HR: 1020h
AN: PP52A-0661    [Abstracts]
TI: Determination of Solar Cycle and Natural Climate Variation Using Both Surface Air/Soil Temperature and Thermal Diffusion Model
AU: * Dong, X
EM: dong@aero.und.edu
AF: University of North Dakota, PO Box 9006, Grand Forks, ND 58202 United States
AU: Gosnold, W
EM: willgosnold@mail.und.nodak.edu
AF: University of North Dakota, PO Box 9006, Grand Forks, ND 58202 United States
AB: Daily air and soil temperatures over KS, NE, SD and ND were obtained from High Plains Regional Climate Center (HPRCC) in Lincoln, NE from May 19, 1981 to December 31, 2003. A least-squares fit of the first five years of data is performed to determine the initial model temperature. A 2-D, finite-difference, conductive heat flow model was used with an initial condition T(x, 0) = 0 and boundary conditions of T(0, t) = the daily air/soil temperatures. The output of the model is a time series matrix of temperature vs. depth. The daily air/soil temperatures were averaged to compile a single record for each state and these data were used as the forcing signals in the model. The key to detection of the solar cycle and natural climate change is the filtering power of thermal diffusion which removes the short period signals (interannual) and retains the long period signals (decadal and centennial) in the upper 100 m. The temperature at a depth of 10 m has a good signal-to-noise ratio and represents 23 percent of its surface amplitude for the period of a solar cycle. There are two findings from this study: (1) Solar cycle, the temperature variations match the variations of the observed solar irradiance. This indicates that we can predict 11-yr solar cycles using both the surface air/soil temperatures as forcing signals in our thermal diffusion model. (2) Natural climate variation over the NGP during an 11-yr cycle ranges from 0.22 to 0.5 ^oC at 10 m deep and 0.42 to 0.94 ^oC at surface. This research is supported by NSF ATM-038384.
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
DE: 7537 Solar and stellar variability (1650)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005