These measurements are made simultaneously in a coordinated manner. SAGE II, launched in October , uses a technique called solar occultation to measure attenuated solar radiation and to determine the vertical distribution of stratospheric aerosols, ozone, nitrogen dioxide, and water vapor around the globe. MCSST data currently extend from November 11, through June 7, , and are updated as new data become available. Volcanic ash, like this from Mount St. Helens, is not really ash, but tiny jagged particles of rock and glass.
A new browser window will open. The research team ran a general circulation model developed at the Max Planck Institute with and without Pinatubo aerosols for the two years following the Pinatubo eruption. By comparing the climate simulations from the Pinatubo eruption, with and without aerosols, the researchers found that the climate model calculated a general cooling of the global troposphere, but yielded a clear winter warming pattern of surface air temperature over Northern Hemisphere continents.
The model demonstrated that the direct radiative effect of volcanic aerosols causes general stratospheric heating and tropospheric cooling, with a tropospheric warming pattern in the winter. It shows that volcanic aerosols force fundamental climate mechanisms that play an important role in the global change process. This temperature pattern is consistent with the existence of a strong phase of the Arctic Oscillation, a natural pattern of circulation in which atmospheric pressure at polar and middle latitudes fluctuates, bringing higher-than-normal pressure over the polar region and lower-than-normal pressure at about 45 degrees north latitude.
It is forced by the aerosol radiative effect, and circulation in winter is stronger than the aerosol radiative cooling that dominates in summer. Acid rain has many ecological effects, especially on lakes, streams, wetlands, and other aquatic environments. Acid rain makes such waters more acidic, which results in more aluminum absorption from soil, which is carried into lakes and streams.
That combination makes waters toxic to crayfish, clams, fish, and other aquatic animals. Learn more about the effects of water pollution. Some species can tolerate acidic waters better than others. However, in an interconnected ecosystem, what affects some species eventually affects many more throughout the food chain, including non-aquatic species such as birds.
Acid rain and fog also damage forests, especially those at higher elevations. The acid deposits rob the soil of essential nutrients such as calcium and cause aluminum to be released in the soil, which makes it hard for trees to take up water. Trees' leaves and needles are also harmed by acids. The effects of acid rain, combined with other environmental stressors, leave trees and plants less healthy, more vulnerable to cold temperatures, insects, and disease. The pollutants may also inhibit trees' ability to reproduce.
Some soils are better able to neutralize acids than others. But in areas where the soil's "buffering capacity" is low, such as parts of the U. Northeast, the harmful effects of acid rain are much greater. Acid deposits damage physical structures such as limestone buildings and cars. And when it takes the form of inhalable fog, acid precipitation can cause health problems including eye irritation and asthma. The only way to fight acid rain is by curbing the release of the pollutants that cause it.
This means burning fewer fossil fuels and setting air-quality standards. In the U. Air-quality standards have also driven U. These trends have helped red spruce forests in New England and some fish populations , for example, recover from acid rain damage.
But recovery takes time, and soils in the northeastern U. Acid rain problems will persist as long as fossil fuel use does, and countries such as China that have relied heavily on coal for electricity and steel production are grappling with those effects. One study found that acid rain in China may have even contributed to a deadly landslide. Small ash particles form a dark cloud in the troposphere that shades and cools the area directly below.
Most of these particles fall out of the atmosphere within rain a few hours or days after an eruption. But the smallest particles of dust get into the stratosphere and are able to travel vast distances, often worldwide. These tiny particles are so light that they can stay in the stratosphere for months, blocking sunlight and causing cooling over large areas of the Earth.
Often, erupting volcanoes emit sulfur dioxide into the atmosphere. Sulfur dioxide is much more effective than ash particles at cooling the climate. The sulfur dioxide moves into the stratosphere and combines with water to form sulfuric acid aerosols. The aerosols can stay in the stratosphere for up to three years, moved around by winds and causing significant cooling worldwide.
Eventually, the droplets grow large enough to fall to Earth.
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