Are Aerosols Reducing Coastal Drizzle And Increasing Cloud Cover

Jul 05, 2005

Scientists sponsored by the Department of Energy are conducting a six-month atmospheric research campaign at the Point Reyes National Seashore, in Marin County, California.

The experiment's goal is to help researchers understand how aerosols -small particles such as soot, dust and smoke - influence the structure of marine stratus clouds, and how aerosols are associated with drizzle – the misty rain regularly produced by these types of clouds.

The scientists think aerosols, which can come from both natural and manmade sources, may be reducing coastal drizzle while increasing cloud cover.

Marine stratus clouds are thin, low-level clouds that cover the sky like a blanket. They are some of the most prevalent clouds on earth, and are an important component of the earth's climate system.

Despite their importance to the earth-ocean-atmosphere system, relatively few comprehensive data sets about marine stratus clouds are available for scientists to draw firm conclusions related to aerosol effects.

To obtain more, and better, data, researchers need to go to the source. The department's Atmospheric Radiation Measurement (ARM) Program is helping them do just that.

Since the Pt. Reyes field campaign began in March, a new $1.4 million ARM Mobile Facility – a portable atmospheric laboratory with sophisticated instruments and data systems – has been stationed about one mile from the beach, collecting data from the clouds as they move onshore.

Starting in July, activities intensify as two research aircraft -sponsored by DOE's Atmospheric Science Program and the U.S. Office of Naval Research--join the campaign.

These instrumented aircraft will obtain in-situ measurements of cloud properties, suspended particles and other atmospheric variables needed to analyze aerosol properties of the marine stratus clouds.

The aircraft data will be used to examine the regional characteristics of the marine stratus clouds being sampled at Pt. Reyes and to examine specific links between aerosol chemistry and cloud structure.

"Current theories--backed by sparse observations - suggest that the presence of manmade aerosol air pollution may cause marine stratus clouds to reflect more incoming sunlight back into space and suppress the production of drizzle within the clouds, which may enable the clouds to exist for a longer period," said Mark Miller, the ARM Program's lead scientist for this field campaign.

"If these theories prove accurate, manmade aerosols could be facilitating changes in regional and global climate through their influence on marine cloud structure. We need to determine how these effects should be represented in global climate simulations."

"With the new ARM Mobile Facility, researchers can now explore previously under-sampled climate regions," said Dr. Raymond Orbach, Director of DOE's Office of Science.

"The portability of the instrumentation allows researchers to make atmospheric measurements similar to those at the other ARM sites for periods up to a year at a time anywhere in the world."

Point Reyes National Seashore, on the coast north of San Francisco, is an ideal place to gather data about marine cloud and drizzle processes. Not only is it one of the foggiest spots in the United States, it's also home to more than 900 plant species, 490 bird species, and 28 species of reptiles and amphibians.

"It's no secret that fragile coastal ecosystems are highly sensitive to changes in their environment. A mere three degree change in temperature for an extended period of time can wipe out an entire segment of marine life," said Don Neubacher, Point Reyes National Seashore Superintendent.

"Anytime we have the opportunity to assist the scientific community in researching issues that affect our biological communities, we will."

The ARM Program - the largest global change research program supported by the Department of Energy - was created to help resolve scientific uncertainties related to global climate change.

Its specific focus is on the crucial role of clouds and their influence on warming and cooling processes in the atmosphere. The program's goal is to improve the treatment of clouds and radiation processes in global climate models.

One of DOE's major goals is to develop global climate models capable of simulating the timing and magnitude of greenhouse gas-induced global warming and the regional effects of such warming.

Previous research has shown that warming and cooling effects from clouds are one of the major sources of uncertainty in simulations of climate change over the next century. It is imperative, therefore, that their treatment in global models be improved.

The multi-laboratory ARM program operates three field research sites gathering climate data in the North Slope of Alaska, the Southern Great Plains and the Tropical Western Pacific.

The new Mobile Facility will enable atmospheric scientists to perform climate research in remote locations around the world. Next year, the ARM Mobile Facility will be deployed in Niamey, Niger, Africa to participate in an international study of the West African monsoon system.

Copyright 2005 by Space Daily, Distributed by United Press International

Explore further: Scientists find meteoritic evidence of Mars water reservoir

add to favorites email to friend print save as pdf

Related Stories

Why is Venus so horrible?

13 hours ago

Venus sucks. Seriously, it's the worst. The global temperature is as hot as an oven, the atmospheric pressure is 90 times Earth, and it rains sulfuric acid. Every part of the surface of Venus would kill you ...

NOAA/NASA satellite sees holiday lights brighten cities

Dec 17, 2014

Even from space, holidays shine bright. With a new look at daily data from the NOAA/NASA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, a NASA scientist and colleagues have identified how ...

Recommended for you

SDO captures images of two mid-level flares

6 hours ago

The sun emitted a mid-level flare on Dec. 18, 2014, at 4:58 p.m. EST. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Solar flares are powerful bursts ...

Image: Christmas wrapping the Sentinel-3A antenna

15 hours ago

The moment a team of technicians, gowned like hospital surgeons, wraps the Sentinel-3A radar altimeter in multilayer insulation to protect it from the temperature extremes found in Earth orbit.

Video: Flying over Becquerel

15 hours ago

This latest release from the camera on ESA's Mars Express is a simulated flight over the Becquerel crater, showing large-scale deposits of sedimentary material.

Spinning up a dust devil on Mars

16 hours ago

Spinning up a dust devil in the thin air of Mars requires a stronger updraft than is needed to create a similar vortex on Earth, according to research at The University of Alabama in Huntsville (UAH).

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.