THE PROPOSED STUDY MAKES USE OF THE SSI OBSERVATIONS MADE BY NASA IN A TIMELY MANNER AND AIMS FOR INTEGRATING SUCH OBSERVATIONS INTO STANDARD EARTH SYSTEM MODEL SIMULATION PRACTICES. IN PRINCIPLES OBSERVED SSI FROM NASA SORCE AND TSIS CAN PROVIDE MORE RELIABLE AND ACCURATE INFORMATION TO THE EARTH SYSTEM MODELERS THAN THE MODEL BASED SSI DATA A POINT THAT WE TRY TO ESTABLISH FROM THE PROPOSED STUDIES. IF A SIGNIFICANT DIFFERENCE CAN BE SEEN FROM OUR PROPOSED PARALLEL SIMULATIONS IT WILL PROVIDE A COMPELLING JUSTIFICATION FOR ALL MODELING CENTERS TO ADOPT TSIS-BASED SSI DATA FOR A MORE REALISTIC SIMULATION OF THE CURRENT CLIMATE AND FUTURE CLIMATE CHANGE. THIS STUDY IS RELATED TO TWO BIG QUESTIONS FOR NASA S EARTH SCIENCE RESEARCH: HOW DOES THE EARTH SYSTEM RESPOND TO NATURAL AND HUMAN-INDUCED CHANGES PARTICULARLY THE NATURE CHANGES (VARIATIONS) FROM SOLAR IRRADIANCE AND HOW WILL THE EARTH SYSTEM CHANGE IN THE FUTURE?