51
|
Comparative Study of Monsoon Rainfall Variability over India and the Odisha State. CLIMATE 2017. [DOI: 10.3390/cli5040079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
52
|
Roxy MK, Ghosh S, Pathak A, Athulya R, Mujumdar M, Murtugudde R, Terray P, Rajeevan M. A threefold rise in widespread extreme rain events over central India. Nat Commun 2017; 8:708. [PMID: 28974680 PMCID: PMC5626780 DOI: 10.1038/s41467-017-00744-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 07/20/2017] [Indexed: 11/30/2022] Open
Abstract
Socioeconomic challenges continue to mount for half a billion residents of central India because of a decline in the total rainfall and a concurrent rise in the magnitude and frequency of extreme rainfall events. Alongside a weakening monsoon circulation, the locally available moisture and the frequency of moisture-laden depressions from the Bay of Bengal have also declined. Here we show that despite these negative trends, there is a threefold increase in widespread extreme rain events over central India during 1950-2015. The rise in these events is due to an increasing variability of the low-level monsoon westerlies over the Arabian Sea, driving surges of moisture supply, leading to extreme rainfall episodes across the entire central subcontinent. The homogeneity of these severe weather events and their association with the ocean temperatures underscores the potential predictability of these events by two-to-three weeks, which offers hope in mitigating their catastrophic impact on life, agriculture and property.Against the backdrop of a declining monsoon, the number of extreme rain events is on the rise over central India. Here the authors identify a threefold increase in widespread extreme rains over the region during 1950-2015, driven by an increasing variability of the low-level westerlies over the Arabian Sea.
Collapse
Affiliation(s)
- M K Roxy
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India.
| | - Subimal Ghosh
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Amey Pathak
- Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - R Athulya
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India
- Department of Physical Oceanography, Cochin University of Science and Technology, Kochi, 682016, India
| | - Milind Mujumdar
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India
| | - Raghu Murtugudde
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, 20742, USA
| | - Pascal Terray
- Sorbonne Universites (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN, LOCEAN Laboratory, 4 Place Jussieu, F-75005, Paris, France
- Indo-French Cell for Water Sciences, IISc-IITM-NIO-IRD Joint International Laboratory, IITM, Pune, 411008, India
| | - M Rajeevan
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India
- Ministry of Earth Sciences, Government of India, Lodhi Road, New Delhi, 110003, India
| |
Collapse
|
53
|
Baek SH, Smerdon JE, Coats S, Williams AP, Cook BI, Cook ER, Seager R. Precipitation, temperature, and teleconnection signals across the combined North American, Monsoon Asia, and Old World Drought Atlases. JOURNAL OF CLIMATE 2017; 30:7141-7155. [PMID: 30449951 PMCID: PMC6235455 DOI: 10.1175/jcli-d-16-0766.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The tree-ring-based North American Drought Atlas (NADA), Monsoon Asia Drought Atlas (MADA), and Old World Drought Atlas (OWDA) collectively yield a near-hemispheric gridded reconstruction of hydroclimate variability over the last millennium. To test the robustness of the large-scale representation of hydroclimate variability across the drought atlases, the joint expression of seasonal climate variability and teleconnections in the NADA, MADA, and OWDA are compared against two global, observation-based PDSI products. Predominantly positive (negative) correlations are determined between seasonal precipitation (surface air temperature) and collocated tree-ring-based PDSI, with average Pearson's correlation coefficients increasing in magnitude from boreal winter to summer. For precipitation, these correlations tend to be stronger in the boreal winter and summer when calculated for the observed PDSI record, while remaining similar for temperature. Notwithstanding these differences, the drought atlases robustly express teleconnection patterns associated with the El Niño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO). These expressions exist in the drought atlas estimates of boreal summer PDSI despite the fact that these modes of climate variability are dominant in boreal winter, with the exception of the Atlantic Multidecadal Oscillation. ENSO and NAO teleconnection patterns in the drought atlases are particularly consistent with their well-known dominant expressions in boreal winter and over the OWDA domain, respectively. Collectively, our findings confirm that the joint Northern Hemisphere drought atlases robustly reflect large-scale patterns of hydroclimate variability on seasonal to multidecadal timescales over the 20th century and are likely to provide similarly robust estimates of hydroclimate variability prior to the existence of widespread instrumental data.
Collapse
Affiliation(s)
- Seung H. Baek
- Corresponding author: Seung H. Baek, 61 Route 9W, Oceanography 205E, Palisades, NY 10964,
| | - Jason E. Smerdon
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York
| | - Sloan Coats
- Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, and National Center for Atmospheric Research, Boulder, Colorado
| | - A. Park Williams
- Lamont-Doherty Earth Observatory, Columbia University, Palisades
| | - Benjamin I. Cook
- NASA Goddard Institute for Space Studies, New York, and Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York
| | - Edward R. Cook
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York
| | - Richard Seager
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York
| |
Collapse
|
54
|
Li Z, Lin X, Cai W. Realism of modelled Indian summer monsoon correlation with the tropical Indo-Pacific affects projected monsoon changes. Sci Rep 2017; 7:4929. [PMID: 28694477 PMCID: PMC5503941 DOI: 10.1038/s41598-017-05225-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 05/25/2017] [Indexed: 11/09/2022] Open
Abstract
El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) tend to exert an offsetting impact on Indian summer monsoon rainfall (ISMR), with an El Niño event tending to lower, whereas a positive IOD tending to increase ISMR. Simulation of these relationships in Phase Five of the Coupled Model Intercomparison Project has not been fully assessed, nor is their impact on the response of ISMR to greenhouse warming. Here we show that the majority of models simulate an unrealistic present-day IOD-ISMR correlation due to an overly strong control by ENSO. As such, a positive IOD is associated with an ISMR reduction in the simulated present-day climate. This unrealistic present-day correlation is relevant to future ISMR projection, inducing an underestimation in the projected ISMR increase. Thus uncertainties in ISMR projection can be in part induced by present-day simulation of ENSO, the IOD, their relationship and their rainfall correlations.
Collapse
Affiliation(s)
- Ziguang Li
- Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.,CSIRO Oceans and Atmosphere, Aspendale, VIC 3195, Australia
| | - Xiaopei Lin
- Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.
| | - Wenju Cai
- Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266100, China.,CSIRO Oceans and Atmosphere, Aspendale, VIC 3195, Australia
| |
Collapse
|
55
|
Abstract
Climatic conditions influence the culture and economy of societies and the performance of economies. Specifically, El Niño as an extreme climate event is known to have notable effects on health, agriculture, industry, and conflict. Here, we construct directed and weighted climate networks based on near-surface air temperature to investigate the global impacts of El Niño and La Niña. We find that regions that are characterized by higher positive/negative network "in"-weighted links are exhibiting stronger correlations with the El Niño basin and are warmer/cooler during El Niño/La Niña periods. In contrast to non-El Niño periods, these stronger in-weighted activities are found to be concentrated in very localized areas, whereas a large fraction of the globe is not influenced by the events. The regions of localized activity vary from one El Niño (La Niña) event to another; still, some El Niño (La Niña) events are more similar to each other. We quantify this similarity using network community structure. The results and methodology reported here may be used to improve the understanding and prediction of El Niño/La Niña events and also may be applied in the investigation of other climate variables.
Collapse
|
56
|
Dhiman RC, Sarkar S. El Niño Southern Oscillation as an early warning tool for malaria outbreaks in India. Malar J 2017; 16:122. [PMID: 28320394 PMCID: PMC5359847 DOI: 10.1186/s12936-017-1779-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 03/15/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Risks of malaria epidemics in relation to El Niño and Southern Oscillation (ENSO) events have been mapped and studied at global level. In India, where malaria is a major public health problem, no such effort has been undertaken that inter-relates El Niño, Indian Summer Monsoon Rainfall (ISMR) and malaria. The present study has been undertaken to find out the relationship between ENSO events, ISMR and intra-annual variability in malaria cases in India, which in turn could help mitigate the malaria outbreaks. METHODS Correlation coefficients among 'rainfall index' (ISMR), '+ winter ONI' (NDJF) and 'malaria case index' were calculated using annual state-level data for the last 22 years. The 'malaria case index' representing 'relative change from mean' was correlated to the 4 month (November-February) average positive Oceanic Niño Index (ONI). The resultant correlations between '+ winter ONI' and 'malaria case index' were further analysed on geographical information system platform to generate spatial correlation map. RESULTS The correlation between '+ winter ONI' and 'rainfall index' shows that there is great disparity in effect of ENSO over ISMR distribution across the country. Correlation between 'rainfall index' and 'malaria case index' shows that malaria transmission in all geographical regions of India are not equally affected by the ISMR deficit or excess. Correlation between '+ winter ONI' and 'malaria case index' was found ranging from -0.5 to + 0.7 (p < 0.05). A positive correlation indicates that increase in El Niño intensity (+ winter ONI) will lead to rise in total malaria cases in the concurrent year in the states of Orissa, Chhattisgarh, Jharkhand, Bihar, Goa, eastern parts of Madhya Pradesh, part of Andhra Pradesh, Uttarakhand and Meghalaya. Whereas, negative correlations were found in the states of Rajasthan, Haryana, Gujarat, part of Tamil Nadu, Manipur, Mizoram and Sikkim indicating the likelihood of outbreaks in La Nina condition. CONCLUSIONS The generated map, representing spatial correlation between ' + winter ONI' and 'malaria case index', indicates positive correlations in eastern part, while negative correlations in western part of India. This study provides plausible guidelines to national programme for planning intervention measures in view of ENSO events. For better resolution, district level study with inclusion of IOD and 'epochal variation of monsoon rainfall' factors at micro-level is desired for better forecast of malaria outbreaks in the regions with 'no correlation'.
Collapse
Affiliation(s)
- Ramesh C Dhiman
- National Institute of Malaria Research (ICMR), Dwarka Sector 8, Delhi, 110077, India.
| | - Soma Sarkar
- National Institute of Malaria Research (ICMR), Dwarka Sector 8, Delhi, 110077, India
| |
Collapse
|
57
|
Evaluating the Hydrological Cycle over Land Using the Newly-Corrected Precipitation Climatology from the Global Precipitation Climatology Centre (GPCC). ATMOSPHERE 2017. [DOI: 10.3390/atmos8030052] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
58
|
El Niño and Southern Oscillation (ENSO): A Review. CORAL REEFS OF THE EASTERN TROPICAL PACIFIC 2017. [DOI: 10.1007/978-94-017-7499-4_4] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
|
59
|
Sullivan A, Luo JJ, Hirst AC, Bi D, Cai W, He J. Robust contribution of decadal anomalies to the frequency of central-Pacific El Niño. Sci Rep 2016; 6:38540. [PMID: 27917936 PMCID: PMC5137076 DOI: 10.1038/srep38540] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/10/2016] [Indexed: 11/10/2022] Open
Abstract
During year-to-year El Niño events in recent decades, major sea surface warming has occurred frequently in the central Pacific. This is distinct from the eastern Pacific warming pattern during canonical El Niño events. Accordingly, the central-Pacific El Niño exerts distinct impacts on ecosystems, climate and hurricanes worldwide. The increased frequency of the new type of El Niño presents a challenge not only for the understanding of El Niño dynamics and its change but also for the prediction of El Niño and its global impacts at present and future climate. Previous studies have proposed different indices to represent the two types of El Niño for better understanding, prediction and impact assessment. Here, we find that all popularly used indices for the central-Pacific El Niño show a dominant spectral peak at a decadal period with comparatively weak variance at interannual timescales. Our results suggest that decadal anomalies have an important contribution to the occurrence of the central-Pacific El Niño over past decades. Removing the decadal component leads to a significant reduction in the frequency of the central-Pacific El Niño in observations and in Coupled Model Intercomparison Project Phase 5 simulations of preindustrial, historical and future climate.
Collapse
Affiliation(s)
| | | | | | - Daohua Bi
- CSIRO Marine and Atmospheric Research, Melbourne, Australia
| | - Wenju Cai
- CSIRO Marine and Atmospheric Research, Melbourne, Australia
| | - Jinhai He
- Nanjing University of Information Science and Technology, Nanjing, China
| |
Collapse
|
60
|
Himmler T, Bayon G, Wangner D, Enzmann F, Peckmann J, Bohrmann G. Seep-carbonate lamination controlled by cyclic particle flux. Sci Rep 2016; 6:37439. [PMID: 27876764 PMCID: PMC5120270 DOI: 10.1038/srep37439] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 10/28/2016] [Indexed: 11/10/2022] Open
Abstract
Authigenic carbonate build-ups develop at seafloor methane-seeps, where microbially mediated sulphate-dependent anaerobic oxidation of methane facilitates carbonate precipitation. Despite being valuable recorders of past methane seepage events, their role as archives of atmospheric processes has not been examined. Here we show that cyclic sedimentation pulses related to the Indian monsoon in concert with authigenic precipitation of methane-derived aragonite gave rise to a well-laminated carbonate build-up within the oxygen minimum zone off Pakistan (northern Arabian Sea). U-Th dating indicates that the build-up grew during past ~1,130 years, creating an exceptional high-resolution archive of the Indian monsoon system. Monsoon-controlled formation of seep-carbonates extends the known environmental processes recorded by seep-carbonates, revealing a new relationship between atmospheric and seafloor processes.
Collapse
Affiliation(s)
- Tobias Himmler
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany.,IFREMER, Marine Geosciences Research Unit, Centre Bretagne, 29280 Plouzané, France
| | - Germain Bayon
- IFREMER, Marine Geosciences Research Unit, Centre Bretagne, 29280 Plouzané, France
| | - David Wangner
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany.,Geological Survey of Denmark and Greenland, DK-1350 Copenhagen K, Denmark
| | - Frieder Enzmann
- Institute of Geosciences, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
| | - Jörn Peckmann
- Institute of Geology, University of Hamburg, 20146 Hamburg, Germany.,Department for Geodynamics and Sedimentology, University of Vienna, 1090 Vienna, Austria
| | - Gerhard Bohrmann
- MARUM - Center for Marine and Environmental Sciences and Department of Geosciences, University of Bremen, 28334 Bremen, Germany
| |
Collapse
|
61
|
Dimri AP, Thayyen RJ, Kibler K, Stanton A, Jain SK, Tullos D, Singh VP. A review of atmospheric and land surface processes with emphasis on flood generation in the Southern Himalayan rivers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 556:98-115. [PMID: 26974566 DOI: 10.1016/j.scitotenv.2016.02.206] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 06/05/2023]
Abstract
Floods in the southern rim of the Indian Himalayas are a major cause of loss of life, property, crops, infrastructure, etc. They have long term socio-economic impacts on the habitat living along/across the Himalayas. In the recent decade extreme precipitation events have led to numerous flash floods in and around the Himalayan region. Sporadic case-based studies have tried to explain the mechanisms causing the floods. However, in some of the cases, the causative mechanisms have been elusive. Various types of flood events have been debated at different spatial and temporal scales. The present study provides an overview of mechanisms that lead to floods in and around the southern rim of the Indian Himalayas. Atmospheric processes, landuse interaction, and glacier-related outbreaks are considered in the overview.
Collapse
Affiliation(s)
- A P Dimri
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - R J Thayyen
- National Institute of Hydrology, Roorkee, Uttarakhand, India
| | - K Kibler
- University of Central Florida, Orlando, FL, USA
| | - A Stanton
- Water Resources Engineering, Oregon State University, Corvallis, OR, USA
| | - S K Jain
- National Institute of Hydrology, Roorkee, Uttarakhand, India
| | - D Tullos
- Water Resources Engineering, Oregon State University, Corvallis, OR, USA
| | - V P Singh
- Department of Biological and Agricultural Engineering, and Zachry Department of Civil Engineering, Texas A & M University, College Station, TX, USA
| |
Collapse
|
62
|
Mohtadi M, Prange M, Steinke S. Palaeoclimatic insights into forcing and response of monsoon rainfall. Nature 2016; 533:191-9. [PMID: 27172043 DOI: 10.1038/nature17450] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/24/2016] [Indexed: 11/10/2022]
Abstract
Monsoons are the dominant seasonal mode of climate variability in the tropics and are critically important conveyors of atmospheric moisture and energy at a global scale. Predicting monsoons, which have profound impacts on regions that are collectively home to more than 70 per cent of Earth's population, is a challenge that is difficult to overcome by relying on instrumental data from only the past few decades. Palaeoclimatic evidence of monsoon rainfall dynamics across different regions and timescales could help us to understand and predict the sensitivity and response of monsoons to various forcing mechanisms. This evidence suggests that monsoon systems exhibit substantial regional character.
Collapse
Affiliation(s)
- Mahyar Mohtadi
- MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Matthias Prange
- MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| | - Stephan Steinke
- MARUM-Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
| |
Collapse
|
63
|
Percolation Phase Transition of Surface Air Temperature Networks under Attacks of El Niño/La Niña. Sci Rep 2016; 6:26779. [PMID: 27226194 PMCID: PMC4880929 DOI: 10.1038/srep26779] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/09/2016] [Indexed: 11/08/2022] Open
Abstract
In this study, sea surface air temperature over the Pacific is constructed as a network, and the influences of sea surface temperature anomaly in the tropical central eastern Pacific (El Niño/La Niña) are regarded as a kind of natural attack on the network. The results show that El Niño/La Niña leads an abrupt percolation phase transition on the climate networks from stable to unstable or metastable phase state, corresponding to the fact that the climate condition changes from normal to abnormal significantly during El Niño/La Niña. By simulating three different forms of attacks on an idealized network, including Most connected Attack (MA), Localized Attack (LA) and Random Attack (RA), we found that both MA and LA lead to stepwise phase transitions, while RA leads to a second-order phase transition. It is found that most attacks due to El Niño/La Niña are close to the combination of MA and LA, and a percolation critical threshold Pc can be estimated to determine whether the percolation phase transition happens. Therefore, the findings in this study may renew our understandings of the influence of El Niño/La Niña on climate, and further help us in better predicting the subsequent events triggered by El Niño/La Niña.
Collapse
|
64
|
Azad S, Rajeevan M. Possible shift in the ENSO-Indian monsoon rainfall relationship under future global warming. Sci Rep 2016; 6:20145. [PMID: 26837459 PMCID: PMC4738276 DOI: 10.1038/srep20145] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/30/2015] [Indexed: 11/09/2022] Open
Abstract
EI Nino-Southern Oscillation (ENSO) and Indian monsoon rainfall are known to have an inverse relationship, which we have observed in the rainfall spectrum exhibiting a spectral dip in 3-5 y period band. It is well documented that El Nino events are known to be associated with deficit rainfall. Our analysis reveals that this spectral dip (3-5 y) is likely to shift to shorter periods (2.5-3 y) in future, suggesting a possible shift in the relationship between ENSO and monsoon rainfall. Spectral analysis of future climate projections by 20 Coupled Model Intercomparison project 5 (CMIP5) models are employed in order to corroborate our findings. Change in spectral dip speculates early occurrence of drought events in future due to multiple factors of global warming.
Collapse
Affiliation(s)
- Sarita Azad
- Indian Institute of Technology Mandi, Mandi 75001 Himachal Pradesh, India
| | - M Rajeevan
- Indian Institute of Tropical Meteorology, Dr Homi Bhabha Road, Pashan 411 008 Pune, India
| |
Collapse
|
65
|
The Challenge of a 4°C World by 2100. HEXAGON SERIES ON HUMAN AND ENVIRONMENTAL SECURITY AND PEACE 2016. [DOI: 10.1007/978-3-319-43884-9_11] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
66
|
Banu S, Guo Y, Hu W, Dale P, Mackenzie JS, Mengersen K, Tong S. Impacts of El Niño Southern Oscillation and Indian Ocean Dipole on dengue incidence in Bangladesh. Sci Rep 2015; 5:16105. [PMID: 26537857 PMCID: PMC4633589 DOI: 10.1038/srep16105] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 08/14/2015] [Indexed: 11/09/2022] Open
Abstract
Dengue dynamics are driven by complex interactions between hosts, vectors and viruses that are influenced by environmental and climatic factors. Several studies examined the role of El Niño Southern Oscillation (ENSO) in dengue incidence. However, the role of Indian Ocean Dipole (IOD), a coupled ocean atmosphere phenomenon in the Indian Ocean, which controls the summer monsoon rainfall in the Indian region, remains unexplored. Here, we examined the effects of ENSO and IOD on dengue incidence in Bangladesh. According to the wavelet coherence analysis, there was a very weak association between ENSO, IOD and dengue incidence, but a highly significant coherence between dengue incidence and local climate variables (temperature and rainfall). However, a distributed lag nonlinear model (DLNM) revealed that the association between dengue incidence and ENSO or IOD were comparatively stronger after adjustment for local climate variables, seasonality and trend. The estimated effects were nonlinear for both ENSO and IOD with higher relative risks at higher ENSO and IOD. The weak association between ENSO, IOD and dengue incidence might be driven by the stronger effects of local climate variables such as temperature and rainfall. Further research is required to disentangle these effects.
Collapse
Affiliation(s)
- Shahera Banu
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, QLD 4059, Australia
| | - Yuming Guo
- School of Population Health, University of Queensland, Brisbane, QLD 4006, Australia
| | - Wenbiao Hu
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, QLD 4059, Australia
| | - Pat Dale
- Environmental Futures Research Institute, Griffith School of Environment, Griffith University, Brisbane, QLD 4111, Australia
| | - John S Mackenzie
- Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
| | - Kerrie Mengersen
- School of Mathematical Sciences and Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4059, Australia
| | - Shilu Tong
- School of Public Health and Social Work, Queensland University of Technology, Brisbane, QLD 4059, Australia
| |
Collapse
|
67
|
Rethinking Indian monsoon rainfall prediction in the context of recent global warming. Nat Commun 2015; 6:7154. [PMID: 25981180 PMCID: PMC4479044 DOI: 10.1038/ncomms8154] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 04/10/2015] [Indexed: 12/01/2022] Open
Abstract
Prediction of Indian summer monsoon rainfall (ISMR) is at the heart of tropical climate prediction. Despite enormous progress having been made in predicting ISMR since 1886, the operational forecasts during recent decades (1989–2012) have little skill. Here we show, with both dynamical and physical–empirical models, that this recent failure is largely due to the models' inability to capture new predictability sources emerging during recent global warming, that is, the development of the central-Pacific El Nino-Southern Oscillation (CP–ENSO), the rapid deepening of the Asian Low and the strengthening of North and South Pacific Highs during boreal spring. A physical–empirical model that captures these new predictors can produce an independent forecast skill of 0.51 for 1989–2012 and a 92-year retrospective forecast skill of 0.64 for 1921–2012. The recent low skills of the dynamical models are attributed to deficiencies in capturing the developing CP–ENSO and anomalous Asian Low. The results reveal a considerable gap between ISMR prediction skill and predictability. Indian summer monsoon rainfall impacts millions of people and accurate forecasts are highly desirable, yet official operational forecasts have failed to predict extreme events in 1994, 2002, 2004 and 2009. Here, the authors use dynamical and physical–empirical models to investigate the reasons for this failure.
Collapse
|
68
|
A tree-ring reconstruction of the South Asian summer monsoon index over the past millennium. Sci Rep 2014; 4:6739. [PMID: 25338702 PMCID: PMC4206867 DOI: 10.1038/srep06739] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 10/06/2014] [Indexed: 11/17/2022] Open
Abstract
The South Asian summer monsoon (SASM) is a major atmospheric synoptic climate system affecting nearly a quarter of the human population. Climate proxy data derived from tree rings, ice cores, speleothems, and other sources can all contribute to an understanding of SASM variability prior to instrumental period. Here, we develop an optimal information extraction (OIE) method, which we use to reconstruct the SASM index (SASMI) over the last millennium using 15 tree-ring chronologies. The record generated is significantly correlated (r = 0.7, p < 0.01) with the instrumental SASMI record on annual timescales; this correlation is higher than that obtained in any previous study. The reconstructed SASMI captures 18 of 26 (69%) reordered historical famine events in India over the last millennium; notably, 11 of 16 short events with durations of 1–3 years are accurately depicted in our reconstruction. Moreover, the reconstructed SASMI is positively correlated with variations in total solar irradiance (TSI) on multi-decadal timescales implying that variations in solar activity may influence the SASM. Based on the response of SASM to 34 significant volcanic events using the superposed epoch analysis, the volcanic forcing may drive a weak SASM in the second year of an eruption.
Collapse
|
69
|
Rainfall Distributions in Sri Lanka in Time and Space: An Analysis Based on Daily Rainfall Data. CLIMATE 2014. [DOI: 10.3390/cli2040242] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
70
|
Increasing summer rainfall in arid eastern-Central Asia over the past 8500 years. Sci Rep 2014; 4:5279. [PMID: 24923304 PMCID: PMC4055903 DOI: 10.1038/srep05279] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 05/16/2014] [Indexed: 11/08/2022] Open
Abstract
A detailed and well-dated proxy record of summer rainfall variation in arid Central Asia is lacking. Here, we report a long-term, high resolution record of summer rainfall extracted from a peat bog in arid eastern-Central Asia (AECA). The record indicates a slowly but steadily increasing trend of summer rainfall in the AECA over the past 8500 years. On this long-term trend are superimposed several abrupt increases in rainfall on millennial timescales that correspond to rapid cooling events in the North Atlantic. During the last millennium, the hydrological climate pattern of the AECA underwent a major change. The rainfall in the past century has reached its highest level over the 8500-year history, highlighting the significant impact of the human-induced greenhouse effect on the hydrological climate in the AECA. Our results demonstrate that even in very dry eastern-Central Asia, the climate can become wetter under global warming.
Collapse
|
71
|
Bhaskaran B. The reversing roles of local and remote circulations on the Indian summer monsoon under a warming scenario. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
72
|
Shinoda T, Hurlburt HE, Metzger EJ. Anomalous tropical ocean circulation associated with La Niña Modoki. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jc007304] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
73
|
Giese BS, Ray S. El Niño variability in simple ocean data assimilation (SODA), 1871–2008. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006695] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
74
|
Steinhaeuser K, Chawla NV, Ganguly AR. Complex networks as a unified framework for descriptive analysis and predictive modeling in climate science. Stat Anal Data Min 2010. [DOI: 10.1002/sam.10100] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
75
|
Chen W, Dong B, Lu R. Impact of the Atlantic Ocean on the multidecadal fluctuation of El Niño–Southern Oscillation–South Asian monsoon relationship in a coupled general circulation model. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jd013596] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
76
|
Cook ER, Anchukaitis KJ, Buckley BM, D'Arrigo RD, Jacoby GC, Wright WE. Asian Monsoon Failure and Megadrought During the Last Millennium. Science 2010; 328:486-9. [PMID: 20413498 DOI: 10.1126/science.1185188] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Edward R Cook
- Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA.
| | | | | | | | | | | |
Collapse
|
77
|
Abstract
El Niño events, characterized by anomalous warming in the eastern equatorial Pacific Ocean, have global climatic teleconnections and are the most dominant feature of cyclic climate variability on subdecadal timescales. Understanding changes in the frequency or characteristics of El Niño events in a changing climate is therefore of broad scientific and socioeconomic interest. Recent studies show that the canonical El Niño has become less frequent and that a different kind of El Niño has become more common during the late twentieth century, in which warm sea surface temperatures (SSTs) in the central Pacific are flanked on the east and west by cooler SSTs. This type of El Niño, termed the central Pacific El Niño (CP-El Niño; also termed the dateline El Niño, El Niño Modoki or warm pool El Niño), differs from the canonical eastern Pacific El Niño (EP-El Niño) in both the location of maximum SST anomalies and tropical-midlatitude teleconnections. Here we show changes in the ratio of CP-El Niño to EP-El Niño under projected global warming scenarios from the Coupled Model Intercomparison Project phase 3 multi-model data set. Using calculations based on historical El Niño indices, we find that projections of anthropogenic climate change are associated with an increased frequency of the CP-El Niño compared to the EP-El Niño. When restricted to the six climate models with the best representation of the twentieth-century ratio of CP-El Niño to EP-El Niño, the occurrence ratio of CP-El Niño/EP-El Niño is projected to increase as much as five times under global warming. The change is related to a flattening of the thermocline in the equatorial Pacific.
Collapse
|
78
|
|
79
|
Ito H, Ito S, Sasaki Y, Matsuura K, Sawamura M. Copper-Catalyzed Enantioselective Substitution of Allylic Carbonates with Diboron: An Efficient Route to Optically Active α-Chiral Allylboronates. J Am Chem Soc 2007; 129:14856-7. [DOI: 10.1021/ja076634o] [Citation(s) in RCA: 266] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hajime Ito
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Shinichiro Ito
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yusuke Sasaki
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Kou Matsuura
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Masaya Sawamura
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| |
Collapse
|
80
|
Abram NJ, Gagan MK, Liu Z, Hantoro WS, McCulloch MT, Suwargadi BW. Seasonal characteristics of the Indian Ocean Dipole during the Holocene epoch. Nature 2007; 445:299-302. [PMID: 17230187 DOI: 10.1038/nature05477] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 11/21/2006] [Indexed: 11/09/2022]
Abstract
The Indian Ocean Dipole (IOD)--an oscillatory mode of coupled ocean-atmosphere variability--causes climatic extremes and socio-economic hardship throughout the tropical Indian Ocean region. There is much debate about how the IOD interacts with the El Niño/Southern Oscillation (ENSO) and the Asian monsoon, and recent changes in the historic ENSO-monsoon relationship raise the possibility that the properties of the IOD may also be evolving. Improving our understanding of IOD events and their climatic impacts thus requires the development of records defining IOD activity in different climatic settings, including prehistoric times when ENSO and the Asian monsoon behaved differently from the present day. Here we use coral geochemical records from the equatorial eastern Indian Ocean to reconstruct surface-ocean cooling and drought during individual IOD events over the past approximately 6,500 years. We find that IOD events during the middle Holocene were characterized by a longer duration of strong surface ocean cooling, together with droughts that peaked later than those expected by El Niño forcing alone. Climate model simulations suggest that this enhanced cooling and drying was the result of strong cross-equatorial winds driven by the strengthened Asian monsoon of the middle Holocene. These IOD-monsoon connections imply that the socioeconomic impacts of projected future changes in Asian monsoon strength may extend throughout Australasia.
Collapse
Affiliation(s)
- Nerilie J Abram
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
| | | | | | | | | | | |
Collapse
|
81
|
Abstract
The El Niño-Southern Oscillation (ENSO) cycle of alternating warm El Niño and cold La Niña events is the dominant year-to-year climate signal on Earth. ENSO originates in the tropical Pacific through interactions between the ocean and the atmosphere, but its environmental and socioeconomic impacts are felt worldwide. Spurred on by the powerful 1997-1998 El Niño, efforts to understand the causes and consequences of ENSO have greatly expanded in the past few years. These efforts reveal the breadth of ENSO's influence on the Earth system and the potential to exploit its predictability for societal benefit. However, many intertwined issues regarding ENSO dynamics, impacts, forecasting, and applications remain unresolved. Research to address these issues will not only lead to progress across a broad range of scientific disciplines but also provide an opportunity to educate the public and policy makers about the importance of climate variability and change in the modern world.
Collapse
|
82
|
Van Noorden R. Predicting monsoons gets easier. Nature 2006. [DOI: 10.1038/news060904-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|