In 1995, CGRER awarded seven seed grants totaling $95,909.
The Effects of Climate Variability on the Occurrence of Extreme Precipitation in the Upper Midwest
A. Allen Bradley established whether changes in atmospheric circulation patterns affect the probability of hydrologic extremes such as Iowa's 1993 floods. By using an innovative regional framework to detect and quantify changes in rainfall extremes, Bradley aimed to find linkages between climate variability and rainfall occurrence probabilities. His work established a regional baseline to quantify anomalous events such as the 1993 floods, and helped to assess the sensitivity of rainfall extremes to potential climate change.
A Numerical Study for the Global Carbon Cycle Through the Atmosphere/Terrestrial Biosphere/Ocean Interaction
Tsing-Chang Chen coupled the recently-developed Iowa Global Carbon Model with a global climatic change computer model that was developed at the National Center for Atmospheric Research (NCAR). This allowed him to combine the unique features of each: those in the Iowa model that assess interactions of the atmosphere, terrestrial biosphere, and ocean, with the features of the NCAR model that allow assessment of regional variations in the global temperature response to non-uniformly-changing CO2 concentrations.
An Investigation of the Effects of Uncertainties in Aerosol Mixing on Radiative Forcing Calculations
Annmarie Elderling studied the ability of atmospheric particles (pollutants such as sulfate aerosols) to cool the earth's temperature. Such particulates may counteract the global warming potential of steadily-rising greenhouse gases. However, calculations about the cooling effects of these particulates are based on several sweeping assumptions about the size composition of the particulate material. Eldering performed numerical studies to quantify the effects of these uncertainties to better understand the radiative properties of these particles.
Determination of the Fluxes and Origin of Methane in Glacingenic Deposits and Landfills of the Upper Midwest
Luis Gonzalez and Suellen Seimkuehler quantified and identified the sources of methane in soils and groundwater in sites in the Upper Midwest. More specifically, they developed methods for characterizing and differentiating between methane produced in landfills and normal background methane — that generated naturally from the loess and till sequences of central Iowa.
Paleoclimatology and Paleohydrology of the North American Interior in the Mid-Cretaceous “Greenhouse World”
Greg Ludvigson, Luis Gonzalez, Robert Brenner, and Brian Witzke investigated the history and variability of the continental climate during the global greenhouse warming of the Cretaceous Period. By measuring the oxygen isotopic ratios of freshwater carbonate minerals, and dating the non-marine deposits of our mid-continent in which these minerals are contained, they reconstructed air circulation patterns, rainfall patterns, temperature patterns, and other elements of the paleoclimate. Their data is useful to other investigators who are validating computer models simulating the Cretaceous climate system, which are significant because of the possibility of modern-day global warming.
Terrestrial-Atmospheric CO2 Exchange
James Raich and Christopher Potter looked at the well-documented seasonal cycle of atmospheric CO2 concentrations: atmospheric CO2 increases in the winter when it’s released from the soil, and decreases in the summer when it’s being stored in growing plants. These researchers coupled, tested, and refined existing computer models, so that they could estimate the seasonal and spatial patterns of this exchange of carbon (as CO2) between the atmosphere and terrestrial ecosystems around the globe.
Dating the Mississippi River Valley with a New Uranium-Series Technique
Mark Reagan proposed to develop a new radiometric technique for dating oxidation of sulfide minerals. He determined the timing of the growth of iron oxide minerals as they replace sulfides by using uranium-series isotopes. This new technique was used to investigate the history of the Mississippi River valley, a poorly understood topic. Reagan traced the river's down-cutting by dating water table levels in mines near the river, and dated other important geological phenomena such as cave formation and rock weathering rates.