# Presentation: 056145

## AERMET

- 8TH Modeling Conference
- RTP, NC
- September 22 – 23, 2005

- Presented by:  Desmond T. Bailey     desmond.bailey@noaa.gov

**Notes:**
Updated for AT Workshop in Raleigh April 7-10.

## The Planetary Boundary Layer (PBL)

- Surface Layer
- 0 to 0.1  Zi (mixing height)
- Dominated by friction
- M-O Similarity applies
- Mixed Layer
- Capped by a stable layer aloft
- Develops due to heating from below
- Wind speed is constant with height

## AERMET Science

- The Planetary Boundary Layer (PBL)
- Convective Boundary Layer (CBL)
- Driven by surface heating
- Develops during the day
- Moderate to strong vertical mixing
- Stable Boundary Layer (SBL)
- Driven by surface cooling
- Develops at night
- Little to no vertical mixing

## AERMET Science

- Properties of the PBL affecting dispersion
- vertical profiles of
- Wind speed
- Temperature
- Vertical turbulence
- Lateral turbulence
- Depth of mixing

## AERMET Science

- Surface Layer
- Similarity Theory
- Applies in the surface layer
- Important scaling parameters
- Friction velocity		fn (wind shear, z0)
- Convective velocity scale	fn (H, Zi, θ )
- Monin-Obukhov length	fn (H, u*, θ )
- Temperature Scale		 fn (H, u* )
- Mixing height

## CBL Regimes

- Surface Layer
- Depth 0 to 50 m
- Dominated by friction
- M-O similarity theory applies
- Turbulence depends on roughness and M-O length
- Mixed Layer
- Depth up to 3000 m
- Wind speed is constant with height
- Turbulence depends on convective velocity scale

## CBL Characteristics

- Monin-Obukhov length < 0
- Depth increases during the day due to surface heating
- Shear and buoyancy contribute to turbulence
- Capped by a stable layer

## Modeling the CBL

- Estimate the sensible heat flux using an energy balance approach
- Given the heat flux, calculate the friction velocity and M-O length using an iterative approach
- Determine the growth of the mixed layer by integrating heat flux over time

## SBL Characteristics

- Monin-Obukhov length > 0
- Develops when surface begins to cool
- Turbulence is shear driven
- Turbulence decays with height
- Mixing is weak
- Problematic
- Not as well understood as the CBL

## Modeling the SBL

- Extension of CBL method for estimating friction velocity and M-O length problematic due to small negative heat flux.
- Alternative method uses the Bulk Richardson Number

## Bulk Richardson Number

- Advantages
- Does not require cloud cover
- Required measurements
- Wind speed at one level in surface layer
- Vertical Temperature gradient in the surface layer

## Evaluation of Bulk Richardson Approach

- Problems were found with the approach used in AERMET 02222
- An evaluation was funded to resolve the problem
- Several alternative implementations were considered
- These were tested using the Kansas, Prairie Grass, and Cinder Cone Butte data bases

## Evaluation of Bulk Richardson Approach

- Problems were found with the approach used in AERMET 02222
- An evaluation was funded to resolve the problem
- Several alternative implementations were considered
- These were tested using the Kansas, Prairie Grass, and Cinder Cone Butte data bases

## Evaluation of Bulk Richardson Approach

- Presented at the 8th AMS/AWMA Joint Conference in Vancover, BC

## Evaluation of Bulk Richardson Approach

- Presented at the 8th AMS/AWMA Joint Conference in Vancover, BC

## Process meteorological data for use in AERMOD

- Raw Data

- QA

- Merge

- Process

- Extract

- Model ready files

## Surface Data

- Supported Formats
_***SAMSON***_
- CD 144
- TD 3280
- HUSWO
_*TD 3505 (ISHD)*_
_*SCRAM*_

**Notes:**
Integrated because it looks at stationary (major & area), mobile, and indoor air sources

Goals of the Strategy:
75% reduction in cancer incidence
Substantial reduction in noncancer risks
Address disproportionate risks (ie, hot spots, sensitive/specific subgroups, minority communities)

## Upper-Air Data

- Supported Formats
_***FSL***_
- TD 6201

**Notes:**
Integrated because it looks at stationary (major & area), mobile, and indoor air sources

Goals of the Strategy:
75% reduction in cancer incidence
Substantial reduction in noncancer risks
Address disproportionate risks (ie, hot spots, sensitive/specific subgroups, minority communities)

## Stage 1 Extract

## Stage 2 Merge

## Stage 3 Process for AERMOD

## Audit Report Surface Data

## Stage 2 Merge Report