

Monday, 23 January 2012: 4:30 PM
Observed Changes in Surface Atmospheric Energy Over Land
Room 355 (New Orleans Convention Center )
Thomas C. Peterson, NOAA/NESDIS/NCDC, Asheville, NC; and K. M. Willett and P. Thorne


The temperature of the surface atmosphere over land has been rising during recent decades. But surface temperature, or, more accurately, enthalpy which can be calculated from temperature, is only one component of the energy content of the surface atmosphere. The other parts include kinetic energy and latent heat. It has been advocated in certain quarters that ignoring these additional terms somehow calls into question global surface temperature analyses. Examination of all three of these components of atmospheric energetics reveals a significant increase in global surface atmospheric energy since the 1970s. Kinetic energy has decreased but by over two orders of magnitude less than the increases in either enthalpy or latent heat which provide approximately equal contributions to the global increases in heat content. To put this increase in atmospheric energy into perspective, a cylinder of air 100 m in diameter and two m high is gaining an equivalent amount of energy as that required to raise a 1,500 kg SUV at a rate of 700 meters per decade. A 9.5 kg bicycle gaining that much gravitational potential energy would, after 10 years, be just above the mesosphere at an elevation of 114 km. The total increase in energy of the lower two meters of the atmosphere over land, 1.9 x 1017 J decade-1, is large but still three orders of magnitude less than the concurrent increase in heat content of the top two meters of the ocean and five orders of magnitude less than the concurrent increases in ocean heat content from 0 to 700 m depth.


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