EXPOSING SYSTEMATIC ERRORS IN ARCTIC CLOUDS IN CLIMATE MODELS AND THEIR IMPLICATIONS FOR CLIMATE CHANGE SIMULATIONSUNPRECEDENTED RAPID AND VISIBLE CLIMATE CHANGES ARE HAPPENING IN THE ARCTIC. CRUMBLING BUILDINGS ROADS AND BRIDGES ERODING SHORELINES AND DIMINISHING SEA ICE ARE BECOMING COMMONPLACE. WHILE ARCTIC CLIMATE CHANGE MAY SEEM PHYSICALLY REMOTE TO THOSE LIVING IN OTHER REGIONS OF THE PLANET IT IS EXPECTED TO HAVE RIPPLE EFFECTS WITH A GLOBAL REACH. LIKE THROWING A ROCK IN A POND THE PERTURBATIONS TO ARCTIC SEA ICE LAND ICE SURFACE TEMPERATURE AND PERMAFROST SPREAD THROUGHOUT THE GLOBE AFFECTING SEA LEVEL THE CARBON CYCLE AND POTENTIALLY AFFECTING ATMOSPHERIC AND OCEANIC CIRCULATION PATTERNS. IMPROVED UNDERSTANDING MODELING AND PREDICTION OF ARCTIC CLIMATE PROCESSES WILL YIELD GLOBAL BENEFITS. UNFORTUNATELY WE ARE STILL FAR FROM BEING ABLE TO ACCURATELY MODEL THE MAGNITUDE OF ARCTIC CLIMATE CHANGE. STATE-OF-THE-ART CLIMATE MODELS DISAGREE MORE ABOUT THE FUTURE OF THE ARCTIC THAN ANY OTHER REGION. ACCORDING TO THESE MODELS THE ARCTIC SURFACE COULD WARM BY AS LITTLE AS 4 K OR AS MUCH AS 14 K BY 2080. THE SAME CLIMATE MODELS ALSO PREDICT A 50-YEAR RANGE IN THE FIRST OCCURRENCE OF AN ICE-FREE ARCTIC SUMMER ANYWHERE FROM THE 2030S TO AS LATE AS THE 2080S. THESE SIGNIFICANT MODEL DISAGREEMENTS ARE IN PART BECAUSE WE STILL DO NOT UNDERSTAND THE RELATIVE IMPORTANCE OF THE KEY MECHANISMS INVOLVED IN RAPID ARCTIC CLIMATE CHANGE. OF THESE MECHANISMS ARCTIC CLOUDCLIMATE FEEDBACKS ARE A MAJOR LIMITING FACTOR IN OUR ABILITY TO PREDICT FUTURE CHANGE. THE IMPORTANCE OF ARCTIC CLOUDS ESPECIALLY LOW CLOUDS TO THE ARCTIC CLIMATE SYSTEM STEMS FROM THEIR LARGE IMPACT ON THE SURFACE RADIATION BUDGET. FOR EXAMPLE THE PRESENCE OR ABSENCE OF CLOUDS DETERMINES THE RATE AT WHICH THE SURFACE COOLS IN WINTER AFFECTING SURFACE TEMPERATURE AND THE GROWTH OF SEA ICE. ACCURATE SIMULATION OF ARCTIC CLOUD RADIATIVE EFFECTS IS REQUIRED NOT ONLY FOR THE ACCURATE SIMULATION OF CURRENT ARCTIC CLIMATE BUT ALSO ITS FUTURE CHANGES. HOWEVER COMPARISONS BETWEEN CLIMATE MODELS AND OBSERVATIONS REVEAL LARGE DIFFERENCES IN ARCTIC CLOUD PROPERTIES AND THEIR RADIATIVE EFFECTS. UNDERSTANDING THE CAUSE(S) OF CLIMATE MODEL CLOUD ERRORS IS NECESSARY TO REDUCE ARCTIC CLIMATE CHANGE UNCERTAINTY. A DETAILED UNDERSTANDING OF THE FACTORS THAT CONTROL ARCTIC CLOUDS IN MODELS IS LACKING; THIS PROPOSAL FILLS THIS GAP. THIS PROJECT DIAGNOSES ATTRIBUTES AND PINPOINTS SOLUTIONS TO MODEL ERRORS IN ARCTIC CLOUDS BY INVESTIGATING THE STATISTICAL LINKAGES BETWEEN ARCTIC CLOUDS AND ATMOSPHERIC DYNAMICS THERMODYNAMICS AND SEA ICE PROPERTIES IN BOTH OBSERVATIONS AND A RANGE OF MODEL SIMULATIONS INCLUDING COUPLED MODEL INTERCOMPARISION PROJECT 5 (CMIP5). THE PROJECT HAS THREE PHASES. (1) QUANTIFY DESCRIBE AND UNDERSTAND THE STATISTICAL LINKAGES BETWEEN CLOUDS AND CLOUD INFLUENCING FACTORS SUCH AS ATMOSPHERIC DYNAMICS THERMODYNAMICS AND SEA ICE IN CMIP5 MODELS AND OBSERVATIONS; (2) COMPARE MODELS AND OBSERVATIONS EXPLAIN AND ATTRIBUTE INTER-MODEL DIFFERENCES IN ARCTIC CLOUDS TO INDIVIDUAL CLOUD INFLUENCING FACTORS FOCUSING ON THE ANNUAL CYCLE; AND (3) ASSOCIATE MODEL ERRORS IN ARCTIC CLOUDS TO SPECIFIC MODEL PROCESSES USING CONDITIONAL COMPOSITING TO PINPOINT THE SITUATIONS IN WHICH MODELS FAIL. OUR UNDERSTANDING OF CLOUDS IS A MAJOR FACTOR LIMITING PREDICTION OF ANTHROPOGENICALLY-FORCED CHANGES IN SEA LEVEL THE CARBON CYCLE AND ATMOSPHERIC AND OCEANIC CIRCULATIONS. A CRITICAL GAP EXISTS IN OUR DETAILED UNDERSTANDING OF THE FACTORS THAT CONTROL ARCTIC CLOUD BEHAVIOR IN CLIMATE MODELS. THIS GAP MUST BE ADDRESSED TO MAKE PROGRESS AND IMPROVE OUR MODELS. THE PROPOSED COMPUTATION AND ANALYSIS OF THE STATISTICAL LINKAGES BETWEEN ARCTIC CLOUDS AND THE MANY CLOUD INFLUENCING FACTORS WITHIN CMIP5 CLIMATE MODELS AND OBSERVATIONS WILL FILL A GAP IN OUR UNDERSTANDING OF HOW DYNAMIC THERMODYNAMIC AND SURFACE SEA ICE CHARACTERISTICS INFLUENCE SIMULATED ARCT