Event Title
Water Vapor and Cloud Formation in the TTL: Simulation Results vs. Satellite Observations
Location
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Start Date
16-10-2012 5:30 PM
End Date
16-10-2012 7:30 PM
Document Type
Poster
Description
Driven by analyzed winds and temperature, domain-filling forward trajectory calculations are used to reproduce water vapor and cloud formations in the tropical tropopause layer (TTL). As with most Lagrangian models of this type, excess water vapor is instantaneously removed from the parcel to keep the relative humidity with respect to ice from exceeding a specified (super) saturation level. The dehydration occurrences serve as an indication of where and when cloud forms. Convective moistening through ice lofting and gravity waves are also included in our simulations as mechanisms that could affect water vapor abundances and cloud formations in the TTL. Our simulations produce water vapor mixing ratios close to that observed by the Aura Microwave Limb Sounder (MLS) and are consistent with the reanalysis tropical tropopause temperature biases, which proves the importance of the cold-point temperature to the water vapor abundances in the stratosphere. The simulation of cloud formation agrees with the patterns of cirrus distribution from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). It proves that the trajectory calculations fed by the analyzed wind and temperature could produce reasonable simulations of water vapor and cloud formation in the TTL.
Water Vapor and Cloud Formation in the TTL: Simulation Results vs. Satellite Observations
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Driven by analyzed winds and temperature, domain-filling forward trajectory calculations are used to reproduce water vapor and cloud formations in the tropical tropopause layer (TTL). As with most Lagrangian models of this type, excess water vapor is instantaneously removed from the parcel to keep the relative humidity with respect to ice from exceeding a specified (super) saturation level. The dehydration occurrences serve as an indication of where and when cloud forms. Convective moistening through ice lofting and gravity waves are also included in our simulations as mechanisms that could affect water vapor abundances and cloud formations in the TTL. Our simulations produce water vapor mixing ratios close to that observed by the Aura Microwave Limb Sounder (MLS) and are consistent with the reanalysis tropical tropopause temperature biases, which proves the importance of the cold-point temperature to the water vapor abundances in the stratosphere. The simulation of cloud formation agrees with the patterns of cirrus distribution from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). It proves that the trajectory calculations fed by the analyzed wind and temperature could produce reasonable simulations of water vapor and cloud formation in the TTL.
