Introduction

Research objectives | Effects on the Environment | How measurements are made | Measurement-based Assessments

Research objectives

Our main goal is to develop a measurement based description of the global aerosol system and its radiative forcing of climate. This will be done by attempts to reduce the uncertainty of the "Global Aerosol System," and by combining the latest global aerosol measurements, modeling, assimilation and analyses techniques.

The GASR investigation has three main objectives:

1. Aerosol optical thickness as measured on June 2003, image constructed from MODIS monthly average data: http://lake.nascom.nasa.gov/movas/

   Global aerosol system: Generate a measurement-based description of the global aerosol system, that includes the optical thickness, of the fine and coarse aerosols, aerosol absorption of sunlight, spectral reflection of sunlight to space, aerosol composition and an estimate of the anthropogenic component due to urban regional pollution and smoke aerosol. The result will be a data set, open to the community, and used here to assess the aerosol effects.

   

 

 

2. Global distribution of MODIS-observed aerosol radiative effect at top of atmosphere from the Terra satellite for Summer 2004 ( left) and Fall 2003 (right).

   Direct forcing: Describe the global distribution of the aerosol direct radiative forcing at the top of the atmosphere and at the surface. Generate profiles of the heating rates by the aerosol, in major heavy aerosol regions. Use several pathways for the estimate to increase the confidence level in the result and estimate uncertainty. Test the predicted response of the climate system to this forcing using models.

   

 

3. Satellite cloud image, true color on the left and cloud content on the right.

   Indirect forcing and precipitation: Study the effect of aerosol on cloud microphysics and cloud albedo (first indirect effect), cloud fraction and precipitation (second indirect effect) and profiles of temperature and humidity that also affect clouds and precipitation (semi-direct effects) in specific regions and periods of times in which it is possible to separate the effect of meteorological fluctuations and the aerosol effect on the cloud properties. Test the predicted response of the climate system to these effects using models.

1. Create a measurement based description of the Global Aerosol System, providing the temporal and spatial distribution of size-resolved aerosol optical thickness and optical properties, as well as estimates of the anthropogenic component.
2. Estimate and evaluate the aerosol direct radiative forcing at the top of atmosphere and at the surface, for anthropogenic component compared with the total aerosol burden.
3. Understand and quantify the aerosol effect on clouds and precipitation, including microphysics, albedo and coverage, especially in regions where aerosol and large scale meteorological conditions can be decoupled.

Research objectives | Effects on the Environment | How measurements are made | Measurement-based Assessments

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