THE OBJECTIVE OF THIS INVESTIGATION IS TO DEVELOP AN ADVANCED CLOUD ICE WATER PATH (IWP) AND CLOUD-TOP HEIGHT (CTH) RETRIEVAL ALGORITHM FROM COMBINED SATELLITE PASSIVE INFRARED (IR) AND MICROWAVE (MW) OBSERVATIONS SO AS TO OVERCOME SENSITIVITY LIMITATIONS IN EACH INDIVIDUAL TECHNIQUE. A GENERALIZED ALGORITHM WILL BE DELIVERED TO NASA DATA CENTER AS NEEDED TO BE APPLIED TO THE PLATFORMS WHERE BOTH IR AND MW OBSERVATIONS ARE ACQUIRED SIMULTANEOUSLY. WE WILL ALSO APPLY THE NEW ALGORITHM TO VIIRS+ATMS (2012- PRESENT) DATA. CURRENT IWP RETRIEVALS FROM SATELLITE-BASED INSTRUMENTS CAN VARY BY A FACTOR OF 10. BECAUSE OF THE LARGE (FOUR ORDERS OF MAGNITUDE) DYNAMIC RANGE IN ICE CLOUD VARIABILITY LIMITATIONS OF INDIVIDUAL INSTRUMENTS (WITH SENSITIVITY IN A SPECTRAL REGION) ARE INEVITABLE. THE NEW EFFORT IN THIS WORK WILL MAKE USE OF COMPLEMENTARY INFORMATION FROM PASSIVE IR AND MW OBSERVATIONS TO DERIVE LONG-TERM CONSISTENT AND COMPREHENSIVE RECORDS FOR GLOBAL ICE CLOUDS. THE NEW RETRIEVAL ALGORITHM IS BUILT UPON SUCCESSFUL ALGORITHMS FOR INDIVIDUAL SENSORS AND TAKES ADVANTAGE OF THE CLOUD PROPERTIES THAT ARE COMMON IN BOTH IR AND MW. ADVANTAGES OF THE PROPOSED ALGORITHM INCLUDE: 1. PASSIVE IR AND MW OBSERVATIONS ARE INDEPENDENT OF SOLAR ILLUMINATION ALLOWING A JOINT UNIFORM ICE CLOUD RETRIEVAL AT DIFFERENT LOCAL TIMES AND LOCATIONS. 2. CLOUD RETRIEVALS WILL BE CARRIED OUT OVER A WIDE DYNAMIC RANGE FROM OPTICALLY THIN TO THICK ICE CLOUDS. 3. RETRIEVALS AT HYBRID SPATIAL RESOLUTIONS WILL BE IMPLEMENTED TO MINIMIZE IMPACTS OF ICE CLOUD INHOMOGENEITY EFFECTS. 4. COMPREHENSIVE ERROR ANALYSIS WILL BE PERFORMED TO CHARACTERIZE AND QUANTIFY UNCERTAINTIES FROM DIFFERENT SOURCES. 5. CAN BE APPLIED TO PLATFORMS WITH SIMULTANEOUS IR AND MW OBSERVATIONS. THE NEW EFFORT WILL PROVIDE THE SCIENTIFIC COMMUNITIES WITH UNPRECEDENTED COVERAGE AND ACCURACY FOR IWP AND CTH. THE PROPOSED JOINT RETRIEVAL ALGORITHM CAN BE EASILY APPLIED TO OTHER EXISTING PLATFORMS WITH SIMILAR IR AND MW CHANNELS E.G. THE AVHRR +MHS ONBOARD NOAA 5TH GENERATION POLAR OPERATIONAL ENVIRONMENTAL SATELLITES AND PLATFORMS IN THE NEAR FUTURE E.G. THE JOINT POLAR SATELLITE SYSTEM (JPSS). THE LONG-TERM AND CONSISTENT CLOUD RECORDS WILL DIRECTLY BENEFIT THE NASA'S EARTH SCIENCE RESEARCH COMMUNITIES IMPROVE OUR UNDERSTANDING OF UNCERTAINTIES IN CURRENT CLOUD RECORDS AND SERVE AS UNIQUE AND VALUABLE OBSERVATIONAL CONSTRAINTS FOR REPRODUCING CLOUD MICROPHYSICAL PROCESSES AND IMPROVING ICE CLOUD PARAMETERIZATIONS IN CLIMATE AND WEATHER MODELS.