EdGCM http://edgcm.columbia.edu Sat, 17 May 2008 08:30:56 +0100 FeedCreator 1.7.2 http://edgcm.columbia.edu/images/M_images/joomla_rss.png http://edgcm.columbia.edu EdGCM http://edgcm.columbia.edu/content/view/78/115/ Submitted in partial fulfillment of: Course No. AOS 331, Prof. Jack Williams, Dept of Geography, Univ. of Wisconsin - Madison. Fall 2006 The early anthropogenic hypothesis by William Ruddiman posits that human influence on climate may have actually begun thousands, not hundreds, of years ago. Increased greenhouse gas levels were not solely caused by greenhouse gas emissions from fossil fuel burning after the start of the Industrial Revolution, but also caused by our ancestors’ first agricultural developments. The resultant rise in temperature then delayed the glacial onset that should have occurred naturally. Through climate simulations with the EdGCM model, we compared pre- and post-industrial levels to estimated natural levels for five greenhouse gases: carbon dioxide, methane, nitrous oxide, and two chlorofluorocarbons (CFCs). Our results put our model at, or very close to, an incipient glacial state, supporting the hypothesis of an overdue glaciation. Outreach - Student Projects Wed, 09 May 2007 14:38:50 +0100 http://edgcm.columbia.edu/outreach/student_projects/snowball_earth_student.html Geologic evidence suggests that during the Sturtian period (~750Ma) of the Neoproterozoic Era the Earth was blanketed by snow and ice. Glacial deposits are found on all continents, including regions that were at low latitudes. Hoffman et al. (1998) brought the snowball Earth hypothesis to the forefront of paleoclimatic scientific interest by offering a specific explanation for the presence of glacial rock formations in mid to low latitude regions, the occurrence of cap carbonates, and the apparent collapse in surface ocean microorganisms. Our experiments using EdGCM examine the possibility that altered obliquity is an alternative possibility for the formation of low latitude glacial deposits. Submitted in partial fulfillment of: Course No. AOS 331, Prof. Jack Williams, Dept of Geography, U. Wisconsin - Madison. Fall 2006 Outreach - Student Projects Wed, 09 May 2007 14:38:50 +0100 http://edgcm.columbia.edu/outreach/exercises/greenland.html Tracking the changes in temperature and snowfall over Greenland is of great interest to scientists because of the concern that global warming could lead to a melting of the Greenland ice sheet and add to rising sea levels. We are interested in using EdGCM to explore whether or not the climate model can give us insight into the potential for snow to increase in a warming climate, especially over Greenland. Outreach - Exercises Sun, 11 Dec 2005 11:18:09 +0100 http://edgcm.columbia.edu/content/view/59/107/ The following exercise explores the topic of Global Warming, but first it discusses how you would use a global climate model, and EdGCM, to construct the appropriate Modern climate control runs that are used as the base map for all climate change simulations. This exercise is used at many of our EdGCM training workshops and is a standard for getting started with EdGCM. The simulations used in this exercise come pre-installed with EdGCM 2.4 to EdGCM 3.0. Outreach - Exercises Mon, 06 Mar 2006 12:27:36 +0100 http://edgcm.columbia.edu/outreach/showcase/snowball_earth_750ma.html Extreme glacial events, the so-called "snowball Earth" intervals, are by far the coldest periods in Earth history, with evidence of ice sheets existing even in tropical regions. By trying to identify the key climate forcings that could have led to such cold conditions, we seek to understand the full natural range of climate variability on Earth. In this report, we simulate the effects of major changes to certain climate forcings in an effort to reproduce, with our model, the climatic conditions suggested by the geologic record. We find that while the combination of reduced solar luminosity, atmospheric CO2 levels, and ocean heat transports does cool the planet significantly, it is still not sufficient to reproduce the first-order characteristics of the Sturtian snowball Earth glaciation. Outreach - Community Showcase Fri, 31 Mar 2006 07:34:38 +0100 http://edgcm.columbia.edu/outreach/showcase/cambodia.html While planning a vacation to Cambodia last fall, I decided to try using an EdGCM simulation to verify information provided in the tour guide books. Though one should not expect statistically significant results from one or two grid cells in a GCM, compared to the limited and qualitative climate information in guidebooks, I discovered that a climate model can provide much more... cloud cover (tanning), soil moisture and ground wetness (camping), wind speed (windsurfing), and diurnal temperature variation. EdGCM, and presumably higher-resolution GCMs, are capable of local scale studies when the scientific accuracy of the results does not require a high degree of quantitative precision. EdGCM provides similar information (spatially and temporally) as guide books and the CIA World Factbook and then provides many additional variables. Outreach - Community Showcase Fri, 12 May 2006 23:59:14 +0100 http://edgcm.columbia.edu/outreach/showcase/21k.html Our first Commmunity Showcase article was written by Paolo Zamparutti of MTG Climate (http://mtgclimate.it) in Italy, and was translated by Giuseppe Petricca. MTG Climate used EdGCM to recreate the climatic conditions of 21 thousand years ago, when our planet was at the peak of the last Ice Age (i.e. The Last Glacial Maximum). Outreach - Community Showcase Mon, 07 Nov 2005 12:00:00 +0100 http://edgcm.columbia.edu/outreach/showcase/21k2.html The first part of this investigation (http://edgcm.columbia.edu/outreach/showcase/21k.html) on the last Ice Age was published on MTG Climate (http://www.mtgclimate.it) in November. It focused on some aspects of the climate of 21 thousand years ago. Now we can use the data given by the Ice Age 21k (http://edgcm.columbia.edu/outreach/showcase/21k.html) simulation to understand what are the fundamental differences between the climate of today and the glacial one: in particular we will focus our attention on the thermal aspect. We will base our studies on a simulation that represents a medium condition of the Wurmian period, when there were some warm and favourable phases and some colder ones. Outreach - Community Showcase Mon, 27 Mar 2006 11:31:38 +0100 http://edgcm.columbia.edu/outreach/showcase/maunder_minimum.html Our second Community Showcase article involves a simulation of the Maunder Minimum. Author Tom Rees recreates the work done in a recent paper by Shindell et al., offering his own insights on the subject of the Maunder Minimum and climate change. Outreach - Community Showcase Tue, 20 Dec 2005 15:19:19 +0100