of all-sky IR radiances of Himawari-8/AHI and reflectivities of
Noon Mar 8 in Room 2155
Abstract: Although a wide variety of satellite have been
used in data assimilation in NWP system, assimilating all-sky radiances
and space-borne radars are still challenging. We have been studying the
assimilation of all-sky IR radiances of the Advanced Himawari Imager
(AHI) onboard Himawari-8 satellite and reflectivity factor profiles of
the Dual Precipitation Radar (DPR) onboard Global Precipitation Mission
(GPM) – Core satellite using the regional JMA’s non-hydrostatic model
(JMA-NHM). Recent results of these two different studies will be
presented in the seminar.
Toward the all-sky AHI radiance
assimilation, we are investigating the reproducibility of model
simulation. The reproducibility depends on characteristics of
observation, NWP model, radiative transfer model (RTM), and matching
technique (e.g. interpolation, super-observation). Preliminary result
on how two major fast RTMs, CRTM and RTTOV, reproduce cloud-affected
radiances will be discussed.
Regarding DPR, we developed an
ensemble-based variational assimilation scheme that incorporated a
radar simulator and a RTM for all-sky MW radiances. We implemented
single-cycle assimilation experiments including DPR and GPM MW imager
(GMI) in combination or separately in a tropical cyclone case, and
found that a combined use brought most accurate analysis and forecast.