A Study of Direct and Cloud-Mediated Radiative Forcing of Climate Due to Aerosols

<p>The Intergovernmental Panel on Climate Change (IPCC) has reported that in the southeastern US and eastern China the general greenhouse warming due to anthropogenic gaseous emissions is dominated by the cooling effect of anthropogenic aerosols. To verify this model prediction in eastern China and southeastern US we analyzed regional patterns of climate changes at 72 stations in eastern China during 1951- 94 (44 years) and at 52 stations in the southeastern US during 1949-94 (46 years) to detect the fingerprint of aerosol radiative forcing. It was found that the mean rates of change of annual mean daily maximum minimum temperatures and diurnal temperature range (DTR) in eastern China were 0.8 -0.2 1.8 and -2.0 C/100 years respectively while the mean rates of change of annual mean daily maximum minimum temperatures and DTR in the southeastern US were -0.2 -0.6 0.2 and -0.8 C/100 years respectively. This indicates that the high rate of increase in annual mean minimum temperature in eastern China results in a slightly warming trend of daily temperature while the high rate of decrease in annual mean maximum temperature and low rate of increase in annual mean minimum temperature lead to the cooling trend of daily temperature in the southeastern US. We found that the warming from the longwave forcing due to both greenhouse gases and aerosols was completely counteracted by the shortwave aerosol forcing in the southeastern US in the past 46 years. A slightly overall warming trend in eastern China is evident; winters have become milder. This finding is explained by hypothesizing that increasing energy usage during the past 44 years has resulted in more coal and biomass burning thus increasing the emission of absorbing soot and organic aerosols in eastern China. Such emissions in addition to well-known Asia dust and greenhouse gases may be responsible for the winter warming trend in eastern China that we have reported here.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>