Fig. 4.
Percentage of extremely high/extremely low, high/low, and normal years in the theoretical observed runoff during three periods: 1492 to 1960 CE (I), 1961 to 2013 CE (II and II′), and 1987 to 2013 CE (III and III′).
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.