A new global surface temperature reconstruction for the Last Glacial Maximum

Abstract. We present a new reconstruction of surface air temperature and sea for the Last Glacial Maximum. The method blends model fields sparse proxy-based point estimates through data assimilation approach. Our updates that Annan Hargreaves (2013), using full range general circulation (GCM) simulations which contributed to three generations PMIP database, major compilations gridded (SST) (SAT) from proxy data, an improved methodology based on ensemble Kalman filter. has global annual mean anomaly -4.5±0.9 ∘C relative pre-industrial climate. This is slightly colder than previous estimate with upwards revision uncertainty due different methodological assumptions. It is, however, substantially less cold recent Tierney et al. (2020). show main reason this discrepancy in choice prior. recommend use multi-model opportunity as potentially offering credible prior, but it important models included ensembles represent sources realistically comprehensively practicable if they are be used way.