Vertical Motion

Long-Term Lidar and Radar Observations of Arctic Stratus at Two Locations

Gijs de Boer, E.W. Eloranta, I.A. Razenkov J.P. Hedrick and J.P. Garcia (The University of Wisconsin - Madison )M.D. Shupe ( NOAA Earth System Research Laboratory )

P 2.20

Mixed-Phase Arctic Stratus Long-Term Stratus PropertiesIntroductionMixed-phase clouds remain a difficult problem for both the observational and mod-eling communities. In particular, improved understanding of mixed-phase clouds in the Arctic is crucial because of radiative effects they impart on a region that is par-ticularly sensitive to change. In order to better understand these cloud structures, the University of Wisconsin Arctic High Spectral Resolution Lidar (AHSRL) has been deployed to two different Arctic locations. The first deployment lasted two months and was to Barrow, AK in support of the Mixed-Phase Arctic Clouds Experiment (M-PACE). The second deployment is ongoing, and so far over two years of data have been collected at Eureka, Canada. In both locations, the lidar was co-located with a NOAA Millimeter Cloud Radar (MMCR). Mixed phase stratus has been readily de-tected at both locations, and we currently have measurements for hundreds of hours of stratus cases. Results shown here are for both locations for single-ayer clouds only. Represented are 532 half-hour cases for Barrow, and 1569 for Eureka.

Observation Sites

The seatainer housing for the AHSRL in Barrow (left) and Eureka (right). The map of the western Arctic (top) shows the differences in location between Barrow and Eureka. (Bathymetric chart produced by and courtesy of the NOAA IBCAO program: http://www.ngdc.noaa.gov/mgg/bathymetry/arctic/arctic.html) Also visible in the Eureka picture is the antenna for the NOAA millimeter cloud radar (MMCR).

N NBarrow

Eureka A View From Above

Acknowledgements

09 October, 2004: Barrow

15 February, 2006: Eureka

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Lidar backscatter cross section (Masked values shown in black and white)

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Lidar backscatter cross section (Masked values shown in black and white)

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0.20.40.60.81.01.21.41.61.82.02.22.42.62.8

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Radar backscatter cross section (Masked values shown in black and white)

12:05 12:10 12:15 12:20 12:25

0.20.40.60.81.01.21.41.61.82.02.22.42.62.8

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Depolarization (Masked values shown in black and white)

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Lidar/Radar Microphysical RetrievalsBased on method by Donovan and Van Lammeren (2001)

15 February, 2006: Eureka

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Effective Diameter (Masked values shown in black and white)

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0.20.40.60.81.01.21.41.61.82.02.22.42.62.8

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Shupe Ice Water Content (Masked values shown in black and white)

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Radar IWC (Shupe, 2005)

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Cloud Mask (Masked values shown in black and white)

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0.20.40.60.81.01.21.41.61.82.02.22.42.62.8

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TOP: Retrieved effective diameter, number density and water content from the AHSRL/MMCR combination.LEFT: A cloud mask derived from the MMCR and AHSRL.RIGHT: Ice water content as derived from the radar only (reflectivity rela-tionship: SHUPE, 2005).BOTTOM: Mean vertical profiles of the retrieved quantities for this half hour period, with ranges plotted.

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CLOUD

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PRECIPITATION

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Figures courtesy of M. Shupe

EUREKA

Satellite Track

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CloudSAT Retrievals

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CALIPSO Attenuated Backscatter (532)

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Lidar backscatter cross section (Masked values shown in black and white)

11:05 11:10 11:15 11:20 11:25

0.20.40.60.81.01.21.41.61.82.02.22.42.62.8

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Doppler Velocity (Masked values shown in black and white)

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Shupe Ice Water Content (Masked values shown in black and white)

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Vertical velocity measurements may help in explaining the horizontal variability of the observed precipitation structure. Here, the doppler spectra are used to look at ver-tical motion in the cloud layer.

The CloudSAT and CALIPSO platforms allow for greater spatial coverage of these clouds. Shown are examples from October 30, 2006. Similarities between the ground and space based observa-tions are shown at right.

This work is funded by NASA (144 QQ61 ), and the US Department of Energy (DE-FG02-06ER64187 ). Special thanks to Matthew Shupe (NOAA), Joe Garcia, Jim Hed-rick, and Igor Razenkov (Wisconsin) for their help with data and measurements.