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March 2008

short takes

An overview of projects throughout the organization

Climate and crops. A looming question for society is the effect of climate change on crops and, in turn, the effects of agricultural land use and management on climate. To help researchers address such issues, Sam Levis (ESSL/CGD) is coupling a crop model to the land component (CLM) of the NCAR-based Community Climate System Model.

The new model will simulate different leaf areas and yields for wheat, corn, and other crops in response to temperature and soil moisture scenarios. In a proof-of-concept simulation, Sam demonstrated a correlation between higher precipitation levels and greater leaf area for a variety of crops in the Midwest.

His next step is to link the crop model to CLM’s carbon-nitrogen cycling model in order to simulate biogeochemical effects of land use and management on the climate system. The goal is to add the crop simulations to CCSM’s land component in about a year.

Alaska to Argentina. Students living on opposite ends of the Americas—northern Alaska and southern Argentina—will have a unique opportunity next month to compare their respective polar climates and environments. The second annual Pole-to-Pole videoconference, part of GLOBE’s International Polar Year activities, takes place on April 8.

As part of GLOBE’s Seasons and Biomes campaign, students and teachers in Alaska and Argentina have been using GLOBE resources to study tundra and taiga biomes. (Tundra biomes feature permanently frozen soil, with lichens, mosses, and other low-growing plants as the predominant vegetation. Taiga, or boreal forest, features needle-leaf trees such as pine and spruce.) The videoconference this year focuses on these biomes.

One of the campaign’s goals is to help students in different biomes interact with both each other and research scientists. During the Pole-to-Pole videoconference, polar, boreal, and other researchers, including Peggy LeMone (ESSL/MMM), will be on hand to answer students’ questions about changing seasonal indicators and their possible links to climate change. Students can also ask questions of each other. A follow-up Web chat and blog is scheduled forApril 10–11. More information

A better handle on dangerous clouds. Data from a new cloud-mapping satellite is helping RAL scientists better assess where in-cloud icing might threaten aircraft.


The heights of cloud tops can be difficult to assess and predict.

Many pilots avoid treacherous winter weather with the help of the Current and Forecast Icing Products (CIP and FIP). CIP and FIP use observations and computer models to paint a three-dimensional picture of current and future cloud layers across the country, including those that might cause aircraft icing. Verifying the skill of techniques that diagnose and predict clouds has been difficult, however, in part because no single instrument can detect and measure multiple cloud layers in three dimensions.

CloudSat, launched in 2006 as part of a series of NASA satellites, includes a cloud radar that maps the top and bottom of most cloud layers beneath it. Using a new validation technique that incorporates CloudSat data, NCAR scientists have found that CIP tends to overpredict the thickness of low clouds by making those cloud tops too high. For higher clouds, CIP tends to commit the opposite error, making the cloud tops too low.

“This method has certainly helped us think about our cloud-top algorithm and shown us some things we didn’t know before,” says RAL’s Cory Wolff. “Compared to other schemes for identifying the height of cloud tops, CIP does fairly well, but there is definitely room for improvement.”

Work is now under way to correct the CIP bias, which could help reduce the number of flights rerouted due to icing risk. Cory presented results in January at the annual meeting of the American Meteorological Society in New Orleans.

In this issue...

Tim Killeen to head geosciences for NSF

Project BudBurst blooms

Upcoming conferences

Ocean’s natural thermostat may protect some coral reefs

Let it melt

Delphi Question

Short Takes

Just One Look


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