The Intraseasonal and Interannual Variability of Arctic Temperature and Specific Humidity Inversions

Temperature and humidity inversions are common in the Arctic's lower troposphere, and are a crucial component of the Arctic's climate system. In this study, we quantify the intraseasonal oscillation of Arctic temperature and specific humidity inversions and investigate its interannual variability using data from the Surface Heat Balance of the Arctic (SHEBA) experiment from October 1997 to September 1998 and the European Centre for Medium-Range Forecasts (ECMWF) Reanalysis (ERA)-interim for the 1979-2017 period. In January 1998, there were two noticeable elevated inversions and one surface inversion. The transitions between elevated and surface-based inversions were associated with the intraseasonal variability of the temperature and humidity differences between 850 and 950 hPa. The self-organizing map (SOM) technique is utilized to obtain the main modes of surface and elevated temperature and humidity inversions on intraseasonal time scales. Low (high) pressure and more (less) cloud cover are related to elevated (surface) temperature and humidity inversions. The frequency of strong (weak) elevated inversions over the eastern hemisphere has decreased (increased) in the past three decades. The wintertime Arctic Oscillation (AO) and Arctic Dipole (AD) during their positive phases have a significant effect on the occurrence of surface and elevated inversions for two Nodes only.National Key Research and Development Program of China [2017YFE0111700]; Opening Fund of Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions, CAS [LPCC2018001, LPCC2018005]; Opening fund of State Key Laboratory of Cryospheric Science [SKLCS-OP-2019-09]; U.S. National Science FoundationOpen access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Multiscale modeling of nano/micro systems by a multiscale continuum field theory

This paper presents a multiscale continuum field theory and its application in modeling and simulation of nano/micro systems. The theoretical construction of the continuum field theory will be briefly introduced. In the simulation model, a single crystal can be discretized into finite element mesh as in a continuous medium. However, each node is a representative unit cell, which contains a specified number of discrete and distinctive atoms. Governing differential equations for each atom in all nodes are obtained. Material behaviors of a given system subject to the combination of mechanical loadings and temperature field can be obtained through numerical simulations. In this work, the nanoscale size effect in single crystal bcc iron is studied, the phenomenon of wave propagation is simulated and wave speed is obtained. Also, dynamic crack propagation in a multiscale model is simulated to demonstrate the advantage and applicability of this multiscale continuum field theory