The Guardian will make broad changes among its most senior editors this year, the newspaper said Thursday, announcing that Janine Gibson, the editor in chief of its operations in the United States, will return to London.

Ms. Gibson, who has led Guardian US as it broke a series of stories based on documents obtained from the former national security contractor Edward J. Snowden, will become editor in chief of theguardian.com and a deputy editor within the larger organization.

In a statement, the Guardian said her new role “will see her accelerating the next stage of the Guardian’s digital transformation.'’