v
William M. Ostrom Woods Hole Oceanographic
Instiution
Woods Hole Oceanographic Institution
Woods Hole, Massachusetts 02543
July 1995
Technical Report
Funding was provided by the Offce of Naval Research through
Grant No. NOOOl4-94-1-0161.
Reproduction in whole or in part is pennitted for any purpose of the United States
Government. This report should be cited as Woods Hole Oceanog. Inst. Tech. Rept.,
WHOI-95-14.
Approved for public release; distribution unlimited.
~~ri Approved for Distribution:
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:ID-~: .- Philp L. Richardson, Chair
rCil Department of Physical Oceanography
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Abstract
An aray of surace and subsurace moorigs were recovered and redeployed in the Arabian
Sea to provide high quality time series of local forcing and upper ocean curents, temperatu, and
the ocean's response to the monsoonal forcing
conductivity in order to investigate the dynamcs of
characteristic of the area. The moored aray was first deployed durng RN Thomas Thmpson
cruse number 40 and then recovered and redeployed durg cruse number 46.
One Woods Hole Oceanogrphic Institution (WOI) surace moorig, two Scripps
Institution of Oceanography (SIO) surace moorings and one of two University of Washigton
(UW Profiing Current Meter moorings were recovered and redeployed durg RN Thoma
Thompson cruse number 46. The aray was deployed in October 1994 as par of the Offce of
Naval Research fuded Arabian Sea experient. Two six-month deployments were planed. The
moorings were deployed at 15.5°N 61.5°E (WOn, 15.7°N 61.3°E (SIO), 15.7°N 61.7°E (UW,
and 15.3°N 61.7°E (UW.
The WHOI surace mooring was outftted with two meteorological data collection systems.
A Vector Averaging Wind Recorder and an IMT system made measurements of wind sped and
direction, sea surace temperatue, ai temperatue, short wave radiation, long wave radiation,
barometrc pressure, relative hundity and precipitation. Subsurace ins.tentation included
Vector Meaurg Current Meters, Multi-Varable Moored Systems, conductivity and temperatue
recorders and single point temperatue recorders.
Expendable bathytermograph (XT) data and conductivity-temperatue-depth (CT) data
were collected whie in transit to the site and at moorig locations. A surace drftr with near-
surace (.25 to 2.5 meters depth) temperatue aray was deployed for thee 12 hour periods durg
the cruse in close proximity to the WHOI surace buoy. Acoustic Doppler Cuent Profùer and
shipboard meteorological data were collected thoughout the cruse.
Ths report describes in a general maner the work that took place durg the RNThma
Thmpson cruise number 46 which was the moorig tuaround cruse for the moored aray
program. A detailed description of the WHOI surace moorig and its instrentation is provided.
Information about the XBT and Cl data and near-surace temperatu data collected durg the
cruse is also included.
2
Table of Contents
Page
List of Figures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
List of Tables ..............................................................................................5
Section 1: Introduction...................................................................................6
Section 2: The Moored Ary ................... . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. 10
A. WHOI Surace Moorig.... .................. ................ .................. ......10
B. WHOI Instrentation.. . .. .. . . . .. .. . . .. . . . . .. .. .. ... .. .. .... . . .. . . . . .. .. . . . .. .. .. . .. 14
1. Meteorological Instrumentation... .................. ........... ............. ...... 14
a. Vector Averaging Wind Recorder.. .. ... . . .. .. . . . . .. . .. .. . . . . .... . . .. . .. .. 14
b. IMT Meteorological System. . . .. .. .. .. '" ... .. .. .... . .. .. .. .. .. ... ... . . .. 18
c. Stand Alone Relative HumdityfTemperatue Inst. ...................... 20
2. Sub-Surace Instrmentation ........ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . 21
a. Buoy Tension Recorder\......... ............. ...... ...... ........ .......... 21
b. Sub-surace Argos Transmitter ............................................ 21
c. SEACA T Conductivity and Temperatue Recorders. . . . . . .. ... . . .... . .. 21
d. Dissolved Oxygen Sensor. . .. . . .. ..... ... .. .. .. .. . . .... .. .. .. .... ... . . . . . .. 24
e. Brancker Temperatue Recorders. .. .. . .. .. . . .. .. .. ... .. .. . . . . ... . .... . . ... 24
f. Miatue Temperatue Recorder (M)... .. ... . . ... .. . . . . . .. . .. .. .. .. ... 26
g. WHOI Vector Measurg Curent Meters ....... ............. ......... ...26
h. USC Multi-Varable Moored System .....................................27
i. LDEO Multi- Varable Moored System. . ... . . . .. . . ... .. . .. . . . .. . . . . .. .. . .. 27
j. Tracor Applied Sciences Bio-Acoustic Instrent...................... 27
Section 3: Ancilar Intrentation.. .. . . . .. . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . .. . . . . . . . 28
A. WHOI Shipboard Meteorological System.......................................... 28
with Near-surace Temperatu Aray........... ... ...............29
B. WHOI Drifter
Section 4: Cruise Chronology. .... .......................................... ..... ........ ............31
Acknpwledgments.............. ......................................................................... 43
References................................... ............................................................. 43
Appendi 1: Cruse Parcipants .. ....... ............ ...... ....... '" ....... ..................... ... 44
Appendi 2: XBT Information..... . .. .. .. ... . . .. .... ... .......... . .. ........... . ..... .. . .. .. .. .. ...45
Appendi 3: CTD Positions.. .... .. .. '" ......... .... .. .. ..... .. ... .. ........... . . .. .. .. ... . . .. .. ... 60
Appendi 4: Instrument Summary.................................................................. 64
Appendi 5: Wind Dirction Comparson Tests...... . . ... ..... .. ...... . ..... .. .... .. .. . . . .. ... .. 67
Appendi 6: WHOI Instrent Time Marks ..................................................... 70
Appendix 7: WHOI VMCM Record Format. ..................................................... 72
Appendi 8: TN 046 Deck Layout Drawings.. .. .... .. . . .. .. .. . .. . .. .. . . ....... .. . . .. .. . . ..... . .. 73
Appendi 9: Deployment and Recovery Inormation About WHOI
Instrmentation of the UW PCM South Mooring ........................ 83
Appendi 10: Antifoulg Coatig Tests ........ . . . . . . .. . . . . . . . .. . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . 85
3
List of Figures
Page
Figue 1: Arabian Sea mooring cruise schedule. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Figue 2: Cruise track and mooring locations........ .......... ......................... ....... ....8
Figue 3: Arabian Sea moored aray instrment locations...................................... 11
Figue 4: WHOI surface mooring schematic................ .......... ......... .................. 12
Figue 5: Near-surace temperatue aray on the WHOI Arabian Sea 1 discus buoy. ......25
Figue 6: Driftng temperature aray used during TN 046......................................30
Figue 7: Schematic of the SIO nortern surace moorig. . . . . .. .. ... .. . . .. . .. .. . .. . . . . . . .. . .. 33
Figue 8: Schematic of the UW southern Profilng Curent Meter moorig. ................ 35
Figue 9: WHOI surace mooring acoustic release surey. ............. ....................... 41
Figue A2-1: A plot of XBT locations durg TN 046. ........................................46
Figue A2-2: Overplot of outbound XBT profies 1-10. ................................. ...... 48
Figue A2-3: Overplot of outbound XBT profies 11-20....................................... 49
Figue A2-4: Overplot of outbound XBT profies 21-30....................................... 50
Figue A2-5: Overplot of outbound XBT profies 31-41...................................... 51
Figue A2-6: Overplot of inbound XBT profies 1-10.......................................... 54
Figue A2-7: Overplot of inbound XBT profiles 11,12, and 14-21. .........................55
Figue A2-8: Overplot of inbound XBT profiles 22-31. . .. . ....... .. .. ..... . . . . .. .. . .... .. .... 56
Figue A2-9: Overplot of inbound XBT profiles 32-37 and 39-42. .......................... 57
Figue A2-1O: Overplot of inbound XBT profiles 43-52. . . . . .. .. .. . . . .. .... . . . . . .... .... . .. .. .. 58
Figue A2-11: Overplot of inbound XBT profies 53, and 55-60. .............................59
Figue A5-1: VA WR and IMT wind diection comparson tests
conducted at WHO!. ........................................................... 68
Figue A5-2: VA WR and IMT wind diection comparson tests
conducted in Muscat, Oman....... ....... ... . . .. .... . . . . .. .. .. . . .. .. ... . . . .. .. 69
Figues A8-1 to 9: Deck layout drawings showing the rotation of moorig equipment
for each phase of the cruise.. ....................................... ...... .74-82
Figu AlO-1: Antifoulg pait test locations on the Arabian Sea 1 discus buoy hull. . . . . . . 87
Figue A10-2 Antifoulg pait test locations on the Arabian Sea 2 discus buoy hull. . . . . . . 88
4
List of Tables
Page
Table 1: Mooring deployment infonnation from Arabian Sea 1................................9
Table 2: Moorig deployment infonnation from Arabian Sea 2. .. . .. .. . . . . .. .. .. ... .. . . . . . . . . .9
Table 3: Arabian Sea 2 Moored Array Instrumentation........................................ 15
Table 4: VA WR Sensor Specifications.. .... .. .. . '" . . .. .. . .. .. .. ... .... . .. ....... . .. .. .. . .. . ... 16
Table 5: IMET Sensor Specifications............................................................19
Table 6: !MET Modules deployed during Arabian Sea 2...................................... 19
Table 7: IMET Modules deployed during Arabian Sea 1.....................................20
Table 8: Sensors mounted on the Arabian Sea 1, WHOI surace buoy
and their respective elevations. .... ............ ...... ............ ........ ..........22
Table 9: Sensors mounted òn the Arabian Sea 2, WHOI surace buoy
and their respective elevations....... ...... ............ ........ ........ ... .........23
Table 10: Temperatue recorders used with the drftng temperatue aray
and their respective depths. ........ ............. ...... ...... .... .......... ..... ....31
the five WHOI VMCMs on the first deployment
Table 11: Noiral depth of
of the southern profiing current meter mooring................................. 36
Table A2-1: Outbound XBT deployment times, positions and correspondig
bucket temperatues from TN 046. ...............................................47
Table A2-2: Inbound XBT deployment ties, positions and correspondig
bucket temperatues from TN 046. ............................................... 52
Table A3-1: CTD stations taken during TN046.....................................................61
5
Section 1: Introduction
The RI Thomas Thompson cruise number 46 (TN046) depared Muscat, Oman, on
the cruse was to recover and redeploy one Woods
14 April 1995 at 0345 UTC. The purose of
Hole Oceanographic Institution (WOn surace moorig, two Scripps Institution of
Washigton (UW subsurace
Oceanography (S10) surace moorings and one University of
profiing curent meter (PCM) mooring. Al of the moorigs were par of the Office of Naval
Research funded Arabian Sea experiment. This was the second of thee cruses planed for the
experient. The final recovery of all moorigs is planed for October 1995. The moorig
deployment schedule is shown in Figue 1.
The cruse involved personnel from the Woods Hole Oceanographic Institution, Scripps
Institution of Oceanography, University of Southern Calorna (USC), Lamont Dohert Ear
Observatory (LDEO), Japan Marne Science and Technology Center (JAMSTEC), and University
lists the cruse parcipants. Figue 2 shows the cruse track and the
of Washington. Appendix 1
moorig locations. Table 1 lists the deployment and recovery dates for the firtsettg of the
moored aray as well as the sureyed anchor positions. Table 2 lists the deployment dates and
positions of the moorigs that were redeployed durng TN046.
Whe enroute to and from the moored aray at the beging and end of the cruse hourly
expendable bathytermograph (XT) data were collected. The XBT positions and severa
composite plots of the XBT profiles appear in Appendi 2. A tota of 35 conductivity-temperatue-
depth (CTD) casts were made throughout the cruise. Casts 6 though 17 and 24 to 35 were done
in a to yo fashion between the surface and 50 meters depth as the ship maitaied position near a
drftg temperatue aray. Most of the other profies were done in conjunction with a parcular
moorig site. Appendix 3 contais a listig of the CTD positions, sta ties and maum depth
of the stations.
Ths report has, in addition to ths introduction, thee sections. The second section
primary describes the WH01 moorig and the instrentation that was deployed on the WH01
moorig. The thd section describes several pieces of ancilar equipment used durg the cruse.
The four section is a chronology of the entie cruse.
6
i I i
1994 I
I '
1995
Oct I Nov Dec i Jan I Feb! Mar ¡ A.pr I May ¡ Jun I Jul Aug i Sep I Oct!
R/V T.Thompson R/V T.Thompson R/V T.Thompson
:¡
D
TN 040 TN 046
First 6 Month Setting of WHOI
and SIO Surface Moorings
I Second 6 Month Setting of WHOI
i
! and SIO Surface Moorings
¡
i Second 6 month deployment of UW ;
First 6 month deployment of UW
Southern PCM Mooring : Southern PCM Mooring
One Year Deployment of UW Northern PCM Mooring
Figue 1. Arabian Sea moorig cruse schedule.
7
°
570E 5g0E 530E 552°goN
260rrS E 51 ° E
240N
240N
~++ ++ +
+ +
++ +
+ +
+ + +
+ +
+
+
+
220N + +
220N
+
+
+
+
+
+
+
200N + 200N
+ +
+
+
+
+ : outbound
+
+ +
+ +
+++
+
++ +
+
1ô ON ++ + 1 Ô ° N
+
inbound +++
. r; _
+.
+ +
+. +
+
+
+ +
+ *
16 ° N + 16 ° N
+
+ .. ..
..
.. ..
moored array
140N
14 ° N
550E 57° E 5g0E 51 ° E 530E 5SoE
Figu 2: Cruse trck and moorig loctions.
8
Table 1. Arabian Sea 1 Mooring Deployment Information
Moorig Deployment Date Recovery Anchor
(WOI Moor. and Time Date and Position
Reference No.) Time
WHOI 15 October 1994 15° 30.04'N
20 Apri 1995
Discus Buoy ~1048 UTC ~ 0105 UTC 61 ° 29.99'E
(969)
SIO Northern 17 October 1994 15° 43.53'N
16 Apri 1995
Buoy ~0723 UTC ~ 0359 UTC 61 ° 15.94'E
SIO Southern 18 October 1994 15°.16.53'N
23 Apri 1995
Buoy ~0649 UTC ~ 0221 UTC 61° 16.11'E
UW Nortern 23 October 1994 Not Recovered 15° 43.90'N
PCM Durng TN 046 61 ° 44.53'E
(972)
UW Southern 19 October 1994 15° 16.37'N
18 Apri 1995
PCM 61 ° 44.07'E
(970)
Table 2. Arabian Sea 2 Mooring Deployment Information
Moorig
Deployment Date Anchor
(WOI Moor. and Time Position
Reference No.)
WHOI 1995 150 30.07'N
22 Apri
Discus Buoy ~ 0939 UTC 610 30.05'E
(975)
SIO Northern 17 April 1995 150 43.39'N
Buoy ~ 0715 UTC 610 15.86'E
SIO Southern 24 April 1995 15°.16.52'N
Buoy ~ 0715 UTC 16.12'E
610
UW Nortern 23 October 1994 15° 43.90'N
PCM 44.53'E
610
(972)
UW Southern 1995 16.11'N
25 Apri 150
PCM ~ 0650 UTC 43.82'E
610
(976)
9