Assessing Goddard Institute for Space Studies ModelE aerosol climatology using satellite and ground-based measurements: A comparison study

Liu, L Lacis, AA Carlson, BE Mishchenko, MI Cairns, B

JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 111:D20 -

A physically based aerosol climatology is important to address questions of global climate change. We evaluate the aerosol climatology used in the GISS ModelE (Schmidt et al., 2006), by characterizing and comparing the geographic distribution and seasonal variability of aerosol optical depth (AOD) and particle size via Angstrom exponent (A) against available satellite and ground-based measurements, i.e., MODIS, MISR, POLDER, AVHRR, and AERONET data. There are a number of model parameters, particularly those related to aerosol size specification, that can be better constrained by comparison to satellite data. Our comparison shows that there are large differences in the satellite and ground-based global distributions of AOD. The differences between the observations increase for the Angstrom exponent. Given the uncertainties associated with satellite retrieval results, the agreement in the distributions of global optical depth between GCM aerosols and satellite data is qualitatively reasonable. However, the Angstrom exponent of the GCM aerosol is clearly biased low compared to satellite data, implying that the GCM aerosol sizes are overestimated. There is qualitative agreement of the ModelE aerosol single scattering albedo pi with TOMS Aerosol Index (AI) and AERONET data. The comparisons show insufficient aerosol absorption at most locations, suggesting a possible underestimation of black carbon distributions in the GCM. However, a more quantitative comparison first requires a readjustment of the GCM aerosol size specification.

melatonin:methods | /neutral/methods | 148

Eastern Pacific cooling and Atlantic overturning circulation during the last deglaciation

Kienast, M Kienast, SS Calvert, SE Eglinton, TI Mollenhauer, G Francois, R Mix, AC

NATURE 443:7113 846-849

Surface ocean conditions in the equatorial Pacific Ocean could hold the clue to whether millennial-scale global climate change during glacial times was initiated through tropical ocean - atmosphere feedbacks or by changes in the Atlantic thermohaline circulation(1). North Atlantic cold periods during Heinrich events and millennial-scale cold events (stadials) have been linked with climatic changes in the tropical Atlantic Ocean and South America(2-4), as well as the Indian and East Asian monsoon systems(5,6), but not with tropical Pacific sea surface temperatures(7). Here we present a high-resolution record of sea surface temperatures in the eastern tropical Pacific derived from alkenone unsaturation measurements. Our data show a temperature drop of 1 degrees C, synchronous ( within dating uncertainties) with the shutdown of the Atlantic meridional overturning circulation during Heinrich event 1, and a smaller temperature drop of 0.5 degrees C synchronous with the smaller reduction in the overturning circulation during the Younger Dryas event. Both cold events coincide with maxima in surface ocean productivity as inferred from Th-230-normalized carbon burial fluxes, suggesting increased upwelling at the time. From the concurrence of equatorial Pacific cooling with the two North Atlantic cold periods during deglaciation, we conclude that these millennial-scale climate changes were probably driven by a reorganization of the oceans’ thermohaline circulation, although possibly amplified by tropical ocean - atmosphere interaction as suggested before(8).

melatonin:paleo | /neutral/paleo | 167

Integration of ice-core, marine and terrestrial records for the Australian Last Glacial Maximum and Termination: a contribution from the OZ INTIMATE group

Turney, CSM Haberle, S Fink, D Kershaw, AP Barbetti, M Barrows, TT Black, M Cohen, T Correge, T Hesse, PP Hua, Q Johnston, R Morgan, V Moss, P Nanson, G Van Ommen, T Rule, S Williams, NJ Zhao, JX D’Costa, D Feng, YX Gagan, MK Mooney, S Xia, Q

JOURNAL OF QUATERNARY SCIENCE 21:7 751-761

The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is conflicting evidence for the degree of hemispheric ‘teleconnection’ and an unresolved debate as to the principle forcing mechanism(s). The available hypotheses are difficult to test robustly, however, because the few detailed palaeoclimatic records in the Southern Hemisphere are widely dispersed and lack duplication. Here we present climatic and environmental reconstructions from across Australia, a key region of the Southern Hemisphere because of the range of environments it covers and the potentially important role regional atmospheric and oceanic controls play in global climate change. We identify a general scheme of events for the end of the last glacial period and early Holocene but a detailed reconstruction proved problematic. Significant progress in climate quantification and geochronological control is now urgently required to robustly investigate change through this period. Copyright (c) 2006 John Wiley & Sons, Ltd.

melatonin:paleo | /neutral/paleo | 152

Technology options for capturing CO2

Elwell, LC Grant, WS

POWER 150:8 60-+

Concerns about global climate change have prompted interest in reducing or eliminating the carbon dioxide (CO2) emissions of fossil fuel-fired power plants. Here’s a guide to the technology and economics of three CO2 capture methods: postcombustion separation Of CO2 from flue gas (applicable to existing plants), and oxygen-fired combustion and precombustion capture (suitable for new coal-fired capacity, including IGCC plants).

melatonin:discuss | /neutral/discuss | 158

Impact of electric power generation on green house gas emissions in Europe: Russia, Greece, Italy and views of the EU Power Plant Supply Industry - a critical analysis

Hammons, TJ

INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 28:8 548-564

This paper analyses the impact of electric power generation on greenhouse gas emissions in Europe (including the Asian part of Russia) with reference to Russia, Greece, Italy, and views of the EU power plant supply industry in respect of the Kyoto protocol. The outlook of power industry development in Russia in the 21st century is first considered and its impact on Russia’s greenhouse gas emissions is examined. Forecasts for developing Russia’s economy and electric power industry in the first half of the 21st century are presented. Possible structural change in the electric power industry in Russia together with dynamic changes Of CO2 emissions from fuel combustion in power plants are examined. It is shown that CO2 emissions from fuel combustion at power plants in Russia may increase 2.7-fold in 50 years. Calculations depict that specific CO2 emissions in Asian Russia exceed greatly that of the European part. It then reviews measures to limit greenhouse gas emissions in Greece. Impact of the currently adopted measures and initiatives to reduce emissions in the Greek energy system for the period up to 2030 is discussed with emphasis on the current decade. Under the scenario for environmental policy, the additional commitments and measures to limit CO2 emissions towards the Kyoto targets are discussed. The paper summarizes a possible Italian strategy for implementing Kyoto protocol mechanisms to meet commitments of the EU Emission Trading Draft Directive, the Italian strategy in the Ministerial documents, and final considerations. It then examines clean power generation technology for the 21st Century and gives a perspective from the EU power plant supply industry. A perspective is presented with respect to impact of global climate change on product development strategy. Fossil fuel based power generation technologies will continue to play an important part of the energy mix in the foreseeable future and different parts of the world will require different technologies to meet their local specific requirements. It will be necessary to continue to develop clean technologies and to promote their use world-wide. (c) 2006 Elsevier Ltd. All rights reserved.

melatonin:discuss | /neutral/discuss | 171