2. DA Experiments with NICAM-LETKF

Ensemble-Based Data Assimilation of GPM/DPR Reflectivity into the Nonhydrostatic Icosahedral Atmospheric Model NICAM

Kotsuki, S. (shunji.kotsuki@riken.jp), K. Terasaki, and T. MiyoshiRIKEN Center for Computational Science, Japan

NICAM-LETKF and GPM/DPR

Level 2 Normal Scan (NS)

Matched Scan (MS)

High-Sensitivity(HS)

width 245 km 125 km 125 kmΔx 5 km 5 km 5kmΔz 250 m 250 m 500 m

Band Ku Ka Ka

3D reflectivityGPM/DPR core satellite (Hou et al. 2014)

NICAM-LETKF (Terasaki et al. 2015)

3. Model Parameter Sensitivity to GPM/DPR

First DA step column max reflectivity for KuPR

DA cycle experiment

Improved by GPM/DPR Degraded by GPM/DPR

T Q

RMSD vs. ERA Interim (2014)

Not successful maybe due to・ model imperfections・ model bias・ too sparse observation

May be useful for parameter DA Parameter sensitivity investigated

Single moment cloud microphysics (6-class)

1/2, ,

0, , , ,( ) /d r s gt r s g r s gv D c D

1/2

0

4

3g

gD

gc

C

NICAM 6-class single moment scheme (NSW6; Tomita 2008)

terminal velocity (m/s)

〇 Numerical Model:・NICAM (Satoh et al. 2008, 2014)

- 28-km resolution- single moment bulk could microphysics

〇 Data Assimilation:・LETKF (Hunt et al. 2007) with 40 members・RTPS (α=0.95)〇 Observations:・NCEP-PREPBUFR・AMSU-A Radiances・GSMaP w/ Gaussian Transform. (Kotsuki et al. 2017)・Dual-frequency Precipi. Radar (DPR)

CD(graupel)

Cr(rain)

NICAM default Sensitivity EXP (21 runs)

min max resolution

Cr 130.0 50 230 8

CD 0.60 0.20 1.00 0.04

ρ: density (kg/m3)D: diameter (m)

vertical profile of KuPR & KaPR

weaklycorrelated

weaklycorrelated

Correlation b/w parameter & DPR