Two air-temperature datasets have been collected in Barrow, Alaska, since 1976.  The National Weather Service (NWS) air temperature record from Barrow is one of the longest (1922-present) and most widely used datasets for demonstrating Arctic warming. The National Oceanic and Atmospheric Administration's ESRL Global Monitoring Division (GMD) station has been gathering meteorological data as well, to complement their atmospheric observations. These 2 stations provide a unique opportunity to assess the quality of these Arctic climate records, and examination of the daily air-temperature differences between these sites reveals distinct daily, seasonal, and long-term patterns.

In the 30 years since the beginning of the GMD record, instrumentation changes were implemented at both sites. One station moved ~0.5 km, but was not documented in the metadata.  Coastal influences are large as well.  These factors caused distinct changes in the stations records which are clearly revealed by their comparison.  In addition, Barrow grew from 2200 to more than 4600 residents. Recent measurements suggest that there is a substantial heat island in the village, particularly in the winter.  Comparison of NWS records in downtown and at the GMD several miles upwind of the village, show a distinct difference between urban and rural temperatures in the early portion of the record.

Unraveling the impacts of each of these factors on the temperature differences between the NWS and GMD sites is challenging and this study only begins to address these issues. However, this study demonstrates that the magnitude of Arctic climatic warming is of a similar magnitude to the “noise” caused the monitoring programs themselves due to instrument bias and change, station moves, urbanization, etc. While recent programs such as the Historical Climate Network are great strides, additional efforts must be made to analyze and correct existing valuable climate archives.