outline introduction: e-rtfdda new enhancement to e-rtfdda preliminary verification

NATIONAL CENTER FOR ATMOSPHERIC RESEARCH

Integration of NCAR DART-EnKF to NCAR-ATEC multi-model, multi-physics and mutli- perturbantion

ensemble-RTFDDA (E-4DWX) forecasting system

Linlin Pan 1, Yubao Liu 1, Gregory Roux 1, Wanli Wu 1, Yonghui Wu 1, Jason Knievel 1, John Pace 2, Scott

Halvorson 2, Frank Gallagher 2

1NCAR/Research Application Laboratory2Dugway Proving Ground, US Army

Outline

1. Introduction: E-RTFDDA2. New enhancement to E-RTFDDA3. Preliminary verification4. Summary and future work

RTFDDA E-RTFDDA

E-RTFDDA Perturbation Approaches

LSM LDAS

RadiationPrecipitation Upper-air weather forcingVegetation …

Para

mete

rs

ETKF CyclingPerturbationsAnd scaling

GFS

Stat. perturb.Other. Perturb.

NAMECMWF

ObsDataAssimilationWeights

Perturbationsin components

may becombined

200+members

MM5

WRFPh

ysics

Sch

em

es a

nd

Para

mete

r p

ertu

rbatio

ns

E-RTFDDA Design and New Features

• Multimodal models

WRF-ARW, MM5, WRF-NMM

• Multi-boundary conditions

GFS, NAM, GEM

• Multi-physics

Major WRF physics parameterization schemes; Stochastic Kinetic Energy Backscattering

• Multiple data assimilation

RTFDDA, 3DVAR, DART-EnKF

Case description and experiment design

• 2012033118 – 2012040318

• Western US

GFS GEM

NAM

06 Z, April 1, 2012 (6h Forecasts)

DART

DART-ENKF Surface Observations

NAM GEM

Wind Speed

GFS DART

Wind Direction

NAM GEM

GFS DART

GFS GEM

NAM DART

Spread of U, valid at 20120406, 6h fcsts

GFS GEM

NAM DART

Spread of V, valid at 20120406, 6h fcsts

GFS GEM

NAM DART

Spread of T, valid at 20120406, 6h fcsts

Combined spread

U

V

U

V

gfs+nam All

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Summary• NCAR E-RTFDDA is a multi-model, multi-physics, multi-

boundary conditions, multi-data assimilation scheme, mesoscale ensemble weather analysis and forecast system for real-time operational forecasting.

• In the present work, we introduces several enhancements to the E-RTFDDA perturbation schemes ， using WRF-NMM, GEM, DART-ENKF and SKEB model and/or technologies.

• Initial tests show that these additional perturbation schemes work properly ， and help mitigate the known underestimation of the E-RTFDDA spread.

• Currently we are implemented these technologies into the operational E-RTFDDA systems. Validation of the real-time forecasts will be conducted to further quantify the effect.

Combined spread

T