scholarly journals EI-Nino southern oscillation and rainfall varIation over Bangladesh

MAUSAM ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 157-162
Author(s):  
A. S. M. SABBIR AHMED ◽  
A. A. MUNIM ◽  
Q. N. BEGUM ◽  
A.M. Choudhury
Keyword(s):  
Southern Oscillation ◽  
Rainfall Data ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Rainfall Analysis ◽  
Rainfall Variation ◽  
Climatic Regions

In the present study, an attempt has been made to examine the variations of rainfall over Bangladesh and to find possible correlation with EI-Nino/Southern Oscillation (ENSO). Four stations have been chosen from four different climatic regions of Bangladesh for this purpose, namely  Jessore, Dhaka. Barisal and Srimangal. The regions have been classified according to annual rainfall amounts. The rainfall data for forty three years, (1950-1992) have been analysed. The yearly mean rainfall shows a distinct negative decreasing tendency with the occurrence of ENSO.The seasonal rainfall analysis shows a somewhat better correlation.  

Overflow Data of Rainwater Discharge Systems Determined from Run off Simulation of Pluviograph Records

1984 ◽  
Vol 16 (8-9) ◽  
pp. 297-309
Author(s):  
R Pecher
Keyword(s):  
Statistical Analysis ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Rainfall Analysis ◽  
Rainfall Variation ◽  
Runoff Variation ◽  
Sewer Systems ◽  
Run Off ◽  
Combined Sewer ◽  
Runoff Model

In the last years, the relieving activity of overflow structures in combined sewer systems was mainly determined by statistical analysis of rainfall data. Due to the rain lost on the surface of a drainage area and to the flow rétardation through the sewer network, the resulting runoff variation differs a lot from the rainfall variation. Therefore, the rainfall measurements of 4 rain gaging stations in Hamburg with a total of 67 recorded years and a rain gaging station in Berlin with 22 recorded years were used to carry out runoff simulations. First of all, a rainfall statistical analysis was performed with the measured rainfall data in order to determine the annual rainfall durations, depths and frequencies in relation to the average rain intensity. The annual overflow data from overflow structures (overflow weirs and overflow basins) of not prerelieved drainage areas were computed by means of a simplified runoff model. The so determined overflow data is considerably lower than the data of rainfall analysis. Hence, overflow data from overflow structures in combined sewer systems wouldn't be satisfying if they are derived from only statistical rainfall analysis. Recorded rainfall events should rather be transformed into runoff events and accordingly analysed. As there were only 5 rain gaging stations available, a generalization of the computed overflow data is still impossible. However, these overflow data seem to be on the whole plausible if compared with rainfall data which were performed in the past only during the summer months.

A comparison of weather systems in 1870 and 1956 leading to extreme floods in the Murray–Darling Basin

2019 ◽  
Vol 69 (1) ◽  
pp. 84
Author(s):  
Jeff Callaghan
Keyword(s):  
19Th Century ◽  
Heavy Rainfall ◽  
Southern Oscillation ◽  
Linear Trend ◽  
Meteorological Data ◽  
Middle Level ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Murray Darling Basin ◽  
The Impact

This research is the extension of a project studying the impact of 19th century severe weather events in Australia and their relation to similar events during the 20th and 21st century. Two floods with the worst known impacts in the Murray–Darling Basin (MDB) are studied. One of these events which occurred during 1956 is relativelywell known and the Bureau of Meteorology archives contain good rainfall data covering the period. Additionally, information on the weather systems causing this rainfall can be obtained. Rainfall, flood and weather system data for this event are presented here and compared with a devastating event during 1870. Although archived Australian rainfall data is negligible during 1870 and there is no record of weather systems affecting Australia during that year, a realistic history of the floods and weather systems in the MDB during 1870 is created. This follows an extensive search through newspaper archives contained in the National Library of Australia’s web site. Examples are presented showing how the meteorological data in 19th century newspapers can be used to create weather charts. Six such events in 1870 are demonstrated and three of these had a phenomenal effect on the Murray–Darling system. The 1870 floods followed drought type conditions and it is remarkable that it was worse in many ways than the 1956 event which followed flood conditions in the MDB during the previous year. The events in 1870 caused much loss of life from drowning in the MDB in particular froman east coast low (ECL) in April 1870 and two Victorian weather systems in September and October 1870. In 1956, there were also record-breaking events especially during March when all-time record monthly rainfall were reported in New South Wales. Overall the greatest impact from flooding across the whole MDB was associated with the 1870 flooding. Analyses of heavy rainfall areas in the MDB showed a linear trend increase from 1900 to 2018. Analysing the same data using an 8-year moving average highlighted three peaks around the five highest annual rainfall years. The largest peak occurred around 1950 and 1956, the second largest around 1973 and 1974 and the third around 2010. Each of these 5 years occurred during negative phases of the Interdecadal Pacific Oscillation (IPO) and positive phases of the Southern Oscillation Index (SOI). Studies have shown that the SOI is a climate driver in the MDB along with a persistent blocking high-pressure systems south of Australia along longitude 140°E with a low to its north. Three major blocking events with record rainfall and flooding in the MDB occurred in 1983, 1984 and 1990. Thiswas during the period 1977–1990 when blocking was conducive to heavy rain in the MDB and was coincidentwith a positive phase of the IPO, thus helping conflictwith the IPO–MDB heavy rainfall relationship. Persistent and unexplained middle level westerly winds kept subtropical Queensland clear of tropical cyclones during the negative phases of the IPO from 1999 to 2009 and during the 1960s, influencing low rainfall in the MDB during those periods.

scholarly journals Impacts of Triple Factors on Flash Flood Vulnerability in Egypt: Urban Growth, Extreme Climate, and Mismanagement

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 24 ◽  
Author(s):  
Mohamed Saber ◽  
Karim I. Abdrabo ◽  
Omar M. Habiba ◽  
Sameh A. Kantosh ◽  
Tetsuya Sumi
Keyword(s):  
Urban Growth ◽  
Flash Flood ◽  
Integrated Approach ◽  
Annual Rainfall ◽  
Flood Hazards ◽  
Hazard Maps ◽  
Flood Vulnerability ◽  
Rainfall Analysis ◽  
Climatic Regions ◽  
Extreme Climate

Urban growth, extreme climate, and mismanagement are crucial controlling factors that affect flood vulnerability at wadi catchments. Therefore, this study attempts to understand the impacts of these three factors on the flash flood vulnerability in different climatic regions in Egypt. An integrated approach is presented to evaluate the urban growth from 1984 to 2019 by using Google Images and SENTINEL-2 data, and to develop hazard maps by using a rainfall-runoff-inundation model (RRI). Annual rainfall trend analysis was performed to evaluate the temporal variability trend. The hazard maps that were created were classified into three categories (low, medium, and high) and integrated with the urban growth maps to evaluate the impacts on the flood-vulnerable areas. The results show a significant increase in urban growth resulting in an increase of prone areas for flood hazards over time. However, the degree of this hazard is mainly related to growth directions. Mismanagement affects urban growth directions in both planned and unplanned growth, whether by loss of control over unplanned growth or by deficiencies in approved plans. The rainfall analysis showed that there is no explicit relationship to increases or decreases in the flood vulnerable areas. An urban planning approach is recommended for risk reduction management based on a comprehensive study considering such factors.

scholarly journals Uncertainty in Estimated Trends Using Gridded Rainfall Data: A Case Study of Bangladesh

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 349 ◽  
Author(s):  
Mohamed Salem Nashwan ◽  
Shamsuddin Shahid ◽  
Xiaojun Wang
Keyword(s):  
Spatial Patterns ◽  
Similarity Index ◽  
Skill Score ◽  
Rainfall Data ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Global Precipitation Climatology Centre ◽  
Rainfall Trends ◽  
Grid Points

This study assessed the uncertainty in the spatial pattern of rainfall trends in six widely used monthly gridded rainfall datasets for 1979–2010. Bangladesh is considered as the case study area where changes in rainfall are the highest concern due to global warming-induced climate change. The evaluation was based on the ability of the gridded data to estimate the spatial patterns of the magnitude and significance of annual and seasonal rainfall trends estimated using Mann–Kendall (MK) and modified MK (mMK) tests at 34 gauges. A set of statistical indices including Kling–Gupta efficiency, modified index of agreement (md), skill score (SS), and Jaccard similarity index (JSI) were used. The results showed a large variation in the spatial patterns of rainfall trends obtained using different gridded datasets. Global Precipitation Climatology Centre (GPCC) data was found to be the most suitable rainfall data for the assessment of annual and seasonal rainfall trends in Bangladesh which showed a JSI, md, and SS of 22%, 0.61, and 0.73, respectively, when compared with the observed annual trend. Assessment of long-term trend in rainfall (1901–2017) using mMK test revealed no change in annual rainfall and changes in seasonal rainfall only at a few grid points in Bangladesh over the last century.

scholarly journals Rainfall Analysis of Vrishabhavathi Valley in Bengaluru Region

2019 ◽  
Vol 8 (4) ◽  
pp. 9287-9290
Keyword(s):  
Heavy Rainfall ◽  
Prediction Models ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Rapid Urbanization ◽  
Flood Prediction ◽  
Rainfall Analysis ◽  
North East ◽  
South West ◽  
South West Monsoon

Vrishabhavathi valley is a part of river Arkavathi. It covers parts of Bengaluru Urban and Ramanagara districts with an area of 381.46 sq. kms. Due to rapid urbanization in Bengaluru lot of pervious strata is converted into non-pervious concrete or asphalt surfaces. Rainfall is a major event, which is resulting flood in Bengaluru city. Recently observed heavy rainfall, rapid urbanization, encroachment of streams and water bodies are the major causes of flooding in Bengaluru. Disturbance to human activities and damages to properties has been observed in Vrishabhavathi valley region due to heavy rainfall especially in heavy rain events. Rainfall data analysis has been carried out statistically and graphically on Vrishabhavathi valley from 1970 to 2018. Rainfall analysis was made on converting daily rainfall data to monthly average data and seasonal analysis of rainfall has made for three different monsoon seasons Pre- monsoon, South- West and North- East monsoon, distribution and frequency of rainfall has been analyzed and results are represented graphically. From the annual rainfall study it is observed that less rainfall variations till 1990 and rainfall pattern seem to be increasing constantly from 1990’s onwards till 2018, particularly in the months of August, September and October. The rainfall contribution during south-west monsoon is almost equal to 50% of total annual rainfall. Rainfall analysis is essential to develop appropriate flood prediction models utilizing latest rainfall data collected (KSNDMC Telemetric station data) and available geospatial data to address the issues of urban flood observed in many locations in Vrishabhavathi valley region and in Bengaluru.

scholarly journals Long term rainfall trend over meteorological sub divisions and districts of India

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 439-450
Author(s):  
SURINDER KAUR ◽  
SUMANT KUMAR DIWAKAR ◽  
ASHOK KUMAR DAS
Keyword(s):  
Uttar Pradesh ◽  
Kendall Test ◽  
Rainfall Data ◽  
Annual Rainfall ◽  
Positive Trend ◽  
Rainfall Analysis ◽  
Increasing Trend ◽  
Long Term Trend ◽  
Agriculture Water

In this paper the long term trend of annual and seasonal rainfall over different districts, Meteorological (Met.) sub-divisions and whole India have been studied using the long term rainfall data for the period from 1901 to 2013. The changes in amount and pattern of rainfall have a significant impact on agriculture, water resources management and overall economy of the country. Mann-Kendall test is applied to check the significance of the trend. Linear Regression and Theil-Sen’s non parametric test has been applied to estimate the trend. The study is carried out for 632 districts and 34 sub divisions of India by utilizing the gridded rainfall data (0.25° × 0.25°) over the main land except Andaman & Nicobar and Lakshadweep islands. Many authors have studied that extreme events are increasing but there is no trend in Pan India’s rainfall. It is observed from the annual rainfall analysis 10% of the number of districts are showing significant increasing trend and 13% significant decreasing (mainly in Uttar Pradesh) trend whereas irrespective of high and low rainfall regions, 10% area of the country is showing significant increasing trend and 8% of the area of the country showing significant decreasing trend in annual rainfall. In Meteorological Sub divisions, east & west UP are showing significant negative trend and some of the coastal sub divisions are showing positive trend. It is also observed that the country’s rainfall is not showing any trend.

scholarly journals DAMPAK VARIABILITAS IKLIM MUSIMAN PADA PRODUKSI PADI SAWAH TADAH HUJAN DI PULAU LOMBOK (IMPACT OF INTERANNUAL CLIMATE VARIABILITY ON RAINFED PADDY PRODUCTION IN LOMBOK ISLAND)

Agromet ◽  
2006 ◽  
Vol 20 (2) ◽  
pp. 38
Author(s):  
I. Yasin ◽  
M. Ma'shum
Keyword(s):  
Agricultural Land ◽  
Rainfall Variability ◽  
Storage System ◽  
Cropping System ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Rain Event ◽  
Rainfall Characteristics ◽  
Rainfall Variation ◽  
Wide Range

<p>Variability of inter-anuual rainfall has great impact on agricultural production. The inter-annual rainfall variability mainly causes cropping and harvest failure in rainfed land due to drought and flood. Although the onset of season is usully known, the characteristic of in coming rainfall is usually not predictable. Thus the understanding of the cause of rainfall variability may lead to establishment of new system to forecast seasonal rainfall characteristics. The aims of this research are to study water availibity for dry direct seeding rice by considering water balance in southern Lombok and understanding the relationship between ENSO phenomena with rain event in Lombok as well using SOI for predicting seasonal rainfall events. The results of this research showed that average rainfall in southern Lombok is 1450 mm with 950 mm the lowest and 2460 the highest. Southern Lombok has three water surplus months (with rainfall >200 mm), and 5 to 6 water deficit months (with less than 100 mm rainfall).. Inter annual rainfall variation is closely correlated to ENSO phenomena where the rainfall tend to be obove normal in La Niña years and below normal in El Niño years. The short term wet months and wide range of rainfall varibility lead to the need to establishment of water storage system and the application of water and cropping management which suitable to rainfall characteristics and local environmental conditions. The use of ENSO and SOI value to forecast seasonal rain events may be suitable and may reduce the risks of cropping system in rainfed agricultural land.</p>

scholarly journals Statistical analysis of seasonal rainfall data in Chandigarh: A case study

2021 ◽  
Vol 889 (1) ◽  
pp. 012024
Author(s):  
Kaamun ◽  
Sahil Arora
Keyword(s):  
Statistical Analysis ◽  
Goodness Of Fit ◽  
Seasonal Forecast ◽  
Rainfall Data ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Maximum Rainfall ◽  
The Past

Abstract The following research focuses on Chandigarh’s annual rainfall of past 50 years i.e. from 1968 to 2017. Parameters like Kurtosis, Variance, Goodness of Fit, Mann-Kendall’s Test were performed along with total annual forecast as well as seasonal forecast was predicted. Seasonal rend was also studied so as to study in detail about the past, present, and future of rainfall in Chandigarh. This study was performed with the help of MS-Excel and ExcelStat. A rising trend was found in Chandigarh for total as well as seasonal rainfall with a maximum rainfall of 1510.9 mm in the year of 1996 and a minimum of 371.1 mm in year 1987, other than this Sen.’s slope was 6.431 whereas skewness was found to be 0.6018.

scholarly journals Monitoring Water Resources over the Kotmale Reservoir in Sri Lanka Using ENSO Phases

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Sewwandhi Chandrasekara ◽  
Venkatraman Prasanna ◽  
Hyun-Han Kwon
Keyword(s):  
Sri Lanka ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Southern Oscillation ◽  
Daily Rainfall ◽  
Sea Surface ◽  
Seasonal Rainfall ◽  
Annual Rainfall ◽  
Average Rainfall ◽  
Enso Phases

In this study, the El Nino Southern Oscillation (ENSO) phase index is used for water management over the Kotmale reservoir in Sri Lanka. Daily rainfall data of 9 stations over the Kotmale catchment during 1960–2005 June-September (JJAS) season is investigated over the Kotmale catchment. The ENSO phases are identified based on the 0.5°C sea surface temperature (SST) anomaly over Nino 3 region. The study has brought out few stations showing increasing and a few decreasing seasonal rainfall trends for JJAS season, while there is no change in the annual rainfall for the catchment. Monthly and seasonal rainfall of all the selected stations showed negative correlation with the sea surface temperature (SST) over the Nino-3 region index during JJAS season with varying magnitudes. During the warm phase of ENSO, below average rainfall is prominent for JJAS season over many stations. The rainfall especially during early September showed a significant below average rainfall during the warm ENSO phase. The seasonal rainfall during neutral and cold ENSO phases does not experience similar significant changes as seen during warm ENSO phase. Inflow of the Kotmale reservoir shows decreasing trend for the period of 1960–2005 in the observation from all stations collectively.

CORRELATION BETWEEN RAINFALL PATTERN AND OIL PALM PERFORMANCE IN SUMATRA AND BORNEO ISLAND DURING EL NIÑO 2015

2018 ◽  
Vol 24 (2) ◽  
pp. 87-96
Author(s):  
Iput Pradiko ◽  
Eko Novandy Ginting ◽  
Nuzul Hijri Darlan ◽  
Winarna Winarna ◽  
Hasril Hasan Siregar
Keyword(s):  
Oil Palm ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Pearson Correlation ◽  
Rainfall Data ◽  
Rainfall Pattern ◽  
Dry Spell ◽  
Male Flowers ◽  
Central South

El Niño 2015 is one of the strongest El Niño. Drought stress due to El Niño could affect oil palm performances. This study was conducted to determine rainfall pattern and oil palm performance in Sumatra and Borneo Island during El Niño 2015. Data employed in this study is monthly rainfall data, Southern Oscillation Index (SOI) January-December 2015, andoil palm performances. Pearson correlation between SOI and rainfall data was used to analyze rainfall pattern, while oil palm performances were observed based on morphological conditions. Result shows that southern part of Sumatra and mostly part of Borneo suffer from more dry spell, dry month, and water deficit such as 37-133 days, 3-5 months, and 349-524 mm respectively. Analysis of rainfall pattern shows that Jambi, South Sumatra, Lampung, Central, South, and East Borneo are significantly (r ≥ +0,60) affected by El Niño 2015. Oil palms in southern part of Sumatra and mostly part of Borneo are suffer from drought stressmarked by the emergence of more than two spear fronds, appearing of many male flowers, malformations on bunches, fronds tend to hanging down, and lower fronds tend to dry.

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