I am a professor and founding director of the Spatial Sciences Institute at the University of Southern California and I have had the privilege of meeting Professor Yu many times over the past 15 years. I was saddened to learn of his passing and my hope is that is ideas and spirit will live on forever.

My condolences to his family and close colleagues and friends and know that I will miss him！

译文：

我是南加州大学空间科学研究所的教授兼创始所长，过去15年间有幸与俞教授多次会面。惊闻他离世的消息，我深感悲痛，希望他的思想与精神能永存于世。

谨向他的家人、亲密同事及朋友致以深切哀悼，并将永远怀念他！