THE NASA OPERATION ICE BRIDGE (OIB) IS DESIGNED TO PROVIDE ELEVATION MEASUREMENTS IN GREENLAND ALASKA AND ANTARCTICA DURING THE NINE YEARS BETWEEN THE END OF THE ICESAT (ICE CLOUD AND LAND ELEVATION SATELLITE) MISSION AND THE START OF THE ICESAT-2 MISSION. EARLY IN THE MISSION THE ALTIMETRY MISSIONS CONSISTED OF ANNUAL SURVEYS OVER EACH ICE SHEET. AS OIB BEGINS ITS NINTH CALENDAR YEAR OF OPERATIONS IN 2017 IT WILL BEGIN PROVIDE MEASUREMENTS MORE AND MORE AIMED AT EXTENDING AND ADDING VALUE TO THE FIRST ICESAT-2 MEASUREMENTS; THESE INCLUDE SEASONAL REPEAT MEASUREMENTS IN GREENLAND WHICH WILL BEGIN TO PROVIDE BASELINE DATA FOR ICESAT-2 S YEAR-ROUND MEASUREMENTS AND SOON TWO-WAVELENGTH LASER-ALTIMETRY MEASUREMENTS TO HELP CALIBRATE POTENTIAL BIASES IN THE ICESAT-2 DATA. IN THE PROPOSED PROJECT WE WILL WORK TOWARDS INTEGRATING THESE TWO NEW COMPONENTS OF THE MISSION INTO THE COMPLETE ICESATTO ICESAT-2 TIME SERIES. USING THE NEW TWO-WAVELENGTH ALTIMETRY MEASUREMENTS NUMERICAL MODELING AND REMOTELY SENSED SURFACEREFLECTANCE MEASUREMENTS WE WILL GENERATE A PRELIMINARY CORRECTION FOR THE SUBSURFACE SCATTERING BIAS IN ICESAT-2 DATA. USING THE NEW MULTI-SEASONAL ALTIMETRY MEASUREMENTS OVER GREENLAND WE WILL DOCUMENT THE PERFORMANCE OF AVAILABLE FIRN-THICKNESS MODELS IN MATCHING SEASONAL HEIGHT CHANGES AND WILL HELP DESIGN ALTIMETRY MISSIONS TO CAPTURE THE FULL RANGE OF SEASONAL BEHAVIORS ACROSS THE ICE SHEET. LAST WE WILL PARTICIPATE AS THE ICE-SHEET ALTIMETRY LEADS IN THE IMBIE-2 ICE-SHEET MASS BALANCE INTERCOMPARISON EXERCISE BRINGING TOGETHER A VARIETY OF ICE-SHEET MASS-CHANGE ESTIMATES FROM A VARIETY OF SOURCES WHICH SHOULD BE A VALUABLE PRELIMINARY STEP TOWARDS INTERPRETATIONS OF THE FIRST ICESAT-2 RESULTS.