Boundary Layer and Dispersion Applications 2 nd M ulti-parameter - - PowerPoint PPT Presentation

Boundary Layer and Dispersion Applications

2nd M ulti-parameter Phased Array Radar Workshop Norman, Oklahoma 18 November 2009

• Dr. Walter D. Bach, Jr.

Environmental Sciences Division Army Research Office walter.d.bach@us.army.mil

Outline

• R&D Needs / Priorities

– M P

AR

– NRC Report : From the Ground Up – OFCM J

AG/ Atmospheric Transport And Diffusion

• PBL Science issues
• Key Challenges

MPAR R&D Needs / Priorities

• Weather Surveillance

– Real time Severe Weather – Nowcast Airport Wind

Hazards

– Enroute ice and turbulence – Heavy precipitation – Hydrometeorology – Initialize NWP wind models

and near PBL

• Aircraft Surveillance

– Cooperative – Non-cooperative

• Other Surveillance

– Airborne release of toxins – Spaceflight ops – Ground truth satellites – Fire Weather / Wildland

Fires

– M udslides – Air Quality and Health – Volcanic Ash – Birds as Hazards – Agriculture

NRC O Obs bservations Sup Supporti ting Fundame mental al In Infras astruct cture f for Mes esoscal ale Monitorin ing and and Predic ediction

• Phenomenology for Observational Requirements

– T

emperature, moisture, and wind velocity universally required

– M ost requirements below 5 km (deepest PBL) – Smaller scale phenomena need high resolution

• Data Assimilation: Synergy of Data and M odels

– M easurement error – Representativeness error – M odel physics

• Special Climate Requirements

– Absolute accuracy – Long term

• M esoscale Observations for Research

– Research obs are often episodic, ephemeral, and of limited area

tending to focus on details of processes. (They) may fail to contribute reliably or consistently to ongoing operations and therefore could be viewed as untrustworthy, disruptive, or even parasitic.

NR NRC R Recom

• mmend

ndations

• ns
• M easurements and Infrastructure

– Lidar and radar profilers for lower troposphere – 400 – Air Quality Sensors – CO, SO2, O3, 2.5 µm aerosols - 200 in

urban; 175 km rural separation

– Soil moisture and temperature profiles - 3000 – Distributive/ collaborative networks of radar and lidar – GOES based water vapor & temperature profiles in

Continental boundary layer

– Upgrade rail / ground transportation systems to WM O

standards

– Facilitate observational network of Vehicle Infrastructure

Integration initiative

NRC R C Repo port

• Nearly all recommendations for improving the

mesoscale observations address BL issues. Few address modeling issues.

• Network site recommendations (~ 125 km

separation) adds finer structure to larger scale features through data assimilation, but are too coarse to address BL heterogeniety issues.

• M easurements, M odeling, and Use should be

designed to work together – within a test bed network concept as recommended by the J AG/ATD and as J AG/JUTB is developing

JAG/ G/ Atmos

• sph

pheric T c Transpor

• rt a

and Diffus usion

• n

R&D &D Strat ategy to y to Meet U t User N r Needs

COORDINATED AGENCY SUPPORT & FUNDING

GOALS

M EASUREM ENT CAP ABILITIES M ODEL EVAL STANDARDS ATD TEST BEDS BRIDGE THE SCALE GAP CAPTURE AND USE EXISTING DATA SETS LOCAL/ REGIONAL M EASUREM ENT SITING Routinely Quantify Uncertainty Interpret Uncertainty

OBJECTIVES

1 mm 1 cm 1 m 10 m 100 m 1 km 10 km 100 km 1000 km

Horizontal grid spacing

CFD

M esoscale

GCM

Model el G Grid id Siz Sizes

DNS LES

Building Urban Storm Fronts Synoptic

Physical M odeling

GAP

1 mm 1 cm 1 m 10 m 100 m 1 km 10 km 100 km 1000 km

Horizontal grid spacing

M odeling Gap

Rawinsondes

RADAR

Diurnal Boundary Layer

Surface Obs

Building Urban Storm Fronts Synoptic

Surface Layer M eso-Net

ACARS

Meas easur urem ement Capa Capabilities at at Model el G Grid id Spac Spacin ing

PBL Sc PBL Scie ience e Issues ues

• Smallest scales of atmospheric motion affected by all

larger scales

• M ajor energy exchange
• M ost variable, least predictable part of atmosphere.
• Few measurements near ground; fewer aloft. Difficult to

characterize existing measurements

• Forecast models are too coarse for local accuracy

– PBL heights – Stability – Shear – Large rms wind direction error

• PBL models (turbulence closure, dispersion) have large

uncertainty and large effects from small changes (chaotic).

Key C Challen lenges es

• Close the knowledge gap between the mesoscale and

microscale modeling capabilities

Observations M odels Theory

• Develop instrumentation for measuring PBL wind,

temperature, and moisture at PBL time & space scales (smaller than models)

• Operate instruments in high impact networks

covering 50 x 50 km footprint continuously.

• Quantify uncertainty in model inputs and predictions
• Represent transport and diffusion in complex flows,

including urban and coastal environments

Que s tions Comme nts

Positive

• Data assimilation of

winds

• Increased space-time

resolution

Negative

• M odel Development
• Uncertainty