scholarly journals Frequency Trend Analysis of Heavy Rainfall Days for Germany

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1950
Author(s):  
Detlef Deumlich ◽  
Andreas Gericke
Keyword(s):  
Heavy Rainfall ◽  
Coastal Region ◽  
Daily Rainfall ◽  
Recent Change ◽  
Trend Test ◽  
Time Interval ◽  
Regional Patterns ◽  
Daily Data ◽  
Hourly Data ◽  
Regional Analyses

Climate change is expected to affect the occurrence of heavy rainfall. We analyzed trends of heavy rainfall days for the last decades in Germany. For all available stations with daily data, days exceeding daily thresholds (10, 20, 30 mm) were counted annually. The Mann–Kendall trend test was applied to overlapping periods of 30 years (1951–2019). This period was extended to 1901 for 111 stations. The stations were aggregated by natural regions to assess regional patterns. Impacts of data inconsistencies on the calculated trends were evaluated with the metadata and recent hourly data. Although the trend variability depended on the chosen exceedance threshold, a general long-term trend for the whole of Germany was consistently not evident. After 1951, stable positive trends occurred in the mountainous south and partly in the northern coastal region, while parts of Central Germany experienced negative trends. The frequent location shifts and the recent change in the time interval for daily rainfall could affect individual trends but were statistically insignificant for regional analyses. A case study supported that heavy rains became more erosive during the last 20 years. The results showed the merit of historical data for a better understanding of recent changes in heavy rainfall.

scholarly journals Synoptic environment associated with heavy rainfall events on the coastland of Northeast Brazil

2013 ◽  
Vol 35 ◽  
pp. 73-78 ◽  
Author(s):  
P. T. Oliveira ◽  
K. C. Lima ◽  
C. M. Santos e Silva
Keyword(s):  
Coastal Area ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
South Atlantic Convergence Zone ◽  
Rain Gauge ◽  
Economic Losses ◽  
Heavy Rainfall Event ◽  
Northeast Brazil ◽  
Daily Data ◽  
Upper Level

Abstract. Northeast Brazil (NEB) has an extensive coastal area, often hit by natural disasters that bring many social and economic losses. The objective of this work was to study the synoptic environment associated with a heavy rainfall event (HRE) on the coastland of NEB. We used daily rainfall data for coastal area of NEB between the states of Rio Grande do Norte and Bahia, divided into two subregions: north and south coastland. This data was obtained from the hydrometeorological network managed by the Agência Nacional de Águas and the daily data reanalysis from the ERAInterim. For the selection of HRE the technique of quantiles was used, thus defined HRE where at least one rain gauge recorded rainfall above 95th percentile. The interannual distribution of events showed occurrence maximum in La Niña years and minimal in El Niño years. The results suggest that the HRE were formed mainly due to the action of upper-level cyclonic vortex, in hight levels, and due to the action to South Atlantic convergence zone, in low levels.

scholarly journals A Comparison Between Global Satellite Mapping of Precipitation Data and High-Resolution Radar Data – A Case Study of Localized Torrential Rainfall over Japan

2021 ◽  
Vol 16 (4) ◽  
pp. 786-793
Author(s):  
Yoshiaki Hayashi ◽  
Taichi Tebakari ◽  
Akihiro Hashimoto ◽  
◽  
Keyword(s):  
High Resolution ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
Radar Data ◽  
Rain Gauge ◽  
Hourly Rainfall ◽  
The Difference ◽  
Microwave Imager ◽  
Satellite Mapping

This paper presents a case study comparing the latest algorithm version of Global Satellite Mapping of Precipitation (GSMaP) data with C-band and X-band Multi-Parameter (MP) radar as high-resolution rainfall data in terms of localized heavy rainfall events. The study also obliged us to clarify the spatial and temporal resolution of GSMaP data using high-accuracy ground-based radar, and evaluate the performance and reporting frequency of GSMaP satellites. The GSMaP_Gauge_RNL data with less than 70 mm/day of daily rainfall was similar to the data of both radars, but the GSMaP_Gauge_RNL data with over 70 mm/day of daily rainfall was not, and the calibration by rain-gauge data was poor. Furthermore, both direct/indirect observations by the Global Precipitation Measurement/Microwave Imager (GPM/GMI) and the frequency thereof (once or twice) significantly affected the difference between GPM/GMI data and C-band radar data when the daily rainfall was less than 70 mm/day and the hourly rainfall was less than 20 mm/h. Therefore, it is difficult for GSMaP_Gauge to accurately estimate localized heavy rainfall with high-density particle precipitation.

Identification and Synoptic Analysis of the Highest Precipitation Linked to Ars in Iran

2021 ◽  
Vol 3 (2) ◽  
pp. 20-32
Author(s):  
Hassan Lashkari ◽  
Neda Esfandiari ◽  
Abbas Kashani
Keyword(s):  
Water Vapour ◽  
Heavy Rainfall ◽  
Daily Rainfall ◽  
Horn Of Africa ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Atmospheric Rivers ◽  
Factors Affecting ◽  
North West ◽  
Integral Data

Atmospheric rivers are long, narrow, concentrated structures of water vapour that are highly associated with rainfall and floods. To identify and introduce the highest rainfall occurring during the presence of atmospheric rivers from November to April (2007-2018) while showing the importance of this phenomenon in creating super heavy rainfall and introducing the areas affected by it, analyzed the synoptic factors affecting them slowly. In order to identify atmospheric rivers, vertical integral data of water vapour flow were used and thresholds were documented on them. The date of occurrence of each atmospheric river with their daily rainfall was examined and ten of the highest rainfall events Station (equivalent to the 95th percentile of maximum rainfall) related to atmospheric rivers was introduced and analyzed. It is found that the South Gram has been directly and indirectly the main source of atmospheric rivers associated with heavy rainfall. The source of most of these atmospheric rivers is at the peak of the Red Sea, the Gulf of Aden and the Horn of Africa. Synonymously, the origins of 7 cases from Atmospheric rivers have been of the Sudanese low pressure and in the remaining three cases have been integrated systems. In Sudanese systems, the predominant structure of the meridional inclination jet and in Integration systems has been oriented. Due to the dominance of a strong upstream current in the vicinity of the highest flux, moisture of heavy convective currents has caused super heavy rainfall and the station with the highest rainfall in the east and North West of the negative omega field or upstream streams.

scholarly journals Heavy rainfall equations for Santa Catarina, Brazil

2011 ◽  
Vol 35 (6) ◽  
pp. 2127-2134 ◽  
Author(s):  
Álvaro José Back ◽  
Alan Henn ◽  
José Luiz Rocha Oliveira
Keyword(s):  
Coastal Region ◽  
Daily Rainfall ◽  
Rain Gauge ◽  
Annual Maximum ◽  
Santa Catarina ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Significance Level ◽  
Intensity Duration Frequency ◽  
Annual Maximum Rainfall

Knowledge of intensity-duration-frequency (IDF) relationships of rainfall events is extremely important to determine the dimensions of surface drainage structures and soil erosion control. The purpose of this study was to obtain IDF equations of 13 rain gauge stations in the state of Santa Catarina in Brazil: Chapecó, Urussanga, Campos Novos, Florianópolis, Lages, Caçador, Itajaí, Itá, Ponte Serrada, Porto União, Videira, Laguna and São Joaquim. The daily rainfall data charts of each station were digitized and then the annual maximum rainfall series were determined for durations ranging from 5 to 1440 min. Based on these, with the Gumbel-Chow distribution, the maximum rainfall was estimated for durations ranging from 5 min to 24 h, considering return periods of 2, 5, 10, 20, 25, 50, and 100 years,. Data agreement with the Gumbel-Chow model was verified by the Kolmogorov-Smirnov test, at 5 % significance level. For each rain gauge station, two IDF equations of rainfall events were adjusted, one for durations from 5 to 120 min and the other from 120 to 1440 min. The results show a high variability in maximum intensity of rainfall events among the studied stations. Highest values of coefficients of variation in the annual maximum series of rainfall were observed for durations of over 600 min at the stations of the coastal region of Santa Catarina.

Minimum Inter-Event Times for Rainfall in the Eastern Monsoon Region of China

2019 ◽  
Vol 62 (1) ◽  
pp. 9-18
Author(s):  
Wenting Wang ◽  
Wenting Wang ◽  
Shuiqing Yin ◽  
Yun Xie ◽  
Mark A. Nearing ◽  
...  
Keyword(s):  
Daily Rainfall ◽  
Precipitation Data ◽  
Monsoon Region ◽  
Average Value ◽  
Event Time ◽  
Hourly Data ◽  
Average Precipitation ◽  
Average Rainfall ◽  
Exponential Method ◽  
Event Times

Abstract.Minimum inter-event time (MIT) is an index used to delineate independent storms from sub-daily rainfall records. An individual storm is defined as a period of rainfall with preceding and succeeding dry periods less than MIT. The exponential method was used to determine an appropriate MITexp for the eastern monsoon region of China based on observed 1-min resolution rainfall data from 18 stations. Results showed that dry periods between storms greater than MITexp followed an exponential distribution. MITexp values varied from 7.6 h to 16.6 h using 1-min precipitation data, which were statistically not different from values using hourly data at p = 0.05. At least ten years of records were necessary to obtain a stable MIT. Values of storm properties are sensitive to the change in MIT values, especially when MIT values are small. Average precipitation depths across all stations were 45% greater, durations were 84% longer, maximum 30-min intensities were 27% greater, and average rainfall intensities were 20% less when using an MIT of 10 h, the average value of MITexp over 18 stations, compared to 2 h. This indicates that more attention should be paid to the use of the MIT index as it relates to storm properties. Keywords: China, Exponential method, Minimum inter-event time, Storm, Storm property.

scholarly journals Analysis of Length of Growing Season in Some Agro-ecological Zones Using Non-parametric Trend Test

2019 ◽  
Vol 11 (2) ◽  
pp. 241-248
Author(s):  
Olumuyiwa Idowu OJO ◽  
Charity C. TEMENU ◽  
Masengo Francois ILUNGA
Keyword(s):  
Rainy Season ◽  
Daily Rainfall ◽  
Growing Season ◽  
Trend Test ◽  
Rainfall Characteristics ◽  
Land Preparation ◽  
Ecological Zones ◽  
Agricultural Enterprise ◽  
Savannah Zone ◽  
Agro Ecological Zones

The ever increasing population and consequently increase in demand for food and the increasing exploitation of the land justifies the need for adequate studies on rainfall as an important factor affecting agricultural production. The date of the onset of rains is an important factor in planning agricultural operations such as land preparation and sowing. The study conducted agro-statistical analysis of rainfall characteristics over three different zones of Nigeria. Daily rainfall data were collected for the period between 1971 and 2005 for 6 stations and were subjected to standard analysis to determine trends and variations in the onset dates, cessation dates, length of rainy season, number of wet days, drought episodes. The results showed that the inter-annual variability of the onset dates is higher than that of cessation dates with a progressive shift in both onset and cessation dates. The length of rainy season varied from 77-291 days in Guinea zone, 77-243 days for Savannah and 73-155 days for the Sahel. Changes in the length of growing season ranged between -9 and -10 for Guinea zone, -21 and 11 days for Savannah zone and -28 and 20 days for the Sahel. Similarly, the numbers of wet days have declined over Nigeria. The information presented in this study are to serve as input for proper land and water resources management for productive agricultural enterprise across the three major agro-ecological zones of Nigeria.

Understanding the importance of hydraulic head timeseries for calibrating a flow model: application to the real case of the Bacchiglione Basin

2020 ◽  
Author(s):  
Mara Meggiorin ◽  
Giulia Passadore ◽  
Andrea Sottani ◽  
Andrea Rinaldo
Keyword(s):  
Missing Values ◽  
Flow Model ◽  
Hydraulic Head ◽  
Parameters Estimation ◽  
Real Case ◽  
Time Interval ◽  
Specific Storage ◽  
Monthly Data ◽  
Calibration Process ◽  
Daily Data

<p>Hydrogeological timeseries of hydraulic head contain important information for modelling the groundwater resource. Calibrating in transient conditions allows to define both conductivity and specific storage fields plus, in case, other flow boundary conditions (BCs) that fit at best the observations. Moreover, by having at least one year of records, different hydrological conditions are considered and fitted.</p><p>The major problem encountered by hydrogeologists is that hydrological records often have missing values. Then, different choices on observation sampling time are possible: for example, using daily data with missing values or monthly data that fastens also the model. These choices can alter the calibration process and affect the parameters estimation.</p><p>This study aims at understanding if and how optimal estimated parameter sets are different and, therefore, if the different choice on the time interval can preclude a proper calibration of the groundwater model. This analysis was performed by calibrating: (i) with all daily data, (ii) with different percentages of missing values on daily data, (iii) with weekly data, (iv) with monthly data and (v) with stationary conditions.</p><p>The estimated parameter sets of the different models obtained by using part of the data available (to simulate the loss of information) are compared to a base model, which is the best fit achieved by using all available daily observations. The flow model and calibration setup are constant for all models, only timeseries‘ observation vary.</p><p>The analysis is carried out on a real case of study: a flow model is built using the software FEFLOW for an area of the Bacchiglione Basin (Veneto, Italy). This area has been selected in a way to facilitate the calibration process. It is located on the plain close to the Leogra river where the aquifer is unconfined. The domain has both upstream and downstream borders roughly perpendicular to the regional groundwater flow direction and passing by sensors recording continuously the hydraulic head. In this way, the following BCs can be assigned: the Dirichlet BCs with transient values of the corresponding recording sensor for the boarders upstream and downstream and no-flow conditions for the lateral borders. Furthermore, inside the study area, there are sensors monitoring the hydraulic head, i.e. transient observations. Two borderline and four central sensors are recording daily values of hydraulic head. The year 2016 was chosen as calibration period, since no data is missing.</p><p>The comparison of resulting conductivity and specific storage fields is carried out by visual inspection of fields heterogeneity and statistical distributions. Moreover, models’ uncertainty is quantified with a calibration-constrained Monte-Carlo analysis.</p><p>The main understanding of this analysis is the anomalous result estimated by the monthly data model respect to other models: both conductivity and specific storage field are different in their heterogeneity and magnitude, reaching unlikely values.</p><p>This comprehension is important because the choice of monthly data is usually done for data scarcity or model fastening, but the effects on estimated fields are evident and important to consider. The analysis shows how different observations types, meaning daily to monthly data, affect the calibration process.</p>

Spatiotemporal patterns of short-duration heavy precipitation in Germany

2020 ◽  
Author(s):  
Nasrin Haacke ◽  
Eva Nora Paton
Keyword(s):  
Short Duration ◽  
Heavy Rainfall ◽  
Sunshine Duration ◽  
Distribution Patterns ◽  
Controlling Factors ◽  
Spatiotemporal Patterns ◽  
Homogeneous Distribution ◽  
Time Interval ◽  
Rainfall Events ◽  
Heavy Rainfall Events

<p>Heavy rainfall events and the high variability of their occurrence have a significant effect on the urban water cycle and are commonly thought to increase in the future. The increasing risk of urban flash floods is a problem jointly faced by the urban infrastructure, water networks and -systems. A better understanding of the diurnal and seasonal precipitation cycles of short-duration heavy rainfall events is therefore required. This study presents the diurnal and seasonal distribution of those events (10-minute and one-hour) in Germany and puts them into a spatial context. Precipitation data from 22 weather stations of the German Weather Service were statistically examined for the period 2000 - 2018. In addition, the spatial and temporal distribution patterns were compared to spatiotemporal patterns of various controlling factors. Three diurnal distribution patterns can be identified: 1) a homogeneous distribution of events over a maximum period of 24 hours in the S-SW, 2) a non-uniform grouping of events in the morning and afternoon predominantly in the NE and 3) an occurrence of heavy rainfall events in the afternoon in a much shorter time interval in the North. These patterns are not necessarily identical for both event durations and suggest different forms and degrees of drivers. From a seasonal perspective, events of both durations occur exclusively between May and September, with the majority occurring in July and August. Temporal distributions can mainly be explained by controlling factors such as sunshine duration and intensity of radiation whereas spatial differences are also linked to geographical altitudes and typical, summery large-scale weather conditions with the main wind direction from the SW.</p>

Regional patterns of polymorphisms in natural populations of Avena barbata

1985 ◽  
Vol 27 (6) ◽  
pp. 639-643
Author(s):  
K. N. Rai
Keyword(s):  
Natural Populations ◽  
Coastal Region ◽  
Morphological Marker ◽  
Regional Patterns ◽  
Avena Barbata ◽  
The North ◽  
Inland Valley ◽  
Region I ◽  
Marker Loci ◽  
South Axis

A detailed survey of polymorphisms at two morphological marker loci (B/b for lemma color and Ls/ls for leafsheath hairiness) was carried out in natural populations of Avena barbata from California. Based on the degrees of polymorphisms at both loci, four major regions (I, II, III, IV) were recognized. The central-north coastal region I was highly polymorphic at both loci, whereas the south-coastal region IV was monomorphic for genotype BB lsls. Inland valley region III was also largely monomorphic for the same genotype. Except region II in which founder effects seemed to have played a significant role leading to low amounts of polymorphism and large differentiations among isolated small populations, temperatures on the east–west axis, and precipitation on the north–south axis appeared to be the primary environmental variables associated with the regional patterns of polymorphisms.Key words: Avena barbata, polymorphism, environmental associations

scholarly journals Investigation of the performance of a simple rainfall disaggregation scheme using semi-distributed hydrological modelling of the Lee catchment, UK

2010 ◽  
Vol 41 (2) ◽  
pp. 134-144
Author(s):  
Marie-Laure Segond ◽  
Howard S. Wheater ◽  
Christian Onof
Keyword(s):  
Daily Rainfall ◽  
Rainfall Runoff ◽  
Rain Gauges ◽  
Expected Performance ◽  
Hourly Data ◽  
Temporal Disaggregation ◽  
Rainfall Runoff Model ◽  
Event Based ◽  
Spatially Varying ◽  
Runoff Model

A simple and practical spatial–temporal disaggregation scheme to convert observed daily rainfall to hourly data is presented, in which the observed sub-daily temporal profile available at one gauge is applied linearly to all sites over the catchment to reproduce the spatially varying daily totals. The performance of the methodology is evaluated using an event-based, semi-distributed, nonlinear hydrological rainfall–runoff model to test the suitability of the disaggregation scheme for UK conditions for catchment sizes of 80–1,000 km2. The joint procedure is tested on the Lee catchment, UK, for five events from a 12 year period of data from 16 rain gauges and 12 flow stations. The disaggregation scheme generally performs extremely well in reproducing the simulated flow for the natural catchments, although, as expected, performance deteriorates for localized convective rainfall. However, some reduction in performance occurs when the catchments are artificially urbanised.

Sign in / Sign up

Export Citation Format

Share Document