A study on the low-altitude clouds over the Southern Ocean using the DARDAR-MASK - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Geophysical Research: Atmospheres Année : 2012

A study on the low-altitude clouds over the Southern Ocean using the DARDAR-MASK

Résumé

A climatology of the thermodynamic phase of the clouds over the Southern Ocean (40-65S,100-160E) has been constructed with the A-Train merged data product DARDAR-MASK for the four-year period 2006-2009 during Austral winter and summer. Low-elevation clouds with little seasonal cycle dominate this climatology, with the cloud-tops commonly found at heights less than 1km. Such clouds are problematic for the DARDAR-MASK in that the Cloud Profiling Radar (CPR) of CloudSat is unable to distinguish returns from the lowest four bins (heights up to 720 - 960m), and the CALIOP lidar of CALIPSO may suffer from heavy extinction. The CPR is further limited for all of the low-altitude clouds (tops below 3km) as they are predominantly in the temperature range from freezing to -20 C, where understanding the CPR reflectivity becomes difficult due to the unknown thermodynamic phase. These shortcomings are seen to flow through to the merged CloudSat-CALIPSO product. A cloud-top phase climatology comparison has been made between CALIPSO, the DARDAR-MASK and MODIS. All three products highlight the extensive presence of supercooled liquid water over the Southern Ocean, particularly during summer. The DARDAR-MASK recorded substantially more ice at cloud-tops as well as mixed phase in the low-elevation cloud-tops in comparison to CALIPSO and MODIS. Moving beneath the cloud-top, the DARDAR-MASK finds ice to be dominant at heights greater than 1 km, once the lidar signal is attenuated. The limitations demonstrated in this study highlight the enormous challenge that remains in better defining the energy and water budget over the Southern Ocean.
Fichier principal
Vignette du fichier
2012JD017800.pdf (2.29 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-00724011 , version 1 (26-08-2020)

Identifiants

Citer

Yi Huang, Steven T. Siems, Michael J. Manton, Alain Protat, Julien Delanoë. A study on the low-altitude clouds over the Southern Ocean using the DARDAR-MASK. Journal of Geophysical Research: Atmospheres, 2012, 117 (D18), pp.D18204. ⟨10.1029/2012JD017800⟩. ⟨hal-00724011⟩
152 Consultations
52 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More