ACFT LANDED WITHOUT LNDG CLRNC FROM TWR. FLC DISTR BECAUSE OF ICING.

Narrative

I WAS FLYING THE ILS 03 APCH TO THE APPLETON; WI; ARPT OUTSIDE THE MARKER; APCH (GREEN BAY) ADVISED US TO CONTACT TWR 'MARKER INBOUND.' UPON XING THE OM WE BECAME PREOCCUPIED WITH THE ACCUMULATION OF ICE ON OUR WINGS. WE BEGAN TO DISCUSS THE APPROPRIATE ACTIONS TO FOLLOW; IN ORDER TO REDUCE THE LIKELIHOOD OF HAVING TO DEICE THE ACFT UPON ARR. AS WE BROKE-OUT OF THE CLOUDS AND SAW THE RWY; OUR ATTN SHIFTED TOWARD THE LNDG PHASE OF THE FLT. DURING OUR DSCNT; THE AURAL 'ALTITUDE ALERT' CHIME SOUNDED. THIS IS PERTINENT BECAUSE IT IS COMPANY POLICY TO SELECT '0000 FT' WHEN CLRED FOR THE APCH (WHICH WE HAD DONE); AND '-49000 FT' WHEN CLRED TO LAND (WHICH WE HADN'T DONE). ALTHOUGH WE BOTH HEARD THE CHIME; NEITHER OF US CALLED TWR TO VERIFY OUR FLT WAS CLRED TO LAND. WE BOTH ASSUMED THAT WE HAD CALLED AND RECEIVED CLRNC TO LAND. UPON TOUCHDOWN AND ROLLOUT TWR ADVISED US OF OUR MISTAKE. MY CAPT WENT INSIDE TO CALL THE TWR ONCE WE SHUT DOWN. THE CTLR STRESSED THE IMPORTANCE OF GETTING A CLRNC DURING RWY SNOW CLRING OPS AND THEN ADVISED US THAT THERE WOULD BE NO PROB. THIS PROB AROSE BECAUSE OF OUR PREOCCUPATION WITH ICE ACCUMULATION. WE ALLOWED THIS RELATIVELY SMALL PROB/CONCERN DISTRACT US FROM OUR PRIMARY DUTIES. THE INCIDENT WAS FURTHER COMPLICATED BY OUR ASSUMPTION THAT A CLRNC HAD BEEN GIVEN; EVEN THOUGH OUR ALT ALERTER CHIME ADVISED US THIS WAS NOT THE CASE! IT IS TROUBLING THAT THE TWR CTLR DID NOT TRY TO CONTACT US. THE ARPT WAS NOT BUSY; WE WERE THE ONLY OP IN THE AIR. PERHAPS IT WOULD BE APPROPRIATE FOR ATC TO ATTEMPT TO CONTACT AN ACFT WHICH IS SUSPECTED OF LNDG WITHOUT A CLRNC; IF AT ALL POSSIBLE. IN ORDER TO REDUCE THE CHANCES OF ALLOWING THIS TO OCCUR AGAIN; I WILL NOT LAND UNLESS THE ALT ALERTER IS SWITCHED TO '-49000 FT'; OR ANOTHER INDICATION OF LNDG CLRNC RECEPTION IS INDICATED IN THE FLT DECK.