 |
|
Pollution shown cutting rainfall in hilly areas
March 09, 2007Manmade climate change due to pollution seriously inhibits precipitation over hills in semi-arid regions, a phenomenon with dire consequences for water resources in the Middle east and many other parts of the world, a study by a Chinese-Israeli research team, led by Prof. Daniel Rosenfeld of the Hebrew University of Jerusalem, has shown.
The Chinese and Israeli researchers showed that the average precipitation on Mount Hua near Xian in central China has decreased by 20 percent along with increasing levels of manmade air pollution during the last 50 years. The precipitation loss was doubled on days that had the poorest visibility due to pollution particles in the air. This explains the widely observed trends of decrease in mountain precipitation relative to the rainfall in nearby densely populated lowlands, which until now had not been directly ascribed to air pollution.
The research study, published in the current issue of the journal Science, is titled "Inverse Relations between Amounts of Air Pollution and Orographic Precipitation" and was written by Prof. Rosenfeld of the Hebrew University's Ring Department of Atmospheric Sciences, Jin Dai and others from the Meteorological Institute of Shaanxi Province, China, and Zhanyu Yao of the Chinese Academy of Meteorological Science.
These findings highlight the threat to vital water resources in polluted regions of the world where hilly-area precipitation makes a significant contribution to the regional water supply, as in the southwestern U.S. central and northern China, and the Middle East. The importance of that is underlined by the realization that it is not high temperatures due to global warming but rather the lack of water that makes a region into an unlivable desert. The authors studied observations of precipitation and visibility starting in 1954 at the top of Mount Hua. They linked the decreasing visibility at its over two-kilometer-high summit with increasing air pollution particles that reach to the clouds. They were able to show that the trend of higher concentrations of these fine, airborne, pollutants (aerosols) is responsible for the observed decreasing trend of mountain precipitation. This is the first time that this link has been demonstrated so conclusively.
The precipitation inhibition process occurs as water vapor condenses on the pollution particles and creates a cloud with a large number of drops that are so small that they float with the air and are slow to coalesce into raindrops or to freeze into sleet and snowflakes. This slowing translates into a net loss of precipitation when the cloud "lifetime" is shorter than the time necessary to release its water. This is the case for clouds that form when they ascend across a ridge and then descend and evaporate on the downwind side.
By making use of precipitation and visibility records that show a direct causal link between the airborne particle pollution and the mountain precipitation losses, the unique China study can serve as a template to bear out hypotheses about the effects of pollution on rainfall that were undertaken previously by Prof. Rosenfeld in hilly regions with similar pollutive conditions. These include California and much of the western United States. Similar trends were already published also for Israel, and observed in South Africa, Portugal, France, Switzerland, Morocco, Canada, Greece and Spain.
Atmospheric aerosols have been described in earlier studies as playing a role in cooling the atmosphere by reflecting some of the incoming solar radiation back into space — thus serving as a counterbalance to global warming resulting from the release of greenhouse gases. The latest study by Prof. Rosenfeld and his Chinese associates shows, however, that this "beneficial" effect is offset by the proven direct link between air pollution and decreased mountain precipitation, and that climate change means much more than "just" global warming.
The Hebrew University of Jerusalem
These findings highlight the threat to vital water resources in polluted regions of the world where hilly-area precipitation makes a significant contribution to the regional water supply, as in the southwestern U.S. central and northern China, and the Middle East. The importance of that is underlined by the realization that it is not high temperatures due to global warming but rather the lack of water that makes a region into an unlivable desert. The authors studied observations of precipitation and visibility starting in 1954 at the top of Mount Hua. They linked the decreasing visibility at its over two-kilometer-high summit with increasing air pollution particles that reach to the clouds. They were able to show that the trend of higher concentrations of these fine, airborne, pollutants (aerosols) is responsible for the observed decreasing trend of mountain precipitation. This is the first time that this link has been demonstrated so conclusively.
The precipitation inhibition process occurs as water vapor condenses on the pollution particles and creates a cloud with a large number of drops that are so small that they float with the air and are slow to coalesce into raindrops or to freeze into sleet and snowflakes. This slowing translates into a net loss of precipitation when the cloud "lifetime" is shorter than the time necessary to release its water. This is the case for clouds that form when they ascend across a ridge and then descend and evaporate on the downwind side.
By making use of precipitation and visibility records that show a direct causal link between the airborne particle pollution and the mountain precipitation losses, the unique China study can serve as a template to bear out hypotheses about the effects of pollution on rainfall that were undertaken previously by Prof. Rosenfeld in hilly regions with similar pollutive conditions. These include California and much of the western United States. Similar trends were already published also for Israel, and observed in South Africa, Portugal, France, Switzerland, Morocco, Canada, Greece and Spain.
Atmospheric aerosols have been described in earlier studies as playing a role in cooling the atmosphere by reflecting some of the incoming solar radiation back into space — thus serving as a counterbalance to global warming resulting from the release of greenhouse gases. The latest study by Prof. Rosenfeld and his Chinese associates shows, however, that this "beneficial" effect is offset by the proven direct link between air pollution and decreased mountain precipitation, and that climate change means much more than "just" global warming.
The Hebrew University of Jerusalem
Precipitation Current Events and Precipitation News RSSClimate change could boost incidence of civil war in Africa
Climate change could increase the likelihood of civil war in sub-Saharan Africa by over 50 percent within the next two decades.
New Method to Measure Snow, Soil Moisture With GPS May Benefit Meteorologists, Farmers
A research team led by the University of Colorado at Boulder has found a clever way to use traditional GPS satellite signals to measure snow depth as well as soil and vegetation moisture, a technique expected to benefit meteorologists, water resource managers, climate modelers and farmers.
How much water does the ocean have?
The calculation of variations in the sea level is relatively simple. It is by far more complicated to then determine the change in the water mass.
New Water Management Tool May Help Ease Effects of Drought
Continued improvement of climate forecasts is resulting in better information about what rainfall and streamflow may look like months in advance.
Cave Study Links Climate Change to California Droughts
California experienced centuries-long droughts in the past 20,000 years that coincided with the thawing of ice caps in the Arctic.
Nitrogen loss threatens desert plant life, study shows
As the climate gets warmer, arid soils lose nitrogen as gas, reports a new Cornell study. That could lead to deserts with even less plant life than they sustain today, say the researchers.
New insight into predicting cholera epidemics in the Bengal Delta
Cholera, an acute diarrheal disease caused by the bacterium Vibrio cholerae, has reemerged as a global killer. Outbreaks typically occur once a year in Africa and Latin America. But in Bangladesh the epidemics occur twice a year - in the spring and again in the fall.
Typhoon Mirinae is already scaring Philippine residents before Halloween
Another typhoon in the northern Philippines really is something to be scared about, and Mirinae is expected to make landfall there in the mid-morning hours on Halloween, October 31.
Mirinae intensifying while moving away from the northern Marianas
Typhoon Mirinae is moving west and away from the Northern Marianas Islands on a track to a landfall in the Philippines by the weekend. As Mirinae has moved west, NASA's infrared and microwave satellite imagery have seen high, strong thunderstorm development, and a developing eye.
Microwave satellite imagery shows an eye developing in Mirinae
Microwave satellite imagery has revealed that Tropical Storm Mirinae is strengthening enough to develop an eye, and that's what it's doing. Mirinae was formerly Tropical Depression 23W, but became a tropical storm and received its name.
More Precipitation Current Events and Precipitation News Articles
 |
Rain, Hail, and Snow (Watts Library) by Trudi Strain Trueit (Author) |
|
Supplementary Precipitation Data by Receiver General for Canada | |
 |
Precipitation: Theory, Measurement and Distribution by Ian Strangeways (Author) Precipitation plays a significant role in the climate system, and this is the first book to provide a comprehensive examination of the processes involved in the generation of clouds, rain, snow and hail, how precipitation is measured, how its distribution has changed over time, and how we still need to make improvements to the way precipitation is measured. It traces our attempts to understand what clouds are, from ancient Greeks to the present day. It also discusses developments in the measurement of precipitation, from rain gauges to satellite techniques, and how these measurements have enabled researchers to estimate global trends, totals, variability and extremes of precipitation. This will be a valuable and fascinating reference for academic researchers in the fields of environmental... |
 |
Understanding Weather: Precipitation (Home Use) It's another day of weather education for Wesley, Agent-in-Training for the Weather Bureau of Investigation. The assignment at hand for our animated character? Precipitation! Wesley examines various forms of precipitation, including dew, rain, fog, sleet and snow. As Wesley learns from his trainer and his Weather Watch, viewers discover that water vapor, uplifted from land and sea, forms clouds through evaporation. Through visits to various locations, viewers also find that weather offers an endless series of learning adventures. Part of the "Understanding Weather" series, which features Wesley, an animated, curious, somewhat daring young fellow, who makes weather fun and comprehensible for even the youngest viewers. Produced by Bill Walker Productions. A Coronet release. (For Home... |
 |
Onesie with rural, precipitation, countryside by Shop Zeus |
 |
1935 Map Czechoslovakia Srazky Precipitations Colour by old-print 1935 MAP CZECHOSLOVAKIA SRAZKY PRECIPITATIONS COLOUR A large colour map or plans from the Atlas of the Republic of Czechoslovakia, atlas of the Czechoslovak Republic, issued by the Czech Academy of Arts. Dates 1935 and size of each map is 33.5 x 17 inches (850 X 430). |
 |
Matched Precipitation Rate Nozzle - Adjustable circle by A.M. Leonard Distribute water evenly regardless of your pattern set. Rain Birds MPR series nozzles do just that. Nozzles have adjustable flow and radius with stainless steel adjustment screw and filter screens. Compatible with other Rain Bird matched flow rate nozzles. For use on the pop-up spray heads and as a replacement nozzle for the shrubbery heads we currently carry. |
|
|
15SQC1 Matched Precipitation Rate Nozzle (Square) by A.M. Leonard |
 |
ORIGINS noImageAvailableSmall 7 oz Precipitation Extra Continuous Moisture Recovery (For Very Dry Skin) by Origins |
|
Precipitation by Various Artists |
| © 2009 BrightSurf.com |