Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NCAR observing system finds high-level moisture with global implications

12.02.2003


Hard-to-detect clouds and water vapor, hidden until now from most atmospheric sensors, could be helping to shape global climate. An instrument package developed by the National Center for Atmospheric Research (NCAR) has detected layers of moisture, indicative of high-level cirrus clouds, that were missed by standard weather balloons and other instruments. The findings are being presented by NCAR scientist Junhong Wang on Tuesday, February 11, in Long Beach, California, at the annual meeting of the American Meteorological Society (AMS).



The undetected moisture and clouds between about 5 and 9 miles high (8-14 kilometers) probably have little effect on daily weather forecasts, but their omission may be corrupting our view of long-term climate. On average, cirrus clouds tend to warm the planet, as they allow sunlight to enter the atmosphere while trapping radiation emitted from the ground.

"Even small amounts of water vapor and cirrus clouds at these heights are extremely important for climate, as they strongly affect Earth’s radiation budget," says Richard Anthes, president of the University Corporation for Atmospheric Research, which operates NCAR. Anthes notes that radiosonde data are often used in computer models to predict the weather, and that the resulting weather analyses are then used for analyzing climate, including the calibration of models that simulate previous and future climates. "It is possible that decades of climate records have underestimated the amount of cirrus clouds in the global atmosphere," says Anthes.


Wang’s study analyzes humidity data collected from the lowest few miles of the atmosphere by radiosondes (weather balloons). Over 1,500 radiosondes are launched each day around the world, forming the backbone of the planet’s weather observing system. Wang and colleagues compared readings from the two inexpensive humidity sensors commonly used on radiosondes with data from Snow White, a high-quality sensor developed by the Swiss firm Meteolabor AG. Snow White is part of a reference-radiosonde package developed at NCAR and deployed in the International H20 Project (IHOP2002), a collaborative study led by NCAR last spring.

In the cold air from about 26,000 to 42,000 feet high, the team found that standard sensors nearly always showed relative humidities ranging from about 10% to 30%. In contrast, more than half of the Snow White deployments showed areas of moisture at these altitudes with relative humidities from 90% to 100%--a strong sign of clouds. In one of these cases, a NASA ground-based lidar (laser-based radar) taking part in IHOP2002 analyzed air near the track of a Snow White deployment. The lidar confirmed that high clouds were actually present.

How do these clouds escape detection? Many of them are "subvisible cirrus," so faint they can’t be seen by the naked eye. "Both ground- based observers and space-based satellites have trouble distinguishing these clouds," according to David Carlson, head of the NCAR Atmospheric Technology Division.

Wang and colleagues hope that their reference radiosonde system, which includes Snow White, will help improve the quality of radiosondes used for day-to-day observing. It may also help scientists correct the data from years past. "If developed and deployed soon," says Wang, "a reference radiosonde could help repair and improve data records over time and space."

NCAR scientist Kevin Trenberth, an expert on global climate, says better observations are critical, especially in the cold, high reaches more than five miles above ground. "Essentially the current radiosondes are not useful for measuring humidity at temperatures below about -4 degree F," says Trenberth. "We need a climate observing system that does a whole lot better."


###
The AMS, founded in 1919, promotes the development and dissemination of information on atmospheric, oceanic, and hydrologic sciences. The society publishes nine well-respected scientific journals, sponsors scientific conferences, and supports public education programs across the country. Additional information on the AMS and its annual meeting is available on the Internet at http://www.ametsoc.org/ams.

The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under primary sponsorship by the National Science Foundation. Opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


"A Reference Radiosonde System for Improving Water Vapor Measurement in IHOP_2002"
Symposium: Observing and Understanding the Variability of Water in Weather and Climate
83rd Annual Meeting, American Meteorological Society
Long Beach, California
Tuesday, February 11, 11:30 AM

Anatta | EurekAlert!
Further information:
http://www.ucar.edu/communications/newsreleases/2003
http://www.ucar.edu/ucar/

More articles from Earth Sciences:

nachricht First evidence of surprising ocean warming around Galápagos corals
22.02.2018 | University of Arizona

nachricht World's first solar fuels reactor for night passes test
21.02.2018 | SolarPACES

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Stiffness matters

22.02.2018 | Life Sciences

Magnetic field traces gas and dust swirling around supermassive black hole

22.02.2018 | Physics and Astronomy

First evidence of surprising ocean warming around Galápagos corals

22.02.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>