Department of Climate and Space Sciences and Engineering in the College of Engineering at the University of Michigan

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Professor Huang in Proceedings of National Academy of Sciences

Posted: November 4, 2014

Professor Huang in Proceedings of National Academy of Sciences

A recent paper co-authored by Associate Professor Xianglei Huang and Postdoctoral Scholar Xiuhong Chen identified a new and unexplored mechanism that amplifies climate change in the Polar Regions and at high altitudes.

The amplification occurs by investigating the efficiency of energy emitted by the surface of the Earth at wavelengths longer than 15 microns. The lead author of this paper is Dr. Daniel Feldman from Lawrence Berkeley Laboratory, Department of Energy.

The paper is titled, “The Role of far-Infrared Surface Emissivity in Climate,” and is on early release of Proceedings of National Academy of Sciences this week.

Approximately half of thermal radiation emitted by the climate system to space comes from wavelengths longer than 15 microns, a portion of spectrum commonly referred as far infrared. However, the treatments of surface radiative properties in the far infrared in state-of-the-art climate models are still oversimplified. By first-principle calculation and validation against available laboratory and in-situ measurement, Huang and Chen have constructed a new data set for the global surface radiative properties in the far infrared.

This new data set has been incorporated into CESM (community earth system model), a flagship climate model in the United States, by the Lawrence Berkeley Laboratory team. Simulations were carried out to assess the impact of the new data set on the simulated climate change by the CESM. With 25 years of simulations, the model results show discernible difference at high latitudes areas by as much as 2K in surface temperature, 10 Wm-2 in outgoing longwave radiation, and 15 percent in frozen surface extent.

In a paper published on Geophysical Research Letters in September 2014, Huang, Chen and AOSS Professor Mark Flanner reported the impact of far-infrared surface properties on simulated radiation budget of high-latitude climate (click here to read more on this). This PNAS study makes important advances and further assesses the impact on the broad context of simulate climate projections.

The two papers together highlight the pressing need of improving treatments of such surface properties in the climate model.

To learn more, please visit PNAS.org.

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