The impact of atmospheric pressure change and rainfall for triggering landslides during weather events

2020 ◽  
Author(s):  
Lucas Pelascini ◽  
Philippe Steer ◽  
Laurent Longuevergne ◽  
Dimitri Lague
Keyword(s):  
Pressure Drop ◽  
Slope Stability ◽  
Atmospheric Pressure ◽  
Weather Conditions ◽  
Pressure Change ◽  
Weather Events ◽  
Pressure Changes ◽  
The Impact ◽  
Landslide Triggering

<p>Landslides are a complex phenomenon which triggering depends on both intrinsic properties of soils and rocks and external influences such as the action of weather conditions, or earthquakes. Around 6,000 landslides failed the 6<sup>th</sup> of September 2018 during the Mw 6.6 Hokkaido Eastern Iburi earthquake (Japan), one day after the typhoon Jebi hit the region. If the ground acceleration induced by the seismic waves likely played a major role in the triggering of these landslides, it is unclear how it compares to the respective role of rainfall and atmospheric pressure drop induced by the typhoon. The aim of this work is therefore to investigate the influence of weather conditions on landslide triggering, and more specifically to characterize the relative contributions of rainfall and atmospheric pressure changes on slope stability.</p><p>For this purpose, a simple model is developed to describe the two mechanisms and to compare their respective impact on slope stability. The model considers a homogeneous isotropic tilted infinite half-space in one dimension. Slope stability is estimated using a safety factor and a Mohr-Coulomb criterion. In the static case, groundwater is accounted for by adding an unconfined aquifer into the model. Analytical models based on diffusion equations have been used to describe the impact of rainfall and atmospheric pressure changes on slope stability (Iverson, 2000; Schulz, 2009). Extracting a response function from these models allows us to compute the stability change due to any rainfall or pressure time series. The model parameters are taken for a typical slope in Taiwan tilted with a 25° angle and with characteristics of a fully saturated loamy soil at 4 m depth and put under conditions similar to the Morakot typhoon, with more than 240 mm of rain on a 24 h period and an associate atmospheric pressure drop of 4 kPa.</p><p>Atmospheric pressure change and rainfall impacts the media in a very different way despite being associated to the same physical phenomenon, pressure diffusion. The atmospheric effect is instantaneous and directly affects the effective stress with a maximum of 4 kPa. This effect decreases over time while the pore pressure is adjusted to the atmosphere. The rainfall effect is delayed in time but has a greater impact on the effective stress, reaching 11.7 kPa almost 2 days after the end of the rainfall event. While atmospheric pressure does not change significantly the safety factor, it can exacerbate the effect of rainfall and advance the failure in time because of the respective temporal lag between the 2 processes.  Therefore, this study may lead to a better understanding of the effect of weather events such as typhoons on landslide triggering and slope stability. Our results call for revisiting in a more systematic approach the role of atmospheric pressure change on landslide triggering during extreme weather events. Because a 1D model may hide some effects associated to hillslope geometry, we then consider 2D numerical models which allow us to offer some first insights on slope stability during weather events, accounting for topography.</p>

Atmospheric pressure compared to rainfall as landslide triggering factors along a hillslope

2021 ◽  
Author(s):  
Lucas Pelascini ◽  
Philippe Steer ◽  
Laurent Longuevergne
Keyword(s):  
Slope Stability ◽  
Pore Pressure ◽  
Water Table ◽  
Atmospheric Pressure ◽  
Pressure Change ◽  
Unconfined Aquifer ◽  
Air Pressure ◽  
Water Infiltration ◽  
Landslide Occurrence ◽  
Pressure Changes

<p>Landslides are one of the sources of natural hazards that cause damages and losses but also shapes the landscape. A better understanding the factors triggering or pre-conditioning landslide occurrence is therefore critical for risk assessment, with implications for hillslope erosion and landscape dynamics Triggering of catastrophic landslides is generally associated with events such as earthquakes or intense rainfalls. In Taiwan, a minimum of 22,705 landslides were reported during the typhoon Morakot in 2009 (Lin et al., 2011). Landslides triggered during storms are generally associated to the intensity and cumulated amount of rainfall, as water infiltration destabilize slopes (Iverson, 2000). However, a correlation has also been reported between slope stability and the change in atmospheric pressure (Schulz, 2009). Indeed, a change in air-pressure can lead in a readjustment in pore pressure, and cause fluid movements normal to the surface. The aim of this study is to characterize the effect of atmospheric pressure changes and define its specific contribution on slope stability when combined with rainfall</p><p>A 2-dimensional analytical model has been developed based on diffusion equations to describe the destabilization induced by water infiltration and atmospheric pressure changes induced by typhoons. As both mechanisms are function of pore pressure, and especially groundwater pore pressure, the water table within a finite-length hillslope is modelled using Townley’s (1995) analytical expression of water flow in a unconfined aquifer. The hillslope itself is a simple tilted half-space with a water divide at the top and a river at the toe forcing the water table to the surface. Slope stability is inferred through a safety factor computed using the coulomb criterion. Both rainfall infiltration and air pressure modify pore pressure through a diffusion process. While rainfall increases water table height and induce large increases in pore pressure within days or hours, , we show that atmospheric-induced pore pressure change is instantaneous and can occur even if the hillslope is fully saturated.</p><p>The model allows to separate the hillslope response into two regimes, upslope or downslope, where the destabilization is mainly linked to rainfall or to atmospheric pressure change, respectively.  Our results suggest that landslide occurring during storms in the downstream part of the hillslope are likely candidate for being triggered by atmospheric pressure change, in particular if the storm occurs with a humid initial condition. We show that the effect of atmospheric pressure changes is not negligible. On contrary, it is crucial to define the amplitude, timing and geometry of the hillslope instability, especially when combined to rainfall.</p>

scholarly journals Modelling the control of groundwater on landslides triggering: the respective role of atmosphere and rainfall during typhoons

2021 ◽  
Author(s):  
Lucas Pelascini ◽  
Philippe Steer ◽  
Maxime Mouyen ◽  
Laurent Longuevergne
Keyword(s):  
Slope Stability ◽  
Pore Pressure ◽  
Atmospheric Pressure ◽  
Pressure Change ◽  
Rainfall Infiltration ◽  
Slope Instability ◽  
Weather Data ◽  
Atmospheric Effects ◽  
Coulomb Failure Criterion ◽  
Pressure Changes

Abstract. Landslides are often triggered by catastrophic events, among which earthquakes and rainfall are the most depicted. However, very few studies have focused on the effect of atmospheric pressure on slope stability, even though weather events such as typhoons are associated with significant atmospheric pressure changes. Indeed, both atmospheric pressure changes and rainfall-induced groundwater level change can generate pore pressure changes with similar amplitude. In this paper, we assess the respective impacts of atmospheric effects and rainfall over the stability of a hillslope. An analytical model of transient groundwater dynamics is developed to compute slope stability for finite hillslopes. Slope stability is evaluated through a safety factor based on the Mohr-Coulomb failure criterion. Both rainfall infiltration and atmospheric pressure variations, which impact slope stability by modifying the pore pressure of the media, are described by diffusion equations. The models have then been forced by weather data from different typhoons that were recorded over Taiwan. While rainfall infiltration can induce pore pressure change up to hundred kPa, its effects is delayed in time due to diffusion. To the contrary, atmospheric pressure change induces pore pressure changes not exceeding a few kPa, but its effect is instantaneous. Moreover, the effect of rainfall infiltration on slope stability decreases towards the toe of the hillslope and is cancelled where the water table reaches the surface, leaving atmospheric pressure change as the main driver of slope instability. This study allows for a better insight of slope stability through pore pressure analysis, and shows that atmospheric effects shouldn’t always be neglected.

scholarly journals Impact of biomass burning emission on total peroxy nitrates: fire plume identification during the BORTAS campaign

2016 ◽  
Vol 9 (11) ◽  
pp. 5591-5606 ◽  
Author(s):  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Piero Di Carlo ◽  
Marcella Busilacchio ◽  
Marco Verdecchia ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Pressure ◽  
Thermal Dissociation ◽  
Ann Model ◽  
Fire Plume ◽  
Pressure Threshold ◽  
Peroxy Nitrates ◽  
Artificial Neural Network Ann ◽  
The Impact

Abstract. Total peroxy nitrate ( ∑ PN) concentrations have been measured using a thermal dissociation laser-induced fluorescence (TD-LIF) instrument during the BORTAS campaign, which focused on the impact of boreal biomass burning (BB) emissions on air quality in the Northern Hemisphere. The strong correlation observed between the  ∑ PN concentrations and those of carbon monoxide (CO), a well-known pyrogenic tracer, suggests the possible use of the  ∑ PN concentrations as marker of the BB plumes. Two methods for the identification of BB plumes have been applied: (1)  ∑ PN concentrations higher than 6 times the standard deviation above the background and (2)  ∑ PN concentrations higher than the 99th percentile of the  ∑ PNs measured during a background flight (B625); then we compared the percentage of BB plume selected using these methods with the percentage evaluated, applying the approaches usually used in literature. Moreover, adding the pressure threshold ( ∼  750 hPa) as ancillary parameter to  ∑ PNs, hydrogen cyanide (HCN) and CO, the BB plume identification is improved. A recurrent artificial neural network (ANN) model was adapted to simulate the concentrations of  ∑ PNs and HCN, including nitrogen oxide (NO), acetonitrile (CH3CN), CO, ozone (O3) and atmospheric pressure as input parameters, to verify the specific role of these input data to better identify BB plumes.

scholarly journals Weather Impact on Airport Performance

Aerospace ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 109 ◽  
Author(s):  
Michael Schultz ◽  
Sandro Lorenz ◽  
Reinhard Schmitz ◽  
Luis Delgado
Keyword(s):  
Traffic Management ◽  
Probability Distributions ◽  
Weather Conditions ◽  
Air Traffic ◽  
Weather Data ◽  
Data Set ◽  
Airport Capacity ◽  
Weather Events ◽  
The Individual ◽  
The Impact

Weather events have a significant impact on airport performance and cause delayed operations if the airport capacity is constrained. We provide quantification of the individual airport performance with regards to an aggregated weather-performance metric. Specific weather phenomena are categorized by the air traffic management airport performance weather algorithm, which aims to quantify weather conditions at airports based on aviation routine meteorological reports. Our results are computed from a data set of 20.5 million European flights of 2013 and local weather data. A methodology is presented to evaluate the impact of weather events on the airport performance and to select the appropriate threshold for significant weather conditions. To provide an efficient method to capture the impact of weather, we modelled departing and arrival delays with probability distributions, which depend on airport size and meteorological impacts. These derived airport performance scores could be used in comprehensive air traffic network simulations to evaluate the network impact caused by weather induced local performance deterioration.

scholarly journals Impacts of Mesonet Observations on Meteorological Surface Analyses

2013 ◽  
Vol 28 (1) ◽  
pp. 254-269 ◽  
Author(s):  
Daniel P. Tyndall ◽  
John D. Horel
Keyword(s):  
Los Angeles ◽  
Urban Areas ◽  
Weather Conditions ◽  
Background Field ◽  
High Impact ◽  
Reporting Practices ◽  
Impact Surface ◽  
Weather Events ◽  
The Impact ◽  
Surface Observations

Abstract Given the heterogeneous equipment, maintenance and reporting practices, and siting of surface observing stations, subjective decisions that depend on the application tend to be made to use some observations and to avoid others. This research determines objectively high-impact surface observations of 2-m temperature, 2-m dewpoint, and 10-m wind observations using the adjoint of a two-dimensional variational surface analysis over the contiguous United States. The analyses reflect a weighted blend of 1-h numerical forecasts used as background grids and available observations. High-impact observations are defined as arising from poor observation quality, observation representativeness errors, or accurate observed weather conditions not evident in the background field. The impact of nearly 20 000 surface observations is computed over a sample of 100 analysis hours during 25 major weather events. Observation impacts are determined for each station as well as within broad network categories. For individual analysis hours, high-impact observations are located in regions of significant weather—typically, where the background field fails to define the local weather conditions. Low-impact observations tend to be ones where there are many observations reporting similar departures from the background. When averaged over the entire 100 cases, observations with the highest impact are found within all network categories and depend strongly on their location relative to other observing sites and the amount of variability in the weather; for example, temperature observations have reduced impact in urban areas such as Los Angeles, California, where observations are plentiful and temperature departures from the background grids are small.

scholarly journals The cyclonic activity and frequency of dangerous weather phenomena over the territory of Belarus

2019 ◽  
pp. 79-93
Author(s):  
Katsiaryna M. Sumak ◽  
Inna G. Semenova
Keyword(s):  
Heavy Rain ◽  
Weather Conditions ◽  
Summer Period ◽  
Severe Convection ◽  
Weather Events ◽  
Atmospheric Fronts ◽  
Significant Damage ◽  
Wet Snow ◽  
The Republic ◽  
The Impact

In recent decades in the world, and in the Republic of Belarus in particular, the question of the impact of weather conditions on the development of sectors of the economy and life of the population has become acute. The sudden changes in weather conditions can lead to adverse and dangerous weather phenomena that cause significant damage to the country’s economy. This paper examines the frequency of dangerous weather phenomena in cyclones of different trajectories that moved through the territory of the Republic of Belarus during the period of 1995–2015. It is identified that southern and western cyclones caused dangerous weather events over the territory of Belarus. The interannual and seasonal frequency of cyclones causing dangerous weather phenomena in Belarus was analyzed. It is shown that the largest number of southern and western cyclones was characteristic mainly for the summer period, as well as the transitional seasons of the year, therefore the dangerous weather phenomena were associated mainly with the development of severe convection on atmospheric fronts. Such phenomena as very heavy rain, snowfall and wind had the highest frequency in cyclones, as in southern as western trajectories. The share of strong sticking of wet snow and large hail were isolated cases and these phenomena were recorded locally over the territory of country.

scholarly journals Methodological issues of improving the system of meteorological support of aviation for agricultural purposes

2020 ◽  
Vol 222 ◽  
pp. 01013
Author(s):  
Natalia Moiseeva ◽  
Gennady Kovalenko ◽  
Vladimir Demchuk
Keyword(s):  
Weather Conditions ◽  
Industrial Complex ◽  
Methodological Issues ◽  
Weather Events ◽  
Observation Network ◽  
Complex Development ◽  
Regional Specificity ◽  
Aircraft System ◽  
Agricultural Areas ◽  
The Impact

The direction of the agro-industrial complex development is considered through the use of agricultural aviation and unmanned aerial vehicles, in particular, the issues of integrated application of methods for meteorological conditions forecasting for solving problems of meteorological support for agricultural aviation are considered. The analysis of the impact of climate change on the development of dangerous weather events and complex weather conditions in areas located in different geographical zones was carried out, and their regional specificity was revealed. The identified climatic features of the considered areas indicate the priority importance of developing a regional observation network. It is assumed that the development and technical modernization of the meteorological network will significantly increase the efficiency of meteorological support for the agro-industrial complex. The article also discusses the use of various types of meteorological information in the model of regional meteorological support for aircraft flights in agricultural areas proposed by the authors. The model is based on a systematic approach in which the “crew - aircraft” system is considered as a single dynamic system that is continuously influenced by changing environmental factors.

scholarly journals Influence of Temperature and Pressure Change on Adiabatic and Isothermal Methanation Processes

2012 ◽  
Vol 9 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Jekaterina Porubova ◽  
Marco Klemm ◽  
Isabel Kiendl ◽  
Karlis Valters ◽  
Darja Markova ◽  
...  
Keyword(s):  
Natural Gas ◽  
Pressure Change ◽  
Theoretical Modelling ◽  
Transport Sector ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
The Impact ◽  
Different Sources ◽  
Thermodynamic Equilibrium Calculations

Abstract Energy plans of many countries anticipate an increased use of biomethane for energy supply, i.e., in power and heat production as well as in the transport sector. Existing infrastructure of natural gas storage, supply and application provides a good platform to facilitate transfer to biomethane utilization on a larger scale. One key element of the biomethane system is the upgrade of the biomass-derived synthesis gas originating from different sources, to a quality of natural gas (SNG - Synthesis Natural Gas) via the methanation process for further injection into the natural gas grid.. The maximisation of efficiency of the methanation process is of critical importance in order to make biomethane technology viable for wider application. The aim of the study was to improve efficiency of the methanation process by finding the optimum temperatures and pressure. Theoretical modelling of adiabatic and isothermal methanation processes by using thermodynamic equilibrium calculations was introduced as a method for the study. The results show the impact of temperature and pressure changes on the overall efficiency of methane production. It can be concluded from the study that knowledge about the relation between temperature, pressure and the efficiency of the methanation process makes it possible to optimize the process under various biomass synthesized gas input conditions.

The role of gap analyses in energy assurance planning

2017 ◽  
Vol 11 (3) ◽  
pp. 181
Author(s):  
Katherine Shea, JD
Keyword(s):  
Local Governments ◽  
Power Loss ◽  
Gap Analysis ◽  
Hurricane Sandy ◽  
Severe Weather ◽  
Power Outages ◽  
Weather Events ◽  
State And Local ◽  
The Impact

Energy-related emergencies, such as power outages or interruptions to other energy supplies, can arise from a number of factors. Common causes include severe weather events—such as snowstorms, hurricanes, or summer storms with strong winds—as well as energy infrastructure that is overburdened, aging, or in need of repair. As past experience indicates, jurisdictions will continue to experience severe weather events, as well as confront infrastructure issues that make future power outages likely. As a result, state and local governments have turned to energy assurance planning, an energy-specific form of planning that helps jurisdictions prepare for and recover from energy emergencies. Energy assurance recognizes that power loss/disruption cannot be eradicated completely, but jurisdictions can mitigate the impact of power loss through effective planning. This article discusses the role of energy assurance planning and provides a description of what energy assurance means and why developing such plans at the state and local levels is important. In addition, this article discusses the role of statutory gap analyses in energy assurance planning and discusses how a gap analysis can be used by planners to identify trends and gaps in energy assurance. To provide context, a recently conducted statutory gap analysis analyzing national emergency backup power trends is provided as a case study. A summary of this project and key findings is included. Finally, this article briefly touches on legislation as an alternative to energy assurance planning, and provides summaries of recent legislative proposals introduced in the aftermath of Hurricane Sandy.

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