SCICEX Hydrographic Data, 1997 and 1998

Introduction:

The Scientific Ice Expeditions (SCICEX) Program is a series of 
scientific field operations within the Arctic Ocean using US Navy 
operational submarines as sampling platforms. The 1997 SCICEX cruise 
aboard the USS Archerfish was the third in the series, and the 1998 
SCICEX cruise aboard the USS Hawkbill was the fourth. The project is  
multi-disciplinary in nature with a broad range of measurement goals 
held by the multiple PI's. The overarching goal is to characterize 
the upper layers of the sampled regions of the Arctic Ocean as completely 
as possible. The measurements described here sampled the upper 800m of 
the ocean with submarine launched conductivity, temperature and depth 
probes.

Data Acquisition and Processing:

The profile data were collected using Sippican model 306700-1 Under-Ice 
Submarine-Launched Expendable Conductivity, Temperature and Depth probes.  
These probes are launched from the submerged submarine, rise under their 
own buoyancy to a depth of about 15 m, then release from their buoyant 
components and free-fall.  Profiles are measured during the free-fall period 
while the probes remain connected to the shipboard datalogger via signal 
cables.  Probe depths are computed based on a known fall rate, temperature 
(T) and conductivity values are measured by probe sensors and returned as 
functions of depth, and salinity (S) is computed from these values.  The 
design accuracy of the probes is 0.02 degrees C in T, 0.05 practical salinity 
units (psu) in S and 5 m in depth except for the uppermost 5 m of the record 
(15-20 m depths), where data are unreliable during equilibration of the 
probe sensors and are typically discarded.  

Data collection software was Sippican MK12 for Windows, version 1.3.  
Subsequent processing was completed with MATLAB (www.mathworks.com) 
running under Windows NT, using the SEAWATER library, a collection of 
oceanographic functions in the MATLAB language developed by the Commonwealth
Scientific and Industrial Research Organisation (CSIRO) in Hobart, 
Australia. Derived variables include pressure (in db, calculated from depth 
and latitude), potential temperature (in degrees C), sigma-t (a representation 
of density in kg/m^3), and sigma-theta (sigma-t calculated with potential 
temperature).

Data Set Coverage:

The 1997 profiles were collected from just north of Fram Strait along 
a transect to the Alaskan Coast, westward along the shelf break to the 
Laptev Sea and back into the interior of the basin, crisscrossing the 
Canadian basin and eventually ending near the Bering Strait.  Distance 
between profiles was variable.  Profile data were generally collected to 
a depth of 1000 m at 1-m intervals in the vertical.  Data were collected 
between September 3 and October 2, 1997. The data are available in ASCII 
text format along with the accompanying documentation in Microsoft Word 
format in the zip file scicex97_xctd.zip.

The 1998 profiles were collected along a transect following the shelf break 
in the Chuckchi Sea, crossing the Arctic Ocean into the interior of the 
Nansen Basin then crossing the Amunsen Basin to the eastern terminus of 
the Lomonosov Ridge.  The cruise track then extended into the Makarov and 
Canada Basins and over the Chuckchi Cap.  Distance between profiles was 
variable.  Profile data were generally collected to a depth of 1000 m at 
1-m intervals.  Data were collected between August 1 and September 2, 1998.
The data are available in ASCII text format along with the accompanying 
documentation in Microsoft Word format in the zip file scicex98_xctd.zip.

An online interactive map, powered by Environmental Systems Research 
Institute's (ESRI's) ArcIMS version 3.1, is available on the product 
Web site. The map displays the spatial distribution of data collection
points, and may be used to select profiles of interest and to view 
data.

Contacts and Acknowledgments:

PI:		Robin D. Muench
		Earth & Space Research

Data Contact:	John T. Gunn
		Earth & Space Research

ONR Grant:	N00014-96-1-0855