Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

Lidar ratio and depolarization ratio for cirrus clouds

Not Accessible

Your library or personal account may give you access

Abstract

We report on studies of the lidar and the depolarization ratios for cirrus clouds. The optical depth and effective lidar ratio are derived from the transmission of clouds, which is determined by comparing the backscattering signals at the cloud base and cloud top. The lidar signals were fitted to a background atmospheric density profile outside the cloud region to warrant the linear response of the return signals with the scattering media. An average lidar ratio, 29 ± 12 sr, has been found for all clouds measured in 1999 and 2000. The height and temperature dependences of the lidar ratio, the optical depth, and the depolarization ratio were investigated and compared with results of LITE and PROBE. Cirrus clouds detected near the tropopause are usually optically thin and mostly subvisual. Clouds with the largest optical depths were found near 12 km with a temperature of approximately -55 °C. The multiple-scattering effect is considered for clouds with high optical depths, and this effect lowers the lidar ratios compared with a single-scattering condition. Lidar ratios are in the 20–40 range for clouds at heights of 12.5–15 km and are smaller than ∼30 in height above 15 km. Clouds are usually optically thin for temperatures below approximately -65 °C, and in this region the optical depth tends to decrease with height. The depolarization ratio is found to increase with a height at 11–15 km and smaller than 0.3 above 16 km. The variation in the depolarization ratio with the lidar ratio was also reported. The lidar and depolarization ratios were discussed in terms of the types of hexagonal ice crystals.

© 2002 Optical Society of America

Full Article  |  PDF Article
More Like This
Classification of particle effective shape ratios in cirrus clouds based on the lidar depolarization ratio

Vincent Noel, Helene Chepfer, Guy Ledanois, Arnaud Delaval, and Pierre H. Flamant
Appl. Opt. 41(21) 4245-4257 (2002)

Measurements of cirrus cloud backscatter color ratio with a two-wavelength lidar

Zongming Tao, M. Patrick McCormick, Dong Wu, Zhaoyan Liu, and Mark A. Vaughan
Appl. Opt. 47(10) 1478-1485 (2008)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (7)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Tables (4)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (17)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved