Oct 2008 1

October 2008

An update provided by

Thomas Nehrkorn

Atmospheric & Environmental Research, Inc.131 Hartwell Ave

Lexington, Massachusetts 02421www.aer.com

High-resolution WRF runs for NACP

Atmospheric and Environmental Research, Inc.

Introduction

Provide overview of available WRF fieldsGenerated at NASA Columbia supercomputer facilityFunding provided by NASA and NOAA

Provide overview of verification procedure and sample verification resultsDiscuss future plans

Oct 20082

Atmospheric and Environmental Research, Inc.

Overview of Time periods and Domains

2004 and 2006:5-domain setup: 40km, 10km, 3@2km resolution

2005:2-domain setup: 40km and 10km

2007:2-domain setup: 40km and 10km (extended further west)

Oct 20083

Atmospheric and Environmental Research, Inc.

WRF domains used for 2004 and 2006

40km: 207x19210km: 349x357 (encloses d03-d05)2km: 251x251 (Moody, WLEF, and Argyle)

Oct 20084

Atmospheric and Environmental Research, Inc.

WRF domains used for 2005

40km: 207x19210km: 393x357 (extended W for OK/CO sites)

Oct 20085

Atmospheric and Environmental Research, Inc.

WRF domains used for 2007

40km: 207x19210km: 521x357 (extended W to CA)

Oct 20086

Atmospheric and Environmental Research, Inc.

WRF runs setup

Using WRF v2.2Customized to provide:

Time-averaged mass-coupled winds, convective fluxes

NARR input used for I.C. and B.C.30-hr Forecasts, initialized every 24 hr (00 UTC)

Use hours 7-30 from each forecast (avoid spin-up)

Outer domain uses analysis nudging to NARRInner domains use 1-way nestingHourly output

Netcdf (WRF native format), all fields archivedARL (compressed, STILT-compatible)

Oct 20087

Atmospheric and Environmental Research, Inc.

WRF runs verification

Winds: using WRF/STILT to colocate:WRF winds as determined from short-term trajectory computationRaob winds at selected pressure levels

925, 850, 700, 500, 400, 300 hPa

PBL heights:Profilers: TEXAQS (2006) and ICARTT (2004)Raobs: derived from T,q,u,vusing WRF/STILT to colocate:

PBL heights computed by STILT from WRF T,q,u,vPBL heights computed by WRF

Oct 20088

Atmospheric and Environmental Research, Inc.

Raob winds results: effects of nudging

For May-Aug 2004, compare:

WRF v2.2 fields with nudging (case06, 40km)WRF v2.1.2 fields without nudging (case09, 40km)

Fields generated during earlier work for Argyle tower simulations

Result show effectiveness of nudging in limiting error growth

Oct 20089

Atmospheric and Environmental Research, Inc.

Raob winds results: outer / inner domains

Results shown for June-July-August 2004:d01 and d02 compared against identical Raobs

Oct 200810

Atmospheric and Environmental Research, Inc.

Raob winds results: outer / inner domains

Results shown for June-July-August 2004:d03-d05 have 1-3 Raobs inside domain

Oct 200811

Atmospheric and Environmental Research, Inc.

Raob winds results: outer / inner domains

Wind errors generally larger in nested domains

Nudging only through B.C. from outer domainSmaller scales get penalized by point statisticsError growth from 12-24 hours evident (viz. jja_d04 in previous slide), but not uniformly at all seasons/domains/levels

Colocations have been performed for all domains, and all years:

2004 and 2006: subsampled forecasts (~1/3)2005 and 2007: all forecasts

Oct 200812

Atmospheric and Environmental Research, Inc.

PBL height verification

Ongoing. Preliminary results:WRF/STILT PBL heights tend to be overestimatesErrors are comparable for d01, d02, and d03

Oct 200813

Atmospheric and Environmental Research, Inc.

PBL height verification

Sample time series of simulated/observed:Simulated values only shown for hours with obs

Oct 200814

Atmospheric and Environmental Research, Inc.

Future Plans

Characterization of uncertaintiesCharacterize transport uncertainties based on Raob wind-colocation error statisticsCharacterize PBL height bias and random errorsExtend PBL height verification:

Extend to ICARTT 2004 profiler dataCross-compare against Raob-derived PBL heights

Extend WRF runs to additional time periodsUse existing setup

Oct 200815

Atmospheric and Environmental Research, Inc.

Future Plans - continued

Pending NSF project:Upgrade to WRF v3, explore different physics options, evaluate impact on WRF fieldsOutstanding issue: Handling of nested domains in STILT

A single particle exiting inner-most domain causes switching to coarser domain for all particlesWe will evaluate the feasibility of importing relevant upgrades from HYSPLIT to STILT

Oct 200816