Program & Methods

program description

The Shore Stations Program collects and provides access to current and historical daily sea surface temperature (SST) and salinity (SSS) measurements observed at shoreline locations along the west coast of the United States. Historically, stations ranged from the southernmost point at La Jolla, CA, to the northernmost point on the west coast, Neah Bay, WA, located at the entrance to the Straits of Juan de Fuca. Currently, this research is funded by California Department of Parks and Recreation, Natural Resources Division,  Award# C1670003.

Currently, all 10 active stations are located in California. Data values are processed and published on the website by program staff at UCSD/Scripps Institution of Oceanography as they become available from each site. Program data are archived on a quarterly basis in the UCSD Library’s Digital Collections.  https://doi.org/10.6075/J0S75GHD

This program ranks as one of the world’s longest, continuous ocean time series and the longest on the Pacific Rim. Measurements at La Jolla began in August 1916, with several other stations dating to the 1920’s. These long time series are essential for identifying coastal ocean warming over the past century and determining its role in intensifying marine heat waves, as well as characterizing fluctuations in warming and cooling from seasonal to multi-decadal time scales. This growing data bank provides us with one of the first opportunities to separate natural from anthropogenic changes in our coastal zone.

These warm and cold anomalies, and the long-term warming trend have significant biological effects on plankton production, fish catch, and seabirds, among many other impacts. They also are associated with changes in sea level, wave heights, and beach erosion, and have recently been linked to climate fluctuations over the southwestern U.S.

Field Methods

Surface Measurements

An insulated sampling bucket is used to collect surface water (approximately 0.5 meter depth) and a calibrated digital thermometer is immediately placed inside the bucket to measure SST to the nearest 0.01ºC. Temperature measurements are rounded and reported to 0.1ºC. For salinity measurements, surface water is poured into glass bottles with airtight seals after rinsing the bottle 3x with sample water.
 
For stations that sample from piers, a sampling bucket is lowered outside the breaking surf or near the end of the pier. For beach stations without piers, the sampler wades out to knee high depth (in calm conditions) and uses a pole sampler or casts the bucket out to deeper water to collect the sample

Near-bottom Measurements (Scripps Pier only, depth approx. 5m)

A Niskin bottle is used for the collection of bottom water at the Scripps Pier location only. The Niskin bottle is lowered to the bottom and raised 1 meter off the bottom. A messenger is sent down the line to trip the bottle and collect the sample at depth. Once back at the surface, a digital thermometer is immediately immersed in the Niskin bottle and the temperature is measured to the nearest 0.01ºC. Temperature measurements are rounded and reported to 0.1ºC. Seawater is drained from the Niskin bottle into glass bottles with air tight seals, after rinsing the bottle 3x with sample water. Earlier bottom samples were collected with Nansen bottles and reversing thermometers.

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Sampling Well 2022

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Sampling Well 1949 (Claude W. Palmer)

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View down the Well (2022)

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Glass bottles to collect seawater for salinity measurements

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Surface sampling bucket

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Niskin bottle (for bottom sampling)

Instrumentation

Temperature

1916  - early 1950s

Although early records on methods and instrumentation are scarce, glass mercury thermometers were the scientific standard during the late 19th century and well into the 20th century. Scripps Institution of Oceanography has it’s own calibration facility that supported the scientific instrumentation for ocean-going vessels and coastal-based studies. At Scripps Pier the earliest measurements were recorded in tenths of a degree Celsius (0.1°C) using calibrated mercury thermometers, but little information can be found on the exact calibration techniques. 

1950s - 2008

Records from 1956 indicate ocean temperature measurements were taken using precision engraved stem mercury immersion thermometers with 0.1°C divisions. The primary source was Kahl Scientific Instruments Corporation, a local San Diego County manufacturer established in 1935. The instruments were calibrated against certified primary standards during the manufacturing process. Instruments used at Scripps Pier and Farallon Islands were recalibrated by the Oceanic Data Facility at SIO in a water bath with 0.01°C temperature control.

2008 - present

In December 2008 the program switched to calibrated digital thermometers because mercury was banned in the state of California. These digital thermometers were custom made by Douglas Alden, and engineer at Scripps Institution of Oceanography. The thermometers read in hundredths of a degree Celsius (0.01°C) and measurements are rounded to the nearest tenth of a degree (0.1°C). Calibrations are performed on a 9 month to yearly basis at the Ocean Data Facility, Calibration Laboratory at SIO with two referenced thermometers.

Salinity

Saltwater samples are analyzed at Scripps Institution of Oceanography on an inductive salinometer, Guideline Model 8410. The Guildline PortASal is calibrated before and after each group of samples with an SIO seawater standard. Periodic checks on the conductivity of the SIO seawater standard are made by comparison with IAPSO Standard Seawater. Salinity values are read to four decimal places (0.0001), and are calculated using the algorithms for the Practical Salinity Scale, 1979 (UNESCO, 1981a). Salinity values are rounded up to two decimal places (0.01) after conversion to PSU and reported to two decimal places. Prior to 1965 salinity was measured using a chlorinity titration method.
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Digital Thermometer

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Inductive Salinometer