Condensed-phase nitric acid in a tropical subvisible cirrus cloud

Nitric acid uptake on subtropical cirrus cloud particles

[1] The redistribution of HNO3 via uptake and sedimentation by cirrus cloud particles is considered an important term in the upper tropospheric budget of reactive nitrogen. Numerous cirrus cloud encounters by the NASA WB-57F high-altitude research aircraft during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) were accompanied by the ...

Microphysical properties of subvisible cirrus

Aircraft measurements of microphysical properties of subvisible cirrus in the tropical tropopause layer

Subvisible cirrus (SVC) clouds are often observed within the tropical tropopause layer (TTL). Some studies suggest that SVC has a significant impact on the earth radiation budget. The Costa Rica Aura Validation Experiment (CR-AVE) sponsored by the National Aeronautics and Space Administration (NASA) took place near San Jose, Costa Rica from 14 January–15 February 2006. The NASA WB-57F sampled S...

In-situ observations and modeling of nitric acid-containing particles in a cirrus cloud formation region

Measurements in nascent ice forming regions are very rare and help understand cirrus cloud formation and the interactions of trace gases with ice crystals. A cirrus cloud has very likely been probed in its formation stage with in-situ and remote sensing instruments onboard the high altitude research aircraft Geophysica M55 in the tropical 5 upper troposphere. Besides microphysical and optical p...

On the origin of subvisible cirrus clouds in the tropical upper troposphere

Spaceborne lidar observations have recently revealed a previously undetected significant population of Subvisible Cirrus (SVC). We show them to be colder than−74 , with an optical depth below 0.0015 on average. The formation and persistence over time of this new cloud population could be related to several atmospheric phenomena. In this paper, we investigate if these clouds follow the same form...