Export, biodegradation, and disinfection byproduct formation of dissolved and particulate organic carbon in a forested headwater stream during extreme rainfall events

Abstract. Despite an increasing recognition of the importance of extreme rainfall events for organic carbon export to inland waters, little attention has been paid to the export and reactivity of particulate organic carbon (POC) and dissolved organic C (DOC) in mountainous headwater watersheds under monsoon climates. To investigate environmental implications of storm-enhanced export of POC and DOC in mountainous headwater streams, we examined the relationships between storm magnitude and C export from a forested watershed in the Haean Basin, South Korea, during 13 storm events over 4 years and compared potentials of DOC and POC for biodegradation and disinfection byproduct (DBP) formation during an extreme rainfall event with a total rainfall of 209 mm. Event mean concentrations and export of POC increased nonlinearly above thresholds of precipitation and discharge, far exceeding the relatively small increases of DOC. The export of POC during a few storm events with a total rainfall above 200 mm per event exceeded the annual organic C export during dry years. During the 209 mm storm event, concentrations of total trihalomethanes formed by POC-derived dissolved components changed synchronously with POC concentrations, exhibiting lower levels than those formed by DOC. During a 30-day incubation at 25 °C, DOC exported during peak flow exhibited rapid biodegradation of labile components within 7 days. In contrast, the concentrations of DOC leached from POC gradually increased following the initial decline. Gradual transformation of POC-derived dissolved materials resulted in greater increases in the intensity of fulvic- and humic-like fluorescent components compared to the DOC treatment. The results highlight the significance of extreme rainfall events as "hot moments" for POC export from mountainous watersheds and also suggest that storm pulses of POC can provide potential sources of reactive organic components that can rapidly biodegrade and form DBPs after being released into headwater streams.

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Storm pulses of particulate and dissolved organic carbon in a forested headwater stream and their environmental implications – importance of extreme rainfall events

Biogeosciences Discussions ◽

10.5194/bgd-11-6877-2014 ◽

2014 ◽

Vol 11 (5) ◽

pp. 6877-6908 ◽

Cited By ~ 1

Author(s):

B.-J. Jung ◽

J.-K. Lee ◽

H. Kim ◽

J.-H. Park

Keyword(s):

Organic Carbon ◽

Extreme Rainfall ◽

Headwater Stream ◽

Storm Event ◽

Extreme Rainfall Event ◽

Storm Events ◽

Environmental Implications ◽

Extreme Rainfall Events ◽

Organic C ◽

Rainfall Events

Abstract. Despite recent debates on erosion-enhanced sinks of CO2 and contrasting findings on the biodegradation of recalcitrant organic materials in large rivers, little attention has been paid to the export and transformations of particulate organic carbon (POC) and dissolved organic C (DOC) in mountainous headwater watersheds under monsoon climates. To comparatively evaluate the significance of heavy monsoon rainfalls for the magnitude and environmental implications of storm-enhanced export of POC and DOC, the relationships between storm magnitude and C export were examined in a mountainous, forested headwater stream in the Haean Basin, South Korea, during 50 storm events over the 4 year monitoring period. We also compared biodegradation and disinfection byproduct (DBP) formation potentials of the DOC and POC exported during an extreme rainfall event. Event mean concentrations and export of POC increased nonlinearly above thresholds of precipitation and discharge, significantly exceeding the increases of DOC. The export of POC during a few storm events with a total rainfall above 200 mm per event exceeded the annual organic C export during dry years. During the large storm event (209 mm), concentrations of total trihalomethanes formed by POC-derived dissolved components changed synchronously with POC concentrations, exhibiting lower levels than those formed by DOC. During a 30 day incubation at 25 °C, both DOC and POC exported during peak flow initially exhibited rapid biodegradation of labile components, whereas POC-derived materials increased continuously not only DOC concentrations, but also fulvic- and humic-like fluorescent components. These results highlight the significance of extreme rainfall events as "hot moments" for POC export and also suggest that storm pulses of POC can provide potential sources of labile DOC components that can rapidly biodegrade and form DBPs in headwater streams, contrasting with other studies assuming mountainous rivers as a passive conduit of organic C.

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Rainfall Trends and Extremes in Saudi Arabia in Recent Decades

Atmosphere ◽

10.3390/atmos11090964 ◽

2020 ◽

Vol 11 (9) ◽

pp. 964 ◽

Cited By ~ 1

Author(s):

Mansour Almazroui

Keyword(s):

Saudi Arabia ◽

Extreme Events ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Annual Rainfall ◽

Economic Damage ◽

Total Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Rainfall Trends

The observed records of recent decades show increased economic damage associated with flash flooding in different regions of Saudi Arabia. An increase in extreme rainfall events may cause severe repercussions for the socio-economic sectors of the country. The present study investigated the observed rainfall trends and associated extremes over Saudi Arabia for the 42-year period of 1978–2019. It measured the contribution of extreme events to the total rainfall and calculated the changes to mean and extreme rainfall events over five different climate regions of Saudi Arabia. Rainfall indices were constructed by estimating the extreme characteristics associated with daily rainfall frequency and intensity. The analysis reveals that the annual rainfall is decreasing (5.89 mm decade−1, significant at the 90% level) over Saudi Arabia for the entire analysis period, while it increased in the most recent decade. On a monthly scale, the most significant increase (5.44 mm decade−1) is observed in November and the largest decrease (1.20 mm decade−1) in January. The frequency of intense rainfall events is increasing for the majority of stations over Saudi Arabia, while the frequency of weak events is decreasing. More extreme rainfall events are occurring in the northwest, east, and southwest regions of Saudi Arabia. A daily rainfall of ≥ 26 mm is identified as the threshold for an extreme event. It is found that the contribution of extreme events to the total rainfall amount varies from region to region and season to season. The most considerable contribution (up to 56%) is found in the southern region in June. Regionally, significant contribution comes from the coastal region, where extreme events contribute, on average, 47% of the total rainfall each month from October to February, with the largest (53%) in November. For the entire country, extreme rainfall contributes most (52%) in November and least (20%) in July, while contributions from different stations are in the 8–50% range of the total rainfall.

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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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CLIMATOLOGY OF EXTREME RAINFALL EVENTS IN EASTERN AND NORTHERN SANTA CATARINA STATE, BRAZIL: PRESENT AND FUTURE CLIMATE

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v31i3.314 ◽

2013 ◽

Vol 31 (3) ◽

pp. 413 ◽

Cited By ~ 3

Author(s):

André Becker Nunes ◽

Gilson Carlos Da Silva

Keyword(s):

Climate Model ◽

Climate Modeling ◽

Linear Trend ◽

Extreme Rainfall ◽

Eastern Region ◽

Santa Catarina ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

History Of ◽

Santa Catarina State

ABSTRACT. The eastern region of Santa Catarina State (Brazil) has an important history of natural disasters due to extreme rainfall events. Floods and landslides are enhancedby local features such as orography and urbanization: the replacement of natural surface coverage causing more surface runoff and, hence, ﬂooding. Thus, studies of this type of events – which directly inﬂuence life in the towns – take on increasing importance. This work makes a quantitative analysis of occurrences of extreme rainfall events in the eastern and northern regions of Santa Catarina State in the last 60 years, through individual analysis, considering the history of ﬂoods ineach selected town, as well as an estimate through to the end of century following regional climate modeling. A positive linear trend, in most of the towns studied, was observed in the results, indicating greater frequency of these events in recent decades, and the HadRM3P climate model shows a heterogeneous increase of events for all towns in the period from 2071 to 2100.Keywords: ﬂoods, climate modeling, linear trend. RESUMO. A região leste do Estado de Santa Catarina tem um importante histórico de desastres naturais ocasionados por eventos extremos de precipitação. Inundações e deslizamentos de terra são potencializados pelo relevo acidentado e pela urbanização das cidades da região: a vegetação nativa vem sendo removida acarretando um maior escoamento superﬁcial e, consequentemente, em inundações. Desta forma, torna-se de suma importância os estudos acerca deste tipo de evento que inﬂuencia diretamente a sociedade em geral. Neste trabalho é realizada uma análise quantitativa do número de eventos severos de precipitação ocorridos nas regiões leste e norte de Santa Catarina dos últimos 60 anos, por meio de uma análise pontual, considerandoo histórico de inundações de cada cidade selecionada, além de uma projeção para o ﬁm do século de acordo com modelagem climática regional. Na análise dos resultados observou-se uma tendência linear positiva na maioria das cidades, indicando uma maior frequência deste tipo de evento nas últimas décadas, e o modelo climático HadRM3P mostra um aumento heterogêneo no número de eventos para todas as cidades no período de 2071 a 2100.Palavras-chave: inundações, modelagem climática, tendência linear.

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IDENTIFICATION OF EXTREME RAINFALL EVENTS USING HIGH-RESOLUTION CARBON ISOTOPE MEASUREMENTS ACROSS TREE-RINGS

10.1130/abs/2017am-306100 ◽

2017 ◽

Author(s):

Rose G. Telus ◽

◽

Brian A. Schubert

Keyword(s):

High Resolution ◽

Carbon Isotope ◽

Tree Rings ◽

Extreme Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Isotope Measurements

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Comparing vulnerability and institutional capacities in three Latin American coastal localities in response to extreme rainfall events

Journal of Coastal Conservation ◽

10.1007/s11852-020-00790-4 ◽

2021 ◽

Vol 25 (1) ◽

Author(s):

Arturo Ruiz-Luna ◽

Claudia Martínez-Peralta ◽

Patricia P. B. Eichler ◽

Leonardo R. Teixeira ◽

Montserrat Acosta-Morel ◽

...

Keyword(s):

Latin American ◽

Extreme Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events

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Tropical cyclone contribution to extreme rainfall over southwest Pacific Island nations

Climate Dynamics ◽

10.1007/s00382-021-05680-5 ◽

2021 ◽

Author(s):

Anil Deo ◽

Savin S. Chand ◽

Hamish Ramsay ◽

Neil J. Holbrook ◽

Simon McGree ◽

...

Keyword(s):

Tropical Cyclone ◽

El Niño ◽

El Nino ◽

Extreme Rainfall ◽

Pacific Island ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Southwest Pacific ◽

Inactive Phase ◽

Pacific Island Nations

AbstractSouthwest Pacific nations are among some of the worst impacted and most vulnerable globally in terms of tropical cyclone (TC)-induced flooding and accompanying risks. This study objectively quantifies the fractional contribution of TCs to extreme rainfall (hereafter, TC contributions) in the context of climate variability and change. We show that TC contributions to extreme rainfall are substantially enhanced during active phases of the Madden–Julian Oscillation and by El Niño conditions (particularly over the eastern southwest Pacific region); this enhancement is primarily attributed to increased TC activity during these event periods. There are also indications of increasing intensities of TC-induced extreme rainfall events over the past few decades. A key part of this work involves development of sophisticated Bayesian regression models for individual island nations in order to better understand the synergistic relationships between TC-induced extreme rainfall and combinations of various climatic drivers that modulate the relationship. Such models are found to be very useful for not only assessing probabilities of TC- and non-TC induced extreme rainfall events but also evaluating probabilities of extreme rainfall for cases with different underlying climatic conditions. For example, TC-induced extreme rainfall probability over Samoa can vary from ~ 95 to ~ 75% during a La Niña period, if it coincides with an active or inactive phase of the MJO, and can be reduced to ~ 30% during a combination of El Niño period and inactive phase of the MJO. Several other such cases have been assessed for different island nations, providing information that have potentially important implications for planning and preparing for TC risks in vulnerable Pacific Island nations.

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Trends in the Frequency of Intense Precipitation Events in Southern and Southeastern Brazil during 1960–2004

Journal of Climate ◽

10.1175/2011jcli3511.1 ◽

2011 ◽

Vol 24 (7) ◽

pp. 1913-1921 ◽

Cited By ~ 33

Author(s):

Mateus da Silva Teixeira ◽

Prakki Satyamurty

Keyword(s):

Extreme Rainfall ◽

Southeastern Brazil ◽

Extreme Rainfall Event ◽

Southern Brazil ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Annual Frequency ◽

Long Term Trends ◽

Increasing Trends

Abstract A new approach to define heavy and extreme rainfall events based on cluster analysis and area-average rainfall series is presented. The annual frequency of the heavy and extreme rainfall events is obtained for the southeastern and southern Brazil regions. In the 1960–2004 period, 510 (98) and 466 (77) heavy (extreme) rainfall events are identified in the two regions. Monthly distributions of the events closely follow the monthly climatological rainfall in the two regions. In both regions, annual heavy and extreme rainfall event frequencies present increasing trends in the 45-yr period. However, only in southern Brazil is the trend statistically significant. Although longer time series are necessary to ensure the existence of long-term trends, the positive trends are somewhat alarming since they indicate that climate changes, in terms of rainfall regimes, are possibly under way in Brazil.

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