There are noise abatement departure procedures—NADP 1 and NADP 2. They target different areas. One targets the area close to the airport and tries to provide some abatement nearby. The other operation looks at providing some abatement a little further away. Either way, both of those procedures have aircraft climbing. At that phase of departure, planes tend to be the loudest—at full throttle.
On October 30th, 2018. See this statement in context.