Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Number of wells required to represent the spatial mean at four different absolute error level as a function of their extent at (a) 0.25 degree, (b) 0.5 degree and (c) 1 degree-scale. The number within the squares indicating basin numbers (Table 1) corresponding to their extent and number of wells
