The Variational Version of the Local Analysis and Prediction System

(LAPS): Hot-start Data Assimilation of Convective Events

Steve Albers, Yuanfu Xie, Hongli Jiang, Dan Birkenheuer, Isidora Jankov, and Zoltan Toth

ESRL/GSDWRF Workshop June 26th 2013

Updated 6/25/2013 1810UTC

Presentation Outline

LAPS Overview

Windsor Tornado

Hazardous Weather TestBed (HWT)

Future Plans

LAPS System Overview

Data Ingest

Intermediatedata files

GSI

FORECAST MODEL (e.g. WRF)

Verification

Analysis Scheme

Downscaling can work as a stand alone module

from background → GSI or other

applications such as Fire wx.

Downscaling is also an integral part of variational LAPS

(aka. STMAS).

Data Background (or cycled forecast)Observations

Standalone downscaling

module

Traditional LAPS

Variational LAPS (with downscaling)

Model prep

LAPS MotivationHigh Resolution (500m – 20km), rapid update (10-60min)

Highly portable system Collaboration with user community - about 150 world wide

Federal Gov’t – NWS, RSA, PADS, FAA, DHS State Gov’t – California Dept of Water Resoures International – Finnish Met. Inst., China Heavy Rain Inst. Local to Global analysis – used by SOS

Wide variety of data sources:

OAR/ESRL/GSD/Forecast Applications Branch *

Transition from Traditional to Fully Variational LAPS

state vars, wind (u,v) clouds / precip

balance and constraintsin multi-scale variational

analysis

Windanalysis

Temp/Ht analysis

Humidity analysis

Cloud analysis

balance

Traditional LAPS analysis: Wind, Temp, Humidity, Cloud, Balance

Ultimately

Temporary hybrid system: Traditional LAPS cloud analysis and

balance

NumericalForecast

model

Large Scale Model First Guess

Cycling Option

Var.LAPS

Cloud Analysis Flow Chart

Cloud Fraction 3-D Isosurface

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(From radars and model first guess)

Cloud Analysis Independent ValidationAll-sky Imager• Compare LAPS simulated all-sky analyses (or forecasts) to actual all-sky imagery

• Validates quality of analyses (or forecasts) of clouds / visibility obstructions

Courtesy: Longmont

Astronomical Society

All-Sky Camera

Sun Glare

Cloud Analysis Independent Validation

All-sky Imager• This example has more clouds with high opacity

• Validation leads to improvements (e.g. parallax correction, thin cirrus)

Courtesy: Longmont Astronomical Society

Sun Glare

Windsor, CO 2008 Tornado Simulations

Model Initial Conditions Boundary Condition Resolution

wrf-wsm6RUCp 3h fcst +

Variational LAPSRUCp+WRF

da_update_bc 1.67km (Xie)

wrf-tomRUCp 3h fcst +

Variational LAPS analysis

RUCp + WRF da_update_bc 3km (Jiang)

Windsor - 700 mb reflectivity initial=2008052217, 1h fcst

Mosaic radar vs. WRF forecast (1.67 km res)

Analyzed Radar / 10 min Forecast

T T

Hazardous Weather Testbed (HWT) Experimental Warning Program (EWP)

2013 Experiment Domains & FieldsForecast: regional domain at 1 km and 3 km resolutions, hourly re-initialization with

15 min model output.• Composite Reflectivity

• CAPE

• CIN

• Updraft Helicity

• Lifted index

• Satellite simulated IR Brightness Temperature

• Fractional Cloud Cover

• Cloud Ceiling

Surface analysis: conus domain at 2.5 km resolution available hourly• Surface Temperature

• Dew Point Temperature

• U,V wind component

• PMSL

• surface pressure

Observed & Forecast IR Satellite Brightness Temp HWT 3km Domain 25 Jun 2013 0400 - 0600Z

• Simulated VIS also available (derived from cloud amount)• Forecasters are naturally familiar with satellite images• Used for objective cloud forecast verification

OBS Forecast

HWT Forecasters’ Input (real time EWP Blog)

LAPS again. Higher CAPE, bow echo. Lower CAPE, bye bye bow echo.Posted on May 14, 2013“In my opinion, the LAPS surface-based CAPE product was one of the stars of the day. Consistently, storms lived and died based on entering and exiting the tongue of higher CAPE values which extended north and northeast from the Big Bend area for most of the day. This first image shows the LAPS surface-based CAPE at 00Z, and the radar at the same time. Shouldn’t be hard to pick out the storm of interest. Note that the storm is still in the tongue of 1000+ J/kg of CAPE as noted on LAPS.

One hour later, the storm is exiting and entering a less favorable instability regime. And predictably, it starts to weaken

Any questions? LAPS nailed it.”CL

Moore Tornado Related Blog Entries LAPS Observations and Determining Future Storm Development…Posted on May 20, 2013 “Just a quick post about observations of the LAPS theta-e field this afternoon. It was interesting to see the near stationary aspect of the theta-e boundary in assoc/w the dryline to our south across portions of north Texas this afternoon. This suggests that continued development is possible late this afternoon especially across northern Texas, where the gradients have been sustained and have even increased lately. However, notice that the gradients have decreased generally across much of Oklahoma where convection and related effects (rain cooled air, cloud shield) have helped to stabilize the environment. The 15-minute temporal resolution of the product can be very useful for diagnosing locations of continued convection especially in rapidly developing convective situations.”

2115UTC 2130UTC

2145UTC 2200UTC

LAPS analysis. Shaded values are sfc theta-e (K), while wind vectors are in blue.

LAPS niche: Good handle on existing convection and lead time on CI

HWT 1km V-LAPS0-3 h Composite Reflectivity Verification

Higher ETS (best at short lead time)Compare WRF initialization schemes, work with DTC?

Var. LAPS Initialization

Moore Tornado 1hr LAPS Forecast

Simulated IR Satellite Forecast

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Simulated IR Satellite LAPS / WRF 6-Hr Forecast Verification

Forecast high clouds sometimes look too thick

Future Plans - Cloud Analysis

Develop and validate forward models and their adjoints for all data sources being used to more fully implement a variational approach

Utilize improved constraints relating various control and derived variables

Combine ensemble background error covariances into multiscale variational analysis, i.e., different scale error covariances applied at different multigrid levels of the variational LAPS analysis

OAR/ESRL/GSD/Forecast Applications Branch *

Cloud Forecast Plans

Improve Hot-Start Elementso Hydrometeors, Temperature, Water Vapor, Vert-Vel

Examine various WRF radiation options and their consistency with microphysics

Consider water vapor given small-scale / partial clouds in a grid-box

Combine with analysis for 4DVAR

OAR/ESRL/GSD/Forecast Applications Branch *