The percent difference between the basin-accumulated NCEP and Cogley annual mean runoff and the NCEP and Leemans and Cramer precipitaiton. NCEP R/P is the ratio of the NCEP simulated runoff to precipitation (runoff ratio), OBS R/P is the ratio of the Cogley runoff to Leemans and Cramer precipitation. The NCEP runoff ratio is greater than one at a few Arctic locations possibly as a result of the snow or permafrost initialization. OBS R/P greater than one is related to the use of two unrelated observationally based datasets. All variables are accumulated over the basins defined in HYDRA.