"常浮现于脑海中的" can be translated into English as "that often comes to mind" or "that frequently surfaces in one's thoughts".
For example:
The memory of that day often comes to mind. （那天的记忆常浮现于脑海中。）
The image of her smiling face frequently surfaces in my thoughts. （她笑脸的画面常浮现于我的脑海中。）