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Tag: Nitrogen

  • Why do the colors of the northern lights change?

    Why do the colors of the northern lights change?

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    (FOX40.COM) — Residents in lower latitudes across the world were able to get a rare sighting of the northern lights on recent nights, which featured an array of colors across the night skies.

    The colors of the aurora borealis are usually green but could appear as other colors including red, blue, pink and purple, according to which compounds from the sun are interacting with compounds on Earth and how high up this is happening in the atmosphere, according to the NOAA Space Weather Prediction Center.

    People across the world captured the astronomical light show as the lights began appearing starting on Friday night and continuing through the weekend.

    The aurora borealis, as the lights are also called, were caused by a rare G5 solar storm, which hasn’t occurred since October 2003.

    The different aurora colors 

    The color of the aurora is determined by altitude and atmospheric compounds, according to the NOAA Space Weather Prediction Center. 

    Nitrogen and oxygen are atmospheric compounds that help determine the color and could be found in different altitudes, the NOAA said. 

    “When charged particles from the sun enter our atmosphere, they interact with those compounds, and the aurora is the visible result,” NOAA officials said in a Facebook post. “Depending on which compounds are being excited by the Sun’s charged particles, different colors will result.” 

    The colors that appear are the result of whether it is oxygen or nitrogen and how much of the sun’s particles are interacting with these at once, according to NOAA.

    The greenish-yellow light is the most familiar color of the aurora and it comes from oxygen, which also emits red light. Nitrogen typically generates a blue light. 

    Molecules from oxygen and nitrogen can give off an ultraviolent light, which can only be detected by special cameras on satellites, NOAA said. 

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    Jeremiah Martinez

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  • Organic nitrogen aerosol plays a vital role in global nitrogen deposition.

    Organic nitrogen aerosol plays a vital role in global nitrogen deposition.

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    Newswise — This study, led by Dr Yumin Li of Southern University of Science and Technology (SUSTech), was a collaboration between Professor Tzung-May Fu’s team at SUSTech and Professor Jian Zhen Yu’s team at Hong Kong University of Science and Technology (HKUST). The research emphasized the previously underestimated significance of atmospheric ON aerosol depositions on ecosystems. Additionally, the ecological effects of ON aerosol depositions are anticipated to increase due to global warming and the decrease in nitrogen oxide emissions from human activities.

    Atmospheric deposition of organic nitrogen (ON) plays a crucial role in the global nitrogen cycle. Surface measurements showed that 2% to 70% of the local atmospheric deposition flux of total nitrogen was organic. However, previous models have largely neglected the spatial and chemical variations of atmospheric ON, leading to inadequate assessment of its global impacts.

    The scientists from SUSTech and HKUST developed a comprehensive global model of atmospheric gaseous and particulate ON, incorporating the latest knowledge on emissions and secondary formations. Their simulated surface concentrations of atmospheric particulate ON (ONp) were highly consistent with global observations, a feat that had not been achieved previously. Additionally, their simulated atmospheric deposition flux aligned with global observations within an order of magnitude. The scientists estimated that the global atmospheric ON deposition was 26 Tg N yr-1. This majority of this deposition (23 Tg N yr-1) occurred in the form of ON aerosol and accounted for 19% of the global atmospheric total N deposition (124 Tg N yr-1). The main sources of ON aerosols were wildfires, ocean emissions, and secondary formation.

    “Our simulation showed that the deposition of ON aerosol from the atmosphere is a crucial external source of nitrogen to nitrogen-limited ecosystems worldwide, such as the boreal forests, tundras, and the Arctic Ocean,” Fu says. In a future warming climate, wildfires will likely become more frequent and intense. Climate warming will also lead to surface ocean stratification, making atmospheric ON deposition an increasingly important source of nitrogen to these ecosystems. “We need to further examine the environmental impacts of atmospheric ON aerosol and how those impacts respond to climate change.”

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    Science China Press

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