The Science of Aerosols

[kassy]

No. There should be a slight change but it would not offset the global changes in temperature (big ocean next to you).

[jai mitchell]

Cross Posted

Nair et. al.

https://www.nature.com/articles/s41612-023-00367-6

Aerosol demasking enhances climate warming over South Asia

Concurrent measurements over the northern Indian Ocean unveiled a ~7% increase in the earth’s surface-reaching solar radiation (surface brightening). Aerosol-induced atmospheric solar heating decreased by ~0.4 K d−1. Our results reveal that under clear sky conditions, anthropogenic emissions over South Asia lead to nearly 1.4 W m−2 heating at the top of the atmosphere during the period March–May. A complete phase-out of today’s fossil fuel combustion to zero-emission renewables would result in rapid aerosol demasking, while the GHGs linger on.

The amount of aerosol forcing is much higher than modeled.  The impacts of this forcing on global atmosphere circulation is much more than modeled.

[morganism]

New technology developed for time-resolved measurement of hydroxyl radicals

Researchers led by Prof. Zhang Weijun from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences have proposed a feasible approach for the rapid detection of hydroxyl radicals.

Based on this technology, a new device called Frequency-modulated Faraday Rotation (FM-FRS) spectrometer has been developed, which can detect OH radicals with high precision. The study was published in Optics Express.

Hydroxyl (OH) radicals are important active oxidants in the atmosphere and are important reaction chain initiators in the oxidation of most compounds. In order to study their reaction processes and mechanisms in detail, they must be measured directly in "real time," i.e., to study them on the time scale of their actual existence. Therefore, detection techniques must be able to respond to rapid changes in the concentration and lifetime of OH radicals.

To address this problem, the researchers developed the FM-FRS spectrometer for highly sensitive and rapid measurement of OH radicals, which was characterized by wide measurement bandwidth, high sensitivity, and good selectivity, and is particularly suitable for kinetic studies of short-lived intermediate radicals.

"We used a special laser beam that is modulated at a very high frequency, up to 150 million times per second," said Cheng Feihu, a member of the team.
Concentration-time profile of OH radical obtained after averaging three pulses at a 200 μs sampling interval.

The researchers used the spectroscopic technique to measure the time-resolved spectral signal of the OH radical near 2.8 μm. The detection limit for OH reached 6.8×108 molecules/cm3 (1σ, 0.2 ms) after three pulse averaging, and decreased to 8.0×107 molecules/cm3 after 100 event integrations, which was in general agreement with the trend of the system performance in the white noise limit.

This work provides a new and alternative tool for studying radical dynamics, not only for OH radicals, but also for other paramagnetic transient molecules.

More information: Feihu Cheng et al, High band-width mid-infrared frequency-modulated Faraday rotation spectrometer for time resolved measurement of the OH radical, Optics Express (2023). DOI: 10.1364/OE.493270

https://phys.org/news/2023-08-technology-time-resolved-hydroxyl-radicals.html

[vox_mundi]

Study Presents Evidence That Recent Reductions In Aerosol Emissions Create an Additional Warming Effect
https://phys.org/news/2024-04-evidence-reductions-aerosol-emissions-additional.html



Recent reductions in emissions of tiny particles, the major cause of air pollution globally, have led to more heat in the Earth's climate system. This is shown in a new international study led by CICERO and published in Communications Earth & Environment.

Satellite measurements clearly show that more heat is entering the Earth's atmosphere from the sun compared to the amount of terrestrial energy escaping to space. This so-called Earth energy imbalance leads to accumulation of heat and warming of the Earth's surface.

In the study, the researchers performed simulations using the latest generation global climate models and compared their results to satellite measurements of the Earth's energy imbalance trend over the 2001–2019 period.

The authors found that the recent reductions in man-made particle emissions needed to be accounted for in order for the models to reasonably match the satellite measurements (see figure above; black vs. orange line). When the authors assumed that the particle emissions did not change over the time period (green line), the simulated heating of the Earth was considerably reduced.

... Hodnebrog says, "Continued reductions of particle emissions may lead to an accelerated surface temperature warming already in this decade."

Øivind Hodnebrog et al, Recent reductions in aerosol emissions have increased Earth's energy imbalance, Communications Earth & Environment[/u] (2024)
https://www.nature.com/articles/s43247-024-01324-8

[kiwichick16]

correct me if i'm wrong , but i think Hansen referred to it as " our Faustian bargain " in his book "Storms of my Grandchildren "