Aerosol structure and vertical distribution in a multi-source dust region

Area of Science:

• Atmospheric Science
• Remote Sensing
• Environmental Monitoring

Background:

• Aerosols significantly impact climate and air quality.
• Understanding vertical aerosol distribution is crucial for atmospheric studies.
• Limited data exists on free troposphere aerosol profiles in western China.

Purpose of the Study:

• To investigate the vertical distribution of aerosols in the free troposphere over Zhangye, China.
• To analyze the sources and characteristics of different aerosol layers.
• To examine the relationship between aerosol distribution and atmospheric conditions.

Main Methods:

• Direct observation of aerosol vertical distribution using surface micro-pulse lidar (MPL4).
• Data collection at Zhangye Station (39.08° N, 100.27° E) during spring 2008.
• Analysis of aerosol layers, extinction coefficients, and diurnal variations.

Main Results:

• Aerosols were classified into upper (4.5-9 km), middle (2.5-4.5 km), and lower (<2.5 km) layers.
• Upper layer aerosols originated from external, high-altitude sources; middle and lower layers had mixed origins.
• Aerosol extinction coefficients varied with altitude and atmospheric stability, indicating aerosol mixing in the middle layer.
• Diurnal variation showed a single peak, higher in the afternoon, influenced by the atmospheric boundary layer.

Conclusions:

• Vertical aerosol distribution is layer-dependent, influenced by altitude, atmospheric conditions, and source regions.
• Aerosol mixing processes are significant in the middle atmospheric layer.
• Micro-pulse lidar is effective for characterizing free troposphere aerosol profiles.