Mineral dust in Greenland ice cores exhibit systematic variations of size distribution and particle concentration changes. East Asian deserts are the dominant source area for dust transported to Greenland. The concentration of dust is low during warm periods while cold phases correspond to high particle concentration. Regarding the size distribution, larger particles were found during colder climates and vice versa. The variability of dust concentrations in Greenlandic ice cores is due to changes both during transport and in the dust sources. Dust size spectra provide information on transport time changes in the past with larger particles surviving only during faster transport. Further investigations regarding a seasonal resolution of dust deposition and dust size data are in progress. The aim of the project is to study the dust deposition in seasonal-to-interannual resolution using dust concentration and size measurements on selected time slices in the NorthGRIP ice core covering the period approximately from 50000 yr BP until 2000 yr BP. Analysis of high resolution dust measurements provide detailed information about past abrupt climate fluctuations that occurred within a short period of time. For the dust measurements Multisizer COULTER COUNTER (CC) is used. The CC is a multi-channel analyzer which provides particle sizing and counting within an overall size range of 0.7 µm to 18 µm. Single particle volumes are measured in liquid samples. A new method to achieve a higher temporal resolution from the NGRIP ice core has been developed. This apparatus enables to sample the ice core in mm resolution without contamination and has been already tested on an Antarctic ice core. First measurements in the NGRIP ice cores using this method will be presented here.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.1: Past Polar Climate and inter-hemispheric Coupling