Title: Temporal and Spatial Variation of Global Coronal Temperature and Emission Measure Derived from Solar Soft X-ray Imagers. Author: Aki Takeda (Montana State University) Abstract: Our Sun is the only star we can resolve its surface structures. Observing the Sun in soft X-ray is an effective way to diagnose the million Kelvin plasma that constitutes a vast majority of solar corona. Long-term monitoring of the Sun by acquiring soft X-ray images naturally provides richer information on the solar corona than the observations with spectrometers or flux sensors in which spatial information is typically integrated and lost. Takeda et al.(2019) calculated temperatures and emission measures applying the filter-ratio method on Yohkoh/SXT images obtained from 1991 through 2001. They demonstrated that the emission-measure weighted average of the spatially resolved temperatures are 20 to 30% lower than those derived from the integrated signals. The comparison of two approach may provide important perspective to interpret other stellar data. They also demonstrated the solar cycle variation of the emission measures of cool(<1.5MK), medium and hot(>2.5MK) components, which may be showing the global response of the corona to the magnetic evolution of the Sun. These analysis by Yohkoh/SXT, however, was made based only on the Northern hemispheric portion of data, because of the stray light pattern appeared on the Southern part of images. Similar study is on-going using Hinode/XRT data, but XRT is also suffering stray light problem since 2012 and considerable effort is being spent to estimate their effect on the temperature analysis. A set of full-Sun soft X-ray images constantly taken over a solar cycle with uniform quality would significantly improve the reliability of the current study.