Holocene and Last Glacial Maximum dust deposition rate: Updated global datasets and interpolated fields

COSENTINO, N. J.; TORRE, G.; LAMBERT, F.; ALBANI, SAMUEL; BORY, ALOYS J.-M.

Roma

Congreso; XXI INQUA Congress; 2023

INQUA

Mineral dust aerosols are a key component of the Earth system, as their dynamics are controlled by and affect climate through diverse mechanisms. To quantify the role of dust on climate variability at glacial-interglacial time scales, it is key to retrieve information on past dust activity as registered geologically in loess deposits, peat bogs, lake and marine sediments, and ice. The two main dust parameters that can be quantified from these archives include deposition rate and particle size distribution. Quantifying these parameters is essential for guiding Earth system simulations with prognostic dust.Several compilations of these parameters exist spanning the last ∼30 thousand years before present (ka BP), the newest released seven years ago. During these last years, there has been significant progress in the global coverage of paleo-dust proxies. Here, we update these previous compilations of global paleo-dust deposition flux and grain size observations. Two improvements are introduced. First, given the expected high variability of dust deposition fluxes during the last deglaciation, this new compilation discriminates between pre-industrial Holocene (PIH, year 1850 AD-11.7 ka BP) and Last Glacial Maximum (LGM, 19.0-26.5 ka BP) observations, filtering out dust flux constraints corresponding to the last deglaciation. Second, we derive an explicit uncertainty of bulk and <10-μm paleo-dust deposition fluxes, specific to each site and time period. We do so by compiling metadata necessary to calculate deposition fluxes, and their measurement uncertainties. Based on these new datasets and Climate-Krigger, a recently released global kriging interpolation algorithm, we will produce global interpolated fields of LGM and PIH dust deposition rate, including uncertainty maps that consider both data density and measurement error.We obtained more than 200 LGM and more than 350 PIH records of bulk and <10-micron dust deposition rate. During the session, we will discuss these new datasets and the resulting interpolation and uncertainty maps, and what new insights they provide on last glacial-interglacial dust activity compared to previous compilation efforts.