Tingjun Zhang

TL;DR: In this paper, the authors present asynthesis of these observations, and conclude that roughly half of the pronounced recent rise in Northern Hemispherewinter temperatures reflects shifts in atmosphericcirculation. But, such changes are not consistent with anthropogenic forcing and include generally positive phases of the North Atlantic and ArcticOscillations and extratropical responses to the El-NinoSouthern Oscillation.

TL;DR: Contributing Authors: J.H. Box, D.O. Robinson, Ian Joughin, S. Smith, and D.W. Walsh.

TL;DR: In this article, the influence of seasonal snow cover on seasonally frozen ground has received relatively little attention and further study is needed, and further studies are needed to evaluate the impact of seasonal cover on the ground thermal regime.

TL;DR: In this article, the authors used the recently published digital version of the International Permafrost Association (IPA) Circum-Arctic map of permafrost and ground ice conditions (the IPA map), together with ancillary data sets of the global land cover characteristics data base and the Global Land One-kilometer Base Elevation data base, to investigate the distribution of ground ice in the Northern Hemisphere.

TL;DR: In this article, the authors use surface weather from three global climate models based on the moderate warming, A1B Intergovernmental Panel on Climate Change emissions scenario and the SiBCASA land surface model to estimate the strength and timing of the positive permafrost carbon feedback (PCF) and associated uncertainty.