AeroCenter AeroCenter is a cross-disciplinary group of scientists at GSFC working on measurement and modeling of atmospheric aerosols. The group was started in 2000 by Yoram Kaufman and coincided with Franco Einaudi’s cross-cutting themes for the Earth Sciences Division. Key AeroCenter activities include: –Bi-weekly seminar series, begun in 2001 –Visitor program, funded by HQ for 2002 –Annual Aerosol Update, begun in 2003 –Annual AeroCenter poster session Contact is maintained via a website ( and an list: –170 members on list –1/3 NASA, 1/3 GEST, 1/3 other affiliates

Global Modeling of Aerosols Global modeling of aerosol distributions is performed with the Goddard Earth Observing System model (GEOS-5) running an online version of the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) model. Aerosol forecasts provided decision making support for several NASA field campaigns (e.g., ARCTAS, TC4, TIGERZ). Coupling of aerosols to other processes in GEOS-5 permit study of aerosol-cloud-chemistry- climate interactions. Assimilation of external aerosol data in GEOS-5 unifies and homogenizes the observations from various NASA observing platforms. GEOS-5 Simulated Aerosol Distribution Figure credit: Peter Colarco, NASA GSFC

Volcanoes Affect Cloud Properties Aerosols affect clouds by changing their brightness, lifetime, and spatial distribution. We can see this in man-made “ship tracks”—bright streaks in clouds caused by pollutants from ocean-going ships. We can also see this in naturally produced aerosols from non-explosive (degassing) volcanoes. Satellite imagery permits an observation-based analysis of volcanic aerosol effects on cloud water content, brightness, and droplet size – key parameters in understanding the effects of clouds on climate. The global magnitude of this effect is unknown because we don’t know how many volcanoes are degassing. Figure credit: Santiago Gassó, GEST-UMBC/NASA GSFC

Warm cloud suceptibility from MODIS The global amount of atmospheric aerosol (suspended particles) has substantially increased since the beginning of the industrialized era. Besides directly reflecting and absorbing sunlight, aerosol can also affect sunlight in an indirect manner by causing changes in cloud properties (making them more reflective). The magnitude of this so-called “indirect effect” since the dawn of the industrial era is highly uncertain, but may have significantly slowed warming due to enhanced greenhouse gases. While we do not know how aerosols affected cloud properties in the pre-satellite era, current observations allow us to identify the clouds that may be more sensitive (“susceptible”) to future pollution. We have achieved this by combining cloud property retrievals from MODIS with a model that estimates the amount of solar radiation reflected by cloudy atmospheres at their current and hypothetical future (perturbed) states. (x ) October 2005 albedo perturbation (susceptibility) from Terra for 10% increase of warm cloud droplet number Perturbation in global reflected solar flux (Wm -2 ) for a uniform 10% increase in warm cloud droplet number

AERONET AERONET is the Aerosol Robotic Network of sun/sky scanning photometers. The purpose of AERONET is to provide a long-term data set to: –Characterize aerosol optical properties –Validate satellite and model retrievals of aerosols –Provide a unifying point for combining models, surface networks, and data from multiple satellite platforms AERONET currently supports more than 400 sites, with ~ 250 active operationally AERONET has international partnerships with other networks, including PHOTONS in France and RIMA in Spain, and discussions are ongoing with China to extend coverage there.

Joint OMI-MODIS Aerosol Retrievals The OMI and MODIS sensors fly in formation in the “A-Train” satellite constellation: –OMI: the Ozone Monitoring Instrument is a hyperspectral imager with capability in the UV and visible –MODIS: the Moderate Resolution Imaging Spectroradiometer measures 36 wavelengths in the visible and near-IR (7 wavelengths used for aerosol retrievals over the ocean) OMI is most sensitive to aerosol absorption, height, and optical thickness MODIS is most sensitive to aerosol particle size and optical thickness Aerosol absorption is a key climate parameter, but poorly known The standard OMI algorithm assumes aerosol height to retrieve aerosol absorption and optical thickness With aerosol optical thickness constrained by MODIS, OMI is free to retrieve both aerosol height and absorption with greater accuracy Figure credit: S. K. Satheesh, IIS, Bangalore, India

Multi-wavelength Raman Lidar Aerosol Observations Lidar observations permit characterization of aerosols at various levels throughout the atmospheric column. This contrasts with the AERONET sun photometers, which characterize the atmospheric column averaged aerosol properties. Characterizing the vertical variability in aerosol properties is important to distinguish, for example, elevated plumes from aerosols at the surface. The focus of this research effort is to: develop and validate the multi-wavelength Raman lidar aerosol profiling technique use simultaneous lidar/AERONET measurements to study the sensitivity of AERONET retrievals to aerosol vertical distribution develop joint algorithms to combine backscatter lidar with AERONET to better characterize the variability of aerosol properties in the vertical. Raman Lidar Lab B33/F421BAERONET Sun photometer NOAA Airborne Aerosol Observatory Aerosol size distribution retrieval using multi-wavelength Raman lidar

Long-range Pollutant Transport E. Asia Outflow N. America InflowMODIS pollution AOD Pollutants are transported from continent to continent. Aerosol pollutants include those arising from industrial activities and forest fires, as distinguished from naturally occurring mineral dust and sea spray aerosols. Such intercontinental or hemispheric transport suggests that pollution from one region could exert far-reaching impacts on climate, weather, and air quality in other regions. This first measurement-based estimate of the trans-Pacific transport of “pollution aerosol” reveals that: About 25% of “pollution aerosol” exported from Asia reaches North America. The North America inflow is equivalent to ~15% of locally generated “pollution aerosol” in the United States and Canada, which is largest in spring but not negligible in other seasons. Model-based estimates agree quite well with the satellite-based estimate in terms of annual amount. Improvements in satellite sensor capabilities make these assessments possible. Figure credit: Hongbin Yu, GEST-UMBC/NASA GSFC

Improving Dust Sources in Global Models Aerosol transport models require information about dust source locations to calculate dust aerosol emissions. –Previous models prescribed static dust source locations, usually based on topography. –In reality, dust sources change strength and distribution in response to seasonal variability in vegetative cover. In this study, the seasonal variability of dust sources in the GOCART model is explored by using satellite observations of vegetative cover to modulate the the model’s dust source function. The new, dynamic dust source improves the interseasonal comparison of simulated aerosol amount to observations from AERONET. February August Dust Source Efficiency AERONET data GOCART simulation with static dust source GOCART simulation with dynamic dust source Figure credit: David Zheng, Montgomery Blair High School Comparison with Data

Tropopause Cirrus Transported Aerosol (Asian Dust, Pollution) Boundary Layer (local aerosol) Example of MPLNET Level 1 Data: Atmospheric Structure Altitude (km) Time UTC MPLNET Sites: current South Pole MPLNET Site: 1999-current What is MPLNET? A federated network of micro pulse lidar sites around the world, coordinated and lead from Goddard Space Flight Center Co-location with related networks, including NASA AERONET Local, regional, and global scale contributions to atmospheric research Satellite validation Aerosol climate and air quality model validation Impact of aerosol & cloud heights on direct and indirect climate effects Support for wide variety of field campaigns Motivation: IPCC - aerosol and cloud profiling requirements for climate studies NASA Earth Science - NRC ACE mission for aerosol/cloud/ocean A-Train and model validation What’s New? Version 2 products released 2008 Continue active publication record (+40 papers since 2000) New Barbados site activated August 2008 Kanpur, India will be next site in 2009 (potentially Singapore too) Field campaigns planned in India and Indonesia in 2009 Investigators, Partners, & Collaborators: Principal Investigator: Judd Welton/613.1 Tim Berkoff/GEST/613.1 Brent Holben/614.4 Si-Chee Tsay/613.2 James Spinhirne/613.1 Sebastian Stewart/SSAI/613.1 Larry Belcher/GEST/613.1 James Campbell/SSAI GSFC Aerocenter Many other national and international partners Micro Pulse Lidar (GSFC Patent) The Micro Pulse Lidar Network (MPLNET): Overview 17 Active Sites