Mid-Holocene high-resolution temperature and precipitation gridded reconstructions over China: Implications for elevation-dependent temperature changes

Driven by enhanced summer insolation in the Northern Hemisphere and land-atmosphere feedbacks during the mid-Holocene (MH), most regions of China were characterized by warmer and wetter summer than present. The MH has been recognized as a benchmark period for climate simulations, but proxy-based reconstructions and model results show some key discrepancies in climate reconstructions. A lack of accurate gridded climate data is a major obstacle to land surface modelling, which is contributing to uncertainties in climate simulations. Here we developed a monthly gridded dataset of temperature and precipitation for MH China through applying eight interpolation methods to 159 pollen-based climate reconstructions for January and July from previous studies. The gridded dataset is consistent with these input records and other independent climate reconstructions at 62 sites. Then, the temperature differences between the MH and pre-industrial period are correlated with elevations in China. Results show a significant elevation-dependent temperature amplification of 0.59 degrees C/km for July during the MH relative to pre-industrial period. In addition, our gridded reconstructions of the MH climate were compared with climate simulations for the MH and for the future medium-emission scenario. Most simulations significantly underestimated the magnitude of climate anomalies during the MH in China. Similar to the MH, a pronounced warming in winter and a strong wetting in summer are projected in China at the end of this century (i.e., 2091-2100), suggesting analogous seasonal changes during the MH and future. This first high-resolution proxy-based gridded climate dataset for MH China can be used in land surface modelling to improve our understanding of terrestrial changes during the MH, which in turn is expected to facilitate the climate simulations. (c) 2022 Elsevier B.V. All rights reserved.