Sitka Area (two stations)


Index

Map of Sitka area
Sitka Magnetic station history
Sitka Magnetic temperature history
Sitka Japonski (Airport) station history
Sitka Japonski (Airport) temperature history
Temperature differences between the two stations


Map of Sitka area


Sitka area, USGS Sitka map sheet, 1951 with minor revisions 1987. Large squares are townships, 6 miles on a side; elevations are in feet. Sitka Magnetic is at USGS Mag Sta on mainland; Sitka Japonski is at airport.

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Sitka Magnetic Station History

Located on the west coast of Baranof island in the SE archipelago, slightly SE of Sitka Japonski. Current coordinates 57 degrees 3' N, 135 degrees 20' W, elevation 67 feet. Station established in 1828 and some fluctuations probably detectable that far back, but data in NCDC file is only from the 20th century. Earlier data had substantial differences from modern observational practices. Instrument documentation (thermometers at 4 feet) starts 8/4/1908. Unknown move downhill 34 feet 10/1/30. Slight move east and 6 feet downhill 3/15/41. Move 1.0 miles NE and 42 feet uphill 4/1/42. Closed 12/18/1989.

Earliest observation time recorded 7 pm (6 pm current time zone), changed to 5 pm (4 pm corrected) 8/4/1908, 10 am (9 am corrected) 10/1/30, 8 am (7 am corrected) 4/1/42, 5 pm (4 pm corrected) 1951, 8 am (7 am corrected) again in July, 4 pm (3 pm corrected) 8/1/75. Time zone change 10/31/83, giving an effective change to 4 pm on that date. Switch to 3 pm 4/25/85.

Observer U.S. Geological Survey.

Record length potentially outstanding, data continuity reasonably good with a total of 5 months missing between 1912 and November 1989.

Comparison of Sitka Japonski and Sitka Magnetic suggests that on annual mean temperature Sitka Japonski was fairly consistently warmer by around 2 degrees F prior to 1975, with a range of 1.5 degrees to 2.7 degrees difference. Since 1975 the temperature difference has been closer to 1.5 degrees, with extremes of 0.9 degrees and 1.8 degrees. The change coincides with the shift from morning to afternoon observations at Sitka Magnetic.

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Sitka Magnetic Temperature History





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Sitka Japonski Station History

Station location at Sitka Japonski Airport, on near-island in Sitka Sound on W coast of Baranof Island. Current coordinates 57 degrees 4' N, 135 degrees 21' W, elevation 36 feet. Temperature initially measured at 56 foot height above ground. Move 21 feet uphill 5/23/80, temperature changed to 24 feet above ground, addition of HO6 series hygrothermometer at that time. Max min thermometers removed and HO6 replaced by HO8 at 6 feet 4/25/89.

Observation time midnight throught. To correct to approximate solar time (135 WMT) portion of record prior to November 1983 when Sitka was on California time should be treated as 11 pm observation time.

Observer FAA throughout.

Record length moderate (since 1944), data continuity excellent, site continuity good except for height changes in temperature sensor.

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Sitka Japonski Temperature History


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Temperature Differences


Note the persistent nighttime warmth at Sitka Japonski (small island) compared to Sitka Mag (somewhat more inland.) Sitka Mag switched from early morning to midafternoon observations in 1975, which probably accounts for a large part of the reduction of the temperature difference at that time. In any event, it is clear that Sitka Japonski cannot be taken as a simple continuation of the old Sitka Mag record.

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