Diversity on subtropical and polar properties as derived from both ground-based lidars and CALIPSO/CALIOP measurements

• Published in: Atmospheric Research
• Main Authors: CORDOBA JABONERO, CARMEN, LOPES, FABIO J.S., LANDULFO, EDUARDO, CUEVAS, EMILIO, OCHOA, HECTOR, GIL-OJEDA, MANUEL
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2017
• Subjects: clouds; optical radar; polar regions; comparative evaluations; maps; brazil; spain; argentina; Antarctic; Argentina; Belgrano; Belgrano II; The Antarctic; Antarc*
• Online Access: http://repositorio.ipen.br/handle/123456789/26773; https://doi.org/10.1016/j.atmosres.2016.08.015

Cirrus (Ci) cloud properties can change significantly from place to place over the globe as a result ofweather processes, reflecting their likely different radiative and climate implications. In this work Cirrus clouds (Ci) features observed in late autumn/earlywinter season at both subtropical and polar latitudes are examined and compared to CALIPSO/CALIOP observations. Lidar measurementswere carried out in three stations: S??o Paulo (MSP, Brazil) and Tenerife (SCO, Canary Islands, Spain), as subtropical sites, and the polar Belgrano II base (BEL, Argentina) in the Antarctic continent. The backscattering ratio (BSR) profiles and the top and base heights of the Ci layers together to their Cirrus Cloud Optical Depth (CCOD) and Lidar Ratio (LR) for Ci clouds were derived. In addition, temperatures at the top and base boundaries of the Ci clouds were also obtained from local radiosoundings to verify pure ice Ci clouds occurrence using a given temperature top threshold (b???38 ??C). Ci clouds observed along the day were assembled in groups based on their predominant CCOD, and classified according to four CCOD-based categories. Ci clouds were found to be vertically-distributed in relation with the temperature, forming subvisual Ci clouds at lower temperatures and higher altitudes than other Ci categories at both latitudes. Discrepancies shown on LR values for the three stations, but mainly remarked between subtropical and polar cases, can be associated to different temperature regimes for Ci formation, influencing the internal ice habits of the Ci clouds, and hence likely affecting the LR derived for the Ci layer. In comparison with literature values, daily mean CCOD/LR for SCO (0.4 ?? 0.4/21 ?? 10 sr), MSP (0.5 ?? 0.5/27 ?? 5 sr) and BEL (0.2 ?? 0.3/28 ?? 9 sr) are in good agreement; however, the variability of the Ci optical features along the day present large discrepancies. In comparisonwith CALIOP data, Ci clouds are observed at similar altitudes (around 10???13kmheight); however, differences are found mostly in ...