Prediction of precipitation associated with a western disturbance using a high‐resolution regional model: role of parameterisation of physical processes

Azadi, Majid; Mohanty, U. C.; Madan, O. P.; Padmanabhamurty, B.

doi:10.1017/s1350482702003055

Cited by 20 publications

(12 citation statements)

References 3 publications

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“…Previous studies have found that mesoscale simulations over the High-Asia mountains may agree well with the limited observations available [e.g., Azadi et al, 2001;Lang and Barros 2004;Barros et al, 2006]. In particular, the Weather Research and Forecasting (WRF) model has been shown to be capable of accurately simulating known patterns of extreme precipitation in the High-Asia mountains [Sato et al, 2008;Li et al, 2009;Maussion et al, 2011Maussion et al, , 2014Sato 2013] and in other high mountains around the world [e.g., Rasmussen et al, 2011;Jiménez et al, 2013;Viale et al, 2013].…”

Section: Introductionmentioning

confidence: 79%

WRF simulations of two extreme snowfall events associated with contrasting extratropical cyclones over the western and central Himalaya

et al. 2015

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Two extreme snowfall events associated with extratropical cyclones, one interacting with the western and one with the central Himalaya, are simulated with the Weather Research and Forecasting (WRF) model over 8 days. One event in January 1999 was driven by a longwave trough over west Asia, with the cyclone becoming terrain‐locked in the western Himalayan notch. Another event in March 2006 was driven by a trough further south and east, facilitating the passage of two successive cyclones along the entire Himalayan ridge, drawing moisture from warm tropical waters. These flow patterns are typical for extreme winter precipitation in the western and central Himalaya, respectively, but were amplified in these two cases. In the WRF simulations, snowfall is confined to the western Himalaya in the January simulation, while a near‐continuous band of accumulated snowfall along the Himalayan ridge forms in the March simulation. Precipitation rate throughout both simulations is largely determined by cross‐barrier moisture flux, which is generally greatest wherever the cyclonic winds converge on the mountains at each time. However, the March 2006 simulation evolves in an environment with greater convective instability upwind of and moisture transport toward the mountains than in the January 1999 event. Hence, greater precipitation rates and more solid snowbands are generated in the March than in the January simulation. However, due to the terrain‐locking of the cyclone in the January event, individual locations receive more persistent snowfall, so that the greatest 8 day accumulations are similar between the two events, although these accumulations are more widespread in the March event.

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Section: Introductionmentioning

confidence: 79%

WRF simulations of two extreme snowfall events associated with contrasting extratropical cyclones over the western and central Himalaya

et al. 2015

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“…Chakravortty and Basu, 1957;Mooley, 1957;Sharma and Subramaniam, 1983;Rangachary and Bandyopadhyay, 1987;Lang and Barros, 2004;Roy and Roy Bhowmik, 2005;Kotal et al, 2014;Dimri et al, 2015) and have been the subject of a number * http://imd.gov.in/section/nhac/wxfaq.pdf of modelling case studies (e.g. Ramanathan and Saha, 1972;Chitlangia, 1976;Gupta et al, 1999;Azadi et al, 2002;Dimri, 2004;Semwal and Dimri, 2012;Dimri and Chevuturi, 2014;Patil and Kumar, 2016). Despite the abundant interest in these systems, little headway has been made in developing a systematic understanding of them.…”

Section: Introductionmentioning

confidence: 99%

The evolution, seasonality and impacts of western disturbances

Hunt

Turner

Shaffrey

2018

Quart J Royal Meteoro Soc

150

184

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Western disturbances (WDs) are upper-level synoptic-scale systems embedded in the subtropical westerly jet stream (STWJ), often associated with extreme rainfall events in north India and Pakistan during boreal winter. Here, a tracking algorithm is applied to the upper-tropospheric vorticity field for 37 years of ERA-Interim reanalysis data, giving a catalogue of over 3000 events. These events are analysed in a composite framework: the vertical structure is explored across a large number of dynamic and thermodynamic fields, revealing a significant northwestward tilt with height, strong ascent ahead of the centre, which sits above the maximum surface precipitation, and a warm-over-cold, dry-over-moist structure, among other signatures of strong baroclinicity. Evolution of the structures of cloud cover and vertical wind speed are investigated as the composite WD passes across northern India. Cloud cover in particular is found to be particularly sensitive to the presence of the Himalayan foothills, with a significant maximum at 300 hPa approximately 1 day after the WD reaches peak intensity. k-means clustering is used to classify WDs according to both dynamical structure and precipitation footprint and the relationship between the two sets of WDs is explored. Finally, the statistical relationship between the STWJ position and WDs on interannual time-scales is explored, showing that WD frequency in north India is highly sensitive to the jet location over Eurasia. Years with a greater number of WDs feature a STWJ shifted to the south, a pattern that is substantially more coherent and reaches as far west as North America during boreal winter. This suggests that it may be possible to predict the statistics of western disturbance events on seasonal time-scales if suitable indicators of jet position can also be predicted.

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“…We tested several model settings (Chang et al, 2005) and selected a configuration with the MRF planetary boundary layer (PBL) scheme, the Dudhia shortwave radiation scheme, and the Goddard longwave radiation scheme with the Grell-Devenyi ensemble convective parameterization (CP) scheme as the control simulation. The choice of the control configuration was also guided by some recent high resolution model simulations over the Indian region (Azadi et al, 2002;Xavier et al, 2006).…”

Section: Model Configuration and Experimental Set Upmentioning

confidence: 99%

The role of land surface processes on the mesoscale simulation of the July 26, 2005 heavy rain event over Mumbai, India

Chang

Kumar

Niyogi

et al. 2009

Global and Planetary Change

100

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Prediction of precipitation associated with a western disturbance using a high‐resolution regional model: role of parameterisation of physical processes

Abstract: In this study a non-hydrostatic version of the PSU/NCAR Betts-Miller (or Grell) schemes as PBL and convection parameterisation schemes respectively are best compared to the other schemes used in this study.

Cited by 20 publications

References 3 publications

WRF simulations of two extreme snowfall events associated with contrasting extratropical cyclones over the western and central Himalaya

WRF simulations of two extreme snowfall events associated with contrasting extratropical cyclones over the western and central Himalaya

The evolution, seasonality and impacts of western disturbances

The role of land surface processes on the mesoscale simulation of the July 26, 2005 heavy rain event over Mumbai, India

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