Atmospheric Aerosols Current Weather and News Aerosols Aerosol Direct vs. Indirect Effects AppalAIR CAN-DOO For Next Class: Read Ch. 2 (pp. 375-376)

Atmospheric Aerosols Aerosols: solid or liquid particles suspended in the air Naturally occurring aerosols: particles from trees, sea salt, dust, and volcanic dust Anthropogenic aerosols: particles from the burning of fossil fuels and biomass, smoke, and agricultural dust Aerosols can influence weather and climate by directly and indirectly affecting the amount of solar radiation reaching the earth’s surface, which can lead to warming and cooling in different regions of the world. Overall RF is negative, however. Aerosol Optical Depth (AOD): variable used by scientists to describe the amount of solar radiation scattered or absorbed by aerosols (Instrument: sun photometer)

Human Activity and Climate Change Aerosols 90% of anthropogenic aerosols are byproducts of fossil fuel burning in the Northern Hemisphere cause either cooling (sulfurous aerosols) or warming (black carbon) of the atmosphere Aerosols can alter the number, mean size, and size distribution of cloud droplets © AMS

Human Activity and Climate Change Aerosols The direct radiative forcing of aerosols is estimated to offset the CO2 warming by almost one-third. (IPCC 2007) © AMS

Global Aerosol Optical Depth

Trends in Global Aerosol Optical Depth IPCC AR5

Direct and Indirect Effects of Aerosols Aerosols scatter and absorb incoming solar radiation and impact cloud microphysics TAKE OUT! Aerosols are microscopic suspended particulates in earth’s atmosphere that occur naturally or as a result of human activity. Aerosols directly interact with incoming solar radiation by either scattering or absorbing that light, effectively limiting the amount that reaches earth’s surface. Many scientists believe that the SE has remained relatively cool because of the high concentration of aerosols in our region. Also, aerosols indirectly affect the surface energy balance by impacting the microphysical processes of cloud formation and precipitation development. Raindrops and snowflakes form on a nucleation site, and aerosols can serve as these nucleation sites. But the problem is when you have a surplus of aerosols, cloud droplets will still form, but since that moisture is spread out over such a large concentration of particles, individual cloud droplets can’t grow large enough to precipitate. Therefore the indirect effects of aerosols lead to increased cloudiness and precipitation suppression, which ultimately cause a net cooling effect at earth’s surface.

Direct and Indirect Effects of Aerosols ** Be very familiar with this diagram! It may appear on Exam IV ** Small black dots = aerosol particles Larger open circles = cloud droplets Straight lines = incident and reflected solar radiation Fig. 2.10 IPCC AR4

5 Minute Writing Prompt What is the difference between the aerosol direct and indirect effect?

The Cloud Albedo Effect results in Negative RF.

-0.82 w m-2 IPCC AR5

Reciprocal Relationship Climate Aerosols

AppalAIR Appalachian Atmospheric Interdisciplinary Research an air quality/climate research and public outreach facility for exploring air pollution formation and transport and the relationship of pollution to a changing climate and its effects on regional ecosystems Participants: Howie Neufeld – Biology Brett Taubman – Chemistry Barkley Sive – Chemistry Rahman Tashakkori – Computer Science Baker Perry – Geography Jim Sherman – Physics Ryan Emanuel – NC State Doug Miller – UNCA Collaborating member of the NOAA-ESRL Global Aerosol Network (http://www.esrl.noaa.gov/gmd/aero/net/app/) and the NASA AErosol RObotic NETwork (AERONET, http://aeronet.gsfc.nasa.gov/)

AppalAIR ASU Campus, Boone, NC 1076 m, lat 36.2º lon -81.7º

Measurement Capabilities Measurements Aerosol light scattering – TSI 3 l integrating nephelometer; Humidified Radiance Research integrating nephelometer Aerosol light absorption – Radiance Research 3 l PSAP; Magee Scientific 7 l aethalometer and custom UV 6 l aethalometer Aerosol Optical Depth-CIMEL 918EBN Aerosol vertical profiles – Micro-Pulse Lidar Aerosol number concentration – TSI CNC 3007 Trace gases – O3, CO2, and H2O All-Sky Imager – Yankee Scientific TSI-440 Direct and Diffuse Irradiance – Kipp&Zonen CM22 Pyranometer Present Weather Detector – Vaisala PWD12 Standard and Micrometeorology Lots more aerosol/trace gas chemistry and microphysics coming…

NOAA GMD Aerosol Sampling Stations

CAN-DOO Climate Action Network through Direct Observations and Outreach Develop the infrastructure for sustaining and expanding public outreach through long‐term climate measurements capable of complementing existing NASA measurements. Enhance public awareness of climate science and NASA’s role in advancing our understanding of the Earth System. Introduce STEM principles to homeschooled, public school, and Appalachian State University students through applied climate science activities. Brett – when does science club begin at Hardin Park?

CAN‐DOO Partners AppalAIR Grandfather Mountain Stewardship Foundation Public education and outreach, citizen science, research-quality meteorological observations Pisgah Astronomical Research Institute (PARI) Summer camp for homeschooled high school students Science Clubs at Watauga County Elementary Schools Hardin Park Elementary School Bethel Elementary School