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World Meteorological Organization Symposium on Nowcasting - WMO

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38<br />

development of the Maintenance Decisi<strong>on</strong> Support System (MDSS) in 2001. MDSS provides<br />

a single platform, which blends existing road and weather data sources with numerical<br />

weather and road c<strong>on</strong>diti<strong>on</strong> models in order to provide a display of the diagnostic and<br />

prognostic state of the atmosphere and roadway (with emphasis <strong>on</strong> the 1- to 48-hour time<br />

period) as well as a decisi<strong>on</strong>-support tool for roadway maintenance treatment opti<strong>on</strong>s. In the<br />

past, the system has been used mainly for strategic purposes 12-24 hours prior to a storm’s<br />

arrival in order to prepare the maintenance vehicles and schedule pers<strong>on</strong>nel. However,<br />

during the 2008–2009 winter seas<strong>on</strong>, MDSS has been modified and applied for use over<br />

Denver Internati<strong>on</strong>al Airport (DIA), including all six runways and the main arterials leading into<br />

the airport. The users at DIA want to utilize MDSS for strategic decisi<strong>on</strong>-making but also have<br />

a need for a more accurate tactical (0-6 hours) comp<strong>on</strong>ent to the system. Currently, MDSS<br />

uses three numerical weather models, model output statistics from two models, and various<br />

pavement and weather–related surface observati<strong>on</strong>s in order to generate both weather and<br />

road surface forecasts. In order to address the short-term forecasting needs, radar data<br />

assimilati<strong>on</strong> and/or high resoluti<strong>on</strong> mesoscale numerical weather models are being assessed<br />

for possible inclusi<strong>on</strong> into MDSS. Additi<strong>on</strong>ally, a n<strong>on</strong>-wintertime MDSS is also being<br />

developed that may also require the additi<strong>on</strong> of other nowcasting capabilities, such as<br />

lightning data and radar storm-tracking (e.g. TITAN).The objective of this presentati<strong>on</strong> is to<br />

provide an overview of the present and future capabilities of the MDSS system as they relate<br />

to the diagnoses and short-term forecasting of weather that may impact the roadway/runway<br />

maintenance operati<strong>on</strong>s for various decisi<strong>on</strong>-makers.<br />

P1.12<br />

The Design and Implementati<strong>on</strong> of B08FDP Data Support System<br />

WANG Yubin[1], YU D<strong>on</strong>gchang[1], SU Debin[1], ZHOU Haiguang[2], ZHOU Y<strong>on</strong>g[3],<br />

LIANG Feng[1]<br />

[1] Beijing <str<strong>on</strong>g>Meteorological</str<strong>on</strong>g> Bureau, Beijing, China;[2] Chinese Academy of <str<strong>on</strong>g>Meteorological</str<strong>on</strong>g><br />

Sciences, Beijing, China;[3] Nati<strong>on</strong>al <str<strong>on</strong>g>Meteorological</str<strong>on</strong>g> Informati<strong>on</strong> Center, Beijing, China<br />

For 2008 Olympic weather service, there were eight nowcasting systems operated in<br />

B08FDP (WWRP/Beijing 2008 Forecast Dem<strong>on</strong>strati<strong>on</strong> Project). In this paper the data<br />

envir<strong>on</strong>ment requirement from the B08FDP participants has been analyzed, which includes<br />

data acquisiti<strong>on</strong>, transmissi<strong>on</strong>, disseminati<strong>on</strong>, m<strong>on</strong>itoring and the data formats. Within the<br />

given domain of the mesoscale observati<strong>on</strong> network, a GPS timer was setup to synchr<strong>on</strong>ize<br />

the data acquisiti<strong>on</strong> and computer timer. The File Alterati<strong>on</strong> M<strong>on</strong>itor (FAM) system based <strong>on</strong><br />

the inotify (a Linux kernel subsystem that provides file system event notificati<strong>on</strong>) was used to<br />

guarantee the data transmissi<strong>on</strong> timeliness and the realtime synchr<strong>on</strong>izati<strong>on</strong> technology for<br />

Doppler radars was used <strong>on</strong> the Doppler radar operati<strong>on</strong>. For supplying a comm<strong>on</strong> data<br />

interface for all FDP participants, XML, NetCDF that c<strong>on</strong>formed to the internati<strong>on</strong>al rule has<br />

been setup for all systems. For a better support to very short range forecasting systems, the<br />

Hi-MAPS (High-resoluti<strong>on</strong> Mesoscale data Acquiring and Pre-processing System) was<br />

developed and operated in Beijing <str<strong>on</strong>g>Meteorological</str<strong>on</strong>g> Bureau. It showed that it has been running<br />

successfully and can provide an efficient data envir<strong>on</strong>ment for B08FDP participants<br />

throughout the dem<strong>on</strong>strati<strong>on</strong> period.<br />

2.6<br />

The forecaster role in operati<strong>on</strong>al <strong>Nowcasting</strong> over complex terrain P1.13<br />

Storm Series Algorithms in the GRAPES-SWIFT<br />

Paolo Ambrosetti [1] Alessandro Hering [1]<br />

[1] MeteoSwiss, CH-6605 Locarno (Switzerland) Hu Sheng, Liang Qiaoqian, Wang Ying, Zeng Qin, Feng Yer<strong>on</strong>g<br />

Guangd<strong>on</strong>g <str<strong>on</strong>g>Meteorological</str<strong>on</strong>g> Bureau, China<br />

<strong>Nowcasting</strong> addresses not <strong>on</strong>ly “severe weather” events, but more and more all kinds of<br />

significant weather changes at local level impacting people and goods. Many weather related<br />

decisi<strong>on</strong>s with ec<strong>on</strong>omic and life protecti<strong>on</strong> c<strong>on</strong>sequences are very often deterministic,<br />

therefore requiring a high accuracy and a great time/space resoluti<strong>on</strong>. These requirements<br />

are mostly satisfied <strong>on</strong>ly at 0-3 hour time range. Particularly in complex terrain like the Alps,<br />

operati<strong>on</strong>al forecasters are under stress dealing with str<strong>on</strong>g meteorological gradients<br />

observed both in space and time. These are usually poor resolved by numerical models,<br />

therefore heuristic nowcasting techniques are necessary. Depending from the parameter or<br />

weather phenomena gridded or object approaches are better suitable. For heavy<br />

thunderstorms the object techniques have dem<strong>on</strong>strated great capability, but the early phase<br />

is usually missed. For road maintenance weather a gridded approach is mostly better suited,<br />

like the snow limit altitude. A blending of the results of the two approaches is mostly left to the<br />

forecaster. The rapid updating of the data, typically 5 minutes, represents a challenge for the<br />

humans, because most of the time there is no relevant or significant change. So the early<br />

phase of the significant change can be easily missed, loosing precious time. To cope with this<br />

problem a high degree of automati<strong>on</strong> has to be introduced. This should assure a very high<br />

probability of detecti<strong>on</strong> (POD) of significant, relevant changes. The experience shows that the<br />

side effect is an also high false alarm ratio (FAR), unacceptable for the end users. The role of<br />

The storm series algorithms in the SWIFT, including storm cell identificati<strong>on</strong>, storm<br />

c<strong>on</strong>vecti<strong>on</strong> assessment, storm tracking and storm positi<strong>on</strong> forecast, are discussed. Storm cell<br />

identificati<strong>on</strong> algorithm tests the intensity and c<strong>on</strong>tinuity of the objective echoes by multipleprescribed<br />

thresholds to build 3-D storms.It uses multiple reflectivity thresholds, newly<br />

designs the techniques of cell nucleus extracti<strong>on</strong> and close-spaced storms processing, and<br />

therefore is capable of identifying embedded cells in multi-cellular storms. The str<strong>on</strong>g area<br />

comp<strong>on</strong>ents at a l<strong>on</strong>g distance are saved as 2-D storms.By using the fuzzy logic technique, a<br />

c<strong>on</strong>vecti<strong>on</strong> index of a storm is obtained. A set of features of storm morphology are combined<br />

to describe c<strong>on</strong>vective characteristics of storm cells, and every feature is given a weight. The<br />

likelihood values that the features match with the c<strong>on</strong>vective characteristics of storm cells are<br />

calculated in the fuzzy logic engine. The c<strong>on</strong>vecti<strong>on</strong> index is the weighted average of all the<br />

likelihood values, and signs the c<strong>on</strong>vective strength of a storm instantly. Storm cells identified<br />

in two c<strong>on</strong>secutive volume scan are associated temporally to determine the cell tracking. The<br />

distance between the centroid of each cell detected in the current volume scan and each of<br />

the first-guess locati<strong>on</strong> is calculated to check distance correlati<strong>on</strong>. Those similar storms with<br />

distance correlati<strong>on</strong> are matched.The moti<strong>on</strong> vector for each storm is computed by using the<br />

103

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