Definition of 3D rainfall thresholds for operative LEWS

2021 ◽  
Author(s):  
Ascanio Rosi ◽  
Antonio Monni ◽  
Angela Gallucci ◽  
Nicola Casagli
Keyword(s):  
Soil Moisture ◽  
False Positives ◽  
Time Interval ◽  
Antecedent Rainfall ◽  
Rainfall Thresholds ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Definition Of ◽  
Landslide Triggering

<p>Rainfall induced landslide is one of the most common hazards worldwide and it is responsible every year of huge losses, both economic and social. <br>Because of the high impact of this kind of natural hazard, the forecasting of the meteorological condition associated with the initiation of landslide has become paramount in the recent years and several papers addressing this issue have been published.<br>When working over large areas, the definition of rainfall thresholds is the most used approach, since it requires few data that can be easily retrieved: landslide triggering date and location and rainfall recording associated to landslide events.<br>The intensity-duration threshold is the most used approach and it showed over the time its potential to be implemented in an operative landslide early warning system (LEWS), but literature papers showed that this approach is affected by a main drawback, i.e., the high number of false positives (events that are not capable of triggering landslides are classified as landslide triggering events).<br>To overcome this problem several authors tried to combine these thresholds with other parameters and recently one of the most promising approach is the use of the antecedent soil moisture condition, but this parameter is note very easily available for large areas and it is difficult to retrieve it in real time, so as it can be used in a LEWS.<br>In our work we used antecedent rainfall to simulate the progressive saturation of the soil and then the soil moisture condition associated with the initiation of landslides.<br>In a given area the total rainfall recorded by each rain gauge over a defined period of time prior the landslide is considered and used to define a parameter named MeAR (Mean Antecedent Rainfall), which represent the mean rainfall of the area over a given time interval, as recorded by all the active rain gauges.<br>The MeAR parameter has been coupled with classical I-D thresholds to define 3D thresholds, where the conditions associated with the initiation of a landslide are defined by a portion of a 3D space, instead of a portion of a 2D plane. This approach has been tested in Emilia-Romagna region (Italy) and it resulted the possibility of reducing false positives from 30% up to 80% on different areas.</p>

scholarly journals Modeling Antecedent Soil Moisture to Constrain Rainfall Thresholds for Shallow Landslides Occurrence

2020 ◽  
Author(s):  
Maurizio Lazzari ◽  
Marco Piccarreta ◽  
Ram L. Ray ◽  
Salvatore Manfreda
Keyword(s):  
Soil Moisture ◽  
Rainfall Intensity ◽  
Shallow Landslide ◽  
Rainfall Thresholds ◽  
Antecedent Soil Moisture ◽  
Correct Definition ◽  
Triggering Conditions ◽  
Definition Of ◽  
Moisture Conditions ◽  
Traditional Approaches

Rainfall-triggered shallow landslide events have caused losses of human lives and millions of euros in damage to property in all parts of the world. The need to prevent such hazards combined with the difficulty of describing the geomorphological processes over regional scales led to the adoption of empirical rainfall thresholds derived from records of rainfall events triggering landslides. These rainfall intensity thresholds are generally computed, assuming that all events are not influenced by antecedent soil moisture conditions. Nevertheless, it is expected that antecedent soil moisture conditions may provide critical support for the correct definition of the triggering conditions. Therefore, we explored the role of antecedent soil moisture on critical rainfall intensity-duration thresholds to evaluate the possibility of modifying or improving traditional approaches. The study was carried out using 326 landslide events that occurred in the last 18 years in the Basilicata region (southern Italy). Besides the ordinary data (i.e., rainstorm intensity and duration), we also derived the antecedent soil moisture conditions using a parsimonious hydrological model. These data have been used to derive the rainfall intensity thresholds conditional on the antecedent saturation of soil quantifying the impact of such parameters on rainfall thresholds.

scholarly journals Spatiotemporal impact of antecedent drought on hot extremes from the nonstationary risk perspective: A case study in eastern China

2021 ◽  
Author(s):  
Pengcheng Xu ◽  
Dong Wang ◽  
Yuankun Wang ◽  
Vijay Singh ◽  
Jianchun Qiu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Eastern China ◽  
Extreme Temperature ◽  
Dependence Structure ◽  
Sensitivity Index ◽  
Driving Mechanism ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition

Hot extremes may adversely impact human health and agricultural production. Owing to anthropogenic and climate changes, the close and dynamic interaction between drought and hot extremes in most areas of China need to be revisited from the perspective of nonstationarity. This study therefore proposes a time-varying Copula-based model to describe the nonstationary dependence structure of extreme temperature (ET) and antecedent soil moisture condition to quantify the dynamic risk of hot extremes conditioned on dry/wet condition. This study proposed a new approach to identify the soil moisture driving law over extreme temperature from the point view of tail monotonicity and nonstationary risk assessment. Owing to the LTI-RTD (left tail increasing and right tail decreasing) tail monotonicity for dependence structure of these two extremes derived from most areas, the driving laws of soil moisture over ET follows DDL1-WDL1 laws (DDL1: drier antecedent soil moisture condition would trigger a higher risk of ET; WDL1: wetter antecedent soil moisture condition would alleviate the occurrence risk of ET). Because of the spatiotemporal divergence of sensitivity index derived from tail monotonicity (SITM), we can conclude that the spatial and temporal heterogeneity of response degree of ET over the variations of antecedent dry/wet conditions is evident. Incorporation of nonstationarity and tail monotonicity helps identify the changes of driving mechanism (laws) between soil moisture and hot extremes. From the comparison of different kinds of nonstationary behaviours over the spatial distribution of conditional probability of ET (CP1), the dependence nonstationarity can impose greater variations on the spatial distribution of conditional risk of ET given antecedent dry condition (CP1).

PENGARUH KONDISI AWAL KELENGASAN TANAH TERHADAP DEBIT PUNCAK HIDROGRAF SATUAN

2017 ◽  
Vol 13 (3) ◽  
pp. 228
Author(s):  
Sasmito Sasmito ◽  
Bambang Triatmodjo ◽  
Joko Sujono ◽  
Sri Harto, Br
Keyword(s):  
Soil Moisture ◽  
Storage Capacity ◽  
Soil Moisture Deficit ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Moisture Deficit

Abstrak: Hidrograf satuan adalah salah satu cara untuk memperkirakan besarnya banjir di sungai akibat hujan pada suatu DAS. Hidrograf satuan sangat populer dan dipakai secara luas di dunia. Metode ini mempunyai fleksibilitas yang rendah terhadap hujan yang berbeda, sehingga hidrograf yang dihasilkan berbeda-beda pada setiap hujan. Hal ini diduga disebabkan antara lain karena teori hidrograf satuan mengabaikan pengaruh kondisi awal kelengasan tanah (antecedent soil moisture condition, AMC) pada proses penurunan hidrograf satuan. Tulisan ini menyajikan hasil penelitian tentang pengaruh AMC terhadap debit puncak hidrograf satuan observasi (qp-obs). Dalam penelitian ini variabel AMC didekati dengan besaran defisit kelengasan tanah (soil moisture deficit, SMD) yang mempunyai makna berlawanan dengan AMC. SMD direpresentasikan dengan variabel Sc (storage capacity) yakni volume udara di dalam pori tanah yang ditinggalkan air karena terevapotranspirasi keluar. Penelitian dilaksanakan dengan menggunakan data hidrologi (hujan, debit aliran, dan evaporasi) yang dikumpulkan dari 3 DAS hulu (upper catchment) di kawasan Gunung Merapi. Percobaan penelitian dilakukan dengan cara menurunkan hidrograf satuan dengan dua cara, yakni cara konvensional (Collins) menghasilkan hidrograf satuan observasi (HSosb), dan cara simulasi menggunakan model tangki menghasilkan hidrograf satuan simulasi (HSsim). Analisis pengaruh Sc dilakukan terhadap debit puncak HSosb dan debit puncak HSsim. Penelitian menghasilkan temuan yang dapat disimpulkan sebagai berikut: (1) Hubungan Sc dan debit puncak hidrograf satuan, menunjukkan semakin besar Sc (semakin kecil AMC) debit puncak HSobs semakin kecil, (2) Formula koreksi yang didapat berbentuk fungsi eksponensial (qp-obs)/(qp-obs-kor)=1,104 e-0,012Sc, dengan qp-obs-kor adalah debit puncak hidrograf satuan observasi terkoreksi, (3)  HS observasi terkoreksi rerata mempunyai debit puncak puncak paling tinggi dibanding debit puncak HSS Nakayasu dan debit puncak HSS Gama 1.

Soil Moisture and Streamflow Relationship in Forested Hillslope: A Perspective on their Hysteretic Behavior.

2021 ◽  
Author(s):  
Bassey Bassey Friday ◽  
Eunhyung Lee ◽  
Sanghyun Kim
Keyword(s):  
Soil Moisture ◽  
Soil Depth ◽  
Meteorological Data ◽  
Hysteretic Behavior ◽  
Bivariate Analysis ◽  
Storm Event ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
General Response

<p>The hysteretic behavior between soil moisture and streamflow has received only little attention in the context of hillslope hydrological processes, despite the overarching role it plays in the understanding of the temporal and spatial dynamics of hillslope responses. In this study, hydro-meteorological data were collected daily on bi-hourly basis from 2009 to 2013 over 56 soil moisture measuring points at various depths (10, 30, and 60 cm) with 147 distinct storm events chosen for investigation. A bivariate analysis approach was implemented to characterize 8,232 hysteretic behaviors between streamflow and soil moisture with a view to exploring its patterns and uniformities using data obtained in the following timescale - the whole period of campaign, seasonally and storm event. In addition, hydrological control features such as antecedent soil moisture, rainfall intensity and duration, soil depth and hillslope positions were examined to establish the degree of control it poses on hillslope responses. Our investigation showed three dominant responses – clockwise, counter-clockwise and no response. Clockwise response which implied that streamflow peaked before soil moisture, governed the entire period of campaign with the frequency of responses significantly decreasing as depth increases, except for some downslope points located around the riparian zone. Furthermore, distinct variation in the hysteretic behavior of the hillslope under seasonal timescale was observed, with clockwise responses dominating summer and fall season whereas counter clockwise responses prevailed in the spring season. Our findings further reveals that antecedent soil moisture condition and soil depth were the major drivers that influenced the general response of the hillslope.</p>

The influence of antecedent soil moisture conditions on the rainfall–runoff threshold value of a roaded catchment used for water harvesting

2013 ◽  
Vol 13 (5) ◽  
pp. 1202-1208
Author(s):  
C. W. Baek ◽  
N. Coles
Keyword(s):  
Soil Moisture ◽  
Rainwater Harvesting ◽  
Threshold Value ◽  
Rainfall Runoff ◽  
Antecedent Soil Moisture ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Antecedent Moisture ◽  
Moisture Conditions ◽  
The Relationship

A roaded catchment (RC) is a representative type of artificial catchment for rainwater harvesting. The rainfall–runoff threshold value of the RC is the main factor which influences the system efficiency and cost. Antecedent soil moisture condition is an important factor which impacts on the determination of the rainfall–runoff threshold value. In this study, rainfall–antecedent soil moisture condition–runoff relationships and the potential efficiency of RCs are presented. Rainfall and runoff data monitored at research sites in Merredin and Mount Barker are used to determine this relationship. Two antecedent moisture criteria; Antecedent Moisture Conditions (AMC) and Average Antecedent Precipitation (AAP) are used to analyse the relationship between previous rainfall and soil moisture for each RC. Monitored results show that AMC is not that suitable to show the relationship between rainfall and antecedent soil moisture condition of the RC in the dryland of Western Australia and it is recommended to use AAP to determine this relationship.

Exploring the potential of soil moisture reanalysis data for improving the identification of regional landslide triggering thresholds

2021 ◽  
Author(s):  
Nunziarita Palazzolo ◽  
David J. Peres ◽  
Enrico Creaco ◽  
Antonino Cancelliere
Keyword(s):  
Soil Moisture ◽  
Rainfall Event ◽  
Rainfall Thresholds ◽  
Rainfall Duration ◽  
Soil Moisture Data ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
Different Depths ◽  
Moisture Conditions ◽  
Landslide Triggering

<p>Landslide triggering thresholds provide the rainfall conditions that are likely to trigger landslides, therefore their derivation is key for prediction purposes. Different variables can be considered for the identification of thresholds, which commonly are in the form of a power-law relationship linking rainfall event duration and intensity or cumulated event rainfall. The assessment of such rainfall thresholds generally neglects initial soil moisture conditions at each rainfall event, which are indeed a predisposing factor that can be crucial for the proper definition of the triggering scenario. Thus, more studies are needed to understand whether and the extent to which the integration of the initial soil moisture conditions with rainfall thresholds could improve the conventional precipitation-based approach. Although soil moisture data availability has hindered such type of studies, yet now this information is increasingly becoming available at the large scale, for instance as an output of meteorological reanalysis initiatives. In particular, in this study, we focus on the use of the ERA5-Land reanalysis soil moisture dataset. Climate reanalysis combines past observations with models in order to generate consistent time series and the ERA5-Land data actually provides the volume of water in soil layer at different depths and at global scale. Era5-Land project is, indeed, a global dataset at 9 km horizontal resolution in which atmospheric data are at an hourly scale from 1981 to present. Volumetric soil water data are available at four depths ranging from the surface level to 289 cm, namely 0-7 cm, 7-28 cm, 28-100 cm, and 100-289 cm. After collecting the rainfall and soil moisture data at the desired spatio-temporal resolution, together with the target data discriminating landslide and no-landslide events, we develop automatic triggering/non-triggering classifiers and test their performances via confusion matrix statistics. In particular, we compare the performances associated with the following set of precursors: a) event rainfall duration and depth (traditional approach), b) initial soil moisture at several soil depths, and c) event rainfall duration and depth and initial soil moisture at different depths. The approach is applied to the Oltrepò Pavese region (northern Italy), for which the historical observed landslides have been provided by the IFFI project (Italian landslides inventory). Results show that soil moisture may allow an improvement in the performances of the classifier, but that the quality of the landslide inventory is crucial.</p>

Impact of climate change on soil moisture condition in Nova Scotia

2012 ◽  
Author(s):  
Raheleh Malekian ◽  
Robert Gordon ◽  
Ali Madani ASABE Member ◽  
Seyyed Ebrahim Hashemi
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Nova Scotia ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Impact Of Climate Change

scholarly journals Effect of soil moisture condition on the conversion rate of oxamyl.

1979 ◽  
Vol 27 (3) ◽  
pp. 191-198
Author(s):  
J.H. Smelt ◽  
A. Dekker ◽  
M. Leistra
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Conversion Rate ◽  
Soil Moisture Content ◽  
Loamy Sand ◽  
Clay Loam ◽  
Moisture Condition ◽  
Soil Moisture Condition ◽  
Incubation Experiments ◽  
Wilting Point

The decomposition of oxamyl in four soils under moist conditions was measured in incubation experiments at 15 deg C. Half-lives of oxamyl in soils with moisture tensions of approx. -9.8 X 103 Pa were 13 days in a clay loam, 14 days in a loamy sand, 34 days in a peaty sand and 39 days in a humic loamy sand. The rate of oxamyl decomposition in the clay loam decreased with decreasing soil moisture content down to values for below wilting point. Oxamyl decomposition in the humic loamy sand decreased with decreasing soil moisture content, but increased sharply in the very dry range. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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