Anomalous Atmospheric Events Leading to the Summer 2010 Floods in Pakistan

Houze, Robert A.; Rasmussen, Kristen L.; Medina, Socorro; Brodzik, S. R.; Romatschke, Ulrike

doi:10.1175/2010bams3173.1

Cited by 220 publications

(199 citation statements)

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“…A possible reason may be that convection is more sensitive to lower tropospheric temperature and moisture perturbations than to upper tropospheric ones [e.g., Kuang, 2010;Tulich and Mapes, 2010;Nie and Kuang, 2012]. Results here are consistent with previous observational and modeling studies which have concluded that orographic lifting is the primary cause of the floods of 2010 and other years in the same region [e.g., Houze et al, 2011;Rasmussen and Houze, 2012]. Martius et al [2013] showed that the upper level PV exerted a significant impact on the orientation and amplitude of the lower level flow that forces orographic lifting.…”

Section: Journal Of Advances In Modeling Earth Systems 101002/2016mssupporting

confidence: 90%

“…This devastating event, affecting about 20 million people and submerging one fifth of Pakistan's land area under water, resulted from a series of extremely heavy rainfall events [e.g., Houze et al, 2011] (also see Figure 1a). …”

Section: Introductionmentioning

confidence: 99%

“…The extreme precipitation events which caused the 2010 flood, as well as other similar precipitation events in the same region, have been studied by a number of investigators [e.g., Houze et al, 2011;Hong et al, 2011;Galarneau et al, 2012;Lau and Kim, 2012;Martius et al, 2013;Kumar et al, 2014;Rasmussen et al, 2014;D. A. Shaevitz et al, The 2010 and floods in India and Pakistan: Dynamical influences on the vertical motion and precipitation, arXiv:1603.01317, http://arxiv.org/abs/1603.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Forcings and feedbacks on convection in the 2010 Pakistan flood: Modeling extreme precipitation with interactive large‐scale ascent

Nie

Shaevitz

Sobel

2016

J Adv Model Earth Syst

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Extratropical extreme precipitation events are usually associated with large-scale flow disturbances, strong ascent and large latent heat release. The causal relationships between these factors are often not obvious, however, and the roles of different physical processes in producing the extreme precipitation event can be difficult to disentangle. Here, we examine the large-scale forcings and convective heating feedback in the precipitation events which caused the 2010 Pakistan flood within the Column Quasi-Geostrophic framework. A cloud-revolving model (CRM) is forced with the large-scale forcings (other than large-scale vertical motion) computed from the quasi-geostrophic omega equation with input data from a reanalysis data set, and the large-scale vertical motion is diagnosed interactively with the simulated convection.Numerical results show that the positive feedback of convective heating to large-scale dynamics is essential in amplifying the precipitation intensity to the observed values. Orographic lifting is the most important dynamic forcing in both events, while differential potential vorticity advection also contributes to the triggering of the first event. Horizontal moisture advection modulates the extreme events mainly by setting the environmental humidity, which modulates the amplitude of the convection's response to the dynamic forcings.When the CRM is replaced by either a single-column model (SCM) with parameterized convection or a dry model with a reduced effective static stability, the model results show substantial discrepancies compared with reanalysis data. The reasons for these discrepancies are examined, and the implications for global models and theoretical models are discussed.

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Section: Journal Of Advances In Modeling Earth Systems 101002/2016mssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Forcings and feedbacks on convection in the 2010 Pakistan flood: Modeling extreme precipitation with interactive large‐scale ascent

Nie

Shaevitz

Sobel

2016

J Adv Model Earth Syst

View full text Add to dashboard Cite

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“…Deep and severe convective events occurring in the vicinity of mountainous regions leading to anomalous rainfall and subsequent flooding, have been the focus of research for a long time due to their often disastrous outcome for human settlements and ecosystems (Maddox et al, 1978;Caracena et al, 1979;Nair et al, 1997;Das et al, 2003Das et al, , 2006Houze et al, 2011;Webster et al, 2011;Rasmussen and Houze, 2012;Rasmussen et al, 2014). Houze et al (2011) identified the occurrence of a synoptic-scale channel of anomalously moist flow towards the mountain barrier in Pakistan (JulyÁ August 2010) to be responsible for the development of very wide precipitating mesoscale convective systems (MCS) producing huge runoff and flooding.…”

Section: Introductionmentioning

confidence: 99%

Improved understanding of an extreme rainfall event at the Himalayan foothills – a case study using COSMO

Shrestha

Dimri

Schomburg

et al. 2015

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C TIn recent years, an increased occurrence of loss and damage of property and human casualties over the southern rim area of the Himalayas, caused by landslides following intense rainfall events, has been reported. An analysis of Tropical Rainfall Measuring Mission (TRMM)-gridded rainfall data shows that events with an exceedance probability of 1.6% for 200 mm/d rainfall are common over this region during the monsoon season. An improved understanding of the mechanisms, which lead to such events, is important for their prediction and to estimate the impact of climate change on their recurrence. In this study, we analyse such an extreme precipitation event, which hit the Uttarakhand region of the central Himalayas on 13 September 2012. We use the operational regional weather forecast model COSMO at a convection-permitting resolution of 2.8 km to simulate this event. The spatial pattern of daily-accumulated precipitation and atmospheric state profiles simulated by the model compared well with the TRMM-gridded data and radiosonde observations, which adds confidence to our model results. Our analysis suggests a three-step mechanism leading to this event:(1) development of an easterly low-level wind along the Gangetic Plain caused by a low pressure system over the central Gangetic Plain; (2) convergence of moisture over the north-western part of India, leading to an increase of potential instability of the air mass along the valley recesses, which is capped by an inversion located above the ridgeline; and (3) strengthening of the north-westerly flow above the ridges, which supports the lifting of the potentially unstable air over the protruding ridge of the foothills of the Himalayas and triggers shallow convection, which on passing through adjacent folds initiates deep convection.

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“…Exceptionally high monsoon rainfall over northern Pakistan during July and August (Houze Jr. et al, 2011;Rajeevan et al, 2011;Webster et al, 2011) No substantial trend in heavy rainfall event frequency in northern Pakistan in past several decades (Wang, S.-Y. et al, 2011;Webster et al, 2011) ( low confi dence)…”

Section: Economic Losses Due To Extreme Weather Eventsmentioning

confidence: 99%