Seminar by Dr. Sun-Seon Lee

Dynamics-Oriented Diagnostics for the Madden–Julian Oscillation

Realistic simulations of the Madden–Julian oscillation (MJO) by global climate models (GCMs) remain a great challenge. To evaluate GCM simulations of the MJO, the U.S. CLIVAR MJO Working Group developed a standardized set of diagnostics, providing a comprehensive assessment of statistical properties of the MJO. Here, a suite of complementary diagnostics has been developed that provides discrimination and assessment of MJO simulations based on the perception that the MJO propagation has characteristic dynamic and thermodynamic structures.

Jasmine - Seminar Room (1010), 10th floor, M Building

Seminar by Prof. Dominik Fleitmann

Speleothems at the interface of climatology, ecology and archaeology

In 2006, Professor Gideon Henderson (Oxford University) stated that "For paleoclimate, the past two decades have been the age of the ice core. The next two may be the age of the speleothem". This rather bold statement suggests that speleothems (stalagmites, stalactites, and flowstones) have the potential to deliver ice-core-like records of past climatic and environmental changes. In his talk, Prof.

Jasmine - Seminar Room (1010), 10th floor, M Building

Seminar by Dr. Thomas Kilpatrick

Satellite observations of convection–wind coupling

Satellite scatterometers measure surface winds over the global oceans, but these observations have historically been limited by rain-related errors. We have recently developed techniques to circumvent these rain-related errors, allowing for direct observational study of convection–wind coupling over the ocean. We use these corrected wind data to detect cool downdrafts from mesoscale convective systems (MCSs) for the first time. These wind observations are validated against surface buoys and satellite observations of cloud-top temperature.

Jasmine - Seminar Room (1010), 10th floor, M Building

Seminar by Dr. Ji-Eun Kim

Heating and Moistening of the MJO during DYNAMO in ECMWF Reforecasts

The Madden-Julian oscillation (MJO), the dominant mode of tropical intraseasonal variability, has profound impacts on a wide range of weather and climate phenomena in the tropics and extratropics. Despite decades of intensive studies, our understanding of its physical mechanisms has remained controversial. While most previous work has focused on processes associated with the MJO itself, comparing the MJO and other types of tropical convection might provide valuable insights into understanding the MJO.

Jasmine - Seminar Room (1010), 10th floor, M Building

Seminar by Dr. Marcus Loefverstroem

On the mutual interaction between atmosphere and ice over the last glacial cycle

Thelast glacial cycle (ca. 115-12 ka) was the most recent in a series of recurringglaciations of the subpolar continents in Eurasia and North America. At thelast glacial maximum (LGM), the Northern Hemisphere ice sheets were ofcontinental scale and lowered the global sea-level by approximately 100 m,which is comparable to the combined volume of Greenland and Antarctica today.The work presented here investigates the mutual interaction between thetime-mean atmospheric circulation and the spatio-temporal evolution of theNorthern Hemisphere ice sheets over the last glacial cycle.

Jasmine - Seminar Room (1010), 10th floor, M Building

Seminar by Dr. Dipayan Choudhury

Drift correction of decadal experiments

Phase Five of the Coupled Model Intercomparison Project (CMIP5) includes a new set of experiments, called the ‘decadal’ or ‘near-term’ predictions, to bridge the gap between weather forecasting systems and climate projections. These experiments are initialized with the observations and provide predictions over 10 or 30-years periods, while also accounting for external forcings. Climate models, being imperfect replicas of the real world, have equilibrium states that differ from that of the observed climatology.

Jasmine - Seminar Room (1010), 10th floor, M Building