observational instrumentation

Hunting for molecular species in newly formed biogenic nanoparticles

Dr. Paul Winkler with the TDCIMS instrument.

New particle formation, the spontaneous creation of new nanometer-sized particles in the atmosphere, is often the dominant source of particles in remote regions. A major part of newly formed aerosol consists of organic material that can be attributed to photo-chemically reacted volatile organic compounds emitted by vegetation. Understanding the mechanisms responsible for the growth of these biogenic nanoparticles into sizes where they may scatter radiation efficiently or change cloud properties is vitally important for assessing the impacts of new particle formation on climate.

MOPITT's 'Multispectral' View of Recent Russian Fires

Russian firefighter

During the summer of 2010, large areas of central Russia were devastated by extensive wildfires burning through forests and dry peat bogs. In addition to the threat from the actual fires, the smoke and pollutants generated by the fires created an air quality crisis for millions of Russians, including residents of Moscow. Figure 1 below shows imagery from the MODIS satellite instrument for Aug. 8; a vast smoke plume is clearly evident.

Cloud Tops and Tropopause

The tropopause

The tropopause is a fundamental boundary of the atmosphere, separating the turbulent mixing dominated troposphere from the much more stable and stratified stratosphere. To examine the role of the tropopause and the jet streams in constraining the cloud distributions, ACD scientists performed an analysis of cloud top and tropopause relationships using the Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) cloud data and National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) tropopause data.

Cirrus distribution mapped with HIRDLS

Frequency of occurrence (%) of cirrus clouds at 121 hPa.

The vertical depths of cirrus in the upper troposphere vary from less to a kilometer to many kilometers. There is interest in knowing these depths in order to understand how cirrus contributes to the heating and cooling rates in the upper troposphere – a positive solar plus infrared heating rate will impart a positive enhancement to the vertical motion field. Measurements of cirrus by the HIRDLS experiment add to our knowledge base, since the HIRDLS experiment is sensitive to the presence of small amounts of cirrus along limb-views in the upper troposphere.

Perturbed Mesospheric Ozone in 2004, 2006, and 2009 NH Winters

SABER observations.

NASA’s SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument on the TIMED satellite measures temperature and ozone through the middle atmosphere from 20 to above 100 km. The SABER measurements in NH winter (mid-January through mid-March) capture the evolution of ozone and temperature during recent unusual winters (Figure 1). It is now well documented that the altitude of the temperature maximum (stratopause) was elevated for significant periods in 2004, 2006, and 2009.

Satellite Observations of Cirrus

Cirrus frequency of occurrence over the western Pacific.

Satellite observations have revealed that cirrus is very prevalent near the tropopause throughout most of the tropics. Cirrus is formed by several processes: a) in-situ rising and freezing of a humid layer, b) blow-off by deep convection, and c) initiation of cirrus formation by the cold temperature perturbations of dynamical waves. The cirrus is of interest since the cirrus restricts the amount of water vapor that is transported from the upper troposphere into the lower stratosphere.

MOPITT multispectral CO observations

Surface CO in China.

The MOPITT team has made significant advances in demonstrating multispectral retrievals of CO (carbon monoxide) with enhanced sensitivity to near-surface CO. MOPITT, (Measurements Of Pollution In The Troposphere), on EOS-Terra, has been measuring CO since March 2000, and is the only satellite instrument with both thermal infrared (TIR) and near infrared (NIR) CO channels. The standard MOPITT V4 product uses TIR-only radiances to produce CO distributions for day/night, ocean/land observations.

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