Some Common Ingredients for Heavy Orographic Rainfall

Lin, Yuh-Lang; Chiao, Sen; Wang, Ting-An; Kaplan, Michael L.; Weglarz, Ronald P.

doi:10.1175/1520-0434(2001)016<0633:scifho>2.0.co;2

Cited by 257 publications

(246 citation statements)

References 25 publications

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“…Orographic lifting has been largely proposed in past studies as a mechanism for triggering heavy precipitation events over the western Mediterranean (e.g. Smith, 1979;Houze, 1993;Lin, 1993;Buzzi et al, 1998;Buzzi and Foschini, 2000;Lin et al, 2001;Rotunno and Ferretti, 2001;Pradier et al, 2002;Bousquet and Smull, 2003;Georgis et al, 2003 among others). Whereas precipitation formation induced by uplift of a stably stratified flow over a mountain ridge has been thoroughly investigated in idealized numerical frameworks, few studies have been devoted to the more challenging issue of a conditionally unstable flow impinging on a mountain range.…”

Section: Introductionmentioning

confidence: 99%

Idealized numerical simulations of quasi‐stationary convective systems over the Northwestern Mediterranean complex terrain

Bresson

Ducrocq

Nuissier

et al. 2012

Quart J Royal Meteoro Soc

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Northwestern Mediterranean coastal regions are frequently affected by torrential rainfall associated with quasi-stationary mesoscale convective systems (MCSs). The present work examines how the characteristics of a conditionally unstable flow impinging on the coastal complex terrain of the Northwestern Mediterranean can affect the location and intensity of quasi-stationary MCSs. The study is based on idealized simulations, but including the major ingredients of Northwestern Mediterranean heavy precipitation events: a moist conditionally unstable marine flow of about 100 km width facing the true terrain, composed of the Massif Central surrounded by the Alps and the Pyrenees.We find that MCSs are located upstream of the mountain range with a slow flow, whereas with a rapid flow the heaviest precipitation is over the Massif Central slopes. In a similar way, when the lateral environment is drier the heaviest precipitation is located upstream whereas a humid environment favours precipitation over the slopes. The dominant lifting mechanism is strongly related to the location of the system: (1) direct orographic triggering for systems over mountain slopes and (2) cold-pool triggering for upstream systems. In addition, the neighbouring mountains interplay through deflection of the flow and induced low-level convergence favoured by slow or dry lateral environments and through cold-pool blocking within valleys. Copyright c 2012 Royal Meteorological SocietyKey Words: deep convection; heavy precipitation; mesoscale processes

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Section: Introductionmentioning

confidence: 99%

Idealized numerical simulations of quasi‐stationary convective systems over the Northwestern Mediterranean complex terrain

Bresson

Ducrocq

Nuissier

et al. 2012

Quart J Royal Meteoro Soc

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“…1a) with an average terrain height of about 2000 m (Chen and Li, 1995;Lin and Chen, 2002) and a few steep peaks of almost 4 km. It is well known that damages are strongly related to the location of the typhoon's landfall and interactions between its circulation and the CMR (Brand and Blelloch 1974;Wu and Kurihara, 1996;Wu and Kuo, 1999;Lin et al, 2001;Chien et al, 2008;Ge et al, 2010). Previous studies pointed out that enormous amounts of rainfall occur and are enhanced due to mountain lifting when a typhoon passes over the CMR (Wu and Kuo, 1999;Lin et al, 2001Wu et al, 2002;Yang et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

et al. 2011

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Abstract.Within 100 h, a record-breaking rainfall, 2855 mm, was brought to Taiwan by typhoon Morakot in August 2009 resulting in devastating landslides and casualties. Analyses and simulations show that under favorable largescale situations, this unprecedented precipitation was caused first by the convergence of the southerly component of the pre-existing strong southwesterly monsoonal flow and the northerly component of the typhoon circulation. Then the westerly component of southwesterly flow pushed the highly moist air (mean specific humidity >16 g/kg between 950 and 700 hPa from NCEP GFS data set) eastward against the Central Mountain Range, and forced it to lift in the preferred area. From the fine-scale numerical simulation, not only did the convergence itself provide the source of the heavy rainfall when it interacted with the topography, but also convective cells existed within the typhoon's main rainband. The convective cells were in the form of small rainbands perpendicular to the main one, and propagated as wave trains downwind. As the main rainband moved northward and reached the southern CMR, convective cells inside the narrow convergence zone to the south and those to the north as wave trains, both rained heavily as they were lifted by the west-facing mountain slopes. Those mesoscale processes were responsible for the unprecedented heavy rainfall total that accompanied this typhoon.

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“…1b, c, for example). As documented in previous studies (Lin et al 2001;Chen et al 2006;Chien et al 2006Chien et al , 2008, this upstream flow is often associated with organized mesoscale convective systems (MCS) forming over the strait, propagating eastward, and producing heavy rain over the sloping mountainous area. In this study, we perform data assimilation experiments to assess the ability of a mesoscale model to predict these precipitating systems.…”

Section: Introductionmentioning

confidence: 59%

Impact of FORMOSAT-3/COSMIC GPS radio occultation and dropwindsonde data on regional model predictions during the 2007 Mei-yu season

Chien

Kuo

2009

GPS Solut

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A study of the impact of FORMOSAT-3/ COSMIC GPS radio occultation (RO) and dropwindsonde data on regional model simulations for a 11-day period during the 2007 Mei-yu season is presented. The Weather Research and Forecasting (WRF) model and its threedimensional variation component, WRF-Var, are used for regional model predictions of heavy rainfall events in Taiwan. Without the use of GPS RO and dropwindsonde data, pressure and relative humidity are, in general, underestimated by the model; temperature predictions have a warm bias at the low level and a cold bias at the high level; and the east-west and north-south component winds have positive and negative biases, respectively. Incorporating GPS RO data tends to improve the prediction for longer integration. The assimilation of dropwindsonde data improves the forecast at the earlier time and at higher levels, and the improvement decreases over time. The reason the dropwindsonde data produce a positive impact earlier and the GPS RO data later is that there are few GPS RO observations in the fine domain. The large-scale simulation is first improved using the GPS RO observations, and the resulting changes can have a positive impact on the mesoscale at the later time. The dropwindsonde observations were taken inside the fine domain such that their impact can be detected early in the simulation. With both types of observation included, the prediction shows even greater improvement.

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Some Common Ingredients for Heavy Orographic Rainfall

Cited by 257 publications

References 25 publications

Idealized numerical simulations of quasi‐stationary convective systems over the Northwestern Mediterranean complex terrain

Idealized numerical simulations of quasi‐stationary convective systems over the Northwestern Mediterranean complex terrain

Mesoscale processes for super heavy rainfall of Typhoon Morakot (2009) over Southern Taiwan

Impact of FORMOSAT-3/COSMIC GPS radio occultation and dropwindsonde data on regional model predictions during the 2007 Mei-yu season

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