Interpolation of temperature and non-urban ozone exposure at high spatial resolution over the western United States

Climate Research

E. Henry Lee¹  William E. Hogsett¹ 

关键词: Spatial interpolation;    Ozone;    Temperature;    Regionalization;    Principal components analysis;    Kriging;    Loess regression;    Western United States;   

DOI  :  10.3354/cr018163

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: In order to assess the impact of natural and anthropogenic stresses on forest ecosystems, it is necessary to interpolate air temperature and tropospheric ozone (O₃) exposure values at high spatial resolution over complex terrain. Theproposed interpolation approach was selected because of its ability to (1) account for the effect of elevation on temperature and their effects on tropospheric ozone, (2) use auxiliary data at higher spatial resolution than the variables of interest toimprove the precision and accuracy of the prediction surfaces, (3) handle large amounts of data, and (4) provide not only a prediction at nonsampled locations but also a prediction standard deviation. The approach used auxiliary digital elevation model(DEM) data at 1 km resolution to improve the precision and resolution of the predictions for temperature and O₃ exposure in the western United States. Initially, the study area was stratified into O₃ regions based on seasonality andvariability of monthly SUM06 values at 111 stations for the period 1990-1992 using rotated principal component analysis. Monthly mean daily maximum air temperatures were spatially interpolated using loess nonparametric regression and kriging of the loessresiduals and interpolated to 2 km grid points of a DEM and to the ambient air quality monitoring points. Monthly O₃ exposures were spatially interpolated using loess fits to relate O₃ levels to elevation, predicted temperature, andthe geographic coordinates and interpolated to 2 km grid points of a DEM. The elevation-based spatial interpolation procedure produced accurate and precise temperature and O₃ exposure surfaces which had desirable statistical properties and werelogically consistent with local topographical features and atmospheric conditions known to influence O₃ formation and transport. The leave-one-out cross-validation mean absolute error was 0.93°C for the monthly mean daily maximum temperatureand 1.93 ppm-h for the monthly SUM06 index for June 1990 for the western United States, comparable to published results for other regions at smaller spatial scales with less complex terrain.

【 授权许可】

Unknown