scholarly journals Large scale and sub-regional connections in the lead up to summer heat wave and extreme rainfall events in eastern Australia

2014 ◽  
Vol 44 (7-8) ◽  
pp. 1823-1840 ◽  
Author(s):  
Ghyslaine Boschat ◽  
Alexandre Pezza ◽  
Ian Simmonds ◽  
Sarah Perkins ◽  
Tim Cowan ◽  
...  
Keyword(s):  
Heat Wave ◽  
Large Scale ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Summer Heat ◽  
Eastern Australia

scholarly journals Impacts of the Madden-Julian Oscillation (MJO) on rainfall in Sri Lanka

MAUSAM ◽  
2021 ◽  
Vol 71 (3) ◽  
pp. 405-422
Author(s):  
JAYAWARDENA I M SHIROMANI PRIYANTHIKA ◽  
WHEELER MATTHEW C ◽  
SUMATHIPALA W L ◽  
BASNAYAKE B R S B
Keyword(s):  
Sri Lanka ◽  
Large Scale ◽  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Southwest Monsoon ◽  
Boreal Winter ◽  
Northeast Monsoon ◽  
Madden Julian Oscillation ◽  
Extreme Rainfall Events ◽  
Rainfall Events

The influence of the Madden Julian Oscillation (MJO) on rainfall in Sri Lanka (SL) is examined based on 30 years of daily station data from 1981-2010. Composites are constructed for each of the eight phases of the MJO defined with the Real-time Multivariate MJO (RMM) index, using daily rainfall data from 44 stations over SL for four climatic seasons and comparing to similar results from a satellite-based rainfall product. Composites of lower tropospheric wind and convective anomaly are also investigated in order to examine how the local rainfall anomalies are associated with large-scale circulations. The greatest impact of the MJO on rainfall over SL occurs in the Second Inter-Monsoon (SIM) and Southwest Monsoon (SWM) seasons. Enhanced rainfall generally occurs over SL during RMM phases 2 and 3 when the MJO convective envelop is located in the Indian Ocean and conversely suppressed rainfall in phases 6 and 7. This rainfall impact is due to the direct influence of the MJO’s tropical convective anomalies and associated low-level circulations in the vicinity of SL. In contrast, the MJO influence during the Northeast Monsoon (NEM) season is slightly less than during the SWM and SIM seasons as a result of the southward shift of the MJO convective envelop during boreal winter. Occurrence of extreme rainfall events is most frequent during phase 2 in First Inter-Monsoon (FIM) phases 2 and 3 in SWM, phases 1, 2 and 3 in SIM and phases 2 and 3 in NEM seasons. The analysis of this study provides a useful reference of when and where the MJO has significant impacts on rainfall as well as extreme rainfall events during four climatic seasons in SL. This information can be used along with accurately predicted MJO phase by dynamical or statistical models, to improve extended range forecasting in SL.

scholarly journals Cross–Time Scale Interactions and Rainfall Extreme Events in Southeastern South America for the Austral Summer. Part I: Potential Predictors

2015 ◽  
Vol 28 (19) ◽  
pp. 7894-7913 ◽  
Author(s):  
Á. G. Muñoz ◽  
L. Goddard ◽  
A. W. Robertson ◽  
Y. Kushnir ◽  
W. Baethgen
Keyword(s):  
South America ◽  
Extreme Events ◽  
Time Scale ◽  
Large Scale ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Rainfall Extreme ◽  
Moisture Advection ◽  
Basic Set

Abstract The physical mechanisms and predictability associated with extreme daily rainfall in southeastern South America (SESA) are investigated for the December–February season in a two-part study. Through a k-mean analysis, this first paper identifies a robust set of daily circulation regimes that are used to link the frequency of rainfall extreme events with large-scale potential predictors at subseasonal-to-seasonal scales. This represents a basic set of daily circulation regimes related to the continental and oceanic phases of the South Atlantic convergence zone (SACZ) and wave train patterns superimposed on the Southern Hemisphere polar jet. Some of these recurrent synoptic circulation types are conducive to extreme rainfall events in the region through synoptic control of different mesoscale physical features and, at the same time, are influenced by climate phenomena that could be used as sources of potential predictability. Extremely high rainfall (as measured by the 95th and 99th percentiles) is associated with two of these weather types (WTs), which are characterized by moisture advection intrusions from lower latitudes and the Pacific Ocean; another three WTs, characterized by above-normal moisture advection toward lower latitudes or the Andes, are associated with dry days (days with no rain). The analysis permits the identification of several subseasonal-to-seasonal scale potential predictors that modulate the occurrence of circulation regimes conducive to extreme rainfall events in SESA. It is conjectured that a cross–time scale interaction between the different climate drivers improves the predictive skill of extreme precipitation in the region.

scholarly journals Documentary evidence of historical floods and extreme rainfall events in Sweden 1400–1800

2015 ◽  
Vol 19 (3) ◽  
pp. 1307-1323 ◽  
Author(s):  
D. Retsö
Keyword(s):  
Large Scale ◽  
18Th Century ◽  
Climatic Factors ◽  
Extreme Rainfall ◽  
Flood Frequency ◽  
Ice Age ◽  
Documentary Evidence ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Atmospheric Circulation Patterns

Abstract. This article explores documentary evidence of floods and extreme rainfall events in Sweden in the pre-instrumental period (1400–1800). The survey shows that two sub-periods can be considered as flood-rich, 1590–1670 and the early 18th century. The result related to a low degree of human impact on hydrology during the period, suggests that climatic factors, such as lower temperatures and increased precipitation connected to the so-called Little Ice Age rather than large-scale atmospheric circulation patterns, should be considered as the main driver behind flood frequency and magnitude.

Installation of blue-green solutions at large scale to mitigate pluvial floods

2020 ◽  
Author(s):  
Elena Cristiano ◽  
Stefano Farris ◽  
Roberto Deidda ◽  
Francesco Viola
Keyword(s):  
Large Scale ◽  
Rainwater Harvesting ◽  
Scale Effects ◽  
Extreme Rainfall ◽  
Green Roofs ◽  
Added Value ◽  
Small Scale ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Harvesting Systems

<p><strong> </strong>The growth of urbanization and the intensification of extreme rainfall events, that has characterized the last century, are leading to an increase of pluvial floods, which are becoming a significant problem in many cities. Among the different solutions proposed and developed to mitigate flood risk in urban areas, green roofs and rainwater harvesting systems have been deeply investigated to reduce the runoff contribution generated from rooftops. These tools have been largely studied at small scale, analysing the flood reduction that can be achieved from one single building or in a small neighbourhood, without considering the large-scale effects. In this work, the potential impact of the installation of green-blue solutions on all the rooftops of a city is evaluated, assuming to place green roofs on flat roofs and rainwater harvesting systems on sloped ones. We investigated nine cities from 5 different countries (Canada, Haiti, United Kingdom, Italy and New Zealand), representing different climatological and geomorphological characteristics. The behaviour of the blue-green solution was estimated with the help of a conceptual lumped ecohydrological model and the mass conservation, using rainfall and temperature time series as climatological input to derive the discharge reduction for different scenarios. Due to the high percentage of sloped roofs in most of the investigated locations, the cost-efficiency analysis highlights that the large-scale installation of rainwater harvesting tanks enables to achieve higher mitigation capacity than green roofs at lower cost. Green roofs, however, present many additional benefits (such as biodiversity contribution, thermal insulation for buildings, pollution reduction and increase of aesthetic added value) that need to be evaluated by urban planners and policy makers. The best achievable performance is given by the coupled system of rainwater harvesting tanks and intensive green roofs: for extreme rainfall events this solution guarantees a discharge reduction up to 20% in most of the cities.</p>

scholarly journals Large-Scale Environmental Conditions Related to Midsummer Extreme Rainfall Events around Japan in the TRMM Region

2018 ◽  
Vol 31 (17) ◽  
pp. 6933-6945 ◽  
Author(s):  
Atsushi Hamada ◽  
Yukari N. Takayabu
Keyword(s):  
Extreme Events ◽  
Environmental Conditions ◽  
Large Scale ◽  
Southern China ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Near Surface ◽  
Rainfall Events ◽  
Precipitation Characteristics ◽  
Large Scale Flow

The precipitation characteristics of extreme events in August determined from 13 years of satellite data around Japan in the TRMM observation region and their relationship with large-scale environmental conditions are examined. Two types of extreme events, extreme rainfall and extreme convective events, are defined in each analysis grid box using maximum near-surface rainfall and maximum 40-dB Z echo-top height in each event, respectively. There are clear differences in precipitation characteristics between the two types of extreme events. Extreme rainfall events are more organized precipitation systems than the extreme convective events, with relatively lower echo-top heights and very low lightning activity. There are also clear differences in the related environmental conditions, where the environments related to the extreme rainfall events are somewhat convectively stable and very humid in almost the entire troposphere. These facts are consistent with our previous studies and reinforce the importance of warm-rain processes in extremely intense precipitation productions. The environments related to the extreme rainfall events exhibit a zonally extended moist anomaly in the free troposphere from southern China to the east of Japan, indicating that the excessive moisture transported from the west by a large-scale flow may partially play a role in producing environmental conditions favorable for extreme rainfall. On the other hand, the environments related to extreme convective events are not associated with free-tropospheric moisture inflow. The relationships with the tropical cyclones and upper-tropospheric dynamical fields are also examined, and are found to be clearly different between the extreme rainfall events and extreme convective events.

Dominant large-scale parameters responsible for diverse extreme rainfall events over vulnerable Odisha state in India

2019 ◽  
Vol 53 (11) ◽  
pp. 6629-6644 ◽  
Author(s):  
Madhusmita Swain ◽  
P. Sinha ◽  
U. C. Mohanty ◽  
S. Pattnaik
Keyword(s):  
Large Scale ◽  
Extreme Rainfall ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Scale Parameters

Trends in sub-hourly, sub-daily and daily extreme rainfall events in eastern Australia

2014 ◽  
Vol 5 (4) ◽  
pp. 667-675 ◽  
Author(s):  
Orpita U. Laz ◽  
Ataur Rahman ◽  
Abdullah Yilmaz ◽  
Khaled Haddad
Keyword(s):  
Daily Rainfall ◽  
Extreme Rainfall ◽  
Positive Trend ◽  
Urban Stormwater ◽  
Catchment Scale ◽  
Extreme Rainfall Events ◽  
Maximum Rainfall ◽  
Rainfall Events ◽  
Eastern Australia ◽  
Significance Levels

Intensity and frequency of extreme rainfall are expected to change in future due to anthropogenic climate change; however, this change may not be uniform across spatial and temporal scale. This paper examines the trends of sub-hourly, sub-daily and daily extreme rainfall events from 38 rainfall stations located in southeast Australia. Two non-parametric tests (Mann–Kendall and Spearman Rho) were applied to detect trends at 10, 5 and 1% significance levels. The sub-hourly (6, 12, 18 and 30 min) and sub-daily (1, 2 and 6 h) annual maximum rainfall events generally showed an upward (positive) trend. However, the longer duration rainfall events (12–72 h) generally showed a downward (negative) trend. It was found that stations showing positive trends were characterized by higher elevations compared with the stations showing negative trends. This finding has important implications for urban stormwater management in the near future as most urban stormwater systems operate on a smaller catchment scale where sub-hourly and sub-daily rainfall events are used in their design.

The Influence of Geographical Factors on Extreme Rainfalls in Lampung Province

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.

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

2013 ◽  
Vol 31 (3) ◽  
pp. 413 ◽  
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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