United States DEPARTMENT of Commerce

A P P E N D I x C : P e r f o r m a n c e M e a s u r e s D e f i n i t i o n s
Data Source NOAA’s Global Carbon Cycle Research Program
Frequency
Annual
Data Storage
NOAA’s Earth System Research Laboratory
Internal Controls Quality assurance and calibration against known standards performed by NOAA.
Data Limitations Number of tall tower/aircraft sites and NOAA’s ability to incorporate these data into advanced carbon models.
Actions to be Taken None
Performance Measure:
Reduced the uncertainty in model simulations of the influence of aerosols on climate
Aerosols are liquid or solid particles suspended in the atmosphere. They force changes in the climate system by (1) directly
absorbing and scattering of radiation from the sun, and (2) by changing the way clouds reflect back solar radiation. While
greenhouse gases warm the atmosphere, aerosols and clouds can both counteract greenhouse gases by reflecting incoming solar
radiation and cooling the atmosphere, or, under different conditions, some aerosols can absorb solar radiation and some clouds
can trap heat, thus heating the atmosphere. The role of aerosols, clouds, and climate is deemed to be the largest single uncertainty
in the prediction of how human activities influence climate change (Intergovernmental Panel on Climate Change [IPCC] 2001).
This GPRA measure now addresses the first of the two factors. In later years the second factor will also be included.
Annual targets quantitatively score the success of each of the individual research tasks in preceding years. Success in each of
these preceding steps is necessary for success in meeting the 10 percent improvement of uncertainty associated with the 2007
goal and the 15 percent improvement in uncertainty for the 2008 goal.
The desired outcome is an improved science-vetted set of options for changing the impact of North American aerosols on climate,
which can be considered by governments, the private sector, e.g., transportation and energy production, and the public. Reductions
in the uncertainties surrounding aerosols relate directly to the confidence with which model simulations can support policy
decisions on the climate issue. Furthermore, since aerosols are also a human-health, air quality issue, there is the opportunity
to quantify “win-win” opportunities of how decisions made to improve air quality may also contribute to reduce the forcing of
climate change.
Data Source
Frequency
Data Storage
Internal Controls
Data Limitations
Actions to be Taken
NOAA’s Atmospheric Composition and Climate Program
Annual
NOAA’s Earth System Research Laboratory
Quality assurance and comparisons against 2001 international assessments by leading experts in the aerosol climate community.
Number of monitoring sites for vertical distribution of aerosols, process studies that include intensive field campaigns and laboratorybased
data, and NOAA’s ability to include these in global models.
None
F Y 2 0 0 7 P E R F O R M A N C E A N D A C C O U N T A B I L I T Y R E P O R T
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