run COPY as user other than postgres

I would like to run the COPY command as a user other than "postgres". I find it a bit of a pain (or at least requiring an extra step or two) to have the postgres user own the files that I am creating with COPY TO. Here is a simple example where the location '/some/path/to/file/file.csv' is owned by another user and it would be very spiffy if I could run the COPY TO as that user. Any ideas?

COPY (
SELECT * FROM
some_table
WHERE
2012 = EXTRACT (YEAR FROM some_column) --AND value IS NOT NULL
)
TO '/some/path/to/file/file.csv' WITH CSV HEADER;