WRF - Developmental Testbed Center

3. average_4pt : Simple four-point average interpolationThe four-point average interpolation method requires at least one valid source data pointfrom the four source points surrounding the point (x,y). The interpolated value is simplythe average value of all valid values among these four points.4. wt_average_4pt : Weighted four-point average interpolationThe weighted four-point average interpolation method can handle missing or maskedsource data points, and the interpolated value is given as the weighted average of all validvalues, with the weight w ij for the source point a ij , 1 ≤ i, j ≤ 2 , given byw = − x − x + y − y .2 2ijmax{0,1 (i) (j) }Here, x i is the x-coordinate of a ij and y j is the y-coordinate of a ij .5. average_16pt : Simple sixteen-point average interpolationThe sixteen-point average interpolation method works in an identical way to the fourpointaverage, but considers the sixteen points surrounding the point (x,y).6. wt_average_16pt : Weighted sixteen-point average interpolationThe weighted sixteen-point average interpolation method works like the weighted fourpointaverage, but considers the sixteen points surrounding (x,y); the weights in thismethod are given byw = − x − x + y − y ,2 2ijmax{0, 2 (i) (j) }where x i and y j are as defined for the weighted four-point method, and 1 ≤ i, j ≤ 4 .7. nearest_neighbor : Nearest neighbor interpolationThe nearest neighbor interpolation method simply sets the interpolated value at (x,y) tothe value of the nearest source data point, regardless of whether this nearest source pointis valid, missing, or masked.WRF-NMM V3: User’s Guide 3-48