Multiscale Data Assimilation Forcing for LASSO

Zhijin Li1,2, Xiaoping Cheng1, William Gustafson3, Heng Xiao3, Andrew Vogelmann4, Satoshi Endo4, Tami Toto4 & Jinwon Kim1

1UCLA, 2JPL, 3PNNL, 4BNL

Breakout Session 2, Monday, 13 March 2017, 4–6 p.m. March 23, 2017 1

LASSO LES Initialization and Large Scale Forcing

~20km

LESisdrivenby• Largescalehorizontalandverticaladvection• Surfacesensibleheatflux,latentheatflux,

albedoandskintemperature

VerticalProfilesforInitializingLES:• Temperature,moisture,andwinds

LargeScaleForcing:• Horizontaladvectionoftemperatureand

moisture• Verticalvelocity• Geostrophicwinds• Horizontaladvectionofhydrometeors(?)

Challenges and Requirements on Large Scale Forcing

Strategy:NestedWRFatacloudresolvingresolutionwithmultiscaledataassimilation(MSDA)

ARMSGP

Threedomainnestedconfiguration

Aresolutionof2 kmintheinnerdomain1. Multi-scale/scale-aware

forcing

2. Forcingfornon-periodic

domains

3. Cloudandprecipitation

relatedvariables(?)

300km

AMulti-ScaleThree-DimensionalVariationalDataAssimilation(MSDA)System

MSDAFeatures:

1. Existing

analysis/reanalysisplus

MSDAδx

2. Developedontopofthe

NCEPWRFGSI

3. Enhancedeffectiveness

ofassimilatingARM

observations

Existinganalysis/reanalysis(FNL,NARR,…)

( )

( ) )()(21

21)(min

)()(21

21)(min

11

11

yxHRHHByxHxBxxJ

yxHRHHByxHxBxxJ

ST

LT

SSSTSSx

LT

ST

LLLTLLx

S

L

ddddddd

ddddddd

d

d

-+-+=

-+-+=

--

--

( ) )()(21

21)(min 11 yxHRyxHxBBxxJ T

SLT

xddddddd --++= --

x = xL + xS

Decompositionoflargeandsmallscales

Smallscaledataassimilation(Lietal.2015MWR;2015,JGR)

Impact of MSDA forcing on LES

3/23/17 5

Obs

LES

MSDA

CloudsinMSDAhavemuchsimilaritywiththoseinLES

MSDA Impact on Vertical Profiles

3/23/17 6

Readytoexploresecondarydiscrepancieswhenmoreverticalprofilesareavailable?

MSDA

Sonde

• MSDAhelpsLESrepresenttheboundarylayer

• DiscrepanciesfromtheSonde profilesignificant

• Multipleverticalprofilesneededtoevaluate

Improved effectiveness of MSDA Using Observing System Experiment (OSE)

Improvedeffectivenessofassimilatingradiances1. Raisedthetoplevelto10hPa2. Increasedtheverticalresolution3. Adjustederrorcovariance

Withsatelliteradiances

W/Osatelliteinfraredradiance

Withsatelliteinfraredradiance

WewilluseOSEstoimprovetheassimilationofvariousmeasurements

On-going and Future Work

March23,2017 8

1. Preparation for being used as a quasi-realtime system

2. Observing system experiments (OSEs) to improve the impact of Raman lidar profile, wind profilers and others on LES.

3. Nesting LES to Cloud-resolving WRF with MSDA

4. Optimization of forcing ensemble members: wide spread of skill scores

5. Implementation of ensemble-MSDA WidespreadofskillscoresofMSDAmembers?