The aim is to measure structure and drift in polar-cap ionospheric layers in order to test current theories and models, identify unexplained behaviour and develop theoretical explanations. The polar cap ionosphere is affected significantly by conditions in the solar wind, so it is important to understand this outer region of our environment, not just to extend our knowledge, but to improve space weather predictions. Specific outcomes will include advances in understanding and predicting the behaviour of the polar cap ionosphere, development of new ionospheric radar techniques, improved models of the polar cap electric field and training of postgraduate students.
This project is also related to ASAC project 128 (ASAC_128).
The particular MOCNESS system from which these CTD data came is one of three net systems. The MOCNESS-1 has nine rectangular nets (1m x 1.4 m) which are opened and closed sequentially by commands through conducting cable from the surface (Wiebe et al., 1976). In this system 'the underwater unit sends a data frame, comprised of temperature, depth, conductivity, net-frame angle, flow count, time, ... number of open net, and net opening/closing, to the deck unit in a compressed hexadecimal format every 2 seconds and from the deck unit to a microcomputer every 4 seconds. Temperature (to approximately 0.01 deg C) and conductivity are measured with SEABIRD sensors. Normally, a modified T.S.K.-flowmeter is used. Both the temperature and conductivity sensors and the flowmeter are mounted on top of the frame so that they face horizontally when the frame is at a towing angle of 45deg. Calculations of salinity (to approximately 0.01 o/oo S), potential temperature (theta), potential density (sigma), the oblique and vertical velocities of the net, and the approximate volume filtered by each net are made after each string of data has been received by the computer. (Wiebe et al., 1985) In addition, data were collected from three other sensors attached to the frame: the Transmissometer, the Fluorometer, and the Downwelling light sensor. A SeaBird underwater pump was also included in the sensor suite.
Any person making substantial use of a data set must communicate with the investigators who acquired the data prior to publication and anticipate that the data collectors will be co-authors of published results. This extends to model results and to data organized for retrospective studies.
The data here are intended for scholarly use by the academic and scientific community, with the express understanding that any such use will properly acknowledge the originating investigator. Use or reproduction of any material herein for any commercial purpose is prohibited without prior written permission from the Biological and Chemical Oceanography Data Management Office.