A stochastic rainfall model that can reproduce important rainfall properties across the timescales from several minutes to a decade

2020 ◽  
Author(s):  
Dongkyun Kim ◽  
Christian Onof
Keyword(s):  
Extreme Values ◽  
Extreme Rainfall ◽  
Rectangular Pulse ◽  
Rainfall Data ◽  
Correlation Structure ◽  
Extreme Rainfall Event ◽  
Moisture Condition ◽  
Antecedent Moisture ◽  
Rainfall Model ◽  
Mean Variance

<p>We introduce a stochastic model reproducing various rainfall characteristics at timescales between 5 minutes and one decade. The model is composed of three moduels as follow: First, the model generates the fine-scale rainfall data based on a type of Bartlett-Lewis rectangular pulse model; Second, sequence of the generated rainstorms are shuffled so that their correlation structure can be preserved; Third, the time series is rearranged at the monthly timescale to reflect the coarse scale correlation structure. The method was tested based on the 69 years of 5-minute rainfall data of Bochum, Germany. The mean, variance, covariance, skewness, and proportion of wet/dry periods were well reproduced at the timescales from 5 minutes to a decade. The extreme values were also successfully reproduced at the timescales between 5 minutes and 3 days. The antecedent moisture condition before an extreme rainfall event was reproduced well too.</p>

scholarly journals Interactions between Convection and a Moist Vortex Associated with an Extreme Rainfall Event over Southern West Africa

2019 ◽  
Vol 147 (7) ◽  
pp. 2309-2328 ◽  
Author(s):  
Marlon Maranan ◽  
Andreas H. Fink ◽  
Peter Knippertz ◽  
Sabastine D. Francis ◽  
Aristide B. Akpo ◽  
...  
Keyword(s):  
West Africa ◽  
Extreme Values ◽  
Vortex Formation ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Squall Line ◽  
Convective System ◽  
Extreme Rainfall Event ◽  
Guinea Coast ◽  
Free Atmosphere

Abstract An intense mesoscale convective system (MCS) in the Guinea Coast region caused one of the highest ever recorded daily rainfall amounts at the Nigerian station Abakaliki on 12 June 2016 (223.5 mm). This paper provides a detailed analysis of the meso- and synoptic-scale factors leading to this event, including some so far undocumented dynamical aspects for southern West Africa. The MCS formed over the Darfur Mountains due to diurnal heating, then moved southwestward along a mid- to lower-tropospheric trough, and developed into a classical West African squall line in a highly sheared environment with pronounced midlevel dryness. Strong moisture flux convergence over Nigeria prior to the MCS passage led to extreme values in precipitable water and was caused by the formation of a local, short-lived heat low. According to the pressure tendency equation, the latter resulted from tropospheric warming due to MCS-forced subsidence as well as surface insolation in the resulting almost cloud-free atmosphere. In this extremely moist environment, the MCS strongly intensified and initiated the formation of a lower-tropospheric vortex, which resulted in a deceleration of the MCS and high rainfall accumulation at Abakaliki. Following the vorticity equation, the vortex formation was realized through strong low-level vortex stretching and upper-level vertical vorticity advection related to the MCS, which became “dynamically large” compared to the Rossby radius of deformation. Eventually, moisture supply and lifting associated with the vortex are suggested to promote the longevity of the MCS during the subsequent westward movement along the Guinea Coast.

Flooding in Jamaica with assessment of riverine inundation of Port Maria, St Mary

2013 ◽  
Vol 184 (1-2) ◽  
pp. 165-170 ◽  
Author(s):  
Arpita Mandal ◽  
Anuradha Maharaj
Keyword(s):  
Extreme Rainfall ◽  
Curve Number ◽  
Flood Plain ◽  
Coastal Areas ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Small Island ◽  
Extreme Rainfall Event ◽  
Ungauged Catchments ◽  
Run Off

Abstract Flash flooding, from extreme rainfall is one of the major natural disasters affecting Jamaica and other small island states of the Caribbean. Flooding in Jamaica is mainly riverine, coastal and depression with the major coastal towns being affected owing to their location on low lying areas. Such localization is driven by increase in urbanization and tourism along the coastal areas. The present work aims in a broad discussion of the flooding in Jamaica with special reference to riverine flooding of Port Maria, the capital of St Mary, one of the parishes lying in the high rain zone of the island and being affected by repeated events of flooding. Analysis of the extreme rainfall event of November 23rd–24th, 2006 shows that it exceeded the 30 yr annual rainfall of the area and the 100 yr return period as calculated from 30 yr annual rainfall data for the island. The Port Maria river lacks a gauging station to monitor flow data and flood discharge peaks. Several methods are used to calculate the run-off in such small ungauged catchments. In this study the Soil Conservation Systems Curve Number (CN) method was used to calculate the run-off from the measured rainfall data using empirical equations. Results show an unprecedented high of 13–14 inches affecting the buildings and other infrastructures, leading to the collapse of a newly constructed bridge over the river Port Maria. The town continues to get flooded from intense short duration rainfall continuing to affect life and property. Flood plain maps exist for the larger watersheds of the island but smaller yet flood prone ones have not been mapped so far. Hence this becomes very important to create a floodplain map showing the extent of the runoff from rainfall with respect to the buildings and other infrastructures of the area. The present work thus aims in creating a spatial distribution map of the runoff from the rainfall measurements aiding in developing a no build zone for this and for other low lying coastal areas of the island.

scholarly journals A hybrid stochastic rainfall model that reproduces some important rainfall characteristics at hourly to yearly timescales

2019 ◽  
Vol 23 (2) ◽  
pp. 989-1014 ◽  
Author(s):  
Jeongha Park ◽  
Christian Onof ◽  
Dongkyun Kim
Keyword(s):  
Extreme Values ◽  
Moving Average ◽  
Rectangular Pulse ◽  
Monthly Rainfall ◽  
Statistical Characteristics ◽  
Rainfall Characteristics ◽  
Novel Approach ◽  
Complex Correlation ◽  
Rainfall Model ◽  
Rainfall Statistics

Abstract. A novel approach to stochastic rainfall generation that can reproduce various statistical characteristics of observed rainfall at hourly to yearly timescales is presented. The model uses a seasonal autoregressive integrated moving average (SARIMA) model to generate monthly rainfall. Then, it downscales the generated monthly rainfall to the hourly aggregation level using the Modified Bartlett–Lewis Rectangular Pulse (MBLRP) model, a type of Poisson cluster rainfall model. Here, the MBLRP model is carefully calibrated such that it can reproduce the sub-daily statistical properties of observed rainfall. This was achieved by first generating a set of fine-scale rainfall statistics reflecting the complex correlation structure between rainfall mean, variance, auto-covariance, and proportion of dry periods, and then coupling it to the generated monthly rainfall, which were used as the basis of the MBLRP parameterization. The approach was tested on 34 gauges located in the Midwest to the east coast of the continental United States with a variety of rainfall characteristics. The results of the test suggest that our hybrid model accurately reproduces the first- to the third-order statistics as well as the intermittency properties from the hourly to the annual timescales, and the statistical behaviour of monthly maxima and extreme values of the observed rainfall were reproduced well.

Real Time Rainfall Monitoring for Pipeline Geohazards

2021 ◽  
Author(s):  
Gerry Ferris ◽  
Patrick Grover ◽  
Aron Zahradka
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Oil And Gas ◽  
Weather Prediction ◽  
Extreme Rainfall ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Extreme Rainfall Event ◽  
Pipeline Failures

Abstract Oil and gas pipelines are subjected to multiple types of geohazards which cause pipeline failures (loss of containment); two of the most common types occur at watercourse crossings and at landslides. At watercourse crossings, the most common geohazard which causes pipeline failures is flooding during which excessive scour may result in the exposure of the buried pipeline and if the exposure results in a free spanning pipeline, then this may fail due to fatigue caused by cyclic loading from vortex-induced vibration. Fortunately the free span length and water velocity combinations that lead to failure can be defined and can be used to identify the flood discharge that should be monitored for in order to trigger actions to manage the hazard and avoid failure. Most watercourse crossings in a pipeline network are on ungauged watercourses and necessitate the use of a proxy gauged watercourse. The “proxy” gauged watercourse is used to infer whether flooding is occurring on the ungauged crossing, and the owner can take appropriate actions. Often the proxy gauged watercourse is too far away or the watercourse may not be representative of the crossing of concern (e.g. large difference in the drainage areas). Real-time rainfall data can be used in conjunction with streamflow monitoring to determine when extreme precipitation has occurred within the ungauged watercourses catchment which may result in flooding. Where pipelines cross landslide prone areas, large scale movements can be initiated, or slow on-going movement rates increased when extreme rainfall occurs. The definition of the extreme rainfall event for slope sites is the key component of providing a suitable warning of potentially dangerous conditions; shallow slides can be caused by short term events from sub-hourly to 3 day duration precipitation events whereas large deep seated (creeping) landslides can be driven by annual and intra-annual rainfall amounts. Monitoring of real time rainfall can be used to determine when extreme rainfall occurs at a landslide site. The density of in-situ weather stations collecting real-time rainfall data prevents the application along remote sections of pipeline routes and within large sections of Canada. Gridded real time rainfall from quantitative precipitation estimations which integrate a multiple data sources including in-situ, numerical weather prediction, satellite and weather radar, can be used to overcome this problem and provide warnings when pre-determined rainfall thresholds are exceeded on a site-specific basis.

scholarly journals A Hybrid Stochastic Rainfall Model That Reproduces Rainfall Characteristics at Hourly through Yearly Time Scale

2018 ◽  
Author(s):  
Jeongha Park ◽  
Christian Onof ◽  
Dongkyun Kim
Keyword(s):  
Time Scale ◽  
Extreme Values ◽  
Moving Average ◽  
Rectangular Pulse ◽  
Monthly Rainfall ◽  
Statistical Characteristics ◽  
Fine Scale ◽  
Rainfall Characteristics ◽  
Rainfall Model ◽  
Scale Properties

Abstract. A novel approach of stochastic rainfall generation that can reproduce various statistical characteristics of observed rainfall at hourly through yearly time scale is presented. The model uses the Seasonal Auto-Regressive Integrated Moving Average (SARIMA) model to generate monthly rainfall. Then, it downscales the generated monthly rainfall to the hourly aggregation level using the Modified Bartlett-Lewis Rectangular Pulse (MBLRP) model, a type of Poisson cluster rainfall model. Here, the MBLRP model is fine-tuned such that it can reproduce the fine-scale properties of observed rainfall. This was achieved by first generating a set of fine scale rainfall statistics reflecting the complex correlation structure between rainfall mean, variance, auto-covariance, and proportion of dry periods, and then coupling it to the generated monthly rainfall, which were used as the basis of the MBLRP parameters to downscale monthly rainfall. The approach was tested at the 29 gauges located in the Midwest to the East Coast of the Continental United States with a variety of rainfall characteristics. The results of the test suggest that our hybrid model accurately reproduces the first through the third order statistics as well as the intermittency properties from the hourly to the annual time scale; and the statistical behaviour of monthly maxima and extreme values of the observed rainfall was well reproduced as well.

scholarly journals Investigation of Trends, Temporal Changes in Intensity-Duration-Frequency (IDF) Curves and Extreme Rainfall Events Clustering at Regional Scale Using 5 min Rainfall Data

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2167 ◽  
Author(s):  
Bezak ◽  
Mikoš
Keyword(s):  
Regional Scale ◽  
Extreme Rainfall ◽  
Rainfall Data ◽  
Extreme Rainfall Event ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Significance Level ◽  
The Past ◽  
Study Results ◽  
Intensity Duration Frequency

High-frequency rainfall data is needed in different practical hydrologic applications, such as the construction of the intensity-duration-frequency curves (IDF). This paper presents an investigation of trends (station-wise and regional) for several rainfall durations that were constructed based on the 5 min rainfall data. Moreover, changes in IDF results for two 22-year sub-samples were also analyzed. Additionally, changes in extreme events clustering at the regional scale were also analyzed. Ten rainfall stations (44 years of data 1975–2018) located in Slovenia (central EU, approx. 20,000 km2) were used in this study. Results indicate that no clear pattern in the detected trends can be found based on the analyzed stations. However, all the statistically significant trends at the significance level of 0.05 for the 5 min rainfall data were negative. Moreover, regional trends for this duration were also statistically significant. The changes in the design rainfall events between two equal sub-samples (1975–1996, 1997–2018) were between −30% and 60%. The investigation of changes in extreme rainfall event clustering indicated that extreme 5, 30, and 60 min events could more frequently occur a few days earlier in spring or summer compared to the past period. On the other hand, longer duration events (i.e., 360 and 720 min) tend to more frequently occur a few days later in autumn compared to the past. In most cases, changes are not statistically significant.

scholarly journals Extreme rainfall impacts on soil CO2 efflux in an urban forest ecosystem in Beijing, China

2016 ◽  
Vol 96 (4) ◽  
pp. 504-514 ◽  
Author(s):  
Wenjing Chen ◽  
Xin Jia ◽  
Chunyi Li ◽  
Haiqun Yu ◽  
Jing Xie ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Forest Ecosystem ◽  
Urban Forest ◽  
Extreme Rainfall ◽  
Rainfall Event ◽  
Extreme Rainfall Event ◽  
Co2 Efflux ◽  
Abrupt Decrease ◽  
Environmental Controls ◽  
Beijing China

Extreme rainfall events are infrequent disturbances that affect urban environments and soil respiration (Rs). Using data measured in an urban forest ecosystem in Beijing, China, we examined the link between gross primary production (GPP) and soil respiration on a diurnal scale during an extreme rainfall event (i.e., the “21 July 2012 event”), and we examined diel and seasonal environmental controls on Rs. Over the seasonal cycle, Rs increased exponentially with soil temperature (Ts). In addition, Rs was hyperbolically related to soil volumetric water content (VWC), increasing with VWC below a threshold of 0.17 m3 m−3, and then decreasing with further increases in VWC. Following the extreme rainfall event (177 mm), Rs showed an abrupt decrease and then maintained a low value of ∼0.3 μmol m−2 s−1 for about 8 h as soil VWC reached the field capacity (0.34 m3 m−3). Rs became decoupled from Ts and increased very slowly, while GPP showed a greater increase. A bivariate Q10-hyperbolical model, which incorporates both Ts and VWC effects, better fits Rs than the Q10 model in summer but not for whole year.

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