Science Seminars

10/20/2011 – Improving Radiometry for Climate Studies

Speaker: Greg Kopp, LASP
Date: Thursday, Oct 20, 2011
Time: 4:00 PM
Location: LSTB

Seminar Abstract:

How well do we know how much energy is coming in to the Earth’s climate system? And — although a much more difficult measurement — how much of that is lost to space? Climate-quality data require more stringent measurement accuracies and stabilities than needed for shorter-term studies. LASP is helping improve the measurements of both the Earth’s incident and reflected radiation via new radiometric instruments. A 33-year spaceborne record of total solar irradiance, the dominant energy driving the Earth’s climate system, has created a climate data record needed for understanding the influences of the Sun on climate. Instrument and calibration improvements are making these the most accurate and stable radiometric spaceborne measurements in existence, as needed for climate studies. Atmospheric water vapor and other greenhouse gases, aerosols, land use, and several additional natural and anthropogenic influences affect the absorption of this incoming shortwave solar energy and can be inferred from accurate outgoing Earth radiance measurements. I will discuss the status of shortwave radiometry for climate studies, including recent progress improving solar irradiance measurements, new understandings of the accuracy of the existing 33-year record, the resulting estimated climate sensitivities to solar variability, and effects of the recently lost Glory mission on this data record, as well as methods of improving radiometric accuracies on future climate missions to benchmark the Earth’s outgoing shortwave radiation.