pdf - Synoptic Typer Tools

Synoptic Typer Tools
Robert Dahni
Information Technologies Branch,
Bureau of Meteorology, Australia
Ryan Smith
Department of Environment and Geography,
University of Manitoba, Canada
CAWCR Seminar 23 February 2011
Presentation Overview
•
Why Synoptic Typing?
•
Synoptic Typer’s History
 Uniqueness of the application
 What happened to Synoptic Typer?
•
Evolution of Synoptic Typer Tools
 The “Canada” connection
 Return to the Bureau of Meteorology
•
Synoptic Typer Tools’ Examples
 Derivation of Synoptic Catalogues
 Verification of Melbourne Forecast Temperatures
 Identification of NSW East Coast Lows?
•
The way forward for Synoptic Typer Tools…
Why Synoptic Typing?
•
Synoptic typing, simply defined, is the process of extracting key
patterns from daily weather maps, i.e. analogues or synoptic types
•
Synoptic classification enables greater understanding of the behaviour
of weather variables, when associated with the synoptic types
•
Source of forecast guidance when the synoptic catalogue and weather
relationships are used with real-time NWP model output
•
But, synoptic classification schemes are varied in the effort required,
methods utilised and level of subjectivity
•
Need for a synoptic classification tool as a common reference point in
the production of synoptic types
Aim of the presentation is to facilitate the re-introduction of
synoptic typing through the implementation of an innovative
synoptic classification program called Synoptic Typer Tools
Synoptic Typer’s History
Dahni, R. R. and Ebert, E. E. 1998. Automated objective synoptic typing to
characterize errors in NWP model QPFs. 12th Conference on Numerical
Weather Prediction, Amer. Meteor. Soc., Phoenix, Arizona.
•
Original synoptic classification work over 10 years ago
•
Attempt at automated objective synoptic typing
•
Simple pattern recognition scheme using MSLP fields
•
Principal components and k-means cluster analyses
•
Academic exercise of IDL v Fortran (2-3 minutes v 2 hours)
•
Conditional verification of NWP model QPFs
•
Lead to the subsequent development of the Synoptic Typer
Synoptic Typer’s History
Dahni, R. R. 2003. An automated synoptic typing system using archived and
real-time NWP model output. 19th International Conference on Interactive
Information and Processing Systems for Meteorology, Oceanography, and
Hydrology, Amer. Meteor. Soc., Long Beach, California.
“The BoM’s synoptic typing system is unique in that no other operational
system exists (to our knowledge) that incorporates both the development
of synoptic types and generation of synoptic type guidance from the
automatic classification of real-time NWP model output”
Ryan, C. J., Jha, A. and Joshi, S. 2003. MENTOR – A performance support
system for forecasters. 19th International Conference on Interactive
Information and Processing Systems for Meteorology, Oceanography, and
Hydrology, Amer. Meteor. Soc., Long Beach, California.
“Automatic synoptic type classification is an important element of the system”
Synoptic Typer GUI (2004)
Synoptic Typer Documentation
http://www.bom.gov.au/inside/itb/mss/projects/synoptictyper/
What happened to Synoptic Typer?
•
MENTOR (student project) did not proceed to implementation
•
Main requirement for Synoptic Typer no longer relevant
•
Some interest in Bureau of Meteorology to use Synoptic Typer output
•
Little interest in Bureau of Meteorology for Synoptic Typer development
•
More interest from overseas to use Synoptic Typer output
•
Some interest overseas (e.g. Canada) for Synoptic Typer development
•
“Gave away” Synoptic Typer application including IDL source code
•
In the meantime (at the Bureau of Meteorology):
Synoptic Typer used to benchmark the performance
(excluding graphics) of the latest desktops and notebooks
Synoptic Typer Performance
Evolution of Synoptic Typer Tools
•
July 2006
Synoptic Typer “… how I can get this great product?” Danny Blair
(Professor, Department of Geography, University of Winnipeg, Canada)
•
November 2006
Synoptic Typer application (including IDL source code) supplied to Danny Blair
•
August 2008
Synoptic Typer rewrite completed by Danny Blair with Ryan Smith (Honours Thesis)
Smith, Ryan P.R. 2008. Synoptic Typer Tools: Designing and Testing an Automated
Synoptic Classification Program. Hons. Thesis, Dept. of Geography, Uni. of
Winnipeg, Manitoba, Canada.
“… to eliminate the need for a Visual Basic interface by designing a graphical
interface in IDL, similar to how Synoptic Typer was originally designed. Visual Basic
was implemented because it was easier for the author to use than was IDL.”
Evolution of Synoptic Typer Tools
•
October 2008
User-Friendly Eigenvector Classification of Gridded Data
Danny Blair1, Ryan Smith1, Robert Dahni2
1 Department
of Geography, University of Winnipeg, Winnipeg, Manitoba, Canada
2 Australian Bureau of Meteorology
Contact: d.blair@uwinnipeg.ca
Presentation by Danny Blair at the “Advances in Weather and Circulation Type
Classification & Applications” conference, Krakow, Poland
“Our intent is to release the IDL source code of Synoptic Typer Tools to the
classification community as an open source program that can be modified by any
user, as long as the resulting code is shared with others.”
•
July 2010
Received Synoptic Typer Tools v1 (including source code) as work in progress
•
December 2010
Synoptic Typer Tools v2 ready for release to the synoptic typing community
Synoptic Typer Tools’ Features
• Classifies 2.5 x 2.5 degree 4-times daily NCEP/NCAR Reanalysis data
• Geopotential heights (pressure levels) or sea-level pressures (1948-present)
• Varimax-rotated (or unrotated) eigenvector and k-means cluster analyses
• User selects time of day, months, seasons or years for classification
• Options to represent grids as daily, monthly or seasonal anomalies
• User selects different numbers of principal components and clusters
• Automated production of multiple runs to compare classifications
• Produces scree plots and variety of classification statistics and graphs
• Helps user choose number of principal components and clusters to retain
• Graphical output includes shaded-color PNG and PostScript maps
• Maps of principal components, types, sample grids, and climate averages
• Data output enables graphs of monthly, seasonal and annual type frequencies
Synoptic Typer Tools Website
Synoptic Typer Tools Downloads
Synoptic Typer Tools GUI (2010)
•
Interactive (GUI based)
IDL application
•
Supported for versions
IDL 6.4+ (Windows)
using freely-available
IDL Virtual Machine
(no IDL license required)
•
Uses NCEP/NCAR
Reanalysis data
4-times daily (1948-2010)
Yearly (netCDF) files
- Geopotential height
(17 pressure levels)
HGT (30.8 GB)
- Pressure (mean sea level)
SLP (1.8 GB)
•
Supported by Department of
Geography, University of
Winnipeg, Manitoba, Canada
(Danny Blair & Ryan Smith)
Synoptic Typer Tools (2010)
Collaboration
“Freely provided working code – whatever its quality – improves
programming and enables others to engage with your research”
Publish your computer code: it is good enough
Nick Barnes, Director, Climate Code Foundation
14 October 2010, Vol 467, Nature, Page 753
Collaboration
Synoptic Typer (2004)
Synoptic Typer Tools’ Example
Melbourne Day+1 Temperature Forecasts
1.
Define region of interest (SE Australia, 50oS-25oS, 132.5oE-157.5oE)
2.
Extract daily 00 UTC SLP data from NCEP reanalysis (1963-2010)
3.
Classify data to determine number of principal components to retain (2-15 PCs)
4.
Classify data again to determine number of clusters to use (4-32 types)
Synoptic Typer Tools (Monthly Averages)
Synoptic Typer Tools (Unrotated PCs)
Synoptic Typer Tools (Unrotated Scree Plot)
?
?
Synoptic Typer Tools (Rotated PCs)
Synoptic Typer Tools (Rotated Scree Plot)
?
?
Number of Principal Components (PCs)?
• Correct number of PCs to retain varies between applications
• Usually number chosen when a statistical threshold is reached
• Scree plot produced to visually determine number of PCs to retain
• But, using scree plot process ignores the classification result
• Classification process can be sensitive to number of PCs retained
• No agreed upon method for determining number of PCs to retain
• Proposed:
“most suitable number of PCs to retain may be when the resulting
members of each synoptic type show the smallest within-type
variance. In other words, when differences between cluster members
reaches a minimum. The sum of squares of the differences between
each cluster member and its cluster average is calculated”
Synoptic Typer Tools (Within-Type Variance)
4 PCs
Number of Clusters (Synoptic Types)?
• Adding more clusters will always result in lower within-type scores
• Desirable to have fewer clusters, with maps sharing common attributes
• No agreed upon method for determining number of clusters to retain
• Proposed:
“most suitable number of clusters to retain be determined by setting a
threshold, similar to the scree method. When mean score of within-type
variance for each cluster type is plotted against varying number of
clusters, a similar diminshing pattern is observed. Lower scores
(indicate less within-type variation) and tightness of the markers
(indicates variation spread between types) are most desirable”
• In the end, selecting the number of types to retain probably has more to
do with the desired resolution of the classification rather than statistics
Synoptic Typer Tools (Within-Type Scores)
29 Types
Synoptic Typer Tools (Composite Maps)
Synoptic Typer Tools (Best Fit Maps)
Synoptic Types (Monthly Frequency)
25
20
TYP02
TYP03
TYP05
TYP10
TYP11
TYP13
TYP18
TYP19
TYP20
TYP21
Percent
15
10
5
0
1
2
3
4
5
6
7
Month
8
9
10
11
12
Synoptic Catalogue
•
Catalogue of 29 synoptic types (SE Australia, 1963-2010)
 total run time, about 30 mins, with memory usage < 500 MB
 output > 3,500 files, about 2 GB total size
 HP Compaq 8000 Managed Desktop (32-bit Windows XP)
Observed/Forecast Temperatures
(Melbourne 1963-2010)
Forecast Verification
Conditional Verification (Synoptic Type)
Conditional Verification (Synoptic Type)
Synoptic Typer Tools’ Example
Identification of NSW East Coast Lows?
Fig. 3 Generic mean sea-level pressure (MSLP) features of NSW maritime lows classified as, (a) ex-tropical cyclones, (b)
inland trough lows, (c) easterly trough lows, (d) wave on front lows, (e) decaying front lows, and (f) lows in the westerlies.
Speer, M.S., Wiles, P, and Pepler, A. 2009. Low pressure systems off the New South Wales coast and
associated hazardous weather: establishment of a database, Aust. Met. & Ocean. Journal, 59, 29-39.
1.
Define region of interest (E Australia, 42.5oS-25oS, 147.5oE-162.5oE)
2.
Extract daily 00 UTC Mar-Aug SLP data from NCEP reanalysis (1948-2010)
3.
Classify data to determine number of principal components to retain (2-20 PCs)
4.
Classify data again to determine number of clusters to use (3-50 types)
DELL Vostro 3500 Notebook (64-bit Windows 7)
Identification of NSW East Coast Lows?
Catalogue of 34 types
?
Best
Fit
Grids
?
Presentation Summary
•
Synoptic Typer was a unique and innovative application
•
Do not be afraid to “give away” your work including source code
•
Synoptic Typer Tools is now an “international” application
•
Consider the derivation and/or use of synoptic catalogues
•
Conditional verification can provide more performance feedback
•
Automated classification schemes are feasible and practical
•
The way forward for Synoptic Typer Tools...
 Implementation (desktop application, service, etc)
 Version 3 (independent data, multiple level classification,
temperature fields, other reanalyses, Linux GUI, etc)
 Feedback…
For Demonstration of Synoptic Typer Tools
Contact Robert Dahni r.dahni@bom.gov.au
Synoptic Typer Tools GUI (Version 3)
Synoptic Typer Tools GUI (Version 3)
Acknowledgements
Ryan Smith Department of Environment and Geography,University of Manitoba, Canada
Harvey Stern Victoria Climate Services Centre
Milos Setek & John Flook National Meteorological and Oceanographic Centre
Agata Imielska New South Wales Climate Services Centre
Bureau of Meteorology, Australia
Milton Speer Climate Change Research Centre, University of New South Wales, Australia
Danny Blair Department of Geography, University of Winnipeg, Canada
Beth Ebert Weather and Environmental Prediction
Centre for Australian Weather and Climate Research, Bureau of Meteorology, Australia
Robert Wilson Data Management and Internet Systems
Information Technologies Branch, Bureau of Meteorology, Australia
Questions…