# Presentation: 871087

## NOAA/NCEP    Washington, Aug. 2005

- Radiation and fog in complex topography -
- Research and operational forecasting with NMM

**NOAA/NCEP    Washington, Aug. 2005**

**Mathias D. Müller**
**Institute of Meteorology, Climatology & Remote Sensing**
**University of Basel, Switzerland**
**Mathias.mueller@unibas.ch**

- Z.Janjic, D. Scherer & A. Bott

## WHAZZZUPP !

**The forecast system at the University of Basel**
**A radiation parameterization of topographic effects**
**Towards a 3D fog model**
**Coffee and Cookies :-)**

## Realtime Forecasts / Nesting

- GFS 00/12 UTC

- NMM-22 & ETA-22 00/12 UTC

- NMM-4  03/15 UTC
- ETA-4 15 UTC

- NMM-2  15 UTC

- 72 h

- 45 h

**Realtime Forecasts / Nesting**

**5 grids**

## 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 CPU‘s, 4 GB Mem, Linux OS
- IDL, 2 TB Disk

**Hardware**

## NWP at the University of Basel - Flow chart

- VAR
- Data

**NWP at the University of Basel - Flow chart**

## CLIMATOLOGY AND REALTIME NDVI

- AUGUST, 13 2003                          AGGREGATED TO 4 KM MODEL RESOLUTION

- CLIMATOLOGY NDVI

- REALTIME NDVI

**NDVI initialization with NOAA-AVHRR**

## Operational Model Statistics

- Total number of Images produced:		~ 20‘000 / 24h
- Programming language for all Graphics:	IDL
- Operating System:			LINUX
- Communication and time synchronisation with forecast Models, running
- on Cronos Cluster.
- Computing Time: NMM22 	~ 60 min	(critical !)
- 		NMM4	~ 90 min
- 		NMM2 	~ 4 hours

- 22 km NMM

| 
Horizontal grid | 284 (lon) x 187 (lat) |
| --- | --- |
| Horizontal resolution | 22 km |
| Vertical resolution | 60 sigma-pressure hybrid levels  |
| Timestep | 72 seconds |
| Model Center | 52° N / 5°E |
| Physics | hydrostatic |
| CPU Time on CRONOS | ~ 38 min |

- 4 km NMM

| 
Horizontal grid | 220 (lon) x 161 (lat) |
| --- | --- |
| Horizontal resolution | 4 km |
| Vertical resolution | 60 sigma-pressure hybrid levels  |
| Timestep | 12 seconds |
| Model Center | 46.5° N / 8°E |
| Physics | non-hydrostatic |
| CPU Time on CRONOS | ~ 90 min |

- 2km NMM

| 
Horizontal grid | 280 (lon) x 201 (lat) |
| --- | --- |
| Horizontal resolution | 2 km |
| Vertical resolution | 45 sigma-pressure hybrid levels  |
| Timestep | 6 seconds |
| Model Center | 47° N / 8°E |
| Physics | non-hydrostatic |
| CPU Time on CRONOS | ~ 4 hours |

**Operational Model Statistics**

- Computing Time of Models is upper limit for Visualisation time

## Forecast Visualisation – key points 

- Model Coordinate Systems (Lambert, Eta-Grid, ..., Lat/Lon)
- Internal Coordinate System (Geographical Lat/Lon)
- Projection / Mapping to different Coordinate Systems for 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)

- Efficiency of Visualisation

- Precomputation of domain dependent but constant layers
- (Topographic Shading, Continent outlines,....)

- Scaling: constant, image optimized, constant-optimized for forecast range

## Maps – transparent, constant and content Layers

## Point Forecasts – Meteograms 

**Point Forecasts – Meteograms **

## Point Forecasts – Tephigrams

**Point Forecasts – Tephigrams**

## Internet – meteoblue.ch 

**Internet – meteoblue.ch **

## Pictograms – it‘s for children

**Pictograms – it‘s for children**

- 2. Decision Tree:

- 1. Local field statistics:

- Rain
- Cloud Cover
- Temperature
- .....

- Rain
- Cloud Cover
- Temperature
- .....

- Rain
- Cloud Cover
- Temperature
- .....

- Rain
- Cloud Cover
- Temperature
- .....

- rain

- no rain

- 3. Web-page compilation:

- clouds

## 3D visualisations – nice and useless?

**3D visualisations – nice and useless?**

## A radiation parameterization of topographic effects 

**A radiation parameterization of topographic effects **

- Mathias Müller, Dieter Scherer

## 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**

## Shortwave radiation  - direct & diffuse

**Shortwave radiation  - direct & diffuse**

- Radiation fluxes from Mesoscale Model

- Land-Surface Model of Mesoscale Model

## Longwave radiation

**Longwave radiation**

- Radiation fluxes from Mesoscale Model

- Land-Surface Model of Mesoscale Model

## Effects of slope angle, slope aspect and shadow

**Effects of slope angle, slope aspect and shadow**

- affects:
-  direct shortwave

## Effects of slope angle, slope aspect and shadow

**Effects of slope angle, slope aspect and shadow**

- affects:
-  direct shortwave

## Effects of slope angle, slope aspect and shadow

**Effects of slope angle, slope aspect and shadow**

- affects:
-  direct shortwave

## Effects of slope angle, slope aspect and shadow

**Effects of slope angle, slope aspect and shadow**

- affects:
-  direct shortwave

## Sky-view factor

**Sky-view factor**

- affects:
-  diffuse shortwave
-  longwave

- 0.5

## Case Studies

**Case Studies**

- Parameterization was tested in the Nonhydrostatic Mesoscale Model (NMM) of
- NOAA/NCEP (version: Z. Janjic)

- 220 Alpine stations

## 2m Temperature Differences

**2m Temperature Differences**

- +2 K
- Sun facing
- -3 K shadow

## 2m Temperature Differences

**2m Temperature Differences**

- Skyview affects:
-  diffuse shortwave
-  longwave

- 0.5

- +2 K in Valleys

## Verification – Clear sky summer conditions (alpine stations)

**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

## Verification – overcast conditions (alpine stations)

**Verification – overcast conditions (alpine stations)**

- 24 December 2003
- Nighttime warming reduces model cold bias

## Benefits from subgrid topography

**Benefits from subgrid topography**

- 4 km Grid with 1 km subgrid topography

**doubles the effect !**

## Parallel run intercomparison (4 km grid)

**Parallel run intercomparison (4 km grid)**

## Conclusions

**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

## 3D fog with NMM and PAFOG

**3D fog with NMM and PAFOG**

- Mathias Müller, Andreas Bott, Zavisa Janjic

## NMM_PAFOG

**NMM dynamical framework**

**PAFOG microphysics**

**NMM_PAFOG**

**Droplet number**
**concentration**

**Liquid water content**

**Condensation/evaporation in the lowest 1500 m is replaced by PAFOG**

## PAFOG microphysics

**PAFOG microphysics**

- Assumption on the droplet size distribution : Log-normal function

- D droplet Diameter

- Dc,0 mean value of D

- σc Standart deviation of the given droplet size distribution (σc=0.2)

- where S is the Supersaturation

- Supersat.

## 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**

## Boundary conditions for dNc 

**Boundary conditions for d*****N******c ***

- 1000m

- PAFOG TOP

## Nesting

**GFS**

**NMM-22**

**NMM-4**

- NMM-2  15 UTC

**Nesting**

**NMM_PAFOG**

- 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!)

## 19:00 MEZ (3 hr forecast)

**19:00 MEZ (3 hr forecast)**

**PAFOG**

**STANDARD**

- 27 Nov 2004

## 22:00 MEZ (6 hr forecast)

**22:00 MEZ (6 hr forecast)**

**STANDARD**

**PAFOG**

- 27 Nov 2004

## 02:00 MEZ (10 hr forecast)

**STANDARD**

**PAFOG**

- 28 Nov 2004

**Accurate sedimentation in PAFOG**
**due to d*****N******c***** computation.**

## 08:00 MEZ (16 hr forecast)

**08:00 MEZ (16 hr forecast)**

**PAFOG**

**STANDARD**

- 28 Nov 2004

## 10:00 MEZ (18 hr forecast)

**STANDARD**

**PAFOG**

- 28 Nov 2004

## qc at 5m height (01:00 MEZ)

***q******c***** at 5m height (01:00 MEZ)**

**PAFOG****	****	****	****	****           STANDARD**

## qc at 5m height (06:00 MEZ)

**PAFOG****	****	****	****	****           STANDARD**

## Nc at 5m height (06:00 MEZ)

***N******c***** at 5m height (06:00 MEZ)**

## Cold air pooling (05:00 MEZ)

**Cold air pooling (05:00 MEZ)**

**too cold !**

## Cold bias problem

**Cold bias problem**

- Z.Janjic

## 19:00 MEZ (3 hr forecast)

**19:00 MEZ (3 hr forecast)**

**PAFOG**

**STANDARD**

- 27 Nov 2004

## 22:00 MEZ (6 hr forecast)

**22:00 MEZ (6 hr forecast)**

**STANDARD**

**PAFOG**

- 27 Nov 2004

## 02:00 MEZ (10 hr forecast)

**02:00 MEZ (10 hr forecast)**

**STANDARD**

**PAFOG**

- 28 Nov 2004

**Accurate sedimentation in PAFOG**
**due to d*****N******c***** computation.**

## 06:00 MEZ (14 hr forecast)

**06:00 MEZ (14 hr forecast)**

**STANDARD**

**PAFOG**

- 28 Nov 2004

**Accurate sedimentation in PAFOG**
**due to d*****N******c***** computation.**

## 08:00 MEZ (16 hr forecast)

**08:00 MEZ (16 hr forecast)**

**PAFOG**

**STANDARD**

- 28 Nov 2004

## 10:00 MEZ (18 hr forecast)

**10:00 MEZ (18 hr forecast)**

**STANDARD**

**PAFOG**

- 28 Nov 2004

## qc at 15m height (02:00 MEZ)

**PAFOG****	****	****	****	****           STANDARD**

## qc at 15m height (06:00 MEZ)

**PAFOG****	****	****	****	****           STANDARD**

## Cold air pooling (05:00 MEZ) new PBL

## Conclusions

**3D model with detailed microphysics**
**Promising first results**
**Computationally very efficient and feasible in todays **
**Operational framework**
**More cases and ‘verification’ needed **

## Temperature Verification

- Forecasthour: 9-32 Temporal resolution: 1 hour

- NMM-4

- ETA-4

- NMM-2

## Temperature Verification

**Temperature Verification**

- Forecasthour: 33-45 Temporal resolution: 1 hour

- ETA-4

- NMM-2

- NMM-4

## 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.

**References**

- 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

## References

- 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.

**References**