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M Santosh - One of the best experts on this subject based on the ideXlab platform.
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landscape response to progressive tectonic and climatic forcing in nw borneo implications for geological and geomorphic controls on flood hazard
Scientific Reports, 2017Co-Authors: David Menier, Manoj Joseph Mathew, Manuel Pubellier, Francois Sapin, Bernard Delcaillau, Numair Ahmed Siddiqui, Mu Ramkumar, M SantoshAbstract:Empirical models have simulated the consequences of uplift and Orographic-precipitation on the evolution of orogens whereas the Effects of these forcings on ridgelines and consequent topography of natural landscapes remain equivocal. Here we demonstrate the feedback of a terrestrial landscape in NW Borneo subject to uplift and precipitation gradient owing to Orographic Effect, and leading to less-predictable flooding and irreversible damages to life and property. Disequilibrium in a large catchment recording the lowest rainfall rates in Borneo, and adjacent drainage basins as determined through χ, a proxy for steady–state channel elevation, is shown to result in dynamic migration of water divide from the windward-side of the orogen towards the leeward-side to attain equilibrium. Loss of drainage area in the leeward-side reduces erosion rates with progressive shortening resulting in an unstable landscape with tectonic uplift, gravity faults and debris flows. 14C dating of exhumed cut-and-fill terraces reveal a Mid–Pleistocene age, suggesting tectonic events in the trend of exhumation rates (>7 mm a−1) estimated by thermochronology, and confirmed by morphotectonic and sedimentological analyses. Our study suggests that divide migration leads to lowered erosion rates, channel narrowing, and sediment accretion in intermontane basins on the leeward-side ultimately resulting in enhanced flooding.
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geological geophysical and inherited tectonic imprints on the climate and contrasting coastal geomorphology of the indian peninsula
Gondwana Research, 2016Co-Authors: Muthuvairavasamy Ramkumar, David Menier, Manoj Joseph Mathew, M SantoshAbstract:Abstract The Indian subcontinent comprises accreted cratonic fragments that underwent subsequent rifting–subduction–collision processes along major mobile belts. It is also a storehouse of a prolonged history of crustal evolution involving repeated episodes of magmatism, volcanism, sedimentation, and metamorphism, and the formation of intracratonic and foreland basins. The geologic–geomorphic evolution of the Peninsula is recorded in relic faults/suture zones that confine Paleozoic, Mesozoic, and Cenozoic sedimentary basins and landforms. In addition, escarpments, plateaus, waterfalls, deltas, planation surfaces, and strandlines are either aligned parallel and/or formed over them. Asymmetric relief across the western–eastern parts of the Peninsula, Orographic Effect on the precipitation pattern and climatic zones provide important constrains on the geologic and geomorphic evolution of the region. Though extensive continental and coastal deposition occurred during Permo-Triassic and Early Cretaceous, only the downwarped grabens of Gondwana basins preserved the sedimentary records. Occurrences of extensive Cenozoic deposits offshore and Neogene–Holocene deltaic deposits along the entire east coast as opposed to the absence of comparable deltaic sequences in the west coast are linked to intense and recurrent episodes of denudation indicating first-order control of basement structures over landscape evolution. Inheritance and continuum of basement structures over climate, and landscape evolution of Peninsular India can also be witnessed by the unique and diverse drainage patterns of major rivers. While most of the major rivers follow a general easterly direction, the landscape morphology of their catchments indicates youthful character and tectonically active nature. The east flowing rivers show an asymmetry between the areal extents of drainage basin size and delta, whereas the west-flowing rivers are short and straight and their catchments are miniscule in comparison with the rivers flowing toward east. The Western Ghats Escarpment forms an Orographic barrier and acts as the main divide between these two drainage systems. There is a disparity between the quanta of sediment discharge as well. In addition, the eastern and western parts of India, across the Western Ghats Escarpment, show significant differences in terms of climatic zones (humid to per-humid on the west while it is arid to subhumid on the east). The west coast is characterized by > 3000 mm/year annual rainfall, that often reaches > 5000 mm/year, dominance of SW monsoon winds, occurrence of narrow ( Here we propose a conceptual tectono-geomorphic model demonstrating the inheritance and continuum of Gondwanan structural trends on the transient landscape of Peninsular India.
David Menier - One of the best experts on this subject based on the ideXlab platform.
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landscape response to progressive tectonic and climatic forcing in nw borneo implications for geological and geomorphic controls on flood hazard
Scientific Reports, 2017Co-Authors: David Menier, Manoj Joseph Mathew, Manuel Pubellier, Francois Sapin, Bernard Delcaillau, Numair Ahmed Siddiqui, Mu Ramkumar, M SantoshAbstract:Empirical models have simulated the consequences of uplift and Orographic-precipitation on the evolution of orogens whereas the Effects of these forcings on ridgelines and consequent topography of natural landscapes remain equivocal. Here we demonstrate the feedback of a terrestrial landscape in NW Borneo subject to uplift and precipitation gradient owing to Orographic Effect, and leading to less-predictable flooding and irreversible damages to life and property. Disequilibrium in a large catchment recording the lowest rainfall rates in Borneo, and adjacent drainage basins as determined through χ, a proxy for steady–state channel elevation, is shown to result in dynamic migration of water divide from the windward-side of the orogen towards the leeward-side to attain equilibrium. Loss of drainage area in the leeward-side reduces erosion rates with progressive shortening resulting in an unstable landscape with tectonic uplift, gravity faults and debris flows. 14C dating of exhumed cut-and-fill terraces reveal a Mid–Pleistocene age, suggesting tectonic events in the trend of exhumation rates (>7 mm a−1) estimated by thermochronology, and confirmed by morphotectonic and sedimentological analyses. Our study suggests that divide migration leads to lowered erosion rates, channel narrowing, and sediment accretion in intermontane basins on the leeward-side ultimately resulting in enhanced flooding.
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geological geophysical and inherited tectonic imprints on the climate and contrasting coastal geomorphology of the indian peninsula
Gondwana Research, 2016Co-Authors: Muthuvairavasamy Ramkumar, David Menier, Manoj Joseph Mathew, M SantoshAbstract:Abstract The Indian subcontinent comprises accreted cratonic fragments that underwent subsequent rifting–subduction–collision processes along major mobile belts. It is also a storehouse of a prolonged history of crustal evolution involving repeated episodes of magmatism, volcanism, sedimentation, and metamorphism, and the formation of intracratonic and foreland basins. The geologic–geomorphic evolution of the Peninsula is recorded in relic faults/suture zones that confine Paleozoic, Mesozoic, and Cenozoic sedimentary basins and landforms. In addition, escarpments, plateaus, waterfalls, deltas, planation surfaces, and strandlines are either aligned parallel and/or formed over them. Asymmetric relief across the western–eastern parts of the Peninsula, Orographic Effect on the precipitation pattern and climatic zones provide important constrains on the geologic and geomorphic evolution of the region. Though extensive continental and coastal deposition occurred during Permo-Triassic and Early Cretaceous, only the downwarped grabens of Gondwana basins preserved the sedimentary records. Occurrences of extensive Cenozoic deposits offshore and Neogene–Holocene deltaic deposits along the entire east coast as opposed to the absence of comparable deltaic sequences in the west coast are linked to intense and recurrent episodes of denudation indicating first-order control of basement structures over landscape evolution. Inheritance and continuum of basement structures over climate, and landscape evolution of Peninsular India can also be witnessed by the unique and diverse drainage patterns of major rivers. While most of the major rivers follow a general easterly direction, the landscape morphology of their catchments indicates youthful character and tectonically active nature. The east flowing rivers show an asymmetry between the areal extents of drainage basin size and delta, whereas the west-flowing rivers are short and straight and their catchments are miniscule in comparison with the rivers flowing toward east. The Western Ghats Escarpment forms an Orographic barrier and acts as the main divide between these two drainage systems. There is a disparity between the quanta of sediment discharge as well. In addition, the eastern and western parts of India, across the Western Ghats Escarpment, show significant differences in terms of climatic zones (humid to per-humid on the west while it is arid to subhumid on the east). The west coast is characterized by > 3000 mm/year annual rainfall, that often reaches > 5000 mm/year, dominance of SW monsoon winds, occurrence of narrow ( Here we propose a conceptual tectono-geomorphic model demonstrating the inheritance and continuum of Gondwanan structural trends on the transient landscape of Peninsular India.
Chulsang Yoo - One of the best experts on this subject based on the ideXlab platform.
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Vertical Variation of Z-R Relationship at Hallasan Mountain during Typhoon Nakri in 2014
Hindawi Limited, 2017Co-Authors: Chulsang YooAbstract:Hallasan Mountain is located at the center of Jeju Island, Korea. Even though the height of the mountain is just 1,950 m, the Orographic Effect is strong enough to cause heavy rainfall. In this study, a rainfall event, due to Typhoon Nakri in 2014, observed in Jeju Island was analyzed fully using the radar and rain gauge data. First, the Z-R relationship Z=ARb was derived for every 250 m interval from the sea level to the mountain top. The resulting Z-R relationships showed that the exponent b could be assumed as constant but that the parameter A showed a significant decreasing trend up to an altitude around 1,000 m before it increased again. The Orographic Effect was found to be most significant at this altitude of 1,000 m. Second, the derived Z-R relationships were applied to the corresponding altitude radar reflectivity data to generate the rain rate field over Jeju Island. This rain rate field was then used to derive the areal-average rain rate data. These data were found to be very similar to the rain gauge estimates but were significantly different from those derived from the application of the Marshall-Palmer equation to the 1.5 km CAPPI data, which is the data type that is generally used by the Korea Meteorological Administration (KMA)
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Calibrating Radar Data in an Orographic Setting: A Case Study for the Typhoon Nakri in the Hallasan Mountain, Korea
MDPI AG, 2017Co-Authors: Chulsang YooAbstract:The Typhoon Nakri passed the Jeju Island in Korea (1–3 August 2014) and recorded one-day rainfall of 1182 mm at Witse-Oreum (a place name where a small volcanic cone is) of the Hallasan Mountain, Korea. This one-day rainfall amount was the highest rainfall that was ever recorded in Korea. As the altitude of Witse-Oreum is 1673 m, it was believed that the Orographic Effect enhanced the rainfall depth significantly. It was also argued that the maximum rainfall could be recorded in some other locations in the Hallasan Mountain. In this study, the rainfall event due to the Typhoon Nakri in the Jeju Island was analyzed using the radar and rain gauge data that were collected during this rainfall event. Fortunately, two radars are available on the eastern and western side of the Jeju Island. The entire Hallasan Mountain is covered by these two radars. A total of 23 rain gauges are also available in the Jeju Island. As a first step, independent ground-level Z-R relations were derived for every 250 m interval from the sea-level. Each Z-R relation was then applied to the corresponding-altitude radar reflectivity data to generate the rain rate field over the Jeju Island. Finally, the generated radar rain rate data were examined fully to evaluate the Orographic Effect in the Hallasan Mountain, also to locate the point where the maximum rain rate was recorded. This result shows that the maximum one-day rainfall amount could be up to 1500 mm, which was about 30% higher than the rain gauge measurement
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analysis on characteristics of Orographic Effect about the rainfall using radar data a case study on chungju dam basin
Journal of Korea Water Resources Association, 2015Co-Authors: Kyoungjun Kim, Chulsang YooAbstract:This study analyzed the characteristics of Orographic Effect using radar data for the Chungju dam basin. First, independent rainfall events were selected by applying the IETD (Interevent Time Definition) and rainfall threshold. Among those independent rainfall events, rather strong events were selected to decide the occurrence condition of Orographic Effect. Also, the average reflectivity was calculated for the entire period and for the period of storm center, and the change in reflectivity was analyzed by comparing the average reflectivity to that in the mountain area. Important rainfall factors were selected and applied to the logistic regression model to decide the occurrence condition of Orographic Effect. Summarizing the results is as follows. First, evaluation of the radar data along the passing line of a storm showed the increase of radar reflectivity in the mountain area. Second, the result of logistic regression analysis showed that the Orographic Effect in the Chungju Dam Basin mostly occurred when the rainfall intensity was higher than 4 mm/hr, the storm velocity was lower than 4 km/hr, and the approach angle was .
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Orographic Effect estimation of rainfall in han river basin 3 regionalization
Journal of The Korean Society of Civil Engineers, 2004Co-Authors: Keewook Kim, Chulsang Yoo, Kyungsoo JunAbstract:Yoo et al. (2004a, b) did the linear regression analysis, non-linear regression analysis, and EOF analysis of rainfall in the Han river basin with respect to the elevation and concluded the existence of Orographic Effect. Especially, the rainfall at the elevation of 600 m has found to be rather high and its variability also to be sensitive to the topographic Effect. However, it is also generally accepted that the Orographic Effect cannot be explained only by the elevation, but many others intermingled altogether. This study is on line with the work by Yoo et al. (2003b) and used the Varimax Method of using Component Correlation Vector for regionalizing the nu river basin. The regionalization here is based on the spatial-temporal variability of rainfall, thus the result derived is to count for relative amount of Orographic Effect, not for dividing the plain and mountain region. This study analyzed five rainfall events which were concluded to have rather large Orographic Effect in Yoo et al. (2003b). The results derived are as follows. (1) Each rainfall event shows a different of regionalization result. That is, the Orographic Effect is different from event to event. (2) The south-eastern part of the Han river basin around Daekwanryung (its elevation over ) is distinguished from other regions. This are seems to have most obvious Orographic Effect within the Han river basin.
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estimation of Orographic Effect on precipitation in the han river basin i regression analysis
Journal of the Korean Society of Civil Engineers B, 2004Co-Authors: Chulsang Yoo, Kyungsoo Jun, Keewook KimAbstract:Linear and non-linear regression analysis of the point precipitation (annual, monthly, dry and wet season) with respect to their elevation have been tried to search a proof of Orographic Effect in the Han river basin. Especially the linear regression analysis was focused on the test of significance for the slope, and the non-linear regression on the search for precipitation increase in a special elevation. To make sure of the presence of Orographic Effect, several precipitation events with their direction from West to East have been selected and applied to the same regression analysis. As results of the study we could found: (1) No significant linearity is not found between the precipitation amount and elevation. (2) Rather obvious increase of the precipitation amount can be found around the elevation of 600 m. (3) precipitation amount variation with respect to the elevation varies depending on the precipitation events considered. Thus the information of elevation may be limited to explain the Orographic Effect.
Manoj Joseph Mathew - One of the best experts on this subject based on the ideXlab platform.
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landscape response to progressive tectonic and climatic forcing in nw borneo implications for geological and geomorphic controls on flood hazard
Scientific Reports, 2017Co-Authors: David Menier, Manoj Joseph Mathew, Manuel Pubellier, Francois Sapin, Bernard Delcaillau, Numair Ahmed Siddiqui, Mu Ramkumar, M SantoshAbstract:Empirical models have simulated the consequences of uplift and Orographic-precipitation on the evolution of orogens whereas the Effects of these forcings on ridgelines and consequent topography of natural landscapes remain equivocal. Here we demonstrate the feedback of a terrestrial landscape in NW Borneo subject to uplift and precipitation gradient owing to Orographic Effect, and leading to less-predictable flooding and irreversible damages to life and property. Disequilibrium in a large catchment recording the lowest rainfall rates in Borneo, and adjacent drainage basins as determined through χ, a proxy for steady–state channel elevation, is shown to result in dynamic migration of water divide from the windward-side of the orogen towards the leeward-side to attain equilibrium. Loss of drainage area in the leeward-side reduces erosion rates with progressive shortening resulting in an unstable landscape with tectonic uplift, gravity faults and debris flows. 14C dating of exhumed cut-and-fill terraces reveal a Mid–Pleistocene age, suggesting tectonic events in the trend of exhumation rates (>7 mm a−1) estimated by thermochronology, and confirmed by morphotectonic and sedimentological analyses. Our study suggests that divide migration leads to lowered erosion rates, channel narrowing, and sediment accretion in intermontane basins on the leeward-side ultimately resulting in enhanced flooding.
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geological geophysical and inherited tectonic imprints on the climate and contrasting coastal geomorphology of the indian peninsula
Gondwana Research, 2016Co-Authors: Muthuvairavasamy Ramkumar, David Menier, Manoj Joseph Mathew, M SantoshAbstract:Abstract The Indian subcontinent comprises accreted cratonic fragments that underwent subsequent rifting–subduction–collision processes along major mobile belts. It is also a storehouse of a prolonged history of crustal evolution involving repeated episodes of magmatism, volcanism, sedimentation, and metamorphism, and the formation of intracratonic and foreland basins. The geologic–geomorphic evolution of the Peninsula is recorded in relic faults/suture zones that confine Paleozoic, Mesozoic, and Cenozoic sedimentary basins and landforms. In addition, escarpments, plateaus, waterfalls, deltas, planation surfaces, and strandlines are either aligned parallel and/or formed over them. Asymmetric relief across the western–eastern parts of the Peninsula, Orographic Effect on the precipitation pattern and climatic zones provide important constrains on the geologic and geomorphic evolution of the region. Though extensive continental and coastal deposition occurred during Permo-Triassic and Early Cretaceous, only the downwarped grabens of Gondwana basins preserved the sedimentary records. Occurrences of extensive Cenozoic deposits offshore and Neogene–Holocene deltaic deposits along the entire east coast as opposed to the absence of comparable deltaic sequences in the west coast are linked to intense and recurrent episodes of denudation indicating first-order control of basement structures over landscape evolution. Inheritance and continuum of basement structures over climate, and landscape evolution of Peninsular India can also be witnessed by the unique and diverse drainage patterns of major rivers. While most of the major rivers follow a general easterly direction, the landscape morphology of their catchments indicates youthful character and tectonically active nature. The east flowing rivers show an asymmetry between the areal extents of drainage basin size and delta, whereas the west-flowing rivers are short and straight and their catchments are miniscule in comparison with the rivers flowing toward east. The Western Ghats Escarpment forms an Orographic barrier and acts as the main divide between these two drainage systems. There is a disparity between the quanta of sediment discharge as well. In addition, the eastern and western parts of India, across the Western Ghats Escarpment, show significant differences in terms of climatic zones (humid to per-humid on the west while it is arid to subhumid on the east). The west coast is characterized by > 3000 mm/year annual rainfall, that often reaches > 5000 mm/year, dominance of SW monsoon winds, occurrence of narrow ( Here we propose a conceptual tectono-geomorphic model demonstrating the inheritance and continuum of Gondwanan structural trends on the transient landscape of Peninsular India.
Cholponbelk Ormukov - One of the best experts on this subject based on the ideXlab platform.
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Asian monsoons and aridification response to Paleogene sea retreat and Neogene westerly shielding indicated by seasonality in Paratethys oysters
Earth and Planetary Science Letters, 2018Co-Authors: Laurie Bougeois, Guillaume Dupont-nivet, Marc De Rafélis, Julia Tindall, Jean-noël Proust, Gert-jan Reichart, Lennart De Nooijer, Zhaojie Guo, Cholponbelk OrmukovAbstract:Asian climate patterns, characterised by highly seasonal monsoons and continentality, are thought to originate in the Eocene epoch (56 to 34 million years ago – Ma) in response to global climate, Tibetan Plateau uplift and the disappearance of the giant Proto-Paratethys sea formerly extending over Eurasia. The influence of this sea on Asian climate has hitherto not been constrained by proxy records despite being recognised as a major driver by climate models. We report here strongly seasonal records preserved in annual lamina of Eocene oysters from the Proto-Paratethys with sedimentological and numerical data showing that monsoons were not dampened by the sea and that aridification was modulated by westerly moisture sourced from the sea. Hot and arid summers despite the presence of the sea suggest a strong anticyclonic zone at Central Asian latitudes and an Orographic Effect from the emerging Tibetan Plateau. Westerly moisture precipitating during cold and wetter winters appear to have decreased in two steps. First in response to the late Eocene (34–37 Ma) sea retreat; second by the orogeny of the Tian Shan and Pamir ranges shielding the westerlies after 25 Ma. Paleogene sea retreat and Neogene westerly shielding thus provide two successive mechanisms forcing coeval Asian desertification and biotic crises.