# Presentation: 173881

## PACIFIC PREDICTABILITY EXPERIMENT:

**LINKS WITH THE INTERNATIONAL POLAR YEAR (IPY)**

**Environmental Modeling Center**
**NOAA/NWS/NCEP**
- USA
- Acknowledgements: Sharan Majumdar, Yucheng Song, Craig Bishop, Istvan Szunyogh, Lacey Holland, Tim Marchok, Jean-Guy Desmarais
*http://wwwt.emc.ncep.noaa.gov/gmb/ens/index.html*

**Zoltan Toth**

## OUTLINE / SUMMARY

**LINKS BETWEEN THORPEX & IPY **
- Both global programs
- THORPEX is weather component of IPY
- Joint field program during IPY
**SCIENTIFIC HYPOTHESES FOR THORPEX-IPY **
- Main sources of observational uncertainty over NH
- Main factors supporting / limiting predictability over two hemispheres
**NOAA’S INTERESTS IN THORPEX-IPY **
- Short-Term Arctic Predictability (STAP)
- 3-90 days forecast of high impact weather, sea ice, ocean wave, land surface
**PACIFIC PREDICTABILITY EXPERIMENT**
- THORPEX-IPY theme
- Complemented by meso-scale studies
**NORTH AMERICAN ENSEMBLE FORECAST SYSTEM**
- Combined Canadian-US ensemble, users from Mexico & elsewhere
- UK Metoffice, FNMOC, AFWA to join in 2006
- Prototype for future Global Ensemble Prediction System (GEPS, legacy of THORPEX)

## LINKS BETWEEN IPY & THORPEX

**International Polar Year (IPY):**
- 	**Multi- and interdisciplinary international research experiment 03/2007-02/2009**
- 	Study areas of strongest climate change impact
- 	Comprehensive research in both polar regions
- 	Strong links to the rest of the globe -
*Theme 3 (of 6): **“Advance our understanding of polar - ****global ****interactions by studying teleconnections on all scales.”*
**THORPEX ****– A World Weather Research Program (WWRP):**** **
- 	**Accelerate improvements in skill/utility of 1-14 day weather forecasts**
- Long-term (10-yrs) ***global ****research program* in areas of:
- 	Observing system, data assimilation, numerical modeling/ensemble, socioec. appl.
- 	Strong link with operational Numerical Weather Prediction (NWP) centers
- 	International program under WMO
*	**Planning initiated with discussions about North Pacific experiment =>*
**Opportunities for IPY - THORPEX Collaboration**
**	****Joint THORPEX-IPY Observing period –**
- Major opportunity for accelerating observing system design work
- Improved weather forecasts for polar regions & IPY activities
- Scientific investigations:
- 		Link between weather and climate processes
- 		Mid-latitude – Polar interactions
***	******THORPEX IS THE WEATHER COMPONENT OF IPY***

## SCIENTIFIC HYPOTHESES FOR THORPEX-IPY RESEARCH

***	******HYPOTHESIS A**** – Initial conditions:*
- Main sources of forecast uncertainty / impediments to extending forecasts to day 14+
- Tropical excitation of waves from the Pacific ocean, especially from Maritime Continent
- The mid-latitude flow regime over the Pacific Ocean
- The polar circulation with episodes of cross polar flow
- Assess relative importance of three sources of uncertainty & their interaction
*What is optimal mix of observations to reduce forecast uncertainty?*
*What is best way of assimilating relevant data?*
*	****HYPOTHESIS B**** – Numerical modeling:**	*
- The level of predictability & forecast skill over the NH vs. SH are influenced by:
- Nature of flow regimes in polar regions
- More symmetric circumpolar vortex with little to no cross polar flow over the Antarctic
- Less symmetric vortex with major episodes of cross polar flow over the Arctic
- Difference in distribution of continents and oceans over two hemispheres
- Much larger contrast between land and ocean masses over NH
- Nature of wave guides for tropical to extratropical energy transfer
- Better defined / spatially locked wave guide (PNA) over NH
- Assess relative role of three factors & their relationship in
- Supporting and limiting atmospheric predictability for
- Global circulation in general
- Different regions of the globe: Polar, mid-latitude, tropical
*What limits NWP models in realistically representing three factors?*
*How NWP forecast & uncertainty information can be best conveyed to users?*
**NEED TO IMPROVE INITIAL STATE, MODEL, OR BOTH TO REACH OUT TO D 14+?**

## NOAA’S INTEREST IN THORPEX-IPY

**SHORT-TERM ARCTIC PREDICTABILITY** (***STAP***, IPY Proposal #798):
**Study variability & predictability of Arctic high impact**
- Atmospheric, ice, ocean, and land surface events
- Their interaction with global processes
- On 3-90 days time scale
**Program elements**
*Observing System*
- Study effect of supplemental Arctic IPY data on NWP skill, including ocean wave & sea ice
- Test new satellite & in  situ platforms/instruments
- Collect adaptive obs. along N-Pacific storm track & its source region in tropics to improve IPY fcsts
*Data Assimilation*
- Develop targeting methods for improved high impact Arctic events
- Improve assimilation of current & future atmos. (over ice/snow), sea ice, & ocean/land surface data
- Contribute to design of new global observing system over 2 polar regions in framework of GEOSS
*Numerical Modeling*
- Identify & diagnose model weaknesses critical for polar regions & polar-extrapolar interactions
- Improve atmospheric, sea ice, &n land surface model formulation
- Accelerate testing & implementation of Hybrid Coordinate Ocean Model (HYCOM) for storm surges
- Develop methods to represent model related uncertainty in ensemble forecasting
- Assess value of high resolution LAM with the CWRF model for high impact Arctic events
- Contribute to TIGGE research goals by developing prototype ensemble forecast system (NAEFS)
*Socio-Economic Applications*
- Provide new probabilistic weather, ice, and ocean products to support Arctic user community
- Develop new procedures for use of forecast information in different Arctic applications
- Quantify effect of existing & improved weather forecast information on key user group

## SHORT-TERM ARCTIC PREDICTABILITY (STAP, #798)

**Principal Investigators:**
- Satellite data / assimilation:
- Jeff Key (NOAA), Chris Velden (SIMSS), John LeMarshall (JCSDA)
- Coupled Atmosphere-ice-ocean-land surface diagnosis and modeling
- Robert Grumbine, Julian Wang, Mel Shapiro (NOAA)
- Socio-Economic Applications:
- James Partain (NOAA), Rebecca Morss (NCAR), Arun Kumar (NOAA)
**Connections with other IPY activities:**
- Cluster 2
- Terrestrial cryosphere, NH (#392 - Grumbine)
- Arctic Sea Ice (#185, Grumbine)
- Cross-cutting (Shapiro, Toth)
- Cluster 4
- Weather-Climate link (Kumar, Wang)
***THORPEX*** (Toth, Shapiro)
- Observing Systems (#129, 138, 699, 732, Key, Velden, LeMarshall)
- Teleconnections (Shapiro, Toth)
- Cluster 5
- Coasts & Margins, Arctic (#182, Partain)
- Cluster 6
- Change: Adaptation, Human (Partain, Morss)

## SHORT-TERM ARCTIC PREDICTABILITY (STAP, #798)

**NOAA IPY Connections**
- IPY activities coordinated by John Calder
- STAP is one of 10 NOAA IPY proposals, linked in particular with:
- Causes & impacts of recent changes in Pacific Arctic (#157, Calder & K. Crane)
- Data Management/Arctic Change Detection (#879, Florence Fetterer)
- Decision support in Alaska & the Arctic (#215, Juniper Neill)
- Arctic climate modelling (#337, Tony Beesley)
- Arctic system reanalysis (#179, John Calder)
- Satellite products (#600, Jeff Key)
**US Connections:**
- Pacific Predictability Experiment (PAPEX)
- Led by David Parsons
- Need for agency (NASA, ONR, NSF) & wider community (univ./private) coordination
- Mesoscale activities may leverage off / complement THORPEX-IPY work
**North American Connections:**
- North American Ensemble Forecast System (NAEFS)
- Improve & expand operational product line to support use in Arctic
**Asia / SH Connections:**
- Through PAPEX
- Coordinated under THORPEX

## PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

**Main interest?**
- Build around THORPEX goals
- Link up with IPY
- Complement it with meso-scale aspects if there is interest
**Field OR laboratory experiment?**
- BOTH
- Lab work (Improve DA, NWP modeling, targeting; Use OSSEs)
- Design field phase
- Generalize field results
- Field work
- Real time test & demonstration
- Support IPY activities (lab work cannot achieve all on ground)
**Timing?**
- Must be driven by IPY, March 2007 – February 2009
**Main theme?**
- Use THORPEX-IPY Science Hypotheses
- Study lifecycle of waves on Pacific Storm Track (from tropics to Arctic)

## PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

***PROPOSE STUDYING LIFECYCLE OF WAVES ON PAC. STORM TRACK***
**Western Tropical Pacific** (ONR, Canada, Asian nations?)
- Energy transfer  from tropics to extra-tropics
- Extra-tropical transition of tropical cyclones
- Convection linked with Madden Julian or other waves
**Western Extra-tropical Pacific** (NOAA, NASA?)
- Initial phase of extra-tropical lows
- Targeted observations with 3-5 day lead time
- Adaptive collection of data
- In situ observations (dropsondes, aerosondes?)
- Complement Winter Storm Reconnaissance (WSR) program over Eastern Pacific
- Adaptive processing of data
- Satellite observations (dynamically controlled thinning etc)
**Arctic Region** (IPY)
- Forecast applications (NAEFS)
- Effect of data on extra-tropical forecasts
**Continental US** (NOAA)
- Assess effect of IPY data on forecasts for cold air outbreaks etc
**Southern Hemisphere **(SH THORPEX partners)
- Compare effect of tropical outbreaks on NH vs. SH storm tracks
- Study differences in predictability over two hemispheres, including polar regions

## PACIFIC PREDICTABILITY EXPERIMENT - PAPEX

***STUDY LIFECYCLE OF WAVES ON PACIFIC STORM TRACK***
**Tropical wave in ensemble forecasts (13-16 May)**
- Connection between NH & SH (NCEP PQPF)
- How well predicted? (ECMWF & NCEP MSLP ensemble mean)
**Midlatitude low, influenced by tropical wave, affects polar region (17-23 May)**
- ECMWF & NCEP MSLP ensemble mean forecast & verifying analysis
- Connection
**Can targeting with in situ observations (dropsondes) help?**
- Results from Winter Storm Reconnessaince over NE-Pacific
- PAPEX can complement WSR data over NW-Pacific
**Is West Coast of US more exposed to “data void” than rest of US? ***(Myth)*
- Beyond 24-36 hrs, all areas equally exposed to “data void”
- Predictability over West Coast may be higher
- “First generation” storms hitting coast at end of well organized storm track
- Rest of continent affected by 2nd generation storms
- ECMWF
**Targeting to improve longer range / second generation storms?**
- Beyond

## SUMMARY OF WINTER STORM RECONNAISSANCE RESULTS

- 60-80% of forecasts improved because of targeted observations
- 12-hour gain in forecast lead time
- RMS forecast errors reduced by 10-20%
- Local improvement similar to that achieved over 20 yrs (1975-95) due to advances in data coverage/quality

- Toth *et al.* (2000)

- NORPEX-98 & WSR 1999-2005
- WSR operational since 2001

## WESTERN VS. EASTERN US PREDICTABILITY

**WESTERN VS. EASTERN US PREDICTABILITY**
**Winter of 2002/03**

- West

- East

*There are seasons when predictability is higher over western US*

*WSR00*

## Individual Case Comparison

-   **1    denotes positive effect**
**  ****0    denotes neutral effect**
** ****-1  denotes negative effect**

**          **
**       **
**22 OVERALL POSITIVE             **
**1  OVERALL  NEUTRAL **
**7**** OVERALL  NEGATIVE**
**           ****73*****% improved***
***           ******23****** ******% degraded***

- OVERALL EFFECT:

-  VR  OBSDATE   P    T    V   OVERALL   REGION  FHOUR
-    E 20050120   1    1    1    1      82W ,37N    72
-   W 20050128   1    1    1    1     123W ,40N    24
-   C 20050205   1    1    1    1      97W ,31N    36
-   H 20050206   1    1    1    1     155W ,19.5N  24
-   C 20050206   1    1    1    1      90W ,43N    72
-   C 20050207   1    1    1    1      90W ,42N    60
-   C 20050208   1   -1    1    1      90W ,42N    36
-  AK 20050208  -1   -1   -1   -1     150W ,61N    48
-   E 20050208   1    0   -1    0      74W ,43N    48
-   C 20050209  -1    1    1    1      93W ,35N    96
-  AK 20050210  -1   -1    1   -1     135W ,55N    24
-   E 20050212   1    1    1    1      88W ,46N    48
-   W 20050213   1    1    1    1     123W ,38N    48
-   W 20050213   1    1   -1    1     123W ,38N    60
-   W 20050213   1    1   -1    1     123W ,38N    72
-  AK 20050219   1    1    1    1     150W ,61N    48
-   W 20050220  -1    1    1    1     118W ,34N    48
-   W 20050221   1    1    1    1     118W ,34N    24
-  AK 20050222  -1   -1   -1   -1     138W ,58N    24
-  AK 20050223  -1    1    1    1     140W ,60N    24
-  AK 20050225   1    1    1    1     140W ,60N    48
-   W 20050225   1    1   -1    1     123W ,40N    72
-   E 20050225   1    1   -1    1      75W ,40N    96
-   E 20050303  -1    1    1    1      86W ,41N    48
-  AK 20050309  -1    1   -1   -1     130W ,57N    36
-   H 20050312   1   -1   -1   -1     157W ,21N    24
-   E 20050313   0    1    1    1      81W ,32N    96
-   E 20050314   1   -1   -1   -1      79W ,32N    72
-   E 20050316  -1   -1   -1   -1      78W ,37N    48
-   W 20050317   1    1    1    1     122W ,38N    48

## WSR05

**WSR05**

- Winds

- Temperature

- Humidity

## Precipitation verification

- Precipitation verification is still in a testing stage due to the lack of station observation data in some regions.

| ETS | 5mm  | 10mm  |
| --- | --- | --- |
| CTL | 16.35 | 18.56 |
| OPR | 16.50 | 20.44 |
| Positive vs. negative cases | 4:1 | 3:1 |

## NORTH AMERICAN ENSEMBLEFORECAST SYSTEM (NAEFS)

- Zoltan Toth, EMC/NCEP/NWS/NOAA, USA
- Jean-Guy Desmarais, MSC/CMC, Canada

## INAUGURATIONCEREMONY

## NORTH AMERICAN ENSEMBLE FORECAST SYSTEM -NAEFS

**Combines global ensemble forecasts from Canada & USA**
-  60+ members per day from MSC & NWS
- Generates products for
- Intermediate users
- E.g., weather forecasters at NCEP Service Centers (US NWS)
- Specialized users
- E.g., hydrologic applications in all three countries
- End users
- E.g., forecasts for public distribution in Canada (MSC) and Mexico (NMSM)
- Requires moderate additional investment for
- New telecommunication arrangements
- Extra coordination in research/development & implementations
**Operational implementation: March 2006**
**Ready to serve IPY and PAPEX community in 2007-2009**

## NAEFS & THORPEX

- Expands national/international collaboration
- Mexico joined in November 2004
- UK Met Office, FNMOC, AFWA to join in 2006
- Provides framework for transitioning research into operations
- Prototype for ensemble component of THORPEX legacy forecast system
**Global Ensemble Prediction System (GEPS)****, part of:**
***Global Interactive Forecast System (GIFS)***

**THORPEX Interactive Grand**
**Global Ensemble (TIGGE)**

**North American Ensemble**
**Forecast System (NAEFS)**

*OPERATIONS*

*RESEARCH*

*Articulates*
*operational needs*

*Transfers*
*New methods*

- THORPEX

- RESEARCH

- LEGACY (GIFS)

- OPERATIONAL

## OUTLINE / SUMMARY

**LINKS BETWEEN THORPEX & IPY **
- Both global programs
- THORPEX is weather component of IPY
- Joint field program during IPY
**SCIENTIFIC HYPOTHESES FOR THORPEX-IPY **
- Main sources of observational uncertainty over NH
- Main factors supporting / limiting predictability over two hemispheres
**NOAA’S INTERESTS IN THORPEX-IPY **
- Short-Term Arctic Predictability (STAP)
- 3-90 days forecast of high impact weather, sea ice, ocean wave, land surface
**PACIFIC PREDICTABILITY EXPERIMENT**
- THORPEX-IPY theme
- Complemented by meso-scale studies
**NORTH AMERICAN ENSEMBLE FORECAST SYSTEM**
- Combined Canadian-US ensemble, users from Mexico & elsewhere
- UK Metoffice, FNMOC, AFWA to join in 2006
- Prototype for future Global Ensemble Prediction System (GEPS, legacy of THORPEX)