Examination and evaluation of real-time oceanographic data on the internet
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and OCEAN BASINS |
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ATMOSPHERE DYNAMICS |
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Introduction to Questions on Ocean Salinity:
- The questions are outlined in three tables ( first page , last page . this page)
- they require examination of various maps of ocean salinity variations
- annual average global ocean salinities.
- salinity of the deep ocean
- latitudinal variations in ocean salinity
- regional influences on ocean salinity
- temporal variation in ocean salinity
- Reminder: you should submit your answers via oncourse .
| Ocean Salinity (contd.) | pt | |||||||||||||||||||||||||||||||||
| Salinity and Salt Contents | ||||||||||||||||||||||||||||||||||
| Global salinity is a function of the total salt concentration in the oceans. Q.13-16 explore the possibility for major episodes of evaporite formation to trigger significant changes in ocean salinity . | ||||||||||||||||||||||||||||||||||
| 13. | The total amount of dissolved salts in the ocean is 5 x 1022 g. This produces an average ocean salinity of approximately 35‰. How much salt (in g) would need to be removed (e.g. deposited as evaporites) to decrease average ocean salinity by 1‰? HINT |
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| 14. | If evaporitic minerals have an average density of 2.5g/cm 3, what volume of salt would need to be removed to achieve the decrease in salinity of 1‰ considered in Q.13? HINT |
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| 15. | Suppose that all of the salt from Q.14 was deposited in
the Mediterranean Sea. How thick a layer of salt would be formed?
HINT
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| 16. | The total thickness of evaporitic layers in the Mediterranean can exceed 200m, and average 30m throughout the basin. Would the deposition of such a thick layer of salt have affected global salinity? HINT |
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| Surface Salinities of the Bay of Bengal | ||||||||||||||||||||||||||||||||||
| Examine surface salinity for the Bay of Bengal using the Levitus atlas ( Atlas Guidelines ) using the guidelines for the display below, which help to set the parameters for the figure, with the box numbers referring to the data settings for the display. Use the ANNUAL maps as described in the guidelines. | ||||||||||||||||||||||||||||||||||
| 17. | From a regional map of global sea salinity estimate the
surface salinity at the following locations in the Bay of Bengal in the
following map display:
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(ii) |
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(iii) |
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| 18. | Describe how surface salinity varies with latitude in the Bay of Bengal? HINT |
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| 19. | Explain the principal cause of the surface salinity variations in Q. 17 and 18. HINT | 2 | ||||||||||||||||||||||||||||||||
| Temporal Variations in Surface Salinities | ||||||||||||||||||||||||||||||||||
| The Levitus atlas of oceanographic physical
and chemical is accessable online and is here used to examine monthly variation
in surface salinities in specific regions. The instructions for use of the atlas are provided on a separately ( Atlas Guidelines ). Use the SEASONAL profiles, selecting salinity and using the guidelines for the display below help to set the parameters for each figure, with the box numbers referring to the sites on the display. In addition an extra box entitled time will appear below the uppermost box (depth). By selecting the buttons for successive seasons (Jan-Mar, Apr-Jun, etc.) an entire seasonal cycle of salinities can be viewed. |
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| 20. | Describe the seasonal changes in salinity for the following
regions in terms of values at different locations within the region and
the timing of their variation throughout the seasonal cycle. Reset the color scale - boxes #6 and #7 - to help provide better color contrasts: display 20‰ to 40‰ for parts (i) and (ii), and 0‰ to 40‰ for part (iii). |
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box (in
guide
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| (i) | the Bay of Bengal |
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| (ii) | Gulf of St. Lawrence |
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| (iii) | Russian Arctic |
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4* | |||||||||||||||||||||||||||
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Department of Geological Sciences,
1001 E. Tenth Street, Bloomington, IN 47405-1403
Phone: (812) 855-5582 Last updated: 22 October 2002
Comments: simon@indiana.edu
Copyright 2000, The Trustees of Indiana University