The Proceedings of the Eighth International Conference on Creationism (2018)

value, Shrag, DePaolo and Richter (1995) provide a reconstructed maximum temperature of 13 ˚C. With 24 ˚C oceans, global air temperatures became unacceptably high. To offset the additional heat arising from the warm oceans, stratospheric aerosols are added to the atmosphere with various distributions. In the wake of the flood it is also assumed that no ice sheets existed over the continents. This significantly affects the topography of Greenland and Antarctica. Although additional conditions need to be changed to match the post-flood environment, the following simulations were performed: Reference (Ref) – This reference run uses default initial and boundary conditions linked to a start date of 1900. Statistically, it should simulate modern day climate conditions. Warm Oceans (WO) – Beginning with the reference run, the ocean’s initial conditions were replaced with a uniform potential temperature of 24 ˚C. This uniform temperature extends from the equator to the poles and from the surface to the greatest depths. Since the ocean is dynamic, the temperature does not remain uniform, but develops over time. Since the simulation only runs for six years, there is not significant cooling of the oceans, but there is a redistribution of surface temperatures as reported in Gollmer (2013). Warm Oceans and Stratospheric Aerosols (WOSA) – Adding to the WO simulation, an optically thick aerosol layer is added. Although the aerosols are distributed through several layers of the stratosphere, the net optical thickness has a value of τ = 2.0 . Optical thickness is tied to the Beer-Lambert Law of transmission, which models intensity as I = I­ 0 e −τ . An optical thickness of 2.0 would reduce direct transmission of sunlight to 13.5% its original value and make the appearance of the sun indistinct in the sky. An aerosol load of this amount is equivalent to a Toba-level volcanic eruption. Warm Oceans, Stratospheric Aerosols and No Ice (WOSANI) – To remove the topographic impact of ice sheets on Greenland and Antarctica, the ice sheets are eliminated. The underlying landmass is exposed and its topography is used. If the ice sheet extends below sea level, it is lowered to sea level, but allowed to remain below this point. This does not account for buoyancy and isostatic rebound of the continents, which involve more significant changes in the boundary conditions. These considerations are saved for a future study. Other than the topographic changes, the conditions of the WOSA simulation are used. Land surface parameters are not changed where the ice sheet is removed; therefore, the albedo of the surface remains unchanged. This should not have a significant impact on the validity of the simulation since any initial buildup of snow and ice would have a similar albedo. Aerosols, Mid-latitude (AM) – Adding a uniform aerosol layer in the WOSA simulation has an effect on the jet stream, which is tied to storm tracks. Instead of using a uniform layer over the entire earth, a band of stratospheric aerosols are placed between 30˚ and 60˚ north latitude. Optical thickness of this band is τ = 2.0 . Other than this change to aerosol distribution, this simulation uses the same conditions as WOSANI. Aerosols, Polar (AP) – For the same reason the AM simulation is introduced, this simulation restricts the stratospheric aerosols to a band ranging from 45˚ to 90˚ north latitude. Other than this change, the simulation has the same conditions as WOSANI. MODEL SIMULATIONS: AEROSOLS AND WIND PATTERNS As discussed previously, the position of precipitation patterns depend on several factors. Although global circulation establishes a general pattern, thermal circulation becomes important when there is a temperature contrast between land and ocean. As demonstrated in Vardiman’s and Brewer’s work, individual weather events can make a significant contribution. However, these patterns are driven by upper-level winds and the position of the polar front, which are connected to the jet stream. These factors play into the behavior of surface winds and the precipitation patterns that ensue. The following is a summary of model comparisons with respect to these issues. Although monthly averages over the course of six simulation years were collected, this discussion will focus only on the last January of the simulation. This month provides the coolest temperatures for the North American continent and will give the best indication of where snowfall is expected. 1. Thermal Circulation Comparisons Figure 6 is a comparison of the temperature and pressure fields for the six simulations mentioned above. Since all except the reference run have warm oceans, the coldest continental temperatures exist in Figure 6a. Temperatures over Greenland are comparable to continental temperatures, but are colder in Figures 6a-c due to the presence of the ice sheet. This is not an albedo effect since this condition was not changed for any of the simulations. This is due, however, to an ice sheet that is up to three kilometers thick. With air temperatures over land being cold compared to ocean it is expected that high surface pressure would exist over land. This is borne out in each of the simulations. Reducing the pressure field to sea level for sake of comparison, each contour plot represents pressure as a departure from 1000 mb, which is close to one atmosphere. Contour lines are drawn in five millibar intervals with pressures below 1000 mb represented as dashed lines. The reference run shows the standard winter pressure pattern. A low pressure system called the Aleutian low is located in the North Pacific. There is a weaker low in the North Atlantic called the Icelandic low. Adding warm oceans (WO), Figure 6b, increases the surface temperature everywhere, but more dramatically towards the equator. The Aleutian low expands over a larger region and the Icelandic low is greatly reduced. High pressure is prominent over the Greenland ice sheet. This drives surface winds off land towards the ocean. Adding a uniform layer of aerosols (WOSA), Figure 6c, reduces all temperatures, but also reduces the temperature contrast between the equator and the pole. The Aleutian low in this case splits in two and shifts landward. This is also present in Figure 6d (WOSANI). In the North Atlantic the presence of the Greenland ice sheet provides the highest pressure in Figure 6c, but its absence in Figure 6d greatly reduces the pressure gradient force in this region. Non-uniform aerosol distributions (AM and AP), in Figures 6e and f restore the temperature contrast between the equator and Gollmer ◀ Post-Flood Ice Age precipitation ▶ 2018 ICC 701