Simulated changes in daily rainfall intensity due to the enhanced greenhouse effect: implications for extreme rainfall events

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.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.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.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.

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Variability and trends in extreme rainfall over India

MAUSAM ◽

10.54302/mausam.v67i4.1406 ◽

2021 ◽

Vol 67 (4) ◽

pp. 745-766

Author(s):

A. K. SRIVASTAVA ◽

G. P. SINGH ◽

O. P. SINGH

Keyword(s):

Rainfall Intensity ◽

Monsoon Season ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Extreme Rainfall Events ◽

North Central ◽

Rainfall Events ◽

North West ◽

North East ◽

Increasing Trends

This study has been attempted to investigate the seasonal and annual trends and variations in the occurrence of extreme rainfall over different Indian region and India as a whole. Trends and variations are examined on the basis of following parameters (i) frequency and magnitude of extreme rainfall intensity (ERI) and its contribution in total rainfall (ii) highest rainfall events (iii) frequency of extreme rainfall events and days (iv) frequency of rainfall events and days with daily rainfall above 100 mm and 200 mm in a grid box (1° × 1°) over different Indian regions and India as a whole. Daily gridded rainfall data from India Meteorological Department (IMD) available at 1° × 1° resolution has been used to examine trends and variations associated with extreme rainfall events. Based on the long term 95 and 99 percentile values of daily total /maximum rainfall as a threshold for extreme rainfall intensity/events of category 1 and category 2 respectively, the trends and variations in above mentioned parameters are analyzed for the periods 1951-2007, 1951-1980 and 1981-2007. The magnitude of highest intensity rainfall is increased over country as a whole and over peninsular India; it is found to be increased by 1% during 1981-2007 as compared to period 1951-1980. The frequency of extreme rainfall intensity (ERI) days of category 1 is found to be significant increasing (0.4 days/decade) over north central region and significant decreasing trend is found over north east region (0.5 days/decade) during the pre-monsoon season. The magnitude of 24 hours highest rainfall in a grid box is found to be significant increasing over all regions under consideration except over north east and south peninsular regions. Over the last ten years period of the present study, most of the 24 hours highest rainfall events in a grid box are seen over west peninsular region. Generalized extreme value (GEV) distribution fitted with annual highest rainfall event over the country as a whole and over different Indian region indicates an increase in magnitude of most probable 24 hours highest rainfall in a grid box during second half of the study period over north central region of the country. Analysis also reveals an increase in frequency and severity of extreme rainfall over north west, north central and west peninsular regions during the period of 1981-2007 as compared to 1950-1980. Annual frequency of days and events with extreme rainfall of both categories is increased most significantly over country during the period of present study (1951-2007). Significant increasing trends in frequency of days with extreme rainfall of both categories is noticed only during the monsoon season while extreme rainfall events showed increasing trends during monsoon and winter season over country as a whole. Number of days and events with daily rainfall in any grid box above 100 mm and 200 mm is observed to be significantly increased over the country. Out of six regions, significant increasing trends in annual number of days with rainfall above 100 mm in a grid box is observed over north central and north east regions and for rainfall above 200 mm significant increase is observed over north west and north central regions.

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The Influence of Geographical Factors on Extreme Rainfalls in Lampung Province

Journal of Engineering and Scientific Research ◽

10.23960/jesr.v1i1.7 ◽

2019 ◽

Vol 1 (1) ◽

pp. 33

Author(s):

M Welly

Keyword(s):

Geographical Location ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Design Flood ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Ungauged Basin ◽

Flood Discharge ◽

Design Rainfall ◽

Geographical Factors

Many people in Indonesia calculate design rainfall before calculating the design flooddischarge. The design rainfall with a certain return period will eventually be convertedinto a design flood discharge by combining it with the characteristics of the watershed.However, the lack of a network of rainfall recording stations makes many areas that arenot hydrologically measured (ungauged basin), so it is quite difficult to know thecharacteristics of rain in the area concerned. This study aims to analyze thecharacteristics of design rainfall in Lampung Province. The focus of the analysis is toinvestigate whether geographical factors influence the design rainfall that occurs in theparticular area. The data used in this study is daily rainfall data from 15 rainfallrecording stations spread in Lampung Province. The method of frequency analysis usedin this study is the Gumbel method. The research shows that the geographical location ofan area does not have significant effect on extreme rainfall events. The effect of risingearth temperatures due to natural exploitation by humans tends to be stronger as a causeof extreme events such as extreme rainfall.Keywords: Influence, geographical, factors, extreme, rainfall.

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Correction to “Analysis of variability and trends of extreme rainfall events over India using 104 years of gridded daily rainfall data”

Geophysical Research Letters ◽

10.1029/2008gl036105 ◽

2008 ◽

Vol 35 (23) ◽

Cited By ~ 10

Author(s):

M. Rajeevan ◽

Jyoti Bhate ◽

A. K. Jaswal

Keyword(s):

Daily Rainfall ◽

Extreme Rainfall ◽

Rainfall Data ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Daily Rainfall Data

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TRMM rainfall estimative coupled with Bell (1969) methodology for extreme rainfall characterization

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-369-163-2015 ◽

2015 ◽

Vol 369 ◽

pp. 163-168 ◽

Cited By ~ 4

Author(s):

E. Schiavo Bernardi ◽

D. Allasia ◽

R. Basso ◽

P. Freitas Ferreira ◽

R. Tassi

Keyword(s):

Temporal Distribution ◽

Daily Rainfall ◽

Tropical Rainfall Measuring Mission ◽

Extreme Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Remote Sensors ◽

Indirect Measures ◽

Equation Error ◽

Convective Cells

Abstract. The lack of rainfall data in Brazil, and, in particular, in Rio Grande do Sul State (RS), hinders the understanding of the spatial and temporal distribution of rainfall, especially in the case of the more complex extreme events. In this context, rainfall's estimation from remote sensors is seen as alternative to the scarcity of rainfall gauges. However, as they are indirect measures, such estimates needs validation. This paper aims to verify the applicability of the Tropical Rainfall Measuring Mission (TRMM) satellite information for extreme rainfall determination in RS. The analysis was accomplished at different temporal scales that ranged from 5 min to daily rainfall while spatial distribution of rainfall was investigated by means of regionalization. An initial test verified TRMM rainfall estimative against measured rainfall at gauges for 1998–2013 period considering different durations and return periods (RP). Results indicated that, for the RP of 2, 5, 10 and 15 years, TRMM overestimated on average 24.7% daily rainfall. As TRMM minimum time-steps is 3 h, in order to verify shorter duration rainfall, the TRMM data were adapted to fit Bell's (1969) generalized IDF formula (based on the existence of similarity between the mechanisms of extreme rainfall events as they are associated to convective cells). Bell`s equation error against measured precipitation was around 5–10%, which varied based on location, RP and duration while the coupled BELL+TRMM error was around 10–35%. However, errors were regionally distributed, allowing a correction to be implemented that reduced by half these values. These findings in turn permitted the use of TRMM+Bell estimates to improve the understanding of spatiotemporal distribution of extreme hydrological rainfall events.

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Application for Terrestrial LiDAR on Mudstone Erosion Caused by Typhoons

Remote Sensing ◽

10.3390/rs11202425 ◽

2019 ◽

Vol 11 (20) ◽

pp. 2425 ◽

Cited By ~ 2

Author(s):

Yeuan-Chang Cheng ◽

Ci-Jian Yang ◽

Jiun-Chuan Lin

Keyword(s):

Erosion Rate ◽

Rainfall Intensity ◽

Extreme Rainfall ◽

Dry Period ◽

Erosion And Deposition ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Terrestrial Lidar ◽

High Gradients ◽

Scanning Lidar

Storms are important agents for shaping the Earth’s surface and often dominate the landscape evolution of mudstone areas, by rapid erosion and deposition. In our research, we used terrestrial scanning LiDAR (TLS) to detect surface changes in a 30 m in height, 60 m in width mudstone slope. This target slope shows the specific erosion pattern during extreme rainfall events such as typhoons. We investigate two major subjects: (1) how typhoon events impact erosion in the target slope, and (2) how rills develop on the hillslopes during these observation periods. There were three scans obtained in 2011, and converted to two observation periods. The permanent target points (TP) method and DEMs of differences were used to check the accuracy of point cloud. The results showed that the average erosion rate was 5 cm during the dry period in 2011. Following the typhoons, the erosion rate increased 1.4 times to 7 cm and was better correlated with the increase in the rainfall intensity than with general precipitation amounts. The hillslope gradient combined with rainfall intensity played a significant role in the geomorphic process. We found that in areas with over 75° gradients with larger rainfall intensity showed more erosion that at other gradients. The gradient also influenced the rill development, which occurred at middle and low gradients but not at high gradients. The rills also created a transition zone for erosion and deposition at the middle gradient where a minimal change occurred.

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Extreme rainfall and drought events in Tamil Nadu, India

Climate Research ◽

10.3354/cr01600 ◽

2020 ◽

Vol 80 (3) ◽

pp. 175-188

Author(s):

R Rajkumar ◽

CS Shaijumon ◽

B Gopakumar ◽

D Gopalakrishnan

Keyword(s):

Tamil Nadu ◽

Daily Rainfall ◽

India Meteorological Department ◽

Extreme Rainfall ◽

Drought Severity ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Significance Level ◽

Spatio Temporal ◽

Temporal Dimensions

In the present study, we examined the exposure of the Tamil Nadu region, India, to droughts and extreme rainfall events using the Standardised Precipitation Evapotranspiration Index (SPEI) and a classification scheme based on daily rainfall. We used high-resolution temperature and rainfall observations from the India Meteorological Department for the period 1951-2016. The robustness of the results was tested using the Mann-Kendall trend (M-K) test and the Kolmogorov-Smirnov (K-S) test. During the study period, there were statistically significant increasing trends in drought area (90% significance level), maximum drought intensity (99% significance level) and maximum drought severity (99% significance level) over the Tamil Nadu region. There has also been an increase in the frequency and intensity of heavy rainfall events in recent years. The spatio-temporal dimensions of this study suggest an increasing exposure of this semi-arid, rain shadow region to severe droughts and extreme rainfall events in recent decades. The results provide sufficient grounds to substantiate the necessity of immediate interventions at the policy level.

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The impact of atmospheric rivers on rainfall in New Zealand

Scientific Reports ◽

10.1038/s41598-021-85297-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jingxiang Shu ◽

Asaad Y. Shamseldin ◽

Evan Weller

Keyword(s):

New Zealand ◽

Austral Summer ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Detection Algorithm ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Atmospheric Rivers ◽

Hydrological Hazards ◽

The Impact

AbstractThis study quantifies the impact of atmospheric rivers (ARs) on rainfall in New Zealand. Using an automated AR detection algorithm, daily rainfall records from 654 rain gauges, and various atmospheric reanalysis datasets, we investigate the climatology of ARs, the characteristics of landfalling ARs, the contribution of ARs to annual and seasonal rainfall totals, and extreme rainfall events between 1979 and 2018 across the country. Results indicate that these filamentary synoptic features play an essential role in regional water resources and are responsible for many extreme rainfall events on the western side of mountainous areas and northern New Zealand. In these regions, depending on the season, 40–86% of the rainfall totals and 50–98% of extreme rainfall events are shown to be associated with ARs, with the largest contributions predominantly occurring during the austral summer. Furthermore, the median daily rainfall associated with ARs is 2–3 times than that associated with other storms. The results of this study extend the knowledge on the critical roles of ARs on hydrology and highlight the need for further investigation on the landfalling AR physical processes in relation to global circulation features and AR sources, and hydrological hazards caused by ARs in New Zealand.

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ANALYSIS OF EXTREME RAINFALL INDICES IN PENINSULAR MALAYSIA

Jurnal Teknologi ◽

10.11113/jt.v78.9677 ◽

2016 ◽

Vol 78 (9-4) ◽

Cited By ~ 2

Author(s):

Nur Shazwani Muhammad ◽

Amieroul Iefwat Akashah ◽

Jazuri Abdullah

Keyword(s):

East Coast ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Peninsular Malaysia ◽

Rainfall Data ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Daily Rainfall Data ◽

Extreme Rain ◽

Increasing Trends

Extreme rainfall events are the main cause of flooding. This study aimed to examine seven extreme rainfall indices, i.e. extreme rain sum (XRS), very wet day intensity (I95), extremely wet day intensity (I99), very wet day proportion (R95), extremely wet day proportion (R99), very wet days (N95) and extremely wet days (N99) using Mann-Kendall (MK) and the normalized statistic Z tests. The analyses are based on the daily rainfall data gathered from Bayan Lepas, Subang, Senai, Kuantan and Kota Bharu. The east coast states received more rainfall than any other parts in Peninsular Malaysia. Kota Bharu station recorded the highest XRS, i.e. 648 mm. The analyses also indicate that the stations in the eastern part of Peninsular Malaysia experienced higher XRS, I95, I99, R95 and R99 as compared to the stations located in the western and northern part of Peninsular Malaysia. Subang and Senai show the highest number of days for wet and very wet (N95) as compared to other stations. Other than that, all stations except for Kota Bharu show increasing trends for most of the extreme rainfall indices. Upward trends indicate that the extreme rainfall events were becoming more severe over the period of 1960 to 2014.

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Extreme Daily Rainfall in Central-Southern Chile and Its Relationship with Low-Level Horizontal Water Vapor Fluxes

Journal of Hydrometeorology ◽

10.1175/jhm-d-19-0036.1 ◽

2019 ◽

Vol 20 (9) ◽

pp. 1829-1850 ◽

Cited By ~ 6

Author(s):

Raúl A. Valenzuela ◽

René D. Garreaud

Keyword(s):

Water Vapor ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Southern Chile ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Rain Gauges ◽

The Andes ◽

Synoptic Forcing ◽

Moisture Fluxes

AbstractExtreme rainfall events are thought to be one of the major threats of climate change given an increase of water vapor available in the atmosphere. However, before projecting future changes in extreme rainfall events, it is mandatory to know current patterns. In this study we explore extreme daily rainfall events along central-southern Chile with emphasis in their spatial distribution and concurrent synoptic-scale circulation. Surface rain gauges and reanalysis products from the Climate Forecast System Reanalysis are employed to unravel the dependency between extreme rainfall and horizontal water vapor fluxes. Results indicate that extreme rainfall events can occur everywhere, from the subtropical to extratropical latitudes, but their frequency increases where terrain has higher altitude, especially over the Andes Mountains. The majority of these events concentrate in austral winter, last a single day, and encompass a north–south band of about 200 km in length. Composited synoptic analyses identified extreme rainfall cases dominated by northwesterly (NW) and westerly (W) moisture fluxes. Some features of the NW group include a 300-hPa trough projecting from the extratropics to subtropics, a surface-level depression, and cyclonic winds at 850 hPa along the coast associated with integrated water vapor (IWV) > 30 mm. Conversely, features in the W group include both a very weak 300-hPa trough and surface depression, as well as coastal westerly winds associated with IWV > 30 mm. About half of extreme daily rainfall is associated with an atmospheric river. Extreme rainfall observed in W (NW) cases has a strong orographic (synoptic) forcing. In addition, W cases are, on average, warmer than NW cases, leading to an amplified hydrological response.

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