Coastal-Inland Distributions of Summer Air Temperature and Precipitation in Northern Alaska

Abstract

Using data from summer air temperature stations from the inland tundra to the immediate coastal area, regression analyses of the air temperature data from 1975 to 1978 were used to predict temperature values across the Alaskan Arctic Coastal Plain based upon latitude and longitude. This provides the best approximation of average values based on existing data. Mean monthly temperature, mean daily range of temperature, and thawing-degree days all increase with distance from the coast. The estimated July normal for Atkasook, 48 km south of the coast, is 8.7°C, while the established 30-yr normal for Barrow, on the coast, is 3.7°C. The July average temperature 6 km due south of the open water of Prudhoe Bay is 2°C higher than on the immediate coast. Within the area under the dominant influence of the sea breeze, regression analyses suggest a more precise relationship between air temperature and distance along the prevailing wind vector (N75°E) than between temperature and distance due north to the sea. The appropriate regression equation was used to locate the average 7°C isotherm for July, which corresponds to the southern border of the littoral zone. Precipitation differences are less distinct across the coastal plain. Trace amounts are observed more frequently along the coast than inland; total amounts inland are somewhat greater, but more variable in occurrence.