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atmosphere seeds

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b SRM Research Institute, Department of Chemistry, SRM University, Kattankulathur, Kancheepuram 603203 (D.t.), India

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a GREMI, UMR 7344, CNRS-Université d'Orléans, 14 rue d'Issoudun, BP 6744, 45067 Orléans Cedex 02, France
E-mail: [email protected]

Enhanced seed germination and plant growth by atmospheric pressure cold air plasma: combined effect of seed and water treatment

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Atmosphere seeds

In?�Falling Through the Atmosphere?�students are introduced to Captain Joseph Kittinger, the only person to have “fallen” almost 20 miles through the atmosphere to land on Earth.

Students first follow his ascent in a balloon, and learn about what the temperature was like, as well as the things he saw and experienced as he rose in the air. Next, students follow his descent down through the atmosphere.

This book helps students visualize what our atmosphere is like, and provides a window into Kittinger’s unique experience.

Furthermore, the team found that the global importance of different gases in the process has changed substantially as a result of human activity. Although biogenic vapors from trees and other vegetation are important for the formation and growth of new particles today (as seen in the photo above), they were even more important in the relatively unpolluted preindustrial atmosphere. In the future, as emissions controls lead to cleaner air, some of the sulfur- and soot-containing particles from fossil fuel burning will be replaced by smaller, probably less toxic, particles from trees once again. (Journal of Geophysical Research: Atmospheres, https://doi.org/10.1002/2017JD026844, 2017)

—Emily Underwood, Freelance Writer

Underwood, E. (2017), Atmospheric particles aren’t the same cloud seeds they once were, Eos, 98, https://doi.org/10.1029/2017EO084233. Published on 07 November 2017.

In the preindustrial atmosphere, the formation of new particles from vapors accounted for about two thirds of cloud-seeding particles. In the current atmosphere, new particle formation accounts for more than half of cloud formation. The authors’ results suggest that ions from cosmic rays are important, but the variation in the intensity of cosmic rays seen over the solar cycle does not have a significant radiative effect.

Scientists have long been interested in how human-generated emissions into the atmosphere affect this gas-to-particle conversion process. To find out, Gordon et al. compared how atmospheric gases formed cloud condensation nuclei before and after the Industrial Revolution.

Citation:

The team made two computer simulations with a global aerosol model: one with natural levels of particle-forming gases before the Industrial Revolution and a second with Earth’s current atmosphere. The models used data from the European Organization for Nuclear Research’s (CERN) Cosmics Leaving Outdoor Droplets (CLOUD) experiment to simulate how vapors such as sulfuric acid, ammonia, organic compounds, and water combine to form aerosol particles. They also included the effect of ionization caused by cosmic rays on the new particle formation rates.