A Thunderstorm Nowcasting System for the Beijing 2008 Olympics: A U.S./China Collaboration by

A Thunderstorm Nowcasting System for the Beijing 2008 Olympics: A U.S./China Collaboration

by

James Wilson1 and Mingxuan Chen2

1. National Center for Atmospheric Research, Boulder, CO 80307-3000 2. Institute of Urban Meteorology, CMA, Beijing 100089

OUTLINE

Olympics 2008 support and B08FDPBeijing Auto-Nowcast systemClimatologyImportant local considerationsPlan

Convective storms frequent Beijing area

For supporting 2008 Olympics, BMB and

NCAR are conducting a joint project on

convective storm nowcasting that is

implementation and further development

of ANC at BMB

http://news.21cn.com/tupian/

Beijing 2008 Forecast Demonstration Project (Beijing 2008 Forecast Demonstration Project (B08FDP, http://www.b08fdp.org/B08FDP, http://www.b08fdp.org/) )

sanctioned by the WMO World Weather Research Programsanctioned by the WMO World Weather Research Program Objective - Test state-of-the-art very short period forecasting systemsObjective - Test state-of-the-art very short period forecasting systems

Participants:Participants:

China/U.S. – Beijing Auto-Nowcast

China - GRAPES

Hong Kong – SWIRLS

Canada – CARDS

Canada/U.S. – MAPLE

U.S. – Niwot

U.S./Australia – RTFV

Australia – STEPS, TIFS

600 km

600

km

200 km

200

km

B08FDP Forecast and Verification Domain

~ 4 radars (S-band & C-band)~ 100 surface stations (AWS)~ 3 profilers~ 14 GPS/MetSatellite (FY-2C & MTSAT)~ 3 radiosondes (4 times/day in Aug)Meso-NWP

OUTLINE

Olympics 2008 and B08FDPBeijing Auto-Nowcast systemClimatologyImportant local considerationsPlan

Data Sets

•Radar•Satellite•Mesonet•Profiler•Sounding•Numerical Model•Lightning

Analysis Algorithms Predictor Fields

Forecaster Input

Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field

Final Prediction

Beijing Auto-Nowcast System

Produces 0-1 hr time and place specific forecast

Expert system utilizes fuzzy logic Ingest multiple data sets Ingest Meso-NWP outputs

Beijing Auto-Nowcast System

4-D Variational Doppler Radar Analysis System (VDRAS)

Extrapolates radar echoes Forecast storm initiation, growth

and dissipation Algorithms derive forecast

parameters based on the characteristics of the boundary-layer, storms, and clouds

Example of Auto-Nowcast 60-min Initiation Forecast

1 hour forecast Verification

Initiationnowcasts

Extrapolationnowcasts

OUTLINE


Distribution of storm initiation or appearance location over Beijing area

Based on 2003~2005 data from Beijing C-band radar (77 cases and > 30 dBZ)

Conclusion:

Most (77%) of those come from a westerly direction

6 ％ of total

17 ％ of total

4 cases north

77 ％ of total

2 cases south

28 cases northwest

9 cases northeast

20 cases southwest

3 cases southeast

11 cases west

28(10)

20(7)

11(4)

9(7)

4(2)

3(2)2(1)

2(2)0

Origin of storms (>30 dBZ) that arrive in or initiate in Beijing area

Based on 2003~2005 data from Beijing C-band radar (79 cases and > 30 dBZ)

inside bracket number storms initiatiated in Beijing

Conclusions:57% move in and

43% initiate28% of those that

move in enhance

OUTLINE


Important local considerations for the Beijing Auto-nowcast system Terrain and southeast winds Convection initiation along convergence lines Sea breeze influences Dissipation or enhancement as storms move from mountains to

plains Dissipation of storms when convergence line moves away

Example 1: Terrain influence with southeast low-level flow

Example 2: Squall line dissipation moving from mountain to plainsC

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Example 3: Squall line enhancement moving from mountain to plainsC

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Example 5: Boundary running away from storm and dissipatingC

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Example 6: Initiation and enhancement of storms when boundaries interact and storms move from mountains to plain/urban areas


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OUTLINE


Ingesting of new local data (Zhangbei C-band radar, AWS surrounding Beijing, FY-2C, profiler, etc.)

Further development and improvement of the nowcast system

Rerun some 2006 cases

Tune parameters and memberships

Add some new algorithms

Radar climatology study

Trial demonstration summer 2007

Formal FDP in 2008

Plan

Thank you for your attention!

Example 4: Storm initiation by convergence lines, rolls also play roleC

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Three S-band Radar Mosaic (Beijing, Tianjin and Shijiazhuang)

06/27/2006 1820UTC

Diurnal Cycle based on Tianjin radar

Minimum over Beijing 1-2 a.m. local

Echo Frequency >35 dBZ

Maximum 6-7 p.m. local

30min fcst (08/01/2006 0916UTC) 60min fcst (08/01/2006 0844UTC)

60min fcst (08/01/2006 0844UTC) Ref (08/01/2006 0947UTC)

growth

steady

decay

initiation

0

13

15

2

14

6

9

13

8

0

2

4

6

8

10

12

14

16

06月份 07月份 08月份

影响系统月分布

Cold vortex

Trough Subtropical high

Jun AugJul

The monthly number of related synoptic system with storms

高层引导风

36. 25% 37. 50%

25%

4. 94%

0. 00%

5. 00%

10. 00%

15. 00%

20. 00%

25. 00%

30. 00%

35. 00%

40. 00%

500引导风 700引导风 850引导风缺数据

500引导风700引导风850引导风缺数据

The percent of related steering wind with storms

500 mb 850 mb700 mb No data

Frequency distribution of convective weather phenomena in Beijing area

Based on surface observations in 5-9 month of 12 years (1994-2005)

Total Thunderstorm Rainstorm

hailstorm Gale

影响系统

49. 39%

37. 04%

13. 58%

0. 00%

10. 00%

20. 00%

30. 00%

40. 00%

50. 00%

60. 00%

冷涡西来槽副高外围Cold vortex Trough Subtropical high

The percent of related synoptic system with storms

A Thunderstorm Nowcasting System for the Beijing 2008 Olympics: A U.S./China Collaboration by

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