、、。
Various aromas are wafting up from the lunch box.
Literal
Lunch-box [from-からは], various side-dishes [possessive-の] smell [subject-が], rising.
立ちのぼる ('to rise, to waft upward') is a compound verb — 立つ 'to stand/rise' + のぼる 'to ascend' — specifically for smoke, steam, or aromas rising. オカズ (おかず) in katakana rather than hiragana gives it a slightly emphasized or casual-stylized feel. The ている progressive captures the ongoing wafting.