Pioneering Climate Change Modeling

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  Space News Business

Pioneering Climate Change Modeling

By BRIAN BERGER
Space News Staff Writer
posted: 19 March 2008
03:06 pm ET








WASHINGTON





NASA’s climate-modeling experts reside not on a sprawling, green government campus an easy distance from the banks of supercomputers they need to do their jobs, but in a seven-story office building in New York, four blocks from the entrance to Columbia University.

The NASA Goddard Institute for Space Studies has been located in Manhattan since its inception more than




45 years ago, a lasting legacy of its founding director, the recently deceased Robert Jastrow.



Jastrow, who died Feb. 8 at age 82, was one of NASA’s first employees, hired away from the Naval Research Laboratory’s Vanguard Project in the wake of Sputnik to head a theoretical division that would be part of the Goddard Space Flight Center then just starting to take shape on U.S. Department of Agriculture land in Maryland just outside Washington.

Jastrow
did not work on Goddard’s Greenbelt, Md., campus. While the field center was being built, he ran the theoretical division from a temporary office above a furniture store in downtown Silver Spring, Md. By 1961, he had convinced NASA management to move his center for theoretical research to New York where he intended to harness the intellectual horsepower of Columbia University to do the deep thinking that ultimately helped give rise to the U.S. Moon program and the Pioneer and Voyager solar system probes.

Today, the Goddard Institute for Space Studies, or GISS for short, is the U.S. space agency’s lead institute for climate change research.



GISS Deputy Director Larry Travis said the institute’s current focus on climate change grew out of the early work it did studying planetary atmospheres with the help of data collected by ground-based telescopes and space probes.



“Our focus has undergone several shifts,” Travis said in a recent interview. “In the very early days, it was focused on astrophysics and space science. It shifted toward Earth science in the late 1960s when a major new activity was taken on by GISS, which was the development of a state-of-the-art weather general-circulation model.”

Travis said one of the early applications of the model was helping NASA perfect the thermal sounder instruments it was building at the time to measure the Earth’s atmospheric temperature profiles from space.

By the mid-1970s, a group headed by GISS researcher Jim Hansen took the institute’s core weather model and began adapting it to model climate.



Hansen, an astronomer and physicist by training, began his scientific career at GISS in 1967 as a research associate and by the early 1970s was deeply involved in the use of polarimeters to study the composition and mechanics of planetary atmospheres. NASA accepted Hansen’s proposal to fly a polarimeter on the Pioneer Venus mission. By the time the spacecraft launched in 1978, Hansen and some of his GISS colleagues had used their spare time to take a weather model designed to look at fairly small regions of Earth on time scales of hours and days and tweak it to look at the entire planet on time scales measured in months, years and decades.



Hansen succeeded Jastrow as the institute’s director in 1981, the same year Hansen and a team of scientists predicted that the buildup of carbon dioxide in Earth’s




atmosphere would start to produce a sustained rise in the Earth’s average temperature as soon as the 1990s – about 20-30 years sooner than previously predicted.

GISS’s
interest in planetary science continued up through the 1990s.




Hansen, for example, served as the principal investigator for a polarimeter that flew on the Galileo probe NASA launched on its long voyage to Jupiter in 1989 – but Travis said the institute today is focused firmly on the intersection of space-based observations and global climate modeling.

“The models and observations always go hand in hand,” Travis said. “The modelers need the observations in order to ensure that the models are realistic, but then ultimately, for predictive capability, the models take over because you can’t observe something that’s in the future.”

GISS occupies five floors of a seven-story building the General Services Administration leases from Columbia University. On the ground floor is Tom’s Restaurant, an eatery made famous by its frequent appearances in “Seinfield,” the long-running U.S. television




comedy.



Franco Einaudi, who oversees GISS as the director of the Earth Sciences Division at Goddard Space Flight Center, said he occasionally is asked to justify keeping GISS in such a high-rent location as Manhattan, but the queries – usually launched by NASA bean counters – never go very far. “Usually the conclusion is that there are lots of advantages to keeping them where they are because there is a very healthy interaction with Columbia University … and the productivity is very high.”



Of the approximately 90 people who work at GISS, 25 are NASA civil servants and about 40 are NASA-funded researchers tied to Columbia University. Travis said this core research staff is supported by a roughly 25-person contractor staff that works for Sigma Space Partners of




Lanham, Md.

Travis said GISS gets about $11 million a year, a sum that covers not only the salaries of the GISS civil servants but of the Columbia personnel as well.

On any given day, the bulk of GISS researchers are busy refining and running climate models, back testing the results against historical records to test the validity of the changes.

“The vast majority of our folks are working on developing improvements in code and testing those by running the respected models with those improvements and comparing them with earlier versions,” Travis said. “They compare and try to understand is this really an improvement.”

Although the climate modeling used to be done in house, that is no longer the case. Travis said




more than 90 percent of the institute’s most demanding computing is done remotely, typically using the banks of supercomputers NASA maintains at Goddard Space Flight Center.

The institute’s best-known research product is a global temperature survey compiled from surface readings around the world and published each winter. The most recent surface temperature analysis, published in January, found that 2007 tied with 1998 for Earth’s second warmest year in a century. Though the survey is widely anticipated by media and climate scientists alike, Travis said it takes very little effort on the part of institute personnel to produce each year.

“In the early days, it took more effort but now it’s a fairly automated tool that involves downloading the [weather] station data then running the programs,” Travis said. “There are just two people who assist Jim in doing that … and it’s not full time for those people.”

GISS is also intimately involved in NASA’s planned 2009 Glory mission, a greenhouse gas measuring satellite featuring an aerosol polarimeter that has heritage with the instruments Hansen and his GISS colleagues worked on as part of Pioneer, Voyager and Galileo.



Though the instrument is being built by a contractor under the supervision of Goddard Space Flight Center personnel, the Glory project scientist is GISS researcher Michael Mishchenko. His GISS colleague Brian Cairns is the instrument scientist for the polarimeter.



Travis said Glory’s aerosol polarimeter will help scientists further improve climate models and make more accurate predictions. Earlier climate models tended to produce a bit more warming than what was actually observed, Travis said, a distortion probably attributable by not taking the affect of aerosols fully into account.

“For a long time people said ‘we’ve got to get the clouds done right since they are of so much importance because they reflect energy back to space,’




” he said. “But aerosols also reflect some energy back to space … and they pose a far more difficult problem because there are so many different types of aerosols.”







GISS at a Glance






Mission:

Employs sophisticated climate models and spacecraft observations
to study and predict global change.


Location:

New York


Director:

James Hansen


Parent Organization:

NASA Goddard Space Flight Center


Annual Budget:

$11 million




Workforce:

25 NASA civil servants, 25 Columbia University researchers, 40 sup�
port contractors.



Year Established:

1961