A Study of Cloud Overlap Assumptions in GCMs from Radar and Lidar at SIRTA
Haeffelin, M.(a), Dufresne, J.L.(a), O'Hirok, W.(b), Protat, A.(c), Chepfer, H.(a), Goukenleuque, C.(a), and Morille, Y., Institut Pierre Simon Laplace, Laboratoire de Météorologie Dynamique, Palaiseau, France (a), University of California at Santa Barbara, USA (b) Institut Pierre Simon Laplace,Centre d'Etude des Environnements Terrestre et Planétaires (c), Vélizy, France
Fourteenth Atmospheric Radiation Measurement (ARM) Science Team Meeting
The atmosphere above mid-latitude continents is frequently composed of multi-layered clouds. The vertical distribution and vertical overlap of clouds in the column have great impact on radiative fluxes at the top of the atmosphere and surface. Few studies have focused on comparing the representations of cloud overlap in GCMs to actual observations of the vertical distribution of clouds. A cloud and radiation observatory near Paris (SIRTA) has been gathering active and passive remote sensing data since 2002. SIRTA's assets are a powerful backscattering lidar combined with a mm-wave cloud radar. We will show how lidar-radar synergy can be used to describe the vertical distribution of clouds, and study biases that occur when using either instrument alone. We will further use these observations to study cloud overlap probabilities and to assess cloud overlap assumptions in GCMs.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).


