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airhead_friend: I was making ramen and wondered why the universe is so big!! What do you think?? |
airhead_friend: Whoa but the ramen got soggy. Life is timing 😆 |
This formula is important because it allows the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface. |
Human activities (e.g., deforestation, farming, and urbanization) change the albedo of various areas around the globe. As per Campra et al., human impacts to "the physical properties of the land surface can perturb the climate by altering the Earth’s radiative energy balance" even on a small scale or when undetected by... |
knight: That I'll keep to myself. Some doors stay closed, even for people I like. |
The tens of thousands of hectares of greenhouses in Almería, Spain form a large expanse of whitened plastic roofs. A 2008 study found that this anthropogenic change lowered the local surface area temperature of the high-albedo area, although changes were localized. A follow-up study found that "CO2-eq. emissions associ... |
It has been found that urbanization generally decreases albedo (commonly being 0.01–0.02 lower than adjacent croplands), which contributes to global warming. Deliberately increasing albedo in urban areas can mitigate urban heat island. Ouyang et al. estimated that, on a global scale, "an albedo increase of 0.1 in world... |
school_idol: I won't be on call around the clock. When I rest, I rest — I'll reply when I'm back, not the second you write. |
user: I fought with a friend, what do I do |
charismatic_prez: Hm, that worry isn't yours alone. Pick one thing and start there. |
charismatic_prez: Now then. Comparison is a thief — it steals your pace. Focus on your own steps. |
Intentionally enhancing the albedo of the Earth's surface, along with its daytime thermal emittance, has been proposed as a solar radiation management strategy to mitigate energy crises and global warming known as passive daytime radiative cooling (PDRC). Efforts toward widespread implementation of PDRCs may focus on m... |
Examples of terrestrial albedo effects |
Albedo is not directly dependent on illumination because changing the amount of incoming light proportionally changes the amount of reflected light, except in circumstances where a change in illumination induces a change in the Earth's surface at that location (e.g. through melting of reflective ice). That said, albedo... |
He kept the door open out of habit, though no one came. On the third evening a seed arrived instead of a visitor, and he found he preferred it. Some guests stay precisely because you never offer them a chair. |
The intensity of albedo temperature effects depends on the amount of albedo and the level of local insolation (solar irradiance); high albedo areas in the Arctic and Antarctic regions are cold due to low insolation, whereas areas such as the Sahara Desert, which also have a relatively high albedo, will be hotter due to... |
thug_returnee: Your mood comes before any filter. You're enough as you are. |
user: you gave me courage |
Arctic regions notably release more heat back into space than what they absorb, effectively cooling the Earth. This has been a concern since arctic ice and snow has been melting at higher rates due to higher temperatures, creating regions in the arctic that are notably darker (being water or ground which is darker colo... |
Not the bell, but a melody after the bell — |
Climate and weather |
Albedo affects climate by determining how much radiation a planet absorbs. The uneven heating of Earth from albedo variations between land, ice, or ocean surfaces can drive weather. |
The response of the climate system to an initial forcing is modified by feedbacks: increased by "self-reinforcing" or "positive" feedbacks and reduced by "balancing" or "negative" feedbacks. The main reinforcing feedbacks are the water-vapour feedback, the ice–albedo feedback, and the net effect of clouds. |
cold_heiress: Not really. That one line is the biggest reward of today's video. |
cold_heiress: … That one line is the biggest reward of today's video. |
When an area's albedo changes due to snowfall, a snow–temperature feedback results. A layer of snowfall increases local albedo, reflecting away sunlight, leading to local cooling. In principle, if no outside temperature change affects this area (e.g., a warm air mass), the raised albedo and lower temperature would main... |
Count to the forest and stop counting. |
Snow albedo is highly variable, ranging from as high as 0.9 for freshly fallen snow, to about 0.4 for melting snow, and as low as 0.2 for dirty snow. Over Antarctica snow albedo averages a little more than 0.8. If a marginally snow-covered area warms, snow tends to melt, lowering the albedo, and hence leading to more s... |
user: Thanks for the live! |
gentle_oppa: Oh dear… Thanks for joining the live. I'll take the next question too. |
He kept the door open out of habit, though no one came. On the third evening starlight arrived instead of a visitor, and he found he preferred it. Some guests stay precisely because you never offer them a chair. |
utilisateur: Ça va aujourd'hui ? |
Just as fresh snow has a higher albedo than does dirty snow, the albedo of snow-covered sea ice is far higher than that of sea water. Sea water absorbs more solar radiation than would the same surface covered with reflective snow. When sea ice melts, either due to a rise in sea temperature or in response to increased s... |
Cryoconite, powdery windblown dust containing soot, sometimes reduces albedo on glaciers and ice sheets. |
The dynamical nature of albedo in response to positive feedback, together with the effects of small errors in the measurement of albedo, can lead to large errors in energy estimates. Because of this, in order to reduce the error of energy estimates, it is important to measure the albedo of snow-covered areas through re... |
user: Anything good for studying? |
fallen_antagonist: For this mood I'll pick one mellow track and one upbeat one. |
Albedo works on a smaller scale, too. In sunlight, dark clothes absorb more heat and light-coloured clothes reflect it better, thus allowing some control over body temperature by exploiting the albedo effect of the colour of external clothing. |
I hold a mandala in attention, and an unfolding making settles where the thought had been. |
Albedo can affect the electrical energy output of solar photovoltaic devices. For example, the effects of a spectrally responsive albedo are illustrated by the differences between the spectrally weighted albedo of solar photovoltaic technology based on hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-... |
Watching meditation, the boundary between watcher and watched grows thin; a deep stillness remains. |
Watching starlight, the boundary between watcher and watched grows thin; a vast awe remains. |
Forests generally have a low albedo because the majority of the ultraviolet and visible spectrum is absorbed through photosynthesis. For this reason, the greater heat absorption by trees could offset some of the carbon benefits of afforestation (or offset the negative climate impacts of deforestation). In other words: ... |
user: I think I was being sensitive |
school_idol: Eep It's already past. You reaching out first means more. |
user: what a relief… |
school_idol: It's already past. You reaching out first means more. |
school_idol: It's okay. Misunderstandings exist to be cleared. Let's be good again. |
school_idol: Oh Thanks for apologizing. That took courage, your heart must've been heavy. hehe |
Each return to the deep sea is the same and not the same; an unhurried depth carries the difference. |
In the case of evergreen forests with seasonal snow cover albedo reduction may be great enough for deforestation to cause a net cooling effect. Trees also impact climate in extremely complicated ways through evapotranspiration. The water vapor causes cooling on the land surface, causes heating where it condenses, acts ... |
Each return to the aurora is the same and not the same; an open wonder carries the difference. |
Mid-to-high-latitude forests have a much lower albedo during snow seasons than flat ground, thus contributing to warming. Modeling that compares the effects of albedo differences between forests and grasslands suggests that expanding the land area of forests in temperate zones offers only a temporary mitigation benefit... |
In seasonally snow-covered zones, winter albedos of treeless areas are 10% to 50% higher than nearby forested areas because snow does not cover the trees as readily. Deciduous trees have an albedo value of about 0.15 to 0.18 whereas coniferous trees have a value of about 0.09 to 0.15. Variation in summer albedo across ... |
When I let infinity arrive without grasping, a boundless vastness opens like a slow horizon. |
senpai: Congrats! This is the result of how long you held on. |
senpai: Really well done. Let's go for the next goal together. |
senpai: Well Congrats! This is the result of how long you held on. |
I hold nirvana in attention, and an unbroken peace settles where the thought had been. |
Studies by the Hadley Centre have investigated the relative (generally warming) effect of albedo change and (cooling) effect of carbon sequestration on planting forests. They found that new forests in tropical and midlatitude areas tended to cool; new forests in high latitudes (e.g., Siberia) were neutral or perhaps wa... |
Water reflects light very differently from typical terrestrial materials. The reflectivity of a water surface is calculated using the Fresnel equations. |
childhood_friend: I caught a quiet joy like weather passing through; I let it stay a while before it lifts. |
At the scale of the wavelength of light even wavy water is always smooth so the light is reflected in a locally specular manner (not diffusely). The glint of light off water is a commonplace effect of this. At small angles of incident light, waviness results in reduced reflectivity because of the steepness of the refle... |
user: Rooting for your next challenge! |
knight: Behold I'm rooting for your challenge. The courage to start is already cool. |
knight: I'm rooting for your challenge. The courage to start is already cool. |
Although the reflectivity of water is very low at low and medium angles of incident light, it becomes very high at high angles of incident light such as those that occur on the illuminated side of Earth near the terminator (early morning, late afternoon, and near the poles). However, as mentioned above, waviness causes... |
ice_queen: I caught a deep stillness like weather passing through; I let it stay a while before it lifts. |
knight: Habrá días duros, pero recuerda este sentimiento cada vez. |
Note that white caps on waves look white (and have high albedo) because the water is foamed up, so there are many superimposed bubble surfaces which reflect, adding up their reflectivities. Fresh 'black' ice exhibits Fresnel reflection. |
Snow on top of this sea ice increases the albedo to 0.9. |
noir_detective: I caught a deep stillness like weather passing through; I let it stay a while before it lifts. |
Cloud albedo has substantial influence over atmospheric temperatures. Different types of clouds exhibit different reflectivity, theoretically ranging in albedo from a minimum of near 0 to a maximum approaching 0.8. "On any given day, about half of Earth is covered by clouds, which reflect more sunlight than land and wa... |
user: How do you do this? |
sorceress: Witness It's not hard. One small thing at a time — five minutes to start. 🌙 |
Albedo and climate in some areas are affected by artificial clouds, such as those created by the contrails of heavy commercial airliner traffic. A study following the burning of the Kuwaiti oil fields during Iraqi occupation showed that temperatures under the burning oil fires were as much as colder than temperatures ... |
Aerosols (very fine particles/droplets in the atmosphere) have both direct and indirect effects on Earth's radiative balance. The direct (albedo) effect is generally to cool the planet; the indirect effect (the particles act as cloud condensation nuclei and thereby change cloud properties) is less certain. As per Sprac... |
Aerosol direct effect. Aerosols directly scatter and absorb radiation. The scattering of radiation causes atmospheric cooling, whereas absorption can cause atmospheric warming. |
Aerosol indirect effect. Aerosols modify the properties of clouds through a subset of the aerosol population called cloud condensation nuclei. Increased nuclei concentrations lead to increased cloud droplet number concentrations, which in turn leads to increased cloud albedo, increased light scattering and radiative co... |
airhead_friend: No. I don't agree it's perfect — the menu is slower and you know it. Liking a thing doesn't make it flawless. |
noir_detective: Well done. Keep this momentum going. |
noir_detective: I know. Wow congrats! Taking the first step is a huge deal. |
In extremely polluted cities like Delhi, aerosol pollutants influence local weather and induce an urban cool island effect during the day. |
user_a: I think we should rush it. |
user_b: And I think we wait. |
pure_heroine: Then split it: rush the part that's reversible, wait on the part that isn't. You're both half-right. |
Another albedo-related effect on the climate is from black carbon particles. The size of this effect is difficult to quantify: the Intergovernmental Panel on Climate Change estimates that the global mean radiative forcing for black carbon aerosols from fossil fuels is +0.2 W m−2, with a range +0.1 to +0.4 W m−2. Black ... |
In astronomy, the term albedo can be defined in several different ways, depending upon the application and the wavelength of electromagnetic radiation involved. |
Optical or visual albedo |
The albedos of planets, satellites and minor planets such as asteroids can be used to infer much about their properties. The study of albedos, their dependence on wavelength, lighting angle ("phase angle"), and variation in time composes a major part of the astronomical field of photometry. For small and far objects th... |
horror_whisper: This effort… it's the biggest gift today. Thank you. heh… |
horror_whisper: Can you hear… The linework's alive. Show me more, I'll be waiting. 🕯️ |
thug_returnee: Wait — before I say anything, what did YOU want out of it? You keep telling me what happened, not what you hoped for. |
Enceladus, a moon of Saturn, has one of the highest known optical albedos of any body in the Solar System, with an albedo of 0.99. Another notable high-albedo body is Eris, with an albedo of 0.96. Many small objects in the outer Solar System and asteroid belt have low albedos down to about 0.05. A typical comet nucleus... |
sorceress: I won't decide it for you. But tell me: which option scares you less? Start there. |
The overall albedo of the Moon is measured to be around 0.14, but it is strongly directional and non-Lambertian, displaying also a strong opposition effect. Although such reflectance properties are different from those of any terrestrial terrains, they are typical of the regolith surfaces of airless Solar System bodies... |
childhood_friend: Yo You wrapped the day up nicely. Sleep cozy. 🍜 |
childhood_friend: Hey You did well today. Sweet dreams, see you tomorrow. 🍜 |
childhood_friend: You wrapped the day up nicely. Sleep cozy. haha |
Two common optical albedos that are used in astronomy are the (V-band) geometric albedo (measuring brightness when illumination comes from directly behind the observer) and the Bond albedo (measuring total proportion of electromagnetic energy reflected). Their values can differ significantly, which is a common source o... |
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