Doug A. Degenstein

Major Influence of Tropical Volcanic Eruptions on the Stratospheric Aerosol Layer During the Last Decade

The variability of stratospheric aerosol loading between 1985 and 2010 is explored with measurements from SAGE II, CALIPSO, GOMOS/ENVISAT, and OSIRIS/Odin space-based instruments. We find that, following the 1991 eruption of Mount Pinatubo, stratospheric aerosol levels increased by as much as two orders of magnitude and only reached background levels between 1998 and 2002. From 2002 onwards, a systematic increase has been reported by a number of investigators. Recently, the trend, based on ground-based lidar measurements, has been tentatively attributed to an increase of SO2 entering the stratosphere associated with coal burning in Southeast Asia. However, we demonstrate with these satellite measurements that the observed trend is mainly driven by a series of moderate but increasingly intense volcanic eruptions primarily at tropical latitudes. These events injected sulfur directly to altitudes between 18 and 20 km. The resulting aerosol particles are slowly lofted into the middle stratosphere by the Brewer-Dobson circulation and are eventually transported to higher latitudes.

The Spatial Heterodyne Observations of Water (SHOW) Instrument for High Resolution Profiling in the Upper Troposphere and Lower Stratosphere

The Spatial Heterodyne Observations of Water (SHOW) instrument is a prototype Canadian satellite instrument specifically designed to make high spatial resolution measurements of water vapor in the upper troposphere and lower stratosphere through vertical imaging of the limb scattered sunlight in a near infrared vibrational absorption band. The spatial heterodyne approach provides sufficient spectral resolution and signal-to-noise performance such that when combined with a multiple scattering forward model and a non-linear inversion, the SHOW measurements can be used to tomographically reconstruct the two dimensional water vapour distribution, i.e. in altitude along the satellite track. Here we present the motivation for the measurement, the instrument concept, prototype specifications and results from simulated measurements and retrievals.

Spatial Heterodyne Spectrometer for Observation of Water (SHOW) aboard the ER-2 Aircraft: Overview of the Instrument

SHOW is designed to vertically resolve water profiles from limb scattered sunlight in the atmosphere. We present the technical design of the prototype that is accommodated for test flight on the NASA Lockheed ER-2 aircraft.

Spatial Heterodyne Spectrometer for Observation of Water for a Balloon Flight: Overview of the Instrument & Preliminary Flight Data Results

SHOW is a Spatial Heterodyne Spectrometer designed to vertically resolve water profiles from limb scattered sunlight. The instrument successfully flew at 35 km float altitude. We present an overview of the instrument and preliminary results.