For the tenth anniversary of the surreal, unforgettable events of September 11, 2001, Philadelphia composer Robert Moran wrote his “Trinity Requiem” for the youth chorus of Trinity Wall Street, the so-called “Ground Zero church” in Lower Manhattan. This Sunday night on “The Lost Chord,” we’ll revisit this beautiful, consoling work and reflect on that September morning of twenty years ago – a morning that still feels like yesterday.

Moran may not be the first artist that would spring to mind for anyone seeking musical solace. The merry prankster ethos runs deep in this pupil of Hans Erich Apostel, Darius Milhaud, and Luciano Berio. Moran gained early notoriety for his compositions on a grand scale, incorporating entire cities (including San Francisco, Graz, Austria, and Bethlehem, Pennsylvania), their automobiles, airplanes, skyscrapers, radio and television stations, marching bands, dancers, theatrical groups, and tens of thousands of performers.

He’s written works for harpsichord and electric frying pan, and any number of performance art pieces, including one, archived on YouTube, that involves musicians walking around a financial district with slide whistles inside giant paper bags.

Flirting with respectability, he collaborated on an opera, “The Juniper Tree,” perhaps the grimmest of Grimm fairy tales, with Philip Glass, and he has composed a number of other works for the stage, including “Desert of Roses” (after Beauty and the Beast), for Houston Grand Opera, and “Alice” (after Lewis Carroll), for the Scottish Ballet. He’s currently at work on a monodrama about God.

Given Moran’s freewheeling reputation, I thought it only appropriate to title this week’s show after one of Salvador Dali’s most famous paintings, “The Persistence of Memory” – both for its surreal associations (a dreamscape of melting watches) and for the deep psychological scars left by the deadliest attacks ever perpetrated on American civilians.

Moran rises to the occasion to provide an ethereal masterpiece, a 30-minute journey to Paradisum, worthy to stand alongside the transcendent Requiem of Gabriel Fauré.

“Trinity Requiem” received its first performance at Trinity Wall Street on September 7, 2011. The second performance took place in St. Paul, Minnesota, on the actual anniversary of the attacks. Locally, it was performed by Mendelssohn Club, at the Basilica of Saints Peter and Paul, on Logan Square in Philadelphia, in 2012.

A compact disc was released on the innova Recordings label, with the Trinity Youth Chorus and members of the Trinity Choir, Trinity Wall Street, under the direction of Robert Ridgell.

Among the handful of miracles that occurred on a day of unthinkable tragedy, a hundred-year-old sycamore tree preserved the church’s St. Paul Chapel, constructed in 1766, from destruction by debris from the World Trade Center, including what would have been a direct hit from a falling I-beam.

On tonight’s broadcast, “Trinity Requiem” will be prefaced by a conversation with the composer. In the time remaining we’ll also hear Moran’s dreamlike “Notturno in Weiss” (“Nocturne in White”), on an aphoristic text by Christian Morgenstern.

Find solace in the purity of music, as we continue to grapple with the legacy of 9/11, this Sunday night at 10:00 EDT, on WWFM – The Classical Network and wwfm.org.