Trends in Storm-Triggered Landslides over Southern California

AbstractChanges in storm-triggered landslide activity for Southern California in a future warming climate are estimated using an advanced, fully three-dimensional, process-based landslide model, the Scalable and Extensible Geofluid Modeling System for landslides (SEGMENT-Landslide). SEGMENT-Landslide is driven by extreme rainfall projections from the Geophysical Fluid Dynamics Laboratory High Resolution Atmospheric Model (GFDL-HIRAM). Landslide changes are derived from GFDL-HIRAM forcing for two periods: 1) the twentieth century (CNTRL) and 2) the twenty-first century under the moderate Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios A1B enhanced greenhouse gas emissions scenario (EGHG). Here, differences are calculated in landslide frequency and magnitude between the CNTRL and EGHG projections; kernel density estimation (KDE) is used to determine differences in projected landslide locations. This study also reveals that extreme precipitation events in Southern California are strongly correlated with several climate drivers and that GFDL-HIRAM simulates well the southern (relative to Aleutian synoptic systems) storm tracks in El Niño years and the rare (~27-yr recurrence period) hurricane-landfalling events. GFDL-HIRAM therefore can provide satisfactory projections of the geographical distribution, seasonal cycle, and interannual variability of future extreme precipitation events (>50 mm) that have possible landslide consequences for Southern California. Although relatively infrequent, extreme precipitation events contribute most of the annual total precipitation in Southern California. Two findings of this study have major implications for Southern California. First is a possible increase in landslide frequency and areal distribution during the twenty-first century. Second, the KDE reveals three clusters in both the CNTRL and EGHG model mean scarp positions, with a future eastward (inland) shift of ~0.5° and a northward shift of ~1°. These findings suggest that previously stable areas might become susceptible to storm-triggered landslides in the twenty-first century.

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Understanding Simulated Extreme Precipitation Events in Madison, Wisconsin, and the Role of Moisture Flux Convergence during the Late Twentieth and Twenty-First Centuries*

Journal of Hydrometeorology ◽

10.1175/jhm-d-11-052.1 ◽

2012 ◽

Vol 13 (3) ◽

pp. 877-894 ◽

Cited By ~ 15

Author(s):

Kathleen D. Holman ◽

Stephen J. Vavrus

Keyword(s):

Twentieth Century ◽

Extreme Precipitation ◽

Moisture Flux ◽

First Century ◽

Moisture Flux Convergence ◽

Extreme Precipitation Events ◽

Late Twentieth ◽

Twenty First Century ◽

Precipitation Events

Abstract Understanding extreme precipitation events in the current and future climate system is an important aspect of climate change for adaptation and mitigation purposes. The current study investigates extreme precipitation events over Madison, Wisconsin, during the late twentieth and late twenty-first centuries using 18 coupled ocean–atmosphere general circulation models that participated in the Coupled Model Intercomparison Project (CMIP3). An increase of ~10% is found in the multimodel average of annual precipitation received in Madison by the end of the twenty-first century, with the largest increases projected to occur during winter [December–February (DJF)] and spring [March–May (MAM)]. It is also found that the observed seasonal cycle of precipitation in Madison is not accurately captured by the models. The multimodel average shows a strong seasonal peak in May, whereas observations peak during midsummer. Model simulations also do not accurately capture the annual cycle of extreme precipitation events in Madison, which also peak in summer. Instead, the timing of model-simulated extreme events exhibits a bimodal distribution that peaks during spring and fall. However, spatial composites of average daily precipitation simulated by GCMs during Madison’s wettest 1% of precipitation events during the twentieth century strongly resemble the spatial pattern produced in observations. The role of specific humidity and vertically integrated moisture flux convergence (MFC) during extreme precipitation events in Madison is investigated in twentieth- and twenty-first-century simulations. Spatial composites of MFC during the wettest 1% of days during the twentieth-century simulations agree well with results from the North American Regional Reanalysis dataset (NARR), suggesting that synoptic-scale dynamics are vital to extreme precipitation events.

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Characteristics and Synoptic Patterns of Regional Extreme Rainfall over the Central and Eastern Tibetan Plateau in Boreal Summer

Atmosphere ◽

10.3390/atmos12030379 ◽

2021 ◽

Vol 12 (3) ◽

pp. 379

Author(s):

Jun Sun ◽

Xiuping Yao ◽

Guowei Deng ◽

Yi Liu

Keyword(s):

Tibetan Plateau ◽

South Asian ◽

Extreme Precipitation ◽

Extreme Rainfall ◽

Precipitation Event ◽

South Asian High ◽

Eastern Tibetan Plateau ◽

Extreme Precipitation Events ◽

Line Type ◽

Precipitation Events

In this research, the observation datasets from 106 gauge stations over the central and eastern areas of the Tibetan Plateau (TP) and the ERA (ECMWF Re-Analysis)-Interim reanalysis datasets in the summers of 1981–2016 are used to study the characteristics and synoptic patterns of extreme precipitation events over the TP. By using a modern statistical method, the abnormal circulation characteristics at high, middle, and low latitudes in the Northern Hemisphere during extreme precipitation events over the central-eastern Tibetan Plateau are discussed, and the physical mechanisms related to the extreme precipitation events are investigated. The results show that the largest amount of extreme precipitation is found in the southern and eastern areas of the TP, where the frequency of daily extreme rainfall events (exceeding 25 mm) and the frequency of all extreme precipitation events both show obvious quasi-biweekly oscillation. When the daily extreme precipitation event threshold over the TP is met and more than 5 stations show daily extreme precipitation at the same time, with at least three of them being adjacent to each other, this is determined as a regional extreme precipitation event. As such, 33 regional daily extreme precipitation events occur during the summer periods of 1981–2016. According to the influence system, the 33 regional extreme precipitation events can be divided into three types, namely the plateau trough type, the plateau shear line type, and the plateau vortex type. For the plateau trough type, the South Asian high is anomalously strong at 100 hPa. For the other two types, the South Asian high is slightly weaker than usual. For the plateau shear line type, the development of the dynamic disturbance is the strongest, reaching 200 hPa. In the plateau trough type and plateau vortex type, the water vapor is transported by the westerly belt and the southwesterly flow from the Bay of Bengal.

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General Features of Extreme Rainfall Events Produced by MCSs over East China during 2016–17

Monthly Weather Review ◽

10.1175/mwr-d-18-0455.1 ◽

2019 ◽

Vol 147 (7) ◽

pp. 2693-2714 ◽

Cited By ~ 4

Author(s):

Liu Zhang ◽

Jinzhong Min ◽

Xiaoran Zhuang ◽

Russ S. Schumacher

Keyword(s):

Extreme Precipitation ◽

Extreme Rainfall ◽

The United States ◽

East China ◽

Small Scale ◽

The South ◽

Rainfall Occurrence ◽

Extreme Precipitation Events ◽

Early Maturing ◽

Precipitation Events

Abstract This study investigated the characteristics of extreme precipitation events associated with mesoscale convective systems (MCSs) in East China (the area east of 96°E) during 2016–17. Over the entire region, 204 events were first identified and classified into synoptic, tropical, MCS, small-scale-storm (SSS), and unclassified types. For 73 MCS-type events, further division and analysis were conducted according to the organizational modes. Results show that MCS-related events occurred most frequently near southern Fujian Province and from April to October with a peak in July. The area of occurrence shifted from the south in spring to the north in summer before going back to the south in autumn. The events occurred most commonly from afternoon to early evening, matured around late afternoon, and ended before dark. Among MCS subcategories, the longest average duration was seen in the multiple-MCS cases. Of the 15 selected multiple-MCS events, 11 were defined as early-maturing type with peak rainfall occurrence before the midpoint of duration while the others were late maturing. Although multiple-MCS events were accompanied by a southwest low-level jet, strong warm-air advection, and convective instability, early-maturing cases had stronger synoptic-scale ascent, moister environments, and smaller surface-based convective available potential energy (SBCAPE) and convection inhibition (SBCIN) at the most extreme rainfall-occurrence point. Compared to the MCS type within all extreme precipitation events over the United States, the percentage was lower in China. However, the events in China exhibit more pronounced seasonal cycle.

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Mudanças na Estrutura Termodinâmica da Atmosfera na Presença de Vórtices Ciclônicos de Altos Níveis: Um Episódio de Precipitação Extrema no Semiárido Brasileiro (Changes in the Atmospheric Thermodynamic Structure in the Presence of Upper Level...)

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v5i4.232865 ◽

2012 ◽

Vol 5 (4) ◽

pp. 877

Author(s):

Magaly De Fatima Correia ◽

Weber Andrade Gonçalves ◽

Maria Regina da Silva Aragão ◽

Maryfrance De Cassia S. Diniz

Keyword(s):

Extreme Precipitation ◽

Extreme Rainfall ◽

Thermodynamic Structure ◽

Extreme Precipitation Events ◽

Brazilian Semiarid ◽

Combined Action ◽

Upper Level ◽

The Relationship ◽

Precipitation Events

A natureza da relação entre a energia potencial convectiva (CAPE), índice de instabilidade K e altas taxas de precipitação sob a influência de vórtices ciclônicos de altos níveis (VCAN) é investigada. Dados de radiossondas realizadas em Petrolina - PE foram utilizados para diagnosticar mudanças na estrutura termodinâmica da atmosfera. Totais diários de precipitação coletados na estação meteorológica de superfície permitiram avaliar a eficiência da utilização dos índices K e CAPE na determinação do grau de instabilidade da atmosfera e previsão de chuvas extremas. A relação entre valores elevados de CAPE e registros de precipitação é evidente no período de estudo. Entretanto, a existência de valores elevados desse índice não implica necessariamente na ocorrência de chuva. As chuvas abundantes e enchentes registradas na região de Petrolina no mês de janeiro de 2004 resultaram da ação conjunta de sistemas atmosféricos de escala local e sinótica. Mecanismos dinâmicos associados com VCAN foram determinantes para liberação ou supressão da atividade convectiva. Palavras - chave: eventos extremos de precipitação, vórtices ciclônicos de altos níveis, convecção, CAPEMAX. Changes in the Atmospheric Thermodynamic Structure in the Presence of Upper Level Cyclonic Vortices: An Episode of Extreme Precipitation in the Brazilian Semiarid ABSTRACT The nature of the relationship between convective potential energy (CAPE), the instability index K and high rainfall rates under the influence of upper level cyclonic vortices is investigated. Upper air sounding data collected in Petrolina – PE, Brazil, were used to diagnose changes in the thermodynamic structure of the atmosphere. Daily precipitation totals observed at the surface meteorological station allowed evaluation of the K and CAPE efficiency in the determination of the degree of atmospheric instability and prediction of extreme rainfall. The relationship between high CAPE values and precipitation is evident in the period of study. However, high CAPE values may not lead to rainfall. The large rainfall totals and flooding registered in the Petrolina region were a result of the combined action of local and synoptic scale atmospheric systems. Dynamical mechanisms associated with VCAN played a major role in the enhancement or inhibition of convective activity.Keywords: extreme precipitation events, upper level cyclonic vortices, convection, CAPEMAX

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The Changing Character of Twenty-First-Century Precipitation over the Western United States in the Variable-Resolution CESM

Journal of Climate ◽

10.1175/jcli-d-16-0673.1 ◽

2017 ◽

Vol 30 (18) ◽

pp. 7555-7575 ◽

Cited By ~ 17

Author(s):

Xingying Huang ◽

Paul A. Ullrich

Keyword(s):

United States ◽

Extreme Precipitation ◽

First Century ◽

Western United States ◽

Fine Grid ◽

Climate Signal ◽

Variable Resolution ◽

Precipitation Climatology ◽

Extreme Precipitation Events ◽

Twenty First Century

Abstract The changing characters of precipitation frequency and intensity have been comprehensively investigated from the recent historical period to the end of the twenty-first century over the western United States. Variable-resolution Community Earth System Model (VR-CESM) ensemble simulations are applied with a fine grid resolution of ~0.25° over the study area. Simulations are forced with prescribed sea surface temperatures, sea ice extent, and greenhouse gas concentrations from the representative concentration pathway 8.5 (RCP8.5) scenario. VR-CESM is shown to be effective at accurately capturing the spatial patterns of the historical precipitation climatology. The results of VR-CESM output provide significantly regional details with crucial enhancement of precipitation representations over complex terrain. In the Intermountain West and U.S. Southwest, a statistically significant increase in mean precipitation and rainy days through midcentury is observed, although this trend is tempered by the end of the century in response to a decrease in relative humidity. Over the Pacific Northwest, extreme precipitation events are observed to increase significantly as a result of increased cool season integrated vapor transport associated with a moistening of the cool seasons and drying through the warm seasons. In particular, extreme precipitation in this region appears to increase more rapidly than would be predicted by the Clausius–Clapeyron relationship. No clear climate signal emerges in mean precipitation or extreme events in the majority of California, where the precipitation climatology is attributed to large interannual variabilities that are tied closely to ENSO patterns.

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On the subseasonal clustering of European extreme precipitation events and its relationship to large-scale atmospheric drivers

10.5194/egusphere-egu21-2946 ◽

2021 ◽

Author(s):

Yannick Barton ◽

Pauline Rivoire ◽

Jérôme Kopp ◽

S. Mubashshir Ali ◽

Olivia Martius

Keyword(s):

Extreme Precipitation ◽

Large Scale ◽

Extreme Rainfall ◽

The Arctic ◽

Extreme Rainfall Events ◽

Baseline Rate ◽

Temporal Clustering ◽

Extreme Precipitation Events ◽

Western Spain ◽

Precipitation Events

Extreme precipitation events that occur in close succession can have important societal and economic repercussions. Few studies have investigated the link between large-scale atmospheric drivers and temporal clustering of extreme precipitation events on a subseasonal scale, i.e. 20-day time scale. Here we use 40 years of reanalysis data (ERA-5) to investigate the link between possibly influential atmospheric variables and the temporal clustering of catchment-averaged extreme rainfall events in Europe. We define extreme events as exceedances above the 99th percentile and runs of consecutive days are declustered. We then explicitly model the seasonal rate of extreme occurrences using penalized cubic splines. The smoothed seasonal rate of extremes is then used to (i) infer the significance of subseasonal clustering and (ii) serves as the baseline rate for the subsequent modelling step. We use a Poisson generalized linear model with the baseline rate set as an offset to model the relationship between the temporal clustering and predictor variables. These variables are the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO), atmospheric blocks, and a measure of the recurrence of synoptic-scale Rossby wave packets (RRWPs).Initial results from four carefully selected catchments reveal the following patterns: for south-western Spain, the NAO, and AO indices tend to be notably lower on significantly clustered extreme rainfall days, whereas for northern Scotland the opposite effect is observed. Also, for south-western Spain, the Greenland atmospheric blocking frequency is significantly enhanced on clustering days. Last, on clustering days in north-western France, Scandinavian blocks are significantly more frequent.For a complementary study on a methodology to identify subseasonal clustering episodes of extreme precipitation events and their contribution to large accumulations please refer to Kopp et al.

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Climate change impact on flood and extreme precipitation increases with water availability

Scientific Reports ◽

10.1038/s41598-020-70816-2 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 4

Author(s):

Hossein Tabari

Keyword(s):

Water Availability ◽

Extreme Precipitation ◽

Hydrological Cycle ◽

First Century ◽

Extreme Precipitation Events ◽

Intensity Changes ◽

Change Impact ◽

Flood Intensity ◽

Water Holding ◽

Precipitation Events

Abstract The hydrological cycle is expected to intensify with global warming, which likely increases the intensity of extreme precipitation events and the risk of flooding. The changes, however, often differ from the theorized expectation of increases in water‐holding capacity of the atmosphere in the warmer conditions, especially when water availability is limited. Here, the relationships of changes in extreme precipitation and flood intensities for the end of the twenty-first century with spatial and seasonal water availability are quantified. Results show an intensification of extreme precipitation and flood events over all climate regions which increases as water availability increases from dry to wet regions. Similarly, there is an increase in the intensification of extreme precipitation and flood with the seasonal cycle of water availability. The connection between extreme precipitation and flood intensity changes and spatial and seasonal water availability becomes stronger as events become less extreme.

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