6 results on '"Schwarzkopf, M.D."'
Search Results
2. The radiative signature of upper tropospheric moistening
- Author
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Soden, Brian J., Jackson, Darren L., Ramaswamy, V., Schwarzkopf, M.D., and Huang, Xianglei
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Greenhouse gases -- Research -- Growth -- Analysis ,Troposphere -- Observations -- Analysis -- Research ,Climate -- Research -- Analysis ,Company growth ,Science and technology - Abstract
Climate models predict that the concentration of water vapor in the upper troposphere could double by the end of the century as a result of increases in greenhouse gases. Such moistening plays a key role in amplifying the rate at which the climate warms in response to anthropogenic activities, but has been difficult to detect because of deficiencies in conventional observing systems. We use satellite measurements to highlight a distinct radiative signature of upper tropospheric moistening over the period 1982 to 2004. The observed moistening is accurately captured by climate model simulations and [ends further credence to mode[ projections of future global warming., The importance of water vapor in regulating climate is undisputed. It is the dominant greenhouse gas, trapping more of Earth's heat than any other gaseous constituent (1). As the climate [...]
- Published
- 2005
3. The influence of ozone precursor emissions from four world regions on tropospheric composition and radiative climate forcing
- Author
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Fry, M.M., Naik, V., Duncan, B.N., Hess, P., MacKenzie, I.A., Marmer, E., Schultz, M.G., Szopa, S., Wild, O., Zeng, G., West, J.J., Schwarzkopf, M.D., Fiore, A.M., Collins, W.J., Dentener, F.J., Shindell, D.T., Atherton, C., and Bergmann, D.
- Subjects
ddc:550 - Abstract
Ozone (O-3) precursor emissions influence regional and global climate and air quality through changes in tropospheric O-3 and oxidants, which also influence methane (CH4) and sulfate aerosols (SO42-). We examine changes in the tropospheric composition of O-3, CH4, SO42- and global net radiative forcing (RF) for 20% reductions in global CH4 burden and in anthropogenic O-3 precursor emissions (NOx, NMVOC, and CO) from four regions (East Asia, Europe and Northern Africa, North America, and South Asia) using the Task Force on Hemispheric Transport of Air Pollution Source-Receptor global chemical transport model (CTM) simulations, assessing uncertainty (mean +/- 1 standard deviation) across multiple CTMs. We evaluate steady state O-3 responses, including long-term feedbacks via CH4. With a radiative transfer model that includes greenhouse gases and the aerosol direct effect, we find that regional NOx reductions produce global, annually averaged positive net RFs (0.2 +/- 0.6 to 1.7 +/- 2 mWm(-2)/TgN yr(-1)), with some variation among models. Negative net RFs result from reductions in global CH4 (-162.6 +/- 2 mWm(-2) for a change from 1760 to 1408 ppbv CH4) and regional NMVOC (-0.4 +/- 0.2 to -0.7 +/- 0.2 mWm(-2)/Tg C yr(-1)) and CO emissions (-0.13 +/- 0.02 to -0.15 +/- 0.02 mWm(-2)/Tg CO yr(-1)). Including the effect of O-3 on CO2 uptake by vegetation likely makes these net RFs more negative by -1.9 to -5.2 mWm(-2)/Tg N yr(-1), -0.2 to -0.7 mWm(-2)/Tg C yr(-1), and -0.02 to -0.05 mWm(-2)/Tg CO yr(-1). Net RF impacts reflect the distribution of concentration changes, where RF is affected locally by changes in SO42-, regionally to hemispherically by O-3, and globally by CH4. Global annual average SO42- responses to oxidant changes range from 0.4 +/- 2.6 to -1.9 +/- 1.3 Gg for NOx reductions, 0.1 +/- 1.2 to -0.9 +/- 0.8 Gg for NMVOC reductions, and -0.09 +/- 0.5 to -0.9 +/- 0.8 Gg for CO reductions, suggesting additional research is needed. The 100-year global warming potentials (GWP(100)) are calculated for the global CH4 reduction (20.9 +/- 3.7 without stratospheric O-3 or water vapor, 24.2 +/- 4.2 including those components), and for the regional NOx, NMVOC, and CO reductions (-18.7 +/- 25.9 to -1.9 +/- 8.7 for NOx, 4.8 +/- 1.7 to 8.3 +/- 1.9 for NMVOC, and 1.5 +/- 0.4 to 1.7 +/- 0.5 for CO). Variation in GWP(100) for NOx, NMVOC, and CO suggests that regionally specific GWPs may be necessary and could support the inclusion
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- 2012
4. Fingerprint of ozone depletion in the spatial and temporal pattern of recent lower-stratospheric...
- Author
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Ramaswamy, V. and Schwarzkopf, M.D.
- Subjects
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OZONE layer depletion , *GLOBAL warming - Abstract
Investigates the role of ozone losses in affecting patterns of temperature change by incorporating the observed increase in stratospheric ozone concentrations from 1979 to 1990 into a general circulation model of the atmosphere.
- Published
- 1996
- Full Text
- View/download PDF
5. Radiative forcing of climate from halocarbon-induced global stratospheric ozone loss.
- Author
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Ramaswamy, V. and Schwarzkopf, M.D.
- Subjects
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ATMOSPHERIC research - Abstract
Determines the radiative forcing of the surface-troposphere system due to the observed decadal ozone losses, and compares it with that due to the increased concentrations of the other main radiatively active gases. Results that suggest that the net decadal contribution of CFCs to the greenhouse climate forcing is substantially less than previously estimated; Details; The Geophysical Fluid Dynamics Laboratory (GFDL); More.
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- 1992
- Full Text
- View/download PDF
6. SPEAR: The Next Generation GFDL Modeling System for Seasonal to Multidecadal Prediction and Projection
- Author
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Paul Ginoux, Hiroyuki Murakami, Shian‐Jian Lin, Fanrong Zeng, Baoqiang Xiang, Salvatore Pascale, Feiyu Lu, David Paynter, Mitchell Bushuk, Thomas L. Delworth, Elena Shevliakova, Liping Zhang, Nathaniel C. Johnson, Seth Underwood, Jan-Huey Chen, Sarah B. Kapnick, Honghai Zhang, Vaishali Naik, M. D. Schwarzkopf, Krista A. Dunne, R. Gudgel, Lucas M. Harris, Xiaosong Yang, Robert Hallberg, William Cooke, Matthew Harrison, Ming Zhao, Paul C.D. Milly, Anthony Rosati, Andrew T. Wittenberg, Sergey Malyshev, Alistair Adcroft, Delworth T.L., Cooke W.F., Adcroft A., Bushuk M., Chen J.-H., Dunne K.A., Ginoux P., Gudgel R., Hallberg R.W., Harris L., Harrison M.J., Johnson N., Kapnick S.B., Lin S.-J., Lu F., Malyshev S., Milly P.C., Murakami H., Naik V., Pascale S., Paynter D., Rosati A., Schwarzkopf M.D., Shevliakova E., Underwood S., Wittenberg A.T., Xiang B., Yang X., Zeng F., Zhang H., Zhang L., and Zhao M.
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Global and Planetary Change ,lcsh:Oceanography ,Climatology ,General Circulation Model ,global climate models ,General Earth and Planetary Sciences ,Environmental Chemistry ,Environmental science ,lcsh:GC1-1581 ,Spear ,Projection (set theory) ,lcsh:GB3-5030 ,lcsh:Physical geography - Abstract
We document the development and simulation characteristics of the next generation modeling system for seasonal to decadal prediction and projection at the Geophysical Fluid Dynamics Laboratory (GFDL). SPEAR (Seamless System for Prediction and EArth System Research) is built from component models recently developed at GFDL—the AM4 atmosphere model, MOM6 ocean code, LM4 land model, and SIS2 sea ice model. The SPEAR models are specifically designed with attributes needed for a prediction model for seasonal to decadal time scales, including the ability to run large ensembles of simulations with available computational resources. For computational speed SPEAR uses a coarse ocean resolution of approximately 1.0° (with tropical refinement). SPEAR can use differing atmospheric horizontal resolutions ranging from 1° to 0.25°. The higher atmospheric resolution facilitates improved simulation of regional climate and extremes. SPEAR is built from the same components as the GFDL CM4 and ESM4 models but with design choices geared toward seasonal to multidecadal physical climate prediction and projection. We document simulation characteristics for the time mean climate, aspects of internal variability, and the response to both idealized and realistic radiative forcing change. We describe in greater detail one focus of the model development process that was motivated by the importance of the Southern Ocean to the global climate system. We present sensitivity tests that document the influence of the Antarctic surface heat budget on Southern Ocean ventilation and deep global ocean circulation. These findings were also useful in the development processes for the GFDL CM4 and ESM4 models.
- Published
- 2020
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