Depolarization ratio and attenuated backscatter for nine cloud types: analyses based on collocated CALIPSO lidar and MODIS measurements Export

@article{citeulike:6090659, abstract = {This paper reports on the relationship between lidar backscatter and the corresponding depolarization ratio for nine types of cloud systems. The data used in this study are the lidar returns measured by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite and the collocated cloud products derived from the observations made by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua satellite. Specifically, the operational MODIS cloud optical thickness and cloud-top pressure products are used to classify cloud types on the basis of the International Satellite Cloud Climatology Project (ISCCP) cloud classification scheme. While the CALIPSO observations provide information for up to 10 cloud layers, in the present study only the uppermost clouds are considered. The layer-averaged attenuated backscatter (γ′) and layer-averaged depolarization ratio (δ) from the CALIPSO measurements show both water- and ice-phase features for global cirrus, cirrostratus, and deep convective cloud classes. Furthermore, we screen both the MODIS and CALIPSO data to eliminate cases in which CALIPSO detected two- or multi-layered clouds. It is shown that low γ′ values corresponding to uppermost thin clouds are largely eliminated in the CALIPSO δ-γ′ relationship for single-layered clouds. For mid-latitude and polar regions corresponding, respectively, to latitude belts 30°-60° and 60°-90° in both the hemispheres, a mixture of water and ice is also observed in the case of the altostratus class. MODIS cloud phase flags are also used to screen ice clouds. The resultant water clouds flagged by the MODIS algorithm show only water phase feature in the δ-γ′ relation observed by CALIOP; however, in the case of the ice clouds flagged by the MODIS algorithm, the co-existence of ice- and water-phase clouds is still observed in the CALIPSO δ-γ′ relationship.}, author = {Cho, Hyoun-Myoung and Yang, Ping and Kattawar, George W. and Nasiri, Shaima L. and Hu, Yongxiang and Minnis, Patrick and Trepte, Charles and Winker, David}, citeulike-article-id = {6090659}, citeulike-linkout-0 = {http://dx.doi.org/10.1364/OE.16.003931}, citeulike-linkout-1 = {http://www.opticsinfobase.org/abstract.cfm?id=154830}, day = {17}, doi = {10.1364/OE.16.003931}, journal = {Opt. Express}, keywords = {backscatter, calipso, cloud, depolarization, lidar}, month = {March}, number = {6}, pages = {3931--3948}, posted-at = {2009-11-09 20:48:15}, priority = {2}, publisher = {OSA}, title = {Depolarization ratio and attenuated backscatter for nine cloud types: analyses based on collocated CALIPSO lidar and MODIS measurements}, url = {http://dx.doi.org/10.1364/OE.16.003931}, volume = {16}, year = {2008} }

TY - JOUR ID - citeulike:6090659 L3 - citeulike-article-id:6090659 N2 - This paper reports on the relationship between lidar backscatter and the corresponding depolarization ratio for nine types of cloud systems. The data used in this study are the lidar returns measured by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) aboard the Cloud- Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite and the collocated cloud products derived from the observations made by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua satellite. Specifically, the operational MODIS cloud optical thickness and cloud-top pressure products are used to classify cloud types on the basis of the International Satellite Cloud Climatology Project (ISCCP) cloud classification scheme. While the CALIPSO observations provide information for up to 10 cloud layers, in the present study only the uppermost clouds are considered. The layer-averaged attenuated backscatter (γ′) and layer-averaged depolarization ratio (δ) from the CALIPSO measurements show both water- and ice-phase features for global cirrus, cirrostratus, and deep convective cloud classes. Furthermore, we screen both the MODIS and CALIPSO data to eliminate cases in which CALIPSO detected two- or multi-layered clouds. It is shown that low γ′ values corresponding to uppermost thin clouds are largely eliminated in the CALIPSO δ-γ′ relationship for single-layered clouds. For mid-latitude and polar regions corresponding, respectively, to latitude belts 30°-60° and 60°-90° in both the hemispheres, a mixture of water and ice is also observed in the case of the altostratus class. MODIS cloud phase flags are also used to screen ice clouds. The resultant water clouds flagged by the MODIS algorithm show only water phase feature in the δ-γ′ relation observed by CALIOP; however, in the case of the ice clouds flagged by the MODIS algorithm, the co-existence of ice- and water-phase clouds is still observed in the CALIPSO δ-γ′ relationship. IS - 6 JF - Opt. Express EP - 3948 TI - Depolarization ratio and attenuated backscatter for nine cloud types: analyses based on collocated CALIPSO lidar and MODIS measurements PB - OSA VL - 16 SP - 3931 KW - backscatter KW - calipso KW - cloud KW - depolarization KW - lidar AU - Cho, Hyoun-Myoung AU - Yang, Ping AU - Kattawar, George AU - Nasiri, Shaima AU - Hu, Yongxiang AU - Minnis, Patrick AU - Trepte, Charles AU - Winker, David PY - 2008/03/17/ UR - http://dx.doi.org/10.1364/OE.16.003931 ER -