Mobile　opportunistic　networks　can　enable　self-organizing　communications　in　complicated　and　dynamic　scenarios.　However,　existing　work　overlooks　the　tempo-spatial　properties　of　information　dissemination　to　time-varying　destination　areas　in　mobile　opportunistic　networks,　which　reveal　whether　such　networks　can　support　emerging　applications　with　dynamic　dissemination　objectives.　In　this　paper,　we　investigate　the　tempo-spatial　properties　of　information　dissemination　across　a　linear　time-varying　area　boundary　with　the　Brownian　motion.　Our　investigations　give　the　distribution　of　delivery　delay　under　the　one-copy　and　the　multiple-copy　forwarding　policies,　where　the　former　has　only　one　information　carrier　in　the　network　and　the　latter　has　more　than　one　information　carrier　at　the　beginning　and　each　delivers　a　copy　of　the　information　to　an　encountered　node　with　a　certain　probability.　The　analytical　results　demonstrate　the　power　of　the　multiple-copy　forwarding　compared　to　the　one-copy　forwarding.