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.

Evaluation of the level of N supply in maize hybrids at different nutritional levels

2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 89-94
Author(s):  
A. Ványiné Széles
Keyword(s):  
Active Ingredient ◽  
Growing Season ◽  
Vegetation Period ◽  
Maize Hybrids ◽  
Leaf Stage ◽  
Stochastic Correlation ◽  
Spad Value ◽  
N Supply ◽  
Average Precipitation ◽  
Average Rainfall

The aim of the research was to determine the effect of fertilisation and year on the SPAD value and on the dynamics of the SPAD value during the growing season.The results proved that the SPAD value steadily decreased over the growing season in a dry year, whereas it increased in a year with favourable precipitation. Fertilisation increased the SPAD values significantly (P<0.001). The significantly highest SPAD value, in both dry years and those with average rainfall, was achieved by applying 60 kg N ha −1 fertiliser active ingredient at the 6-leaf stage, and 120 kg N ha −1 at both the 12-leaf stage and the 50% silking stage.The correlation between fertilisation and SPAD values was greatly affected by the year, being closest in 2004 when there was an average precipitation supply, and weakest in 2007, the driest year. The correlation between the factors was weak at the 6-leaf stage, but became stronger as the vegetation period proceeded.As the growing season progressed, the SPAD values decreased in the dry year, but increased in the year with average precipitation supplies. Nutrient uptake was relatively intensive until the 12-leaf stage in the average year. In the dry year, the decrease in the SPAD value was the most intensive at the 50% silking stage.There was no stochastic correlation between the SPAD value measured at the 6-leaf stage and the yield, but the correlation between the two variables became stronger during the vegetation period.

scholarly journals Determination of the Initial 137Cs Fallout on the Areas Contaminated by Chernobyl Fallout

2007 ◽  
Vol 26 (-1) ◽  
pp. 35-38 ◽  
Author(s):  
Grzegorz Poręba ◽  
Andrzej Bluszcz
Keyword(s):  
Precipitation Data ◽  
Chernobyl Fallout ◽  
Loess Area ◽  
Average Value ◽  
Soil Redistribution ◽  
South West ◽  
Nuclear Weapon Testing ◽  
Weapon Testing ◽  
137Cs Fallout

Determination of the Initial137Cs Fallout on the Areas Contaminated by Chernobyl FalloutThe fallout radioisotope137Cs is widely used to study rates and patterns of soil redistribution. This method requires the knowledge about the initial fallout of cesium in the study area. This paper describes the method of establishing the initial fallout of cesium for a study area which is contaminated by Chernobyl fallout. The study was carried out on the loess area near the Ujazd village (South-West Poland). The137Cs activities for reference soil cores varied from 4.41(24) kBq/m2to 5.97(26) kBq/m2. The average value of the reference inventory of137Cs for the study area is 5.23(15) kBq/m2. The calculated contribution of the Chernobyl137Cs fallout in the total cesium is equal 69%. Moreover the annual values of the137Cs fallout based on the precipitation data were calculated and presented. This study provides the method of calculating the137Cs fallout connected with the nuclear weapon testing based on the precipitation data. Moreover, this study also indicated that the spatial variability on the highly contaminated by Chernobyl cesium study area is small (RSD about 10%) and thus it is possible to use the cesium method to study soil redistribution.

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.

scholarly journals Comparing CLIGEN-Generated Storm Patterns with 1-Minute and Hourly Precipitation Data from China

2018 ◽  
Vol 57 (9) ◽  
pp. 2005-2017 ◽  
Author(s):  
Wenting Wang ◽  
Shuiqing Yin ◽  
Dennis C. Flanagan ◽  
Bofu Yu
Keyword(s):  
Rainfall Intensity ◽  
Rainfall Data ◽  
Central China ◽  
Cumulative Distribution ◽  
Precipitation Data ◽  
Adjustment Factor ◽  
Stochastic Weather Generator ◽  
Hourly Precipitation ◽  
Hourly Data ◽  
Two Parameters

AbstractClimate Generator (CLIGEN) is a stochastic weather generator that has been widely used to generate daily precipitation and storm patterns for hydrological and erosion prediction models. Rainfall data with measurement intervals ≤ 30 min are required to compute two parameters for generating storm patterns, namely, the cumulative distribution of the time to peak rainfall intensity (TimePk) and the mean daily maximum 30-min rainfall intensity (MX.5P). High-resolution rainfall data, however, are not widely available around the world. One-minute precipitation data for 18 stations in eastern and central China were aggregated into hourly intervals to evaluate methods to optimally prepare TimePk and MX.5P for CLIGEN. Four sets of the two parameters were used to run CLIGEN for comparison: C0, using the original 1-min data; C1, replacing TimePk with those computed with hourly data; C2, replacing MX.5P with those computed with hourly data with an adjustment factor; and C3, replacing both parameters with those computed with hourly data, and the MX.5P was adjusted as for C2. Results showed that 1) MX.5P computed with hourly data was systematically lower than that computed with the 1-min data, and the bias could be corrected by multiplying by an adjustment factor of 1.40; 2) the difference in generated storm patterns between C0 and C1 was insignificant; and 3) results from C2 and C3 agreed well with those generated from C0. Hourly precipitation data can be used to prepare CLIGEN input parameter values for generating storm patterns for sites where only hourly data are available.

scholarly journals Triggering verbal presuppositions

2010 ◽  
Vol 20 ◽  
pp. 684 ◽  
Author(s):  
Marta Abrusan
Keyword(s):  
Event Time ◽  
Starting Point ◽  
Rough Approximation ◽  
The Matrix ◽  
Event Times

This paper offers a predictive mechanism to derive the presuppositions of verbs. The starting point is the intuition, dating back at least to Stalnaker (1974), that the information conveyed by a sentence that is in some sense independent from its main point is presupposed. The contribution of this paper is to spell out a mechanism for deciding what will become the main point of the sentence and how to calculate independence. It is proposed that this can be calculated by making reference to event times. As a very rough approximation, the main point of an utterance is what (in a sense to be defined) has to be about the event time of the matrix predicate and the information that the sentence conveys but is not (or does not have to be) about the event time of the matrix predicate is presupposed. The notion of aboutness used to calculate independence is based on Demolombe and Farinas del Cerro (2000).

scholarly journals Desempenho na estimativa de precipitação pelo radar meteorológico do oeste de Santa Catarina

2020 ◽  
Vol 12 (6) ◽  
pp. 2249
Author(s):  
Murilo Fretta José ◽  
Rosandro Boligon Minuzzi
Keyword(s):  
Poor Performance ◽  
Precipitation Data ◽  
The West ◽  
Santa Catarina ◽  
Natural Systems ◽  
Average Precipitation ◽  
Precipitation Estimation ◽  
The Mean ◽  
Meteorological Radar ◽  
Different Time Scales

Apesar da sua eficiência, o radar meteorológico apresenta erros que são sensíveis às calibrações e às físicas envolvidas nos sistemas naturais. O objetivo neste estudo foi analisar o desempenho na estimativa de precipitação pelo radar meteorológico do oeste (RMO) de Santa Catarina em diferentes escalas de tempo. No período de 6 outubro de 2017 à 31 de janeiro de 2018, foram comparados dados de precipitação acumulados (> 1 mm) em 10 minutos, 60 minutos e 24 horas por nove estações pluviométricas com as estimadas pelo radar. A avaliação da estimativa de precipitação pelo RMO foi realizada por meio do coeficiente de correlação, o Erro Médio, o Erro Padrão de Estimativa, os Índices de Concordância e de Confiança e pela Eficiência de Nash-Sutcliffe. Para os acumulados em 24 horas e 60 minutos o radar tende a superestimar a precipitação em média de 5,82 mm e 1,62 mm, com um desempenho considerado ‘muito bom’ e ‘mediano’, respectivamente. Para a precipitação de 10 minutos os resultados foram diversificados e com um desempenho ‘ruim’. Como o desempenho do radar tende a diminuir quanto menor a escala de tempo de estimativa de precipitação a calibração do RMO se faz necessário.  Performance in precipitation estimation by meteorological radar in the West of Santa Catarina A B S T R A C TDespite its efficiency, weather radar has errors that are sensitive to the calibrations and physics involved in natural systems. The objective of this study was to analyze the performance in the estimation of precipitation by the Meteorological Radar of the West (MRW) of Santa Catarina at different time scales. In the period from October 6, 2017 to January 31, 2018, accumulated precipitation data (> 1 mm) were compared in 10 minutes, 60 minutes and 24 hours for nine rainfall stations with those estimated by radar. The MRW estimation of precipitation was performed using the correlation coefficient, the Mean Error, the Standard Error of Estimation, the Concordance and Confidence Indexes, and the Nash-Sutcliffe Efficiency. For the accumulated in 24 hours and 60 minutes the radar tends to overestimate the average precipitation of 5,82 mm and 1,62 mm, with a performance considered 'very good' and 'medium', respectively. For the 10 minute rainfall the results were diverse and with 'poor' performance. As the radar performance tends to decrease the lower the time scale of precipitation estimation the MRW calibration becomes necessary.Keywords: calibration, remote sensing, hidrological station.

scholarly journals DOWNSCALING OF DAILY AVERAGE RAINFALL OF KOTA BHARU KELANTAN, MALAYSIA

2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Muhammad Noor ◽  
Tarmizi Ismail
Keyword(s):  
Coupled Model ◽  
Daily Rainfall ◽  
Circulation Model ◽  
Global Circulation Model ◽  
Global Circulation ◽  
Average Rainfall ◽  
Intercomparison Project ◽  
The Mean ◽  
Grid Points ◽  
Good Relation

Downscaling Global Circulation Model (GCM) output is important in order tounderstand the present climate as well as future climate changes at local scale. In this study,Random Forest (RF) was used to downscale the mean daily rainfall at Kota Bahru meteorologicalstation located in Kelantan Malaysia. The RF model was used to downscale daily rainfall fromGCM of Coupled Model Intercomparison Project Phase 5 (CMIP5), BCC-CSM1.1. The potentialpredictors were selected using stepwise regression at grid points located around the study area.Quantile mapping was used to remove the bias in the prediction. The results showed that the RFmodel was able to establish a good relation between observed and downscaled rainfall. TheQuantile mapping was found to perform well to correct errors in prediction. The statisticalmeasures of performance of downscaling and bias correction approaches show that they are ableto replicate daily observed rainfall with Nash-Schutclif efficiency greater than 0.75 for all themonths. It can be concluded that RF and Quantile mapping are reliable and effective methods fordownscaling rainfall.

Extreme rainfall events during and following heatwaves

2021 ◽  
Author(s):  
Christoph Sauter ◽  
Christopher White ◽  
Hayley Fowler ◽  
Seth Westra
Keyword(s):  
Natural Hazards ◽  
Rainfall Intensity ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Rainfall Extremes ◽  
Average Rainfall ◽  
Time Of Year ◽  
The Impact

&lt;p&gt;Heatwaves and extreme rainfall events are natural hazards that can have severe impacts on society. The relationship between temperature and extreme rainfall has received scientific attention with studies focussing on how single daily or sub-daily rainfall extremes are related to day-to-day temperature variability. However, the impact multi-day heatwaves have on sub-daily extreme rainfall events and how extreme rainfall properties change during different stages of a heatwave remains mostly unexplored.&lt;/p&gt;&lt;p&gt;In this study, we analyse sub-daily rainfall records across Australia, a country that experiences severe natural hazards on a frequent basis, and determine their extreme rainfall properties, such as rainfall intensity, duration and frequency during SH-summer heatwaves. These properties are then compared to extreme rainfall properties found outside heatwaves, but during the same time of year, to examine to what extent they differ from normal conditions. We also conduct a spatial analysis to investigate any spatial patterns that arise.&lt;/p&gt;&lt;p&gt;We find that rainfall breaking heatwaves is often more extreme than average rainfall during the same time of year. This is especially prominent on the eastern and south-eastern Australian coast, where frequency and intensity of sub-daily rainfall extremes show an increase during the last day or the day immediately after a heatwave. We also find that although during heatwaves the average rainfall amount and duration decreases, there is an increase in sub-daily rainfall intensity when compared to conditions outside heatwaves. This implies that even though Australian heatwaves are generally characterised by dry conditions, rainfall occurrences within heatwaves are more intense.&lt;/p&gt;&lt;p&gt;Both heatwaves and extreme rainfall events pose great challenges for many sectors such as agriculture, and especially if they occur together. Understanding how and to what degree these events co-occur could help mitigate the impacts caused by them.&lt;/p&gt;

Cool- and Warm-Season Precipitation Reconstructions over Western New Mexico

2009 ◽  
Vol 22 (13) ◽  
pp. 3729-3750 ◽  
Author(s):  
D. W. Stahle ◽  
M. K. Cleaveland ◽  
H. D. Grissino-Mayer ◽  
R. D. Griffin ◽  
F. K. Fye ◽  
...  
Keyword(s):  
United States ◽  
New Mexico ◽  
Large Scale ◽  
Annual Ring ◽  
Warm Season ◽  
Atmospheric Dynamics ◽  
Precipitation Data ◽  
Cool Season ◽  
The North ◽  
Average Precipitation

Abstract Precipitation over the southwestern United States exhibits distinctive seasonality, and contrasting ocean–atmospheric dynamics are involved in the interannual variability of cool- and warm-season totals. Tree-ring chronologies based on annual-ring widths of conifers in the southwestern United States are well correlated with accumulated precipitation and have previously been used to reconstruct cool-season and annual precipitation totals. However, annual-ring-width chronologies cannot typically be used to derive a specific record of summer monsoon-season precipitation. Some southwestern conifers exhibit a clear anatomical transition from the earlywood and latewood components of the annual ring, and these exactly dated subannual ring components can be measured separately and used as unique proxies of cool- and warm-season precipitation and their associated large-scale ocean–atmospheric dynamics. Two 2139-yr-long reconstructions of cool- (November–May) and early-warm season (July) precipitation have been developed from ancient conifers and relict wood at El Malpais National Monument, New Mexico. Both reconstructions have been verified on independent precipitation data and reproduce the spatial correlation patterns detected in the large-scale SST and 500-mb height fields using instrumental precipitation data from New Mexico. Above-average precipitation in the cool-season reconstruction is related to El Niño conditions and to the positive phase of the Pacific decadal oscillation. Above-average precipitation in July is related to the onset of the North American monsoon over New Mexico and with anomalies in the 500-mb height field favoring moisture advection into the Southwest from the North Pacific, the Gulf of California, and the Gulf of Mexico. Cool- and warm-season precipitation totals are not correlated on an interannual basis in the 74-yr instrumental or 2139-yr reconstructed records, but wet winter–spring extremes tend to be followed by dry conditions in July and very dry winters tend to be followed by wet Julys in the reconstructions. This antiphasing of extremes could arise from the hypothesized cool- to early-warm-season change in the sign of large-scale ocean–atmospheric forcing of southwestern precipitation, from the negative land surface feedback hypothesis in which winter–spring precipitation and snow cover reduce surface warming and delay the onset of the monsoon, or perhaps from an interaction of both large-scale and regional forcing. Episodes of simultaneous interseasonal drought (“perfect” interseasonal drought) persisted for a decade or more during the 1950s drought of the instrumental era and during the eighth- and sixteenth-century droughts, which appear to have been two of the most profound droughts over the Southwest in the past 1400 yr. Simultaneous interseasonal drought is doubly detrimental to dry-land crop yields and is estimated to have occurred during the mid-seventeenth-century famines of colonial New Mexico but was less frequent during the late-thirteenth-century Great Drought among the Anasazi, which was most severe during the cool season.

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