Science Questions

Discrepancies in Measured Cirrus Ice Particles Scatter plot of ice crystal number concentration from two different probes used during TWP-ICE. The differences are significant because the total number concentration could be overestimated by 300%, extinction by 106%, and ice water content by 49% if shattering or bouncing ice crystals explains the discrepancies.

Understanding the microphysical properties—ice water content, ice crystal size, shape, density, distribution, et al—of cirrus clouds is a critical factor in determining their radiative effects in the atmosphere. Discrepancies among measurements taken from different instruments, regarding the number and size of small ice crystals (maximum diameter < 50 micrometers) within the same cirrus clouds, is the dilemma that SPARTICUS hopes to help resolve.

Data from SPARTICUS will allow scientists to move forward with greater confidence in answering the following questions:

  1. To what degree do small particles (i.e., < 50 µm diameter) contribute to the mass and radiative properties of midlatitude cirrus?
  2. How do cloud-scale dynamical processes control the evolution of cirrus properties through nucleation, particle growth, and sublimation?
  3. What degree of complexity is required in cloud property retrieval algorithms, and what minimal set of algorithms can be used to rigorously describe cirrus microphysical properties using ground-based ACRF data?