John Krasting
Stephanie WeberThe instrumental record of global climate is no more than 150 years long, so there are limitations in focusing solely on this relatively recent period. Changes in climate forcing during this time have been modest, particularly when compared to projected 21st century changes due to human activities. The instrumental climate record is also too short to unambiguously identify low-frequency climate variability. To address both of these limitations, much of my research involves comparisons of climate model simulations with the paleoclimate record, which contains abundant evidence of large changes in climate in the more distant past. My research has involved a broad range of topics including the climate of the last ice age, the effects of mountains on regional aridity, the response of climate to changes in the earth’s orbit, and the response of the tropical circulation to high-latitude climate forcing.
Some of my research has also focused on the analysis of simulations of climate variations during the period of instrumental records, when climate data are most abundant and comprehensive. For instance, I have attempted to identify the roles of natural and anthropogenic forcing in the changes in climate that have been observed during the 20th century. Thus my efforts to compare climate model simulations with the climate record proceed from two complementary approaches: modeling the distant past, in which climate changes are relatively large but data are uncertain, and modeling the more recent era, in which climate changes are more modest but more precise data are available. Over the next ten to twenty years, distinctions between these two approaches will diminish as more sophisticated methods are used to extend the climate record backward in time using paleoclimatic and paleoceanographic data.
Research Group
Graduate Students:
John Krasting
Stephanie Weber
We have begun a quantitative analysis of the feedback processes operating in the new climate models under development at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory (GFDL). We are currently attempting to quantify the importance of individual radiative feedback mechanisms in each version of the model and compare a number of different methods of diagnosing radiative feedbacks. Ultimately, we would like to better understand the physical mechanisms responsible for differences in climate sensitivity among models. The proposed research will be coordinated with the National Center for Atmospheric Research (NCAR), which will pursue similar goals in analyzing results from their latest climate model.
http://www.envsci.rutgers.edu/~broccoli/research.html
Written by A. J. Broccoli
Last Updated: April 19, 2006