Kyoko Ikeda

Associate Scientist II
TIIMES - RAL
WCAS

Contact Information:
PO Box 3000, Boulder, CO 80307-3000
Office: FL2 - 3050
Telephone: 303-497-2842
Email: kyoko@ucar.edu

Project Summary:

I joined TIMES in 2005.  Funded by the NCAR Water Cycle Program, my work focused on idealized simulations of continental-scale convective organizations over the continental U.S. under Dr. Changhai Liu’s supervision.  More recently, I examined idealized simulations of continental-scale convective organizations over the U.S. using 10-day average of diurnally variant fields from ETA model analysis data.  Additionally, idealized squall line simulations were performed to investigate the sensitivity of Seifert-Beheng and Noppel et al. microphysical schemes to aerosol concentrations.  My recent efforts concentrate on two-dimensional idealized simulations of squall-type organized convective systems using Lin, WSM6, and Thompson microphysics schemes that are currently available in the WRF model in order to study the impact of cloud microphysical parameterizations on simulations of such precipitation systems.

Work done in FY 2007 (Kyoko Ikeda and Changhai Liu):

1. Idealized WRF simulations of continental-scale convective organizations over the continental U.S. was performed using 10-day average of diurnally variant fields from ETA model analysis data for two cases.  Generally, the simulations produced convections each day over the eastern slopes of the Rocky Mountains in Colorado as observed, but they were less persistent and propagated slower compared with the observations likely due to the coarse model resolution of 10 km.

2. Cloud-resolving idealized WRF simulations of squall-type organized convective systems were performed to examine the effect of various aerosol concentrations (maritime and continental) on Seifert-Beheng and Noppel et al. microphysical schemes.  Preliminary results showed that while general evolution of the system was similar for maritime and continental cases for each microphysical scheme, aerosol concentrations impacted time trend of accumulative rainfall.  Aerosol concentrations characteristic of maritime air persistently produced more rain during the earlier stage of the system and had broader raindrop size spectra.  The total accumulative rainfall in 10 hours was case dependent.  The result also showed that the core of the convection in the more-recently developed Noppel et al. microphysical scheme was not at the leading edge of the system unlike results from the Seifert-Beheng scheme.  Detail study on this topic will continue in the upcoming fiscal year.

Future plan:

I will continue investigating the impact of cloud microphysical parameterizations on simulations of organized convective systems.  The study will focus on comparisons of partitioning of various microphysical processes among the Lin, 6-class graupel-phase microphysical model (WSM6), and Thompson microphysical schemes.  In addition, I will take part in high resolution regional climate simulations of snowpack, evapo-transpiration, and runoff in the western states—a study which is planned to start in FY 2008—under guidance of Dr. Liu.

Publications:

Brandes, E. A., K. Ikeda, G. Zhang, M. Schoenhuber, R. M. Rasmussen, 2007: A statistical and physical description of hydrometeor distributions in Colorado snowstorms using a video disdrometer. J. Appl. Meteor. Climat., 46, 634-650.

Ikeda, K., R. M. Rasmussen, W. Hall, G. Thompson, 2007: Observations of freezing drizzle in extratropical cyclonic storms during IMPROVE-2. J. Atmos. Sci., 64, 3016-3043, doi: 10.1175/JAS3999.1.