scholarly journals Analysis of Multi-Scale Hydrometeorological Triggering Flash Flood Event of the 13 July 2020 in North Luwu, South Sulawesi

2021 ◽  
Vol 893 (1) ◽  
pp. 012014
Author(s):  
J A I Paski ◽  
E E S Makmur ◽  
D S Permana ◽  
M H Nurrahmat ◽  
A S Praja ◽  
...  
Keyword(s):  
Water Vapor ◽  
Flash Flood ◽  
Mass Movement ◽  
Intraseasonal Oscillation ◽  
Boreal Summer ◽  
Eastern Region ◽  
Easterly Wind ◽  
Australian Monsoon ◽  
Multi Scale ◽  
The North

Abstract During 12-13 July 2020, heavy rainfall had caused Masamba, Rongkong, and Rada rivers to overflow, causing flash floods in the North Luwu regency. This event resulted in many casualties; at least 38 people died and displaced thousands of people. This study presents an analysis of the multi-scale hydrometeorological settings that led to the development of these intense storms in the North Luwu fl ood. Boreal Summer Intraseasonal Oscillation (BSISO) Normalized PC2 has entered phases 4 and 5 on 7 - 13 July 2020, associated with cloud growth in the Indonesian Maritime Continent. Besides, the sub-seasonal tropical disturbance of Kelvin Waves is convectively active in the Sulawesi region on 7 - 13 July, increasing the intensity of rainfall at the location. Sea Surface Temperatures (SSTs) were in warmer conditions in the Bonne Bay region south of North Luwu, supplying more water vapor into the atmosphere. The easterly wind (Australian monsoon) enhanced the diurnal cycle of the water vapor mass movement from Bonne Bay to the highlands of North Luwu. From the observation of GPM satellite imagery, the accumulation of spatial rainfall on July 12 and 13 was concentrated in the eastern region of Sulawesi, which reached >150 mm/day and >50 mm/day in North Luwu.

Inter-basin and Multi-time Scale Interactions in generating the 2019 Extreme Indian Ocean Dipole

2021 ◽  
pp. 1-39
Author(s):  
Lei Zhang ◽  
Weiqing Han ◽  
Zeng-Zhen Hu
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Intraseasonal Oscillation ◽  
Tropical Indian Ocean ◽  
Forecast Model ◽  
Tropical Pacific ◽  
Boreal Summer ◽  
Indian Ocean Dipole Event ◽  
Easterly Wind ◽  
Western Tropical Pacific

AbstractAn unprecedented extreme positive Indian Ocean Dipole event (pIOD) occurred in 2019, which has caused widespread disastrous impacts on countries bordering the Indian Ocean, including the East African floods and vast bushfires in Australia. Here we investigate the causes for the 2019 pIOD by analyzing multiple observational datasets and performing numerical model experiments. We find that the 2019 pIOD is triggered in May by easterly wind bursts over the tropical Indian Ocean associated with the dry phase of the boreal summer intraseasonal oscillation, and sustained by the local atmosphere-ocean interaction thereafter. During September-November, warm sea surface temperature anomalies (SSTA) in the central-western tropical Pacific further enhance the Indian Ocean’s easterly winds, bringing the pIOD to an extreme magnitude. The central-western tropical Pacific warm SSTA is strengthened by two consecutive Madden Julian Oscillation (MJO) events that originate from the tropical Indian Ocean. Our results highlight the important roles of cross-basin and cross-timescale interactions in generating extreme IOD events. The lack of accurate representation of these interactions may be the root for a short lead time in predicting this extreme pIOD with a state-of-the-art climate forecast model.

Effects of 2017 Early Flash Flooding on Agriculture in Haor Areas of Sunamganj

2021 ◽  
Vol 12 (1-2) ◽  
pp. 117-125
Author(s):  
S Mondal ◽  
L Akter ◽  
HJ Hiya ◽  
MA Farukh
Keyword(s):  
Agricultural Production ◽  
Flash Flood ◽  
Eastern Region ◽  
Fish Production ◽  
Flood Events ◽  
Flash Flooding ◽  
The North ◽  
North Eastern ◽  
Boro Rice

The Sunamganj district is covered by major Haor systems in the north-eastern region of Bangladesh. Flash flood is the most commonly occurring water related disaster in the Haor areas. During the flash flood it is very common that people lost their primary agricultural productions which are the only source of their livelihood. The present study focuses on the effects of 2017 early flash flooding on rice and fish production of Sunamganj Haor areas. The flood caused enormous damage to agriculture such as rice especially Boro rice and fish production on which the Haor dwellers rely upon for their livelihood. The total affected land of Boro rice cultivation in Haors of Sunamganj was 149,224 hectare and the total amount of damaged rice was 393,855 metric ton (MT). The total number of affected farmers was 315,084. The early flash flood also affects the quality of Haor water which caused the death of fishes. The total amount of damaged fish was 49.75 MT and the loss was 158.70 lakh taka. The total number of affected fishermen was 44,445. This findings could be very useful for the environmental scientists to predict the probable future effects on agricultural production due to early flash flood events in Sunamganj Haors areas. Environ. Sci. & Natural Resources, 12(1&2): 117-125, 2019

scholarly journals Water Vapor Changes Affect Cross-Seasonal Strong Drought Events in the Eastern Region of Northwest China

2021 ◽  
Vol 9 ◽  
Author(s):  
Yu Zhang ◽  
Kang Liu ◽  
Yaohui Li ◽  
Wei Shen ◽  
Yulong Ren ◽  
...  
Keyword(s):  
Water Vapor ◽  
Global Climate ◽  
Northwest China ◽  
Water Vapor Transport ◽  
Eastern Region ◽  
The South ◽  
Vapor Flux ◽  
Weather Forecasts ◽  
The North ◽  
Depth Study

Drought in eastern Northwest China (ENC) is severely affected by water vapor conditions. An in-depth study of the primary sources of water vapor and its characteristics, at intraseasonal and interannual timescales, was conducted. This information is crucial for further study of the causes and mechanisms of extreme droughts and floods in the ENC. This study evaluated the spatial distribution and transport characteristics of water vapor over ENC during the 1981–2019 period based on the fifth generation of the European Center for Medium-Range Weather Forecasts atmospheric reanalyzes data of the global climate (ERA5). We studied the water vapor transport routes, water vapor convergence, water vapor budgets as well as the changes in water vapor fluxes and budgets over time in four areas surrounding ENC. The Mediterranean Sea, Black Sea, Caspian Sea, Indian Ocean, Bay of Bengal, and the South China Sea were the main sources of water vapor in ENC, supplemented by mid to high-latitude continental sources. The monthly change in water vapor flux in ENC exhibited the peak on July. The transport of water vapor in ENC was mainly toward the east and north. For most cross-seasonal drought events, the water vapor output is the main way in the south boundary and the west boundary. However, for the longest duration of cross-seasonal strong drought events, it is characterized by that the water vapor output is the main way in the south boundary, while the water vapor input in the north boundary is obviously weak. Water vapor paths in cross-seasonal strong drought events are analyzed, by which the Hybrid Single-Particle Lagrangian Integrated Trajectory model (HYSPLIT). The intensity of the subtropical high in the western Pacific is weak and the position is south, which corresponds to the occurrence of cross-seasonal strong drought in the ENC.

Interactions between Boreal Summer Intraseasonal Oscillations and Synoptic-Scale Disturbances over the Western North Pacific. Part II: Apparent Heat and Moisture Sources and Eddy Momentum Transport*

2011 ◽  
Vol 24 (3) ◽  
pp. 942-961 ◽  
Author(s):  
Pang-Chi Hsu ◽  
Tim Li
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Wave Train ◽  
Intraseasonal Oscillation ◽  
Momentum Transport ◽  
Boreal Summer ◽  
Synoptic Scale ◽  
Mean Flow ◽  
The North ◽  
Intraseasonal Oscillations

Abstract The interactions between the boreal summer intraseasonal oscillation (ISO) and synoptic-scale variability (SSV) are investigated by diagnosing the atmospheric apparent heat source (Q1), apparent moisture sink (Q2), and eddy momentum transport. It is found that the synoptic Q1 and Q2 heating (cooling) anomalies are in phase with cyclonic (anticyclonic) vorticity disturbances, aligned in a southeast–northwest-oriented wave train pattern over the western North Pacific (WNP). The wave train is well organized and strengthened (loosely organized and weakened) during the ISO active (suppressed) phase. The nonlinearly rectified Q1 and Q2 fields due to the eddy–mean flow interaction account for 10%–30% of the total intraseasonal Q1 and Q2 variabilities over the WNP. During the ISO active (suppressed) phase, the nonlinearly rectified intraseasonal Q1 and Q2 heating (cooling) appear to the northwest of the ISO enhanced (suppressed) convection center, favoring the northwestward propagation of the ISO. A diagnosis of the zonal momentum budget shows that the eddy momentum flux convergence forces an intraseasonal westerly (easterly) tendency to the north of the ISO westerly (easterly) center during the ISO active (suppressed) phase. As a result, the eddy momentum transport may contribute to the northward propagation of the boreal summer ISO over the WNP.

scholarly journals Exploring the Effect of Rainfall Variability and Water Extent in Tanguar Haor, Sunamganj

2020 ◽  
pp. 66-76
Keyword(s):  
Flash Flood ◽  
Monsoon Season ◽  
Rainfall Variability ◽  
Ecological Effect ◽  
Eastern Region ◽  
Financial Loss ◽  
Secondary Sources ◽  
The North ◽  
Rainfall Patterns ◽  
Basin Area

Tanguar haor is located in the north-eastern region of Bangladesh and frequently experienced extreme events such as high rainfall that affect the haor basin area with flash floods on a regular basis. Tanguar haor is usually foreseen to severe disastrous conditions for the reason of changes in rainfall patterns and water extent. The study was conducted at Tanguar haor of Sunamganj district. This study mainly focuses on the year to year rainfall variability (2001-2018) and water extent (2002-2018) in the Tanguar haor area. The specific objective of the study was to explore the effect of rainfall variability and water extent in Tanguar haor. Information and data were collected mainly from secondary sources. Analysis of data and assess the ecological effect of changes in rainfall patterns and water extent were the main activities of the study along with others. The findings of the study were changeability in rainfall patterns and water extent frequently caused a flash flood in pre-monsoon and monsoon season in the Tanguar haor area. Flash flood causes a vast amount of financial loss for the living people of the Tanguar haor that makes them more vulnerable to live well. The result of this study may help to gather new knowledge on the consequences of rainfall variability and water extent in the haor basin area. It may add significance to the management of flash flood and severe stress in the haor basin area.

scholarly journals Analysis of flash flood regimes in the North-Western and South-Eastern Mediterranean regions

2012 ◽  
Vol 12 (5) ◽  
pp. 1255-1265 ◽  
Author(s):  
P. Tarolli ◽  
M. Borga ◽  
E. Morin ◽  
G. Delrieu
Keyword(s):  
Flash Flood ◽  
Eastern Mediterranean ◽  
Western Region ◽  
Eastern Region ◽  
The South ◽  
Eastern Area ◽  
South Eastern ◽  
The North ◽  
Rainfall Depth ◽  
North Western

Abstract. This work analyses the prominent characteristics of flash flood regimes in two Mediterranean areas: the North-Western Mediterranean region, which includes Catalonia, France and Northern Italy, and the South-Eastern Mediterranean region, which includes Israel. The two regions are characterized by similarities in the hydro-meteorological monitoring infrastructure, which permits us to ensure homogeneity in the data collection procedures. The analysis is articulated into two parts. The first part is based on use of flood peak data, catchment area and occurrence date for 99 events (69 from the North-Western region and 30 from the South-Eastern region). Analysis is carried out in terms of relationship of flood peaks with catchment area and seasonality. Results show that the envelope curve for the South-Eastern region exhibits a more pronounced decreasing with catchment size with respect to the curve of the North-Western region. The differences between the two relationships reflect changes in the effects of storm coverage and hydrological characteristics between the two regions. Seasonality analysis shows that the events in the North-Western region tend to occur between August and November, whereas those in the South-Eastern area tend to occur in the period between October and May, reflecting the relevant patterns in the synoptic conditions leading to the intense precipitation events. In the second part, the focus is on the rainfall-runoff relationships for 13 selected major flash flood events (8 from the North-Western area and 5 from the South-Eastern area) for which rainfall and runoff properties are available. These flash floods are characterised in terms of climatic features of the impacted catchments, duration and amount of the generating rainfall, and runoff ratio. Results show that the rainfall duration is shorter and the rainfall depth lower in the South-Eastern region. The runoff ratios are rather low in both regions, whereas they are more variable in the South-Eastern area. No clear relationship between runoff ratio and rainfall depth is observed in the sample of floods, showing the major influence of rainfall intensity and the initial wetness condition in the runoff generation for these events.

scholarly journals Estimate of the Predictability of Boreal Summer and Winter Intraseasonal Oscillations from Observations

2011 ◽  
Vol 139 (8) ◽  
pp. 2421-2438 ◽  
Author(s):  
Ruiqiang Ding ◽  
Jianping Li ◽  
Kyong-Hwan Seo
Keyword(s):  
Spatial Distribution ◽  
Intraseasonal Variability ◽  
Intraseasonal Oscillation ◽  
Longwave Radiation ◽  
Boreal Summer ◽  
Boreal Winter ◽  
Potential Predictability ◽  
The North ◽  
Intraseasonal Oscillations ◽  
The North Pacific

AbstractTropical intraseasonal variability (TISV) shows two dominant modes: the boreal winter Madden–Julian oscillation (MJO) and the boreal summer intraseasonal oscillation (BSISO). The two modes differ in intensity, frequency, and movement, thereby presumably indicating different predictabilities. This paper investigates differences in the predictability limits of the BSISO and the boreal winter MJO based on observational data. The results show that the potential predictability limit of the BSISO obtained from bandpass-filtered (30–80 days) outgoing longwave radiation (OLR), 850-hPa winds, and 200-hPa velocity potential is close to 5 weeks, comparable to that of the boreal winter MJO. Despite the similarity between the potential predictability limits of the BSISO and MJO, the spatial distribution of the potential predictability limit of the TISV during summer is very different from that during winter. During summer, the limit is relatively low over regions where the TISV is most active, whereas it is relatively high over the North Pacific, North Atlantic, southern Africa, and South America. The spatial distribution of the limit during winter is approximately the opposite of that during summer. For strong phases of ISO convection, the initial error of the BSISO shows a more rapid growth than that of the MJO. The error growth is rapid when the BSISO and MJO enter the decaying phase (when ISO signals are weak), whereas it is slow when convection anomalies of the BSISO and MJO are located in upstream regions (when ISO signals are strong).

Characteristics of Low Pressure Systems Associated with Intraseasonal Oscillation of Rainfall over Bangladesh during Boreal Summer

2014 ◽  
Vol 142 (12) ◽  
pp. 4758-4774 ◽  
Author(s):  
Daisuke Hatsuzuka ◽  
Tetsuzo Yasunari ◽  
Hatsuki Fujinami
Keyword(s):  
Indian Monsoon ◽  
Intraseasonal Oscillation ◽  
Low Pressure ◽  
Boreal Summer ◽  
Horizontal Scale ◽  
The North ◽  
Vertical Scale ◽  
Active Peak ◽  
The Ganges ◽  
Low Pressure Systems

Abstract Characteristics of low pressure systems (LPSs) responsible for submonthly-scale (7–25 days) intraseasonal oscillation (ISO) in rainfall over Bangladesh and their impact on the amplitude of active peaks are investigated for 29 summer monsoon seasons. Extreme and moderate active peaks are obtained based on the amplitude of 7–25-day-filtered rainfall series. By detecting the LPSs that formed over the Indian monsoon region, it was found that about 59% (62%) of extreme (moderate) active peaks of rainfall are related to LPSs. These LPSs have horizontal scale of about 600 km and vertical scale of about 9 km. For the extreme active peak, the locations of the LPS centers are clustered significantly over and around Bangladesh, accompanied by the maximum convergence in the southeast sector of the LPSs. After their formation, they tend to remain almost stationary over and around Bangladesh. In contrast, for the moderate active peak, the LPS centers are located over the Ganges Plain around 85°E, and the maximum convergence of the LPSs occurs around their centers. This difference in the convergence fields is closely associated with the geographical features to the north and east of Bangladesh and the horizontal scale of the LPSs. These features suggest that the amplitude of the active peaks in the submonthly-scale ISO is modulated by small differences in the locations of the LPS centers. These findings suggest that improved predictions of both genesis location and the tracks of the LPSs are crucial to forecasting seasonal rainfall over Bangladesh.

Examining the Kinships System of the Bodo

Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 186-192
Author(s):  
Dr. Oinam Ranjit Singh ◽  
Dr. Nushar Bargayary
Keyword(s):  
Social Relationships ◽  
Social Cohesion ◽  
Social Relationship ◽  
Vital Role ◽  
Eastern Region ◽  
The North ◽  
Kinship System ◽  
North Eastern ◽  
The World ◽  
The Relationship

The Bodo of the North Eastern region of India have their own kinship system to maintain social relationship since ancient periods. Kinship is the expression of social relationship. Kinship may be defined as connection or relationships between persons based on marriage or blood. In each and every society of the world, social relationship is considered to be the more important than the biological bond. The relationship is not socially recognized, it fall outside the realm of kinship. Since kinship is considered as universal, it plays a vital role in the socialization of individuals and the maintenance of social cohesion of the group. Thus, kinship is considered to be the study of the sum total of these relations. The kinship of the Bodo is bilateral. The kin related through the father is known as Bahagi in Bodo whereas the kin to the mother is called Kurma. The nature of social relationships, the kinship terms, kinship behaviours and prescriptive and proscriptive rules are the important themes of the present study.

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