Generation of Simulated Atmospheric Datasets for Ingest into Radiative Transfer Models

Generation of Simulated Atmospheric Datasets for Ingest into Radiative Transfer Models

Jason A. Otkin, Derek J. Posselt, Erik R. Olson, and Raymond K. Garcia

Cooperative Institute for Meteorological Satellite StudiesSpace Science and Engineering Center

University of Wisconsin–Madison

Outline

• Review prior MURI-funded MM5 model simulations

– Convective initiation event (IHOP)

– Upper-tropospheric jet streak (THORPEX)

• Compare WRF & MM5 model simulations of a severe weather outbreak

• Examine the most recent MURI-funded model simulation

– WRF simulated extratropical cyclone (ATREC)

• Data processing with 32-CPU Altix system

Procedure

1. Use a sophisticated mesoscale model (such as the MM5 or WRF) to produce a highly realistic simulated atmospheric dataset

2. Use forward model calculations performed on simulated temperature, water vapor, and cloud microphysical profiles to generate infrared spectra with high spectral resolution

3. Retrieve temperature and water vapor from top of atmosphere radiances and compare with original simulated atmosphere to assess retrieval accuracy

MM5 Model Characteristics

• Non-hydrostatic numerical model that solves the full non-linear primitive equations on user-defined terrain-following sigma levels

• Prognostic variables include perturbation pressure, u, v, w, qw, as well as mixing ratios for other microphysical variables

• Employs a 24-category topography and land-use dataset with varying horizontal resolution


• Can run multiple 1- and 2-way interactive and moving nests

• Includes programs for FDDA, 3DVAR, and analysis nudging

• Contains a sophisticated LSM to provide heat and moisture fluxes at the surface


• Employs leap frog temporal differencing with an Asselin filter to remove “computational mode” noise arising from the leap frog scheme

• 2nd order centered differencing scheme used for the horizontal and vertical advection terms

• Contains 4th order horizontal diffusion/filter terms

• MM5 has an effective resolution of ~10 * x

IHOP Convective Initiation Event

Objectives:• Demonstrate satellite potential to

observe moisture convergence prior to convective initiation

• Demonstrate potential to observe fine-scale rapidly-evolving water vapor structures

GOES-11 10.7 micron imagery: 1803-2355 UTC 12 June 2002

Event Overview:• Mostly clear environment preceding late afternoon convection• Very complex low-level moisture structures and wind fields• Convection initiated in the presence of strong convergence along a fine-scale low-level water vapor gradient

IHOP Convective Initiation Event

MM5 Model Configuration:• 4 km grid spacing with 60

vertical levels• Initialized at 06 UTC on 12 June

with 10-km RUC data and then run for 24 hours

• Nudged toward RUC analyses during 6-hr spin-up period

• Goddard microphysics• MRF planetary boundary layer• RRTM/Dudhia radiation• OSU land-surface model• No cumulus parameterization

Geographical region covered by MM5 domain

IHOP Simulation Results

Observed GOES-11 imagery Simulated GOES-11 imagery

1900 UTC 1900 UTC



2000 UTC 2000 UTC



2100 UTC 2100 UTC



2200 UTC 2200 UTC



2300 UTC 2300 UTC


• Color-shaded plot depicts 2-meter mixing ratio

• White iso-surfaces encompass cloud boundaries

• Wind vectors at 1.5 km AGL

THORPEX Jet Streak Case

Overview:• Significant upper-level jet

streak with winds in excess of 180 knots

• Mixture of clear skies with scattered areas of lower- and upper-level clouds

• Domain coverage includes Aqua overpass, ER-2 flight, and G4 dropsondes

• Extensive observations were taken as part of THORPEX, GWINDEX, and NOAA NCEP Winter Storms Research Program

GOES-9 10.7 micron imagery: 2100 UTC 12 March 2003 –

0400 UTC 13 March 2003

THORPEX Jet Streak Case

Geographical region covered by MM5 domains

MM5 Model Configuration:• 36-12-4 km grid spacing with

50 vertical levels• Initialized at 12 UTC on 11

March with 1° AVN data and then run for 48 hours

• Goddard microphysics• Eta planetary boundary layer• RRTM/Dudhia radiation• No land-surface model• Grell cumulus scheme on

outer two domains with explicit convection on inner 4-km domain

THORPEX Simulation Results


2200 UTC 2200 UTC



2300 UTC2300 UTC



0000 UTC0000 UTC



0100 UTC0100 UTC



0200 UTC0200 UTC

WRF Model Characteristics

• Integrates fully compressible non-hydrostatic equations on a mass-based terrain-following coordinate

• Can be run either for idealized or real-data cases

• Options for one and two-way interactive nests

• Contains a prototype moving nest


• Option to use 2nd or 3rd order Runge-Kutta temporal integration

• Option to use 2nd to 6th order horizontal and vertical advection schemes

• Effective resolution is ~ 7 * x


• Includes the NOAH LSM to calculate surface moisture and energy fluxes– Land use categories determine the surface properties at

each grid point

• Version 2 contained a basic version of 3DVAR with a research grade version to be released later this month

WRF-MM5 Comparison: Northern Plains Severe Weather Outbreak

• Occurred during the evening of 24-25 June 2003

• Over 100 tornadoes reported across the region

• Manchester, SD destroyed by F4 tornado

• Very complex cloud conditions to model

Model Configuration

• 42 hr simulation initialized at 1200 UTC 23 June 2003

• 290 x 290 grid point domain with 4 km horizontal spacing and 50 vertical levels

MM5 WRF

• Goddard microphysics

• MRF PBL

• RRTM/Dudhia radiation

• Explicit cumulus convection

• OSU land surface model

• WSM6 microphysics

• YSU PBL

• RRTM/Dudhia radiation

• Explicit cumulus convection

• NOAH land surface model

Horizontal Variability

MM5 WRF

2.5 km Water Vapor Mixing Ratio

Liquid Cloud Water

• WRF has much finer horizontal resolution than the MM5

• WRF effective resolution is ~7*x

• MM5 effective resolution is ~10*x

Simulated Ice Microphysics

• WSM6 scheme generates less (more) ice mass in the upper (middle) troposphere

- WSM6 contains a new diagnosis of ice crystal concentration

• Much lower altitude of the ice mixing ratio maximum in the WRF simulation

- Goddard scheme assumes a constant sedimentation rate while a variable rate is used by the WSM6 scheme

Simulated Ice Microphysics

• MM5 Goddard scheme assumes a constant ice diameter of 20 m

• WRF WSM6 employs a method that relates the mean ice diameter to the amount of ice mass and the number concentration of ice particles

- Generates a more realistic distribution of ice particle sizes

Simulated Radiances

• WRF simulation is characterized by much greater horizontal variability

ATREC Extratropical Cyclone Case

Overview:• Intense extratropical

cyclone developing over the Gulf Stream

• Significant cloud shield with extensive region of stratiform precipitation

• Scattered convection along trailing cold front

ATREC Extratropical Cyclone Case

WRF Model Configuration:• 1070x1070 grid point domain

with 2 km grid spacing and 50 vertical levels

• Initialized at 00 UTC on 05 December with 1° GFS data and then run for 24 hours

• WSM6 microphysics• Yonsei University (YSU)

planetary boundary layer• RRTM/Dudhia radiation• NOAH land-surface model• Explicit cumulus

Geographical region covered by WRF domain

SGI Altix

• We are able to perform very large memory-intensive model simulations with very fine horizontal resolution

• Used hardware money received by Allen Huang from the Navy DURIP program to purchase 24 CPUs with 192 Gb of memory

• Used grant money received by Bob Aune to purchase 8 additional CPUs

• Approximately 3 times faster than old cluster

• 10 Tb of external disk storage

Generation of Simulated Atmospheric Datasets for Ingest into Radiative Transfer Models

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