Climatic Variability in the Kuparuk Region, North-central Alaska: Optimizing Spatial and Temporal Intepolation in a Sparse Observation Network

(Received 8 March 2002; accepted in revised form 16 August 2002 ) ABSTRACT. Air temperature fields are required as input to spatial models in ecology, geocryology, and biogeochemistry. Air temperature data from a sparse, irregular meteorological network in the Kuparuk region of north-central Alaska were interpolate d spatially and temporally to provide a 13-year (1987-1999) series of thawing degree-day fields at 1 km2 resolution. Procedures involved standardizing diverse temperature records and applying topographically and climatologically aided interpolation, using station data and digital elevation models, to incorporate the effects of local topography. The accuracy of the interpolation procedures was assessed using cross validation. Considering the number of data points used for interpolation, their distributio n, and the size of the area, the combination of climatologically assisted and topographically informed spatial interpolation proce dures provides adequate representation of the annual degree-day fields for the Kuparuk region. Spatially integrated mean absolute err or does not exceed 3% in any year. To investigate the spatial distribution of interpolation uncertainties, the cross-validation er rors obtained at each station for each year were interpolated spatially to a regular 1 · 1 km grid consistent with the degree-day fields.