Aerosol feedbacks

Driver and partly aerosol feedbacks, for ACTMs or for NWP (data exchange with a limited time period) off-line or on-line access coupling, with or without the following iterations with corrected fields)... 

New computationally efficient chemical solver NWP-Chem 2008 First version with indirect aerosol feedbacks (Korsholm 2009)... 

Offline way of integration with reading ACTM output files by HIRLAM can also improve the NWP if aerosol feedback mechanisms are incorporated into HIRLAM. However, this way could be too expensive if high-resolution ACT forecast is available. For example, some tests can be done using the CAC, DERMA, EMEP, MATCH or SILAM models (considering feedbacks with Enviro-HIRLAM version). The OAS1S4 coupler software (Redler et ah, this volume) could be tested for this work. 

DMS has been observed in the marine atmosphere since the early 1970s, but it was not until the mid-1980s that there was interest in this gas as being a natural source for sulfate CCN. Sulfate aerosols are, in number terms, the dominant source of CCN. The major role clouds play in the climate system leads to possible climatic implications if changes to DMS production occurred. Furthermore, the dependence of this production on environment conditions means that scope for a feedback process arises this feedback is called the Charlson hypothesis. ... 

One such feedback is the influence of clouds and water vapor. As the climate warms, more water vapor enters the atmosphere. But how much And which parts of the atmosphere, high or low And how does the increased humidity affect cloud formation While the relationships among clouds, water vapor, and global climate are complicated in and of themselves, the situation is further complicated by the fact that aerosols exert a poorly understood influence on clouds. 

Schematic representation of global iron connections linked through the state of the land surface, aerosol loading, marine productivity, and climate. Positive feedbacks are represented by solid arrowheads and negative feedbacks by open circles. Feedbacks of uncertain sign are represented by open arrowheads. Linking mechanisms are in italics. Taps represent mechanisms that modulate primary processes. Source-. From Jickells, T. D., et al. (2005). Science, 308, 67-71. (See companion website for color version.)...

The concept of PAUR II is summarised schematically in the following way Stratospheric ozone variations, tropospheric ozone variations, aerosol origin and composition variations UV-B flux variations and variations in photodissociation rates Induced modulation and feedback of tropospheric O3 and other photochemical species Comparison of calculations with campaign observations. 

As Mitra (2004) pointed out, the Indian oceanic experiment (INDOEX) was the first complex problem-oriented observational international program aimed mainly at studies of the aerosol-induced radiative and climatic forcing of regional and global climate that take respective feedbacks into account. The preliminary stage of the accomplishment of INDOEX began in 1996-1997, and the basic part of complex observations was accomplished in 1998-1999 with the participation of specialists from different countries (India, U.S.A., Western Europe, Mauritius, and the Maldives). The obtained results were based on the use of surface, ship, aircraft, and satellite observational means. 

The main difficulty in understanding the causes of climate change is connected with the impossibility of considering climatic feedbacks sufficiently reliably. Primarily, this refers to cloud-radiation feedback, direct and indirect (by the effect on radiation properties of clouds) impacts of atmospheric aerosols on climate, and the impact of the atmosphere-ocean interaction on climate formation. 

Module of feedback mechamisms Direct gas aerosol forcing Cloud condensation nuclei model Other semidirect indirect effects... 

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