Diapositive 1

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NOAA/NCEP Washington, Aug. 2005
Radiation and fog in complex topography
- Research and operational forecasting with NMM
Z.Janjic, D. Scherer A. Bott
Mathias D. Müller Institute of Meteorology,
Climatology Remote Sensing University of Basel,
Switzerland Mathias.mueller_at_unibas.ch
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WHAZZZUPP !
The forecast system at the University of
Basel A radiation parameterization of
topographic effects Towards a 3D fog
model Coffee and Cookies -)
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Realtime Forecasts / Nesting
GFS 00/12 UTC
NMM-22 ETA-22 00/12 UTC
5 grids
72 h
NMM-4 03/15 UTC ETA-4 15 UTC
NMM-2 15 UTC
45 h
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Hardware
Weather Forecast Post Processing Beowulf
Cluster Theoretical Performance 386 Gflops1
Master 2 x 2.4 GHz Xeon Cpu's, 2GB Mem1
Fileserver 1.1TB Disk36 Nodes 2 x 2.4 GHz Xeon
Cpu's, 2GB MemGigabit Ethernet and SCI
interconnect Visualisation Preprocessing 2 x
3.0 GHz Xeon CPUs, 4 GB Mem, Linux OS IDL, 2 TB
Disk
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NWP at the University of Basel - Flow chart
VAR Data
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NDVI initialization with NOAA-AVHRR
CLIMATOLOGY AND REALTIME NDVI
CLIMATOLOGY NDVI
REALTIME NDVI
AUGUST, 13 2003
AGGREGATED TO 4 KM MODEL RESOLUTION
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22 km NMM
  4 km NMM
Operational Model Statistics
Forecast output of 5 Model Grids 35 GB /
24h Total number of Images produced 20000 /
24h Programming language for all
Graphics IDL Operating System LINUX Communic
ation and time synchronisation with forecast
Models, running on Cronos Cluster. Computing
Time NMM22 60 min (critical !) NMM4 90
min NMM2 4 hours
  2km NMM
Computing Time of Models is upper limit for
Visualisation time
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Forecast Visualisation key points
Efficiency of Visualisation
Data and Information Reduction / Aggregation
(storage and resolution restrictions) (e.g.
Smoothing, Skipping, 24h-precipitation)
Conversion / Computation of Variables for
visualisation from raw model output (e.g.
Vorticity, CAPE, Helicity, Streamlines)
Precomputation of domain dependent but constant
layers (Topographic Shading, Continent
outlines,.)
Model Coordinate Systems (Lambert, Eta-Grid, ,
Lat/Lon) Internal Coordinate System
(Geographical Lat/Lon) Projection / Mapping to
different Coordinate Systems for Visualisation
Scaling constant, image optimized,
constant-optimized for forecast range
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Maps transparent, constant and content Layers
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Point Forecasts Meteograms
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Point Forecasts Tephigrams
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Internet meteoblue.ch
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Pictograms its for children
3. Web-page compilation
2. Decision Tree
1. Local field statistics
rain
no rain
Rain Cloud Cover Temperature ..
Rain Cloud Cover Temperature ..
clouds
Rain Cloud Cover Temperature ..
Rain Cloud Cover Temperature ..
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3D visualisations nice and useless?
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A radiation parameterization of topographic
effects
Mathias Müller, Dieter Scherer
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Parameterization features
Considers Slope and azimuth angle of absorbing
surface Shadows Sky-view restriction Negligible
computational costs Computation of radiative
mean fluxes for model grid cells based on higher
resolution DEM Interface between land-surface
model and radiative transfer model Relatively
easy to include in other models (sandwich-like)
Parameterization features
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Shortwave radiation - direct diffuse
Radiation fluxes from Mesoscale Model
Land-Surface Model of Mesoscale Model
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Longwave radiation
Radiation fluxes from Mesoscale Model
Land-Surface Model of Mesoscale Model
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Effects of slope angle, slope aspect and shadow

• affects
• direct shortwave

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Effects of slope angle, slope aspect and shadow

• affects
• direct shortwave

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Effects of slope angle, slope aspect and shadow

• affects
• direct shortwave

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Effects of slope angle, slope aspect and shadow

• affects
• direct shortwave

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Sky-view factor
0.5

• affects
• diffuse shortwave
• longwave

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Case Studies
Parameterization was tested in the Nonhydrostatic
Mesoscale Model (NMM) of NOAA/NCEP (version Z.
Janjic)
220 Alpine stations
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2m Temperature Differences
2 K Sun facing -3 K shadow
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2m Temperature Differences
0.5
2 K in Valleys

• Skyview affects
• diffuse shortwave
• longwave

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Verification Clear sky summer conditions
(alpine stations)
22 June 2003 Nighttime warming reduces model
cold bias (0.5K) Problem of verification
Stations are located in valleys but radiation
affects slopes
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Verification overcast conditions (alpine
stations)
24 December 2003 Nighttime warming reduces
model cold bias
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Benefits from subgrid topography
doubles the effect !
4 km Grid with 1 km subgrid topography
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Parallel run intercomparison (4 km grid)
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Conclusions
Mean radiation flux based on high resolution
DEM Modifies temperature in a full physics NMM
run up to /-3 K Reduces nighttime cold bias by
about 0.5-1 K No computational costs during time
integration Easy to implement, sandwich-like
module for mesoscale models
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3D fog with NMM and PAFOG
Mathias Müller, Andreas Bott, Zavisa Janjic
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NMM_PAFOG
Droplet number concentration
Liquid water content
NMM dynamical framework
PAFOG microphysics
Condensation/evaporation in the lowest 1500 m is
replaced by PAFOG
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PAFOG microphysics
Supersat.
where S is the Supersaturation
Assumption on the droplet size distribution
Log-normal function
D droplet Diameter
Dc,0 mean value of D
sc Standart deviation of the given droplet size
distribution (sc0.2)
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GRID of NMM_PAFOG
50 x 50 x 45 27 layers in the lowest 1000 m 11
soil layers Thickness(cm) 0.5 0.75
1.2 1.8 2.7 4.0 6.0 10 30 60 100
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Boundary conditions for dNc
1000m
PAFOG TOP
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Nesting
GFS
NMM-22
NMM_PAFOG GRID 50 x 50 x 45 (11 soil
layers) dx 1 km dt 2s (dynamics) / 10s
(physics) CPU 40 min/24hr on 9 Pentium-4 (very
efficient!)
NMM_PAFOG
NMM-4
NMM-2 15 UTC
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1900 MEZ (3 hr forecast)
PAFOG
STANDARD
27 Nov 2004
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2200 MEZ (6 hr forecast)
PAFOG
STANDARD
27 Nov 2004
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0200 MEZ (10 hr forecast)
PAFOG
STANDARD
Accurate sedimentation in PAFOG due to dNc
computation.
28 Nov 2004
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0800 MEZ (16 hr forecast)
PAFOG
STANDARD
28 Nov 2004
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1000 MEZ (18 hr forecast)
PAFOG
STANDARD
28 Nov 2004
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qc at 5m height (0100 MEZ)
PAFOG STANDARD
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qc at 5m height (0600 MEZ)
PAFOG STANDARD
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Nc at 5m height (0600 MEZ)
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Cold air pooling (0500 MEZ)
too cold !
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Cold bias problem
Z.Janjic
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1900 MEZ (3 hr forecast)
PAFOG
STANDARD
27 Nov 2004
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2200 MEZ (6 hr forecast)
PAFOG
STANDARD
27 Nov 2004
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0200 MEZ (10 hr forecast)
PAFOG
STANDARD
Accurate sedimentation in PAFOG due to dNc
computation.
28 Nov 2004
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0600 MEZ (14 hr forecast)
PAFOG
STANDARD
Accurate sedimentation in PAFOG due to dNc
computation.
28 Nov 2004
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0800 MEZ (16 hr forecast)
PAFOG
STANDARD
28 Nov 2004
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1000 MEZ (18 hr forecast)
PAFOG
STANDARD
28 Nov 2004
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qc at 15m height (0200 MEZ)
PAFOG STANDARD
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qc at 15m height (0600 MEZ)
PAFOG STANDARD
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Cold air pooling (0500 MEZ) new PBL
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Conclusions
3D model with detailed microphysics Promising
first results Computationally very efficient and
feasible in todays Operational framework More
cases and verification needed
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Temperature Verification
Forecasthour 9-32 Temporal resolution 1 hour
NMM-2
ETA-4
NMM-4
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Temperature Verification
Forecasthour 33-45 Temporal resolution 1 hour
NMM-2
ETA-4
NMM-4
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References
Berry, E.X Pranger, M. P. (1974), Equation for
calculating the terminal velocities of water
drops, J. Appl. Meteor. 13, 108-113.
Bott, A. (1989), A positive definite advection
schemme obtained by nonlinear renormalization of
the advective fluxes, Monthly Weather Review 117,
1006-1015.
Bott, A. Trautmann, T. (2002), PAFOG a new
efficient forecast model of radiation fog and
low-level stratiform clouds, Atmospheric Research
64, 191-203.
Chaumerliac, N., Richard, E. Pinty, J.-P.
(1987), Sulfur scavenging in a mesoscale model
with quasi-spectral microphysic Two dimensional
results for continental and maritime clouds, J.
Geophys. Res. 92, 3114- 3126.
Janjic, Z. I., 2003 A Nonhydrostatic Model
Based on a New Approach. Meteorology and
Atmospheric Physics, 82, 271-285. Janjic, Z. I.,
J. P. Gerrity, Jr. and S. Nickovic, 2001 An
Alternative Approach to Nonhydrostatic
Modeling.  Monthly Weather Review, 129, 1164-1178
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References
Sakakibara, H. (1979), A scheme for stable
numerical computation of the condensation
process with large time step, J. Meteorol. Soc.
Japan 57, 349-353.
Twomey, S. (1959), The nuclei of natural cloud
formation. Part ii The supersaturation in
natural clouds and the variation of cloud droplet
concentration, Geophys. Pura Appl. 43, 243-249.