Time lag between the tropopause height and ⁷Be activity concentrations on surface air

Area of Science:

• Atmospheric Science
• Environmental Science
• Radiochemistry

Background:

• Beryllium-7 (7Be) is a cosmogenic radionuclide found in the atmosphere.
• Seasonal variations in atmospheric circulation influence the distribution of 7Be.

Purpose of the Study:

• To investigate the relationship between tropopause height, surface air temperature, and 7Be concentrations.
• To determine if tropopause height and temperature can serve as indicators for 7Be transport time.

Main Methods:

• Correlation analysis of seasonal tropopause height, surface air temperature, and 7Be activity concentrations.
• Statistical analysis to assess the significance of observed relationships.

Main Results:

• A strong positive correlation (R = 0.94) was found between tropopause height and surface 7Be concentration.
• A strong positive correlation (R = 0.97) was observed between surface air temperature and 7Be activity.
• Higher temperatures and tropopause heights correlate with shorter 7Be transport times.

Conclusions:

• Tropopause height and temperature are reliable indicators of 7Be transport time to the surface.
• Atmospheric convection, driven by temperature, facilitates rapid vertical transport of 7Be.
• Surface 7Be concentrations respond to tropopause height changes within approximately three days.