Greenland ice sheet surface mass loss: recent developments in observation and modeling

Surface processes currently dominate Greenland ice sheet (GrIS) mass loss. We review recent developments in the observation and modelling of GrIS surface mass balance (SMB), published after the July 2012 deadline for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Since IPCC AR5 our understanding of GrIS SMB has further improved, but new observational and model studies have also revealed that temporal and spatial variability of many processes are still poorly quantified and understood, e.g. bio-albedo, the formation of ice lenses and their impact on lateral meltwater transport, heterogeneous vertical meltwater transport (‘piping’), the impact of atmospheric circulation changes and mixed-phase clouds on the surface energy balance and the magnitude of turbulent heat exchange over rough ice surfaces. As a result, these processes are only schematically or not at all included in models that are currently used to assess and predict future GrIS surface mass loss

An Approach For A Multi-Carrier Spread Spectrum System With Rake Receiver

Multi carrier spread spectrum is a new kind of modulation technique and can be viewed as the dual technique to direct sequence #1#. Hence manyinvestigations have been focussing on detection in the frequency domain #2#, #3#. However, we analyze the multi carrier spread spectrum #MC-SS# signal in the time domain. In out paper we compare time and frequency domain properties of both techniques, DS-SS and MC-SS and prove that the auto correlation function #ACF# of a MC code signal is independent from the code sequence in contrast to a DS code signal. Finally,we will show that the behavior of ACF allows the use of a time domain RAKE receiver for MC like it is used many DS systems