Ice Cloud Parameterizations for the Global Climate Models
Faculty Mentor Name
Dorothea Ivanova
Format Preference
Poster
Abstract
Cirrus clouds are one of the biggest uncertainties in radiative budget, crucial to the understanding of the short- and long-term trends in climate. Improved parameterizations of cirrus clouds in global climate models (GCMs) require good understanding of the cloud properties and especially the role of small ice crystals in cirrus. Cirrus clouds have an important impact on earth's climate by influencing the radiation balance and hydrological cycle. Ice clouds play an important role in the climate system, but they are often poorly represented in climate models. Improved parameterizations of cirrus clouds in GCMs require good understanding of the cloud properties and especially of the role of small ice crystals in cirrus. A goal of this proposed project is to help improve climate prediction through better representation of the microphysical cirrus properties in GCMs. We aim to create a GCM parameterization for bimodal size spectra in mid-latitude cirrus clouds and a trimodal size distribution parameterization for tropical cirrus. Both are expected to predict different behavior of the size distributions (SD) for the same ice water content (IWC) and temperatures. As temperature decreases beyond -35°C, the magnitude of the small mode is uncertain with the tropical scheme, but predictable with the midlatitude scheme. This is a fundamental question and indicates that the radiative properties of tropical and mid-latitude cirrus are considerably different for the same IWC. This may also point to the different mechanisms by which convective and non-convective cirrus are generated.
Ice Cloud Parameterizations for the Global Climate Models
Cirrus clouds are one of the biggest uncertainties in radiative budget, crucial to the understanding of the short- and long-term trends in climate. Improved parameterizations of cirrus clouds in global climate models (GCMs) require good understanding of the cloud properties and especially the role of small ice crystals in cirrus. Cirrus clouds have an important impact on earth's climate by influencing the radiation balance and hydrological cycle. Ice clouds play an important role in the climate system, but they are often poorly represented in climate models. Improved parameterizations of cirrus clouds in GCMs require good understanding of the cloud properties and especially of the role of small ice crystals in cirrus. A goal of this proposed project is to help improve climate prediction through better representation of the microphysical cirrus properties in GCMs. We aim to create a GCM parameterization for bimodal size spectra in mid-latitude cirrus clouds and a trimodal size distribution parameterization for tropical cirrus. Both are expected to predict different behavior of the size distributions (SD) for the same ice water content (IWC) and temperatures. As temperature decreases beyond -35°C, the magnitude of the small mode is uncertain with the tropical scheme, but predictable with the midlatitude scheme. This is a fundamental question and indicates that the radiative properties of tropical and mid-latitude cirrus are considerably different for the same IWC. This may also point to the different mechanisms by which convective and non-convective cirrus are generated.