An ensemble reconstruction of global monthly sea surface temperature and sea ice concentration 1000–1849

Abstract

This paper describes a global monthly gridded Sea Surface Temperature (SST) and Sea Ice Concentration (SIC) dataset for the period 1000–1849, which can be used as boundary conditions for atmospheric model simulations. The reconstruction is based on existing coarse-resolution annual temperature ensemble reconstructions, which are then augmented with intra-annual and sub-grid scale variability. The intra-annual component of HadISST.2.0 and oceanic indices estimated from the reconstructed annual mean are used to develop grid-based linear regressions in a monthly stratified approach. Similarly, we reconstruct SIC using analog resampling of HadISST.2.0 SIC (1941–2000), for both hemispheres. Analogs are pooled in four seasons, comprising of 3-months each. The best analogs are selected based on the correlation between each member of the reconstructed SST and its target. For the period 1780 to 1849, We assimilate historical observations of SST and night-time marine air temperature from the ICOADS dataset into our reconstruction using an offline Ensemble Kalman Filter approach. The resulting dataset is physically consistent with information from models, proxies, and observations.

A decade of cold Eurasian winters reconstructed for the early 19th century

“…S7d ). A recent sea-surface temperature reconstruction 30 (Fig. S7e ) shows warming off the coast of Newfoundland, perhaps supporting BRW CCC and BRW NCAR more than EKF400v2.…”

“…Further linkages might involve the oceans. The climate system and particularly the oceans recovered only slowly from the sequence of eruptions in the early 19th century 30 . In a recent sea-surface temperature reconstruction 30 (Fig.…”

“…The climate system and particularly the oceans recovered only slowly from the sequence of eruptions in the early 19th century 30 . In a recent sea-surface temperature reconstruction 30 (Fig. S6e ), the period 1808/9–1815/6 is cooler than the reference period, especially in the tropics, but with warmer-than-average regions in the North Atlantic.…”

A Bayesian Approach to Historical Climatology for the Burgundian Low Countries in the 15<sup>th</sup> Century

“…In first place we have Historical simulations for Palaeo-RA -Past 600 years with Observed forcings (HIPPO) which are composed of 40 full-forcing members of the ECHAM 6.3 model with T63 horizontal and L47 vertical resolutions. Sea Surface Temperatures (SST) and Sea Ice Conditions (SIC) have been prescribed from either Samakinwa et al (2021) or HadISST2 (Titchner and Rayner, 2014), using for the latter 10 different realizations so that SST and SIC uncertainties are taken into account. Vegetation and Land Use / Land Change (LULC) have also been prescribed.…”

“…Vegetation and Land Use / Land Change (LULC) have also been prescribed. Moreover, almost all radiative forcings have been selected following CMIP6 / PMIP4 past2k specifications (Jungclaus et al, 2017) with standard PMIP4 volcanic forcings (e.g., Sigl et al, 2015;Toohey and Sigl, 2017) for the first 20 members and Samakinwa et al (2021) for the remaining members of the ensemble.…”