Upstream flow effects revealed in the EastGRIP ice core using Monte Carlo inversion of a two-dimensional ice-flow model

Abstract. The Northeast Greenland Ice Stream (NEGIS) is the largest active ice stream on Sheet (GrIS) and a crucial contributor to ice-sheet mass balance. To investigate ice-stream dynamics gain information about past climate, deep core drilled in upstream part of NEGIS, termed East Ice-core Project (EastGRIP). Upstream flow can introduce climatic bias into cores through advection deposited under different conditions further upstream. This particularly true for EastGRIP due its location inside an eastern flank GrIS. Understanding ultimately correcting such effects requires atmospheric at time snow deposition. We use two-dimensional Dansgaard–Johnsen model simulate along three approximated lines between summit sheet (GRIP) EastGRIP. Isochrones are traced radio-echo-sounding images these dated with GRIP ice-core chronologies. observed depth–age relationship constrains Monte Carlo method which used determine unknown parameters. calculate backward-in-time particle trajectories source found present estimates surface elevation accumulation rates deposition site. Our results indicate that increased increasing distance predominantly responsible constant annual layer thicknesses upper column EastGRIP, inverted parameters suggest basal melting sliding important factors determining NEGIS. this study form basis applying corrections variety measurements, useful constraints more sophisticated modelling approaches future.