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Apr 8, 2016 5:00 EST

ASSESSING THE EXTENT OF INCREASED SALINITY

iCrowdNewswire - Apr 8, 2016

SUMMARY

Data off the south shore of Oahu, Hawaii, show that salinity has increased by 0.7 over the past 35 years.  We will use the Wave Glider to reoccupy a portion of the Hawaii-Tahiti Shuttle Experiment and study the causes of this salinity increase.   Dramatic water changes, like this increase in salinity, affect ocean circulation, weather and the global climate system.  An example of the repercussions of dramatic/large water mass changes is the warm water “blob” off the western coast of North America.  This anomaly spans 1000 km by 1000 km and is 4.5 F warmer than average for the region.  It is believed that this “blob” is the cause of California’s ongoing massive drought.

The causes and ramifications of increased salt content in the Hawaiian Islands region are currently poorly understood.  A similar project looking at increased salinity in the Atlantic indicates that changes in salinity can be attributed to changes in evaporation-precipitation and ocean circulation.  Both would cause changes in global climate and fisheries.  Station ALOHA, the site of the world’s longest oceanographic time series, is located north of the Hawaiian islands.  Data from 1988-present show an increase in salinity at the subsurface salinity maximum?.  Because this water is formed at the evaporation maximum and is the most saline water in the region, this is indicates evaporation has increased over time.

To put the Wave Glider data into context, 7 years of Seaglider data from 2008-present will provide a picture of local seasonal and physical variations around the Hawaiian Islands.  These data will help isolate long-term changes in the dataset from the background climatology.

DESCRIPTION

Depending on the stage of development of the Wire Walker, we will either tow a line of temperature and salinity sensors (SBE 37 and SBE 39) or tow a Wire Walker behind the Wave Glider.  Both of these setups will provide extensive data to compare to the 1979-1980 data set.

If we use the line of temperature and salinity sensors, we would pilot one Wave Glider south along 158W following the Hawaii-Tahiti Shuttle Route.  The second Wave Glider would travel the same route during a different month of the year.  This will provide a valuable seasonal comparison.  If we are able to choose the months of observation March – April and August – September would be optimal;  simply because there is more data available from Seaglider missions during these months.

If we use the Wire Walker the first Wave Glider would be used for field testing. The second Wave Glider would travel south from Oahu along 158W, reoccupying a portion of the Tahiti-Shuttle Experiment route while towing the Wire Walker.  Real-time data return would be possible if we include a cable supporting an inductive modem.

ADDITIONAL DETAILS

A portion of the $2000 would go towards a scanner with the ability to convert the booklets of Hawaii-Tahiti Shuttle Experiment data into a digitized dataset.  These data would then be made available publically.

Contact Information:

Kelly Pearson
University of Hawaii

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