Use of ARM Raman, HSRL and MMCR measurements to characterize cirrus cloud properties and life cycle
Authors
Robert E. Holz — University of Wisconsin/CIMMS
Ralph Kuehn — University of Wisconsin, Madison
David D. Turner — NOAA Earth System Research Laboratory
Category
Cloud Properties
Description
The sensitivity of the millimeter cloud radar (MMCR) to optically thin single‐layer cirrus at the Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site is investigated using collocated Raman lidar observations. The sensitivity is characterized in terms of cloud optical depth (OD) and infrared (IR) radiative flux using over three years of coincident Raman lidar and MMCR observations. For cases when the Raman lidar is not fully attenuated (OD < 2.0), the MMCR detects approximately 70% of the total cloud OD with the majority of missed cloud OD occurring near cloud top. If only MMCR observations are used for computing cloudy top‐of‐atmosphere (TOA) infrared (IR) flux, the missed cloud OD results in TOA flux biases from 0 to over 100 W/m2; however, the most frequently occurring bias is approximately 16 W/m2. This result highlights the importance of combining Raman lidar, or other sensitive cloud lidars that are able to measure cloud extinction directly, with the MMCR in order to accurately characterize the cloud radiative forcing for thin cirrus cases
