Airborne High Spectral Resolution Lidar and Research Scanning Polarimeter Measurements During RACORO

Chris Hostetler NASA - Langley Research Center
Richard Ferrare NASA LaRC
John Hair NASA - Langley Research Center
Anthony (Tony) Cook NASA - Langley Research Center
David Harper NASA - Langley Research Center
Sharon Burton NASA - Langley Research Center
Michael Obland NASA - Langley Research Center
Raymond Rogers NASA - Langley Research Center
Amy Scarino Science Systems and Applications, Inc.
Brian Cairns Columbia University
Mikhail Alexandrov Columbia University
Matteo Ottaviani NASA, Postdoc Prgrm/NASA Goddard Inst. for Space Studies
Kirk Knobelspiesse Columbia University
Haflidi Jonsson Naval Postgraduate School - CIRPAS

Category: Field Campaigns

Working Group: Cloud-Aerosol-Precipitation Interaction

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During the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) campaign conducted over the ARM Climate Research Facility’s SGP site during June 2009, the CIRPAS Twin Otter and NASA B200 King Air conducted coordinated flights in order to investigate aerosol-cloud interactions, improve cloud simulations in climate models, and validate ARM remotely sensed cloud properties. Measurements from the airborne High Spectral Resolution Lidar (HSRL) on board the B200 are being used to identify location of Twin Otter measurements relative to cloud and aerosol locations and to provide the vertical context for the Twin Otter in situ measurements. This figure shows the aerosol backscatter profiles measured by the HSRL on June 18 and shows the altitude of the Twin Otter relative to aerosol and clouds during this joint flight.

The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) and the NASA Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP) were deployed on the NASA B200 King Air aircraft that participated in the RACORO mission during June 2009. The HSRL measured profiles of aerosol extinction (532 nm), backscatter (532 and 1064 nm), and depolarization (532 and 1064 nm). The RSP instrument measured total and linearly polarized radiance in nine spectral bands that were used to retrieve column aerosol optical thickness, size distribution, and refractive index, as well as cloud optical thickness and cloud droplet effective radius. The HSRL and RSP collected data during 19 science flights during June 2009; of these, 15 flights were coordinated with the CIRPAS Twin Otter, and 16 flights included overpasses of the SGP Central Facility. The HSRL profiles have been used to determine the vertical context for the Twin Otter measurements, characterize the boundary layer and distribution of aerosols within the boundary layer, examine the impact of relative humidity on aerosol parameters, and examine the variability of aerosols near clouds. Aerosol intensive parameters derived from HSRL data are used to infer specific aerosol types and mixtures of those types. An aerosol type associated with urban pollution was found to provide the largest contribution to aerosol optical thickness measured during the campaign. The RSP measurements are being used to derive cloud drop effective radius and width of cloud drop size distribution as well as to derive aerosol properties. Cloud drop effective radius derived from RSP on June 18 was found to be between 5–7.5 micrometers and in excellent agreement with cloud drop effective radius derived from coincident forward scattering spectrometer probe (FSSP) measurements of cloud drop size distribution near cloud top. RSP retrievals of aerosol properties and coincident ground-based Raman lidar aerosol profiles will also be presented.

This poster will be displayed at ASR Science Team Meeting.

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