WE PROPOSE TO DERIVE AND INTERPRET DYNAMIC OCEAN TOPOGRAPHY (DOT) FROM ICESAT ALTIMETRY FOR THE SUB-ARCTIC SEAS FROM 2004 TO 2009. DOT IS THE ELEVATION OF THE SEA SURFACE ABOVE THE GEOID. ITS HORIZONTAL GRADIENTS ARE THE DRIVING FORCE OF GEOSTROPHIC UPPER OCEAN CIRCULATION AND THE DIFFERENCE BETWEEN DOT AND OCEAN BOTTOM PRESSURE (OBP) IS EQUIVALENT TO THE STERIC PRESSURE ANOMALY (STP) WHICH IS A MEASURE OF AVERAGE OCEAN DENSITY AND FRESHWATER CONTENT (FWC). THESE PROPERTIES CIRCULATION AND FRESHWATER CONTENT ARE IMPORTANT IN THE SUB-ARCTIC SEAS BECAUSE THESE REGIONS ARE THE SITES OF CONVECTIVE VERTICAL HEAT EXCHANGE THAT IS A CRITICAL LINK IN THE GLOBAL THERMOHALINE CIRCULATION AND BECAUSE SUB-ARCTIC CIRCULATION PATTERNS ARE CRITICAL TO EXCHANGE WITH THE ARCTIC OCEAN AND THE ICE COVER AND CIRCULATION IN THE ARCTIC OCEAN.SAMPLING DOT IN THE SUB-ARCTIC HAS BEEN PROBLEMATIC BECAUSE OF THE 62 -64 N NORTHERN LATITUDE LIMIT OF THE TOPEX/POSEIDON/JASON SATELLITE ALTIMETERS. FURTHER ALTHOUGH THE GRAVITY AND CLIMATE RECOVERY EXPERIMENT (GRACE) SAMPLES OBP IN THE SUB-ARCTIC SEAS VERY WELL THE BOUNDARY CURRENTS THAT DOMINATE CIRCULATION IN THE GREENLAND AND LABRADOR SEAS ARE IN NEARSHORE REGIONS WHEREGRACE OCEAN SIGNALS ARE PARTLY MASKED BY GRAVITY SIGNALS ARISING FROM MASS CHANGES ON THE GREENLAND ICE SHEET.ICESAT DOT IN THE SUB-ARCTIC SEAS WOULD DIRECTLY ADDRESS BOTH THESE PROBLEMS. ICESAT-DERIVED DOT AND UPPER OCEAN CIRCULATION HAVE BEEN SUCCESSFULLY COMPARED TO DYNAMIC HEIGHTS AND CIRCULATION MEASURED IN THE CANADA BASIN BY IN SITU HYDROGRAPHY [AUTHORS 2011]. IN COMBINATION WITH GRACE-DERIVED OBP ICESAT-DERIVED DOT HAS REVEALED TRENDS IN CIRCULATION AND FRESHWATER PATHWAYS OVER THE WHOLE ARCTIC OCEAN FROM 2004 TO 2008 [AURTHOR ET AL. 2012]. ICESAT ALTIMETRY HAS ALSO BEEN COMPARED TO TOPEX/POSEIDON ON A GLOBAL OCEAN SCALE [AUTHORS 2005] BUT IT HAS NOT BEEN USED FOR DOT AND CIRCULATION DETERMINATION FOR THE OPEN OCEAN PARTICULARLY THE SUB-ARCTIC SEAS. THIS STUDY WILL FILL THE SATELLITE ALTIMETRY GAP BETWEEN THE MID-LATITUDE OCEANS AND THE ARCTIC OCEAN DURING A PERIOD (2004-2008) OF PROFOUND CHANGE IN THE HIGH LATITUDES.BECAUSE CHANGES IN OBP ARE THE SUM OF CHANGES IN DOT AND STERIC PRESSURE ICESAT DOT COMBINED WITH IN SITU HYDROGRAPHIC MEASUREMENTS OF STP GIVE AN ESTIMATE OF OBP THAT IS NOT CONTAMINATED BY LEAKAGE OF GRAVITY SIGNALS DUE TO CHANGES IN THE GREENLAND ICE SHEET. THIS ICESAT-HYDROGRAPHY-DERIVED OBP WILL BE COMPARED TO GRACE OBP TO DETERMINE THE LEAKAGE OF ICE SHEET MASS SIGNALINTO THE GRACE OBP AND VICE VERSA.INTERPRETATION OF THE ICESAT DOT OBSERVATIONS WILL REST ON TECHNIQUES WE HAVE USED FOR UNDERSTANDING THE CIRCULATION AND FRESHWATER CHANGES IN THE ARCTIC OCEAN. COMPARED TO THE ARCTIC OCEAN WORK WE WILL BE AIDED BY ABSENCE OF THE ARCTIC OCEAN REQUIREMENT OF FINDING OPEN WATER LEADS FOR DOT DETERMINATION AND BY THE QUANTITY OF SUPPORTING ARGO HYDROGRAPHIC DATA AVAILABLE FOR THE SUB- ARCTIC SEAS. WE ALSO LOOK FORWARD TO BEING ABLE TO COMPARE ICESAT RESULTS TO TOPEX AND JASON RESULTS IN AN OVERLAP REGION EXTENDINGTO AT LEAST 60 N. AS A SIDE BENEFIT THE LESSONS WE LEARN DERIVING OPEN OCEAN DOT FROM ICESAT WILL INFORM DESIGN OF THE OPEN OCEAN PROCESSING SCHEMES FOR ICESAT2.IN DERIVING SUB-ARCTIC DOT FROM ICESAT WE WILL BE AIDED BY OUR UNFUNDED COLLABORATOR AUTHOR AT JPL. AURTHORS OF THE UNIVERSITY OF SOUTH FLORIDA WILL ADVISE ON GRACE OBP PROVIDING SPECIAL GRACE PRODUCTS AND THE GRACE DE-ALIASING MODEL. MODEL OUTPUT WE WOULD USE TO HELP INTERPRET THE DOT AND OBP OBSERVATIONS WILL BE PROVIDED BY AUTHOR(PIOMAS) AND AUTHOR(ECCO-2). AUTHOR WILL PROVIDE TOPEX ALTIMETRY FOR COMPARISON WITH ICESAT DOT.