Tropical Warm Pool International Cloud Experiment (TWP-ICE): Cloud and Rain Characteristics in the Australian Monsoon

Abstract

iii SUMMARYThe impact of oceanic convection on its environment and the relationship between the characteristics of the convection and the resulting cirrus characteristics is still not understood. An intense airborne measurement campaign combined with an extensive network of ground-based observations is being planned for the region near Darwin, Northern Australia, during January-February, 2006, to address these questions. The Tropical Warm Pool -International Cloud Experiment (TWP-ICE) will be the first field program in the tropics that attempts to describe the evolution of tropical convection, including the large scale heat, moisture, and momentum budgets, while at the same time obtaining detailed observations of cloud properties and the impact of the clouds on the environment. The emphasis will be on cirrus for the cloud properties component of the experiment. Cirrus clouds are ubiquitous in the tropics and have a large impact on their environment but the properties of these clouds are poorly understood. A crucial product from this experiment will be a dataset suitable to provide the forcing and testing required by cloud-resolving models and parameterizations in global climate models. This dataset will provide the necessary link between cloud properties and the models that are attempting to simulate them.The experiment is a collaboration between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program, the Bureau of Meteorology (BoM), the National Aeronautics and Space Administration (NASA), the European Commission DG RTD-1.2, and several United States, Australian, Canadian, and European Universities. This experiment will be undertaken over a 4-week period in early 2006. January and February corresponds to the wet phase of the Australia monsoon. This season has been selected because, despite Darwin's coastal location, the convection that occurs over and near Darwin at this time is largely of maritime origin with a large fetch over water. Based on previous experiments, the convection appears typical of maritime convection with widespread convection that has complex organization, but is not as deep or as intense as continental or coastal convection. Therefore, it is expected that the convection and cloud characteristics will be representative of conditions typical for wide areas of the tropics.TWP-ICE seeks to build on a number of past experiments. Tropical Ocean Global Atmosphere-Coupled Ocean Atmosphere Response Experiment (TOGA-COARE) was an extensive tropical campaign that focused largely on the organization of deep convection and on processes associated with the ocean/atmosphere interface. More recently, the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) and Egrett Microphysics Experiment with Radiation Lidar and Dynamics (EMERALD) experiment have focused on deep organized convection systems typical of coastal areas. In both of these experiments, the emphasis was on observing properties of cirrus clouds and processes of the ...

Cloud-System-Resolving Model Simulations of Tropical Cloud Systems Observed during the Tropical Warm Pool-International Cloud Experiment

“…The Tropical Warm Pool-International Cloud Experiment (TWP-ICE, May et al 2008) took place in Darwin, Australia during January and February 2006. The experiment provided an extensive data set describing tropical cloud systems, their evolution and interaction with the large-scale environment.…”

“…Convection in the break period is usually stronger, deeper and more isolated than during the active monsoon; it has a strong diurnal cycle, high lightning activity, and is often initiated by coastal circulation like sea-breezes (May and Ballinger 2007;Keenan and Carbone 1992). Within the two large scale regimes, 4 convective regimes may be defined (after May et al 2008). These 4 regimes were sampled during the intense observing period of TWP-ICE.…”