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Note: links are provided to journal articles (abstracts and full articles), summaries written for non-specialists (popular summaries), or other relevant web sites.
Dr. Shindell's research is concerned with global climate change, climate variability, and Atmospheric Chemistry. He uses mathematical models of the atmosphere and oceans which run on supercomputers to investigate chemical changes such as the depletion of the ozone layer, climate changes such as global warming, and the connections between these two.
Within the general topics of long-term climate changes and atmospheric composition, his research can be grouped into several specific main areas.
While the average temperature of the Earth has been slowly increasing over recent decades, much larger warming trends have been seen over the Northern Hemisphere continents during winter (as shown in the figure below, based on the GISS Global Surface Air Temperatures. At the same time, the wintertime stratospheric vortex over the Arctic seems to have been increasing in strength (see for example the Nature (1998) reference in the 'Stratospheric ozone response to increasing greenhouse gases' section). Observations indicate that the two trends are closely related via dynamical coupling between the stratosphere and the troposphere. Similarly, changes in atmospheric circulation appear to have played a major role in the cooling seen over Antarctica during recent decades (see the figure below). We have been investigating the causes and impacts of these trends, with a focus on determining if the regional warming and cooling patterns result from natural variability or are due to human activities. Simulations have explored the response to volcanic eruptions, solar variations, greenhouse gas increases and polar ozone depletion. Historical datasets also show large regional variations. From the mid-1600s to the early 1700s, there is believed to have been a minimum in solar irradiance, called the Maunder Minimum. Concurrently, surface temperatures appear to have been at or near their lowest values of the last millenium in the Northern Hemisphere, and European winter temperatures were reduced by 1-1.5 C. We have simulated the difference between that period and a century later, when solar output remained relatively high over several decades. We find that changes in naturally occurring climate variability patterns can play a major role in large regional changes (especially cooling over North America and Europe as solar output decreases).
Southern Hemisphere climate response to ozone changes and greenhouse gas increases? Geophysical Research Letters, 2004. Abstract and full paper
General circulation modeling of Holocene climate variability. Quaternary Science Reviews, 2004. Abstract and full paper
Dynamic winter climate response to large tropical volcanic eruptions since 1600? Journal of Geophysical Research, 2004. Abstract and full paper.
Volcanic and solar forcing of climate change during the preindustrial era. Journal of Climate, 2003. Abstract and full paper.
The Sun vs the Volcano: Drivers of regional climate change. Popular summary.
How linear is the Arctic Oscillation response to greenhouse gases? Journal of Geophysical Research, 2002. Abstract and full paper.
Solar forcing of regional climate change during the Maunder Minimum. Science, 2001. Abstract and full paper.
Glaciers, Old Masters, and Galileo: The Puzzle of the Chilly 17th Century. Popular summary
Northern Hemisphere winter climate response to greenhouse gas, ozone, solar and volcanic forcing. Journal of Geophysical Research, 2001. Abstract and full paper.
Greenhouse Gas Influence on Northern Hemisphere Winter Climate Trends. Popular summary
Simulation of recent northern winter climate trends by greenhouse-gas forcing. Nature, 1999. Abstract and full paper.
Variations in the strength of solar radiation are thought to affect the Earth's climate, though their degree of influence is a subject of intense debate at present. Solar output varies both over the long-term (centuries), which will impact long-term climate trends, and over the shorter-term (the 11 year solar cycle). To understand if climate models are capable of simulating the long-term
atmospheric and climate response to solar irradiance changes, we first test
their ability to simulate the roughly 11 year solar cycle changes, which have
been observed from satellites over the past few decades. Variations in
temperatures, ozone amounts, and the altitude at which the atmosphere has a
given pressure have been correlated with the solar cycle. We test how well
our model can reproduce these observations, and thus gauge its ability to
simulate long-term climate responses to solar variations.
General circulation modeling of Holocene climate variability. Quaternary Science Reviews, 2004. Abstract and full paper.
The relative importance of solar and anthropogenic forcing of climate change between the Maunder Minimum and the present. Journal of Geophysical Research, 2004. Abstract and full paper.
Volcanic and solar forcing of climate change during the preindustrial era. Journal of Climate, 2003. Abstract and full paper.
GRIPS solar experiments intercomparison project: initial results. Papers in Meteorological and Geophysics, 2003. Abstract.
2xCO2 and solar variability influences on the troposphere through wave-mean flow interactions. Journal of the Meteorological Society of Japan, 2002. Abstract and full paper.
Solar forcing of regional climate change during the Maunder Minimum. Science, 2001. Abstract and full paper.
Solar Variability, Ozone, and Climate. Popular summary.
Northern Hemisphere winter climate response to greenhouse gas, ozone, solar and volcanic forcing. Journal of Geophysical Research, 2001. Abstract and full paper.
Solar Cycle Variability, Ozone, and Climate. Science, 1999. Abstract and full paper.
Effects of solar cycle variability on the lower stratosphere and the troposphere. Journal of Geophysical Research, 1999. Abstract.
The surface temperature of the Earth increased significantly during the twentieth century. Attribution of this warming is an extremely complex problem, however. We have investigated the changes in climate forcings, those factors external to the climate system which affect the global energy balance, to improve understanding of the relative importance of these factors in the observed global warming. These forcings can then be used to drive simulations with our climate model. This model can simulate past climates, and the results compared with observations, to evaluate its performance. This helps us to understand how confident we can be in its projections of future conditions.
Efficacy of climate forcings. Journal of Geophysical Research, 2005. Abstract and full paper.
An emissions-based view of climate forcing by methane and tropospheric ozone. Geophysical Research Letters, 2005. Abstract and full paper.
Present day atmospheric simulations using GISS ModelE: Comparison to in-situ, satellite and reanalysis data. Journal of Climate, 2006. Abstract and full paper.
Preindustrial-to-present-day radiative forcing by tropospheric ozone from improved simulations with the GISS chemistry-climate GCM. Atmospheric Chemistry and Physics, 2003. Abstract and full paper.
An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era. Atmospheric Chemistry and Physics, 2002. Abstract and full paper.
Climate forcings in Goddard Institute for Space Studies SI2000 simulations. Journal of Geophysical Research, 2002. Abstract and full paper.
Climate and ozone response to increased stratospheric water vapor. Geophysical Research Letters, 2001. Abstract and full paper.
The buildup of greenhouse gases in the Earth's atmosphere traps heat in the lower part of the atmosphere, leading to increased temperatures at the surface of the Earth (Global Warming). At higher altitudes in the atmosphere, temperatures decrease in response to increasing greenhouse gases. Additionally, increasing emissions of greenhouse gases will alter the composition of the stratosphere. While recent ozone trends have been driven largely by increases in halogen abundance resulting from chlorofluorocarbon (CFC) emissions, climate change will play an increasing role in governing ozone amounts in the future, and ozone changes will feed back on climate as ozone is itself a greenhouse gas. Current research combines the climate and chemistry changes in the GISS model to predict future ozone amounts both over the polar regions and at lower latitudes. Changes in stratospheric water vapor, also a greenhouse gas, and in transport between the troposphere and stratosphere are also current research topics.
Data from NASA satellites via the TOMS home page
Modelling atmospheric stable water isotopes and the potential for constraining cloud processes and stratosphere-troposphere water exchange. Journal of Geophysical Research, 2005 Abstract and full paper.
A comparison of model-simulated trends in stratospheric temperatures. Quarterly Journal of the Royal Meteorological Society, 2003. Abstract and full paper.
Whither Arctic Climate? Science, 2003. Abstract and full paper.
Uncertainties and assessments of chemistry-climate models of the stratosphere. Atmospheric Chemistry and Physics, 2003. Abstract and full paper.
An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era. Atmospheric Chemistry and Physics, 2002. Abstract and full paper.
Dynamic-chemical coupling of the upper troposphere and lower stratosphere region. Chemosphere, 2002. Abstract.
Separating the influence of halogen and climate changes on ozone recovery in the upper stratosphere. Journal of Geophysical Research, 2002. Abstract.
Impact of future climate and emission changes on stratospheric aerosols and ozone. Journal of the Atmospheric Sciences, 2002. Abstract.
Climate and ozone response to increased stratospheric water vapor. Geophysical Research Letters, 2001. Abstract and full paper.
Reaction of Ozone and Climate to Increasing Stratospheric Water Vapor. Popular summary.
Radiative cooling by stratospheric water vapor: big differences in GCM results. Geophysical Research Letters, 2001. Abstract.
The impact of greenhouse gases and halogenated species on the future solar UV radiation doses. Geophysical Research Letters, 2000. Abstract.
Interannual variability of the Antarctic ozone hole in a GCM. Part 2: A comparison of unforced and QBO induced variability. Journal of the Atmospheric Sciences, 1999. Abstract.
Why do the Ozone Holes Vary in Size? Popular summary.
Increased Polar Stratospheric Ozone Losses and Delayed Eventual Recovery owing to Increasing Greenhouse Gas Concentrations. Nature, 1998. Abstract and full paper.
Are Increasing Greenhouse Gases creating an Arctic Ozone Hole? Popular summary.
Climate Change and the Middle Atmosphere. Part IV: Ozone Photochemical response to Doubled CO2. Journal of Climate, 1998. Abstract .
Climate Change and the Middle Atmosphere. Part III: The Doubled CO2 Climate Revisited. Journal of Climate, 1998. Abstract.
The potential influence of ClO O2 on stratospheric ozone depletion chemistry. Journal of Atmospheric Chemistry, 1997. Abstract.
Interannual variability of the Antarctic ozone hole in a GCM. Part 1: The influence of tropospheric wave variability. Journal of the Atmospheric Sciences, 1997. Abstract.
Limits on heterogeneous processing in the Antarctic spring vortex from a comparison of measured and modeled chlorine. Journal of Geophysical Research, 1997. Abstract.
Chlorine monoxide in the Antarctic spring vortex. 2. A comparison of measured and modeled diurnal cycling over McMurdo Station, 1993. Journal of Geophysical Research, 1996. Abstract.
The chlorine budget of the lower polar stratosphere: Upper limits on ClO, and implications of new Cl2O2 photolysis cross sections. Geophysical Research Letters, 1995. Abstract
As greenhouse gases warm the Earth's lower atmosphere (the troposphere), they
will change the rate of chemical reactions there. Furthermore, the abundance of
key chemical species such as methane and water vapor will change. Over the
long-term, emissions of chemicals that lead to ozone formation (primarily
nitrogen oxides from industrial pollution) will also change as energy use
patterns change, especially in developing countries. Changes in the amount of
ozone in the atmosphere which result from these emissions will affect the
Earth's climate. Changes in the chemical cleansing power (the oxidation
capacity) of the troposphere will affect the ability of the atmosphere to
remove pollutants released into it at the surface, and therefore may alter the
amount of ozone depleting molecules reaching the stratospheric ozone layer.
We are investigating the effects of long-term emissions trends using a version of the GISS climate model that includes atmospheric chemistry. Prediction of long-term trends in climate, surface ultraviolet radiation (dependent upon ozone levels), and air pollution (having adverse affects on human health in urban areas, and on agriculture in farming areas) are our goals. The composition simulated in the model is evaluated against a range of observations, including aircraft, balloon and satellite measurements.
Modelling atmospheric stable water isotopes and the potential for constraining cloud processes and stratosphere-troposphere water exchange. Journal of Geophysical Research, 2005. Abstract and full paper.
Impacts of chemistry-aerosol coupling on tropospheric ozone and sulfate simulations in a general circulation model. Journal of Geophysical Research, 2005. Abstract and full paper.
An emissions-based view of climate forcing by methane and tropospheric ozone. Geophysical Research Letters, 2005. Abstract and full paper.
Impacts of climate change on methane emissions from wetlands. Geophysical Research Letters, 2004. Abstract and full paper.
The impact of horizontal transport on the chemical composition in the tropopause region: Lightning NOx and streamers. Advances in Space Research, 2004. Abstract and full paper.
Preindustrial-to-present-day radiative forcing by tropospheric ozone from improved simulations with the GISS chemistry-climate GCM. Atmospheric Chemistry and Physics, 2003. Abstract and full paper.
Sensitivity studies of oxidative changes in the troposphere in 2100 using the GISS GCM. Atmospheric Chemistry and Physics, 2003. Abstract and full paper.
Atmospheric composition, radiative forcing and climate change as a consequence of a massive methane release from gas hydrates. Paleoceanography, 2003. Abstract and full paper.
An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era. Atmospheric Chemistry and Physics, 2002. Abstract and full paper.
Dynamic-chemical coupling of the upper troposphere and lower stratosphere region. Chemosphere, 2002. Abstract.
Chemistry-climate interactions in the Goddard Institute for Space Studies general circulation model: 1. Tropospheric chemistry model description and evaluation. Journal of Geophysical Research, 2001. Abstract.
Chemistry-climate interactions in the Goddard Institute for Space Studies general circulation model 2. New insights into modeling the preindustrial atmosphere. Journal of Geophysical Research, 2001. Abstract.
Origin and variability of upper tropospheric nitrogen oxides and ozone at northern mid-latitudes. Atmospheric Environment, 2001. Abstract.
Climate change and a global city: The potential consequences of climate variability and change - Metro East Coast. Report for the U.S. Global Change Research Program, National Assessment of the potential consequences of climate variability and change for the United States, 2001
Atmospheric composition and climate have been intertwined for billions of years, especially via methane, which is both a powerful greenhouse gas and is chemically reactive. Simplified versions of our climate model have been used to study composition-climate interactions during the distant past (paleoclimate), providing information about the climate system's response to changes which provide insight into our potential future.
A note on the relationship between ice core methane concentrations and insolation. Geophysical Research Letters, 2004. Abstract and full paper.
Atmospheric composition, radiative forcing and climate change as a consequence of a massive methane release from gas hydrates. Paleoceanography, 2003. Abstract and full paper.
Dr. Shindell is also a Lecturer in the Department of Earth and Environmental Sciences at Columbia University in New York City
Atmospheric Composition
The Physics of the Atmosphere
Fundamentals of Atmospheric Chemistry
Stratospheric Chemistry and Ozone
Tropospheric Chemistry
Our Understanding of Atmospheric Chemistry
Text: Chemistry of Atmospheres, R. P. Wayne, Oxford Science Pub.
Reference: Aeronomy of the Middle Atmosphere, G. Brasseur and S. Solomon, D. Reidel, 1986
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