51
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Li Z, Cai W, Lin X. Dynamics of changing impacts of tropical Indo-Pacific variability on Indian and Australian rainfall. Sci Rep 2016; 6:31767. [PMID: 27546030 PMCID: PMC4992885 DOI: 10.1038/srep31767] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 07/27/2016] [Indexed: 11/26/2022] Open
Abstract
A positive Indian Ocean Dipole (IOD) and a warm phase of the El Niño-Southern Oscillation (ENSO) reduce rainfall over the Indian subcontinent and southern Australia. However, since the 1980s, El Niño's influence has been decreasing, accompanied by a strengthening in the IOD's influence on southern Australia but a reversal in the IOD's influence on the Indian subcontinent. The dynamics are not fully understood. Here we show that a post-1980 weakening in the ENSO-IOD coherence plays a key role. During the pre-1980 high coherence, ENSO drives both the IOD and regional rainfall, and the IOD's influence cannot manifest itself. During the post-1980 weak coherence, a positive IOD leads to increased Indian rainfall, offsetting the impact from El Niño. Likewise, the post-1980 weak ENSO-IOD coherence means that El Niño's pathway for influencing southern Australia cannot fully operate, and as positive IOD becomes more independent and more frequent during this period, its influence on southern Australia rainfall strengthens. There is no evidence to support that greenhouse warming plays a part in these decadal fluctuations.
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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
| | - 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
| | - Xiaopei Lin
- Physical Oceanography Laboratory/CIMST, Ocean University of China and Qingdao National Laboratory for Marine Science and Technology, Qingdao 266100, China
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52
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High sensitivity of Indian summer monsoon to Middle East dust absorptive properties. Sci Rep 2016; 6:30690. [PMID: 27465689 PMCID: PMC4964619 DOI: 10.1038/srep30690] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/04/2016] [Indexed: 11/20/2022] Open
Abstract
The absorptive properties of dust aerosols largely determine the magnitude of their radiative impacts on the climate system. Currently, climate models use globally constant values of dust imaginary refractive index (IRI), a parameter describing the dust absorption efficiency of solar radiation, although it is highly variable. Here we show with model experiments that the dust-induced Indian summer monsoon (ISM) rainfall differences (with dust minus without dust) change from −9% to 23% of long-term climatology as the dust IRI is changed from zero to the highest values used in the current literature. A comparison of the model results with surface observations, satellite retrievals, and reanalysis data sets indicates that the dust IRI values used in most current climate models are too low, tending to significantly underestimate dust radiative impacts on the ISM system. This study highlights the necessity for developing a parameterization of dust IRI for climate studies.
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53
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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.
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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
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54
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Revadekar JV, Varikoden H, Murumkar PK, Ahmed SA. On the relationship between sea surface temperatures, circulation parameters and temperatures over west coast of India. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 551-552:175-185. [PMID: 26874773 DOI: 10.1016/j.scitotenv.2016.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 01/27/2016] [Accepted: 02/02/2016] [Indexed: 06/05/2023]
Abstract
The oceans and the atmosphere are tightly linked and they together form the most dynamic component of the climate system. Topography and proximity to the surrounding seas of the region determine the temperature of the area. West Coast (WC) of India is a high elevated region surrounded by large oceanic area, therefore, an attempt is made in this study to examine the trends and variability in temperature over WC in relation to oceanic phenomena. Temperature over the WC shows considerable year-to-year variation with anomalous cool years in recent warm epoch. Therefore, sea surface temperature (SST) and associated winds have been analyzed to understand possible mechanism behind the variation in temperatures over the WC. During the winter, north-easterlies prevail over the WC which blows from land to ocean. Variations in SSTs alter the strength of these winds to cause anomalies in temperature over the WC. Indian Ocean Dipole (IOD) appears to have a dominant role in climate of the WC, whereas SSTs over the equatorial Pacific do not show any impact on temperatures over the WC. Study indicates that the strengthening of north-easterlies due to negative phase of Indian Ocean Dipole causes cooling over the WC of India.
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Affiliation(s)
- J V Revadekar
- Center for Climate Change Research, Indian Institute of Tropical Meteorology, Pune 411008, India.
| | - Hamza Varikoden
- Center for Climate Change Research, Indian Institute of Tropical Meteorology, Pune 411008, India
| | - P K Murumkar
- Center for Climate Change Research, Indian Institute of Tropical Meteorology, Pune 411008, India; Department of Geology, Central University of Karnataka, Kalaburagi, India
| | - S A Ahmed
- Department of Geology, Central University of Karnataka, Kalaburagi, India
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55
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Zhao P, Wang B, Liu J, Zhou X, Chen J, Nan S, Liu G, Xiao D. Summer precipitation anomalies in Asia and North America induced by Eurasian non-monsoon land heating versus ENSO. Sci Rep 2016; 6:21346. [PMID: 26916258 PMCID: PMC4768350 DOI: 10.1038/srep21346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/22/2016] [Indexed: 11/09/2022] Open
Abstract
When floods ravage Asian monsoon regions in summer, megadroughts often attack extratropical North America, which feature an intercontinental contrasting precipitation anomaly between Asia and North America. However, the characteristics of the contrasting Asian-North American (CANA) precipitation anomalies and associated mechanisms have not been investigated specifically. In this article, we firmly establish this summer CANA pattern, providing evidence for a significant effect of the land surface thermal forcing over Eurasian non-monsoon regions on the CANA precipitation anomalies by observations and numerical experiments. We show that the origin of the CANA precipitation anomalies and associated anomalous anticyclones over the subtropical North Pacific and Atlantic has a deeper root in Eurasian non-monsoon land surface heating than in North American land surface heating. The ocean forcing from the ENSO is secondary and tends to be confined in the tropics. Our results have strong implications to interpretation of the feedback of global warming on hydrological cycle over Asia and North America. Under the projected global warming due to the anthropogenic forcing, the prominent surface warming over Eurasian non-monsoon regions is a robust feature which, through the mechanism discussed here, would favor a precipitation increase over Asian monsoon regions and a precipitation decrease over extratropical North America.
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Affiliation(s)
- Ping Zhao
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China.,Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing, China
| | - Bin Wang
- International Pacific Research Center, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, HI, USA.,Earth System Modeling Center, Nanjing University of Information Science and Technology, Nanjing, China
| | - Jiping Liu
- Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, NY, USA
| | - Xiuji Zhou
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
| | - Junming Chen
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
| | - Sulan Nan
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
| | - Ge Liu
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
| | - Dong Xiao
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing, China
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56
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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.
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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
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57
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Runge J, Petoukhov V, Donges JF, Hlinka J, Jajcay N, Vejmelka M, Hartman D, Marwan N, Paluš M, Kurths J. Identifying causal gateways and mediators in complex spatio-temporal systems. Nat Commun 2015; 6:8502. [PMID: 26443010 PMCID: PMC4633716 DOI: 10.1038/ncomms9502] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/28/2015] [Indexed: 11/08/2022] Open
Abstract
Identifying regions important for spreading and mediating perturbations is crucial to assess the susceptibilities of spatio-temporal complex systems such as the Earth's climate to volcanic eruptions, extreme events or geoengineering. Here a data-driven approach is introduced based on a dimension reduction, causal reconstruction, and novel network measures based on causal effect theory that go beyond standard complex network tools by distinguishing direct from indirect pathways. Applied to a data set of atmospheric dynamics, the method identifies several strongly uplifting regions acting as major gateways of perturbations spreading in the atmosphere. Additionally, the method provides a stricter statistical approach to pathways of atmospheric teleconnections, yielding insights into the Pacific-Indian Ocean interaction relevant for monsoonal dynamics. Also for neuroscience or power grids, the novel causal interaction perspective provides a complementary approach to simulations or experiments for understanding the functioning of complex spatio-temporal systems with potential applications in increasing their resilience to shocks or extreme events.
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Affiliation(s)
- Jakob Runge
- Potsdam Institute for Climate Impact Research, PO Box 60 12 03, Potsdam 14412, Germany
- Department of Physics, Humboldt University, Newtonstrasse 15, Berlin 12489, Germany
| | - Vladimir Petoukhov
- Potsdam Institute for Climate Impact Research, PO Box 60 12 03, Potsdam 14412, Germany
| | - Jonathan F. Donges
- Potsdam Institute for Climate Impact Research, PO Box 60 12 03, Potsdam 14412, Germany
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, Stockholm 11419, Sweden
| | - Jaroslav Hlinka
- Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod vodárenskou věží 2, Prague 8 18207, Czech Republic
| | - Nikola Jajcay
- Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod vodárenskou věží 2, Prague 8 18207, Czech Republic
- Department of Atmospheric Physics, Charles University, V Holešovičkách 2, Prague 8 18000, Czech Republic
| | - Martin Vejmelka
- Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod vodárenskou věží 2, Prague 8 18207, Czech Republic
| | - David Hartman
- Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod vodárenskou věží 2, Prague 8 18207, Czech Republic
- Computer Science Institute, Charles University, Malostranské náměstí, 2/25, Prague 1, 18000, Czech Republic
| | - Norbert Marwan
- Potsdam Institute for Climate Impact Research, PO Box 60 12 03, Potsdam 14412, Germany
| | - Milan Paluš
- Department of Nonlinear Dynamics and Complex Systems, Institute of Computer Science, Academy of Sciences of the Czech Republic, Pod vodárenskou věží 2, Prague 8 18207, Czech Republic
| | - Jürgen Kurths
- Potsdam Institute for Climate Impact Research, PO Box 60 12 03, Potsdam 14412, Germany
- Department of Physics, Humboldt University, Newtonstrasse 15, Berlin 12489, Germany
- Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen AB24 3UE, UK
- Department of Control Theory, Nizhny Novgorod State University, Gagarin Avenue 23, Nizhny Novgorod 606950, Russia
- Institute of Applied Physics of the Russian Academy of Sciences, Ul Ulyanova 46, 603950, Nizhny Novgorod, Russia
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58
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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.
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59
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60
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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]
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61
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Kumar KR, Revadekar JV, Tiwari YK. AIRS retrieved CO2 and its association with climatic parameters over India during 2004-2011. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 476-477:79-89. [PMID: 24463028 DOI: 10.1016/j.scitotenv.2013.12.118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 12/04/2013] [Accepted: 12/29/2013] [Indexed: 06/03/2023]
Abstract
Atmospheric Infrared Sounder (AIRS) retrieved mid-tropospheric Carbon Dioxide (CO2) have been used to study the variability and its association with the climatic parameters over India during 2004 to 2011. The study also aims in understanding transport of CO2 from surface to mid-troposphere over India. The annual cycle of mid-tropospheric CO2 shows gradual increase in concentration from January till the month of May at the rate ~0.6 ppm/month. It decreases continuously in summer monsoon (JJAS) at the same rate during which strong westerlies persists over the region. A slight increase is seen during winter monsoon (DJF). Being a greenhouse gas, annual cycle of CO2 show good resemblance with annual cycle of surface air temperature with correlation coefficient (CC) of +0.8. Annual cycle of vertical velocity indicate inverse pattern compared to annual cycle of CO2. High values of mid-tropospheric CO2 correspond to upward wind, while low values of mid-tropospheric CO2 correspond to downward wind. In addition to vertical motion, zonal winds are also contributing towards the transport of CO2 from surface to mid-troposphere. Vegetation as it absorbs CO2 at surface level, show inverse annual cycle to that of annual cycle of CO2 (CC-0.64). Seasonal variation of rainfall-CO2 shows similarities with seasonal variation of NDVI-CO2. However, the use of long period data sets for CO2 at the surface and at the mid-troposphere will be an advantage to confirm these results.
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Affiliation(s)
- K Ravi Kumar
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, India
| | - J V Revadekar
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, India
| | - Yogesh K Tiwari
- Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, India.
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62
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Shaw AK, Kelly KA. Linking El Niño, local rainfall, and migration timing in a tropical migratory species. GLOBAL CHANGE BIOLOGY 2013; 19:3283-3290. [PMID: 23821605 DOI: 10.1111/gcb.12311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 06/10/2013] [Accepted: 06/25/2013] [Indexed: 06/02/2023]
Abstract
Current climate models project changes in both temperature and precipitation patterns across the globe in the coming years. Migratory species, which move to take advantage of seasonal climate patterns, are likely to be affected by these changes, and indeed, a number of studies have shown a relationship between changing climate and the migration timing of various species. However, these studies have almost exclusively focused on the effects of temperature change on species that inhabit temperate zones. Here, we explore the relationship between rainfall and migration timing in a tropical species, Gecarcoidea natalis (Christmas Island red crab). We find that the timing of the annual crab breeding migration is closely related to the amount of rain that falls during a 'migration window' period prior to potential egg release dates, which is in turn related to the Southern Oscillation Index, an atmospheric El Niño-Southern Oscillation Index. As reproduction in this species is conditional on successful migration, major changes in migration patterns could have detrimental consequences for the survival of the species. This study serves to broaden our understanding of the effects of climate change on migratory species and will hopefully inspire future work on rainfall and tropical migrations.
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Affiliation(s)
- Allison K Shaw
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, 08544, USA; Division of Evolution, Ecology and Genetics, Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia; Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, 55108, USA
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63
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Predicting Pacific Decadal Variability. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/147gm06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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64
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Ishizaki Y, Yoshimura K, Kanae S, Kimoto M, Kurita N, Oki T. Interannual variability of H218O in precipitation over the Asian monsoon region. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd015890] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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65
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Staver AC, Levin SA. Integrating theoretical climate and fire effects on savanna and forest systems. Am Nat 2012; 180:211-24. [PMID: 22766932 DOI: 10.1086/666648] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The role of fire and climate in determining savanna and forest distributions requires comprehensive theoretical reevaluation. Empirical studies show that climate constrains maximum tree cover and that fire feedbacks can reduce tree cover substantially, but neither the stability nor the dynamics of these systems are well understood. A theoretical integration of rainfall effects with fire processes in particular is lacking. We use simple, well-supported assumptions about the percolation dynamics of fire spread and the demographic effects of climate and fire on trees to build a dynamic model examining the stability of tree cover in savannas and forests. Fire results in the potential for one or possibly two stable equilibria, while the effects of increasing rainfall on tree demography result in (discontinuous) increases in tree cover and in forest tree dominance. As rainfall increases, the system moves from (1) stable low tree cover to (2) bistability of low and high tree cover to (3) stable high tree cover. Thus, theory suggests that tree cover uniquely determined by climate at low and high rainfall but determined by fire feedbacks at intermediate rainfall-as empirical studies suggest-may be a universal feature of systems where fire has strong effects on tree demography.
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Affiliation(s)
- A Carla Staver
- Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, USA.
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66
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Mishra V, Smoliak BV, Lettenmaier DP, Wallace JM. A prominent pattern of year-to-year variability in Indian Summer Monsoon Rainfall. Proc Natl Acad Sci U S A 2012; 109:7213-7. [PMID: 22529372 PMCID: PMC3358870 DOI: 10.1073/pnas.1119150109] [Citation(s) in RCA: 172] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dominant patterns of Indian Summer Monsoon Rainfall (ISMR) and their relationships with the sea surface temperature and 850-hPa wind fields are examined using gridded datasets from 1900 on. The two leading empirical orthogonal functions (EOFs) of ISMR over India are used as basis functions for elucidating these relationships. EOF1 is highly correlated with all India rainfall and El Niño-Southern Oscillation indices. EOF2 involves rainfall anomalies of opposing polarity over the Gangetic Plain and peninsular India. The spatial pattern of the trends in ISMR from 1950 on shows drying over the Gangetic Plain projects onto EOF2, with an expansion coefficient that exhibits a pronounced trend during this period. EOF2 is coupled with the dominant pattern of sea surface temperature variability over the Indian Ocean sector, which involves in-phase fluctuations over the Arabian Sea, the Bay of Bengal, and the South China Sea, and it is correlated with the previous winter's El Niño-Southern Oscillation indices. The circulation anomalies observed in association with fluctuations in the time-varying indices of EOF1 and EOF2 both involve distortions of the low-level monsoon flow. EOF1 in its positive polarity represents a southward deflection of moist, westerly monsoon flow from the Arabian Sea across India, resulting in a smaller flux of moisture to the Himalayas. EOF2 in its positive polarity represents a weakening of the monsoon trough over northeastern India and the westerly monsoon flow across southern India, reminiscent of the circulation anomalies observed during break periods within the monsoon season.
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Affiliation(s)
- Vimal Mishra
- Civil and Environmental Engineering, University of Washington, Seattle, WA 98195, USA.
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67
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Sun J, Wang H. Changes of the connection between the summer North Atlantic Oscillation and the East Asian summer rainfall. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jd017482] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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68
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Kim ST, Yu JY, Lu MM. The distinct behaviors of Pacific and Indian Ocean warm pool properties on seasonal and interannual time scales. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jd016557] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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69
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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]
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70
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Xu C, Sano M, Nakatsuka T. Tree ring celluloseδ18O ofFokienia hodginsiiin northern Laos: A promising proxy to reconstruct ENSO? ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016694] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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71
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Dobler A, Ahrens B. Four climate change scenarios for the Indian summer monsoon by the regional climate model COSMO-CLM. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd016329] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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72
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Webster PJ, Jian J. Environmental prediction, risk assessment and extreme events: adaptation strategies for the developing world. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:4768-97. [PMID: 22042897 PMCID: PMC3270389 DOI: 10.1098/rsta.2011.0160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The uncertainty associated with predicting extreme weather events has serious implications for the developing world, owing to the greater societal vulnerability to such events. Continual exposure to unanticipated extreme events is a contributing factor for the descent into perpetual and structural rural poverty. We provide two examples of how probabilistic environmental prediction of extreme weather events can support dynamic adaptation. In the current climate era, we describe how short-term flood forecasts have been developed and implemented in Bangladesh. Forecasts of impending floods with horizons of 10 days are used to change agricultural practices and planning, store food and household items and evacuate those in peril. For the first time in Bangladesh, floods were anticipated in 2007 and 2008, with broad actions taking place in advance of the floods, grossing agricultural and household savings measured in units of annual income. We argue that probabilistic environmental forecasts disseminated to an informed user community can reduce poverty caused by exposure to unanticipated extreme events. Second, it is also realized that not all decisions in the future can be made at the village level and that grand plans for water resource management require extensive planning and funding. Based on imperfect models and scenarios of economic and population growth, we further suggest that flood frequency and intensity will increase in the Ganges, Brahmaputra and Yangtze catchments as greenhouse-gas concentrations increase. However, irrespective of the climate-change scenario chosen, the availability of fresh water in the latter half of the twenty-first century seems to be dominated by population increases that far outweigh climate-change effects. Paradoxically, fresh water availability may become more critical if there is no climate change.
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Affiliation(s)
- Peter J Webster
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
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73
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Staver AC, Archibald S, Levin SA. The global extent and determinants of savanna and forest as alternative biome states. Science 2011; 334:230-2. [PMID: 21998389 DOI: 10.1126/science.1210465] [Citation(s) in RCA: 417] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Theoretically, fire-tree cover feedbacks can maintain savanna and forest as alternative stable states. However, the global extent of fire-driven discontinuities in tree cover is unknown, especially accounting for seasonality and soils. We use tree cover, climate, fire, and soils data sets to show that tree cover is globally discontinuous. Climate influences tree cover globally but, at intermediate rainfall (1000 to 2500 millimeters) with mild seasonality (less than 7 months), tree cover is bimodal, and only fire differentiates between savanna and forest. These may be alternative states over large areas, including parts of Amazonia and the Congo. Changes in biome distributions, whether at the cost of savanna (due to fragmentation) or forest (due to climate), will be neither smooth nor easily reversible.
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Affiliation(s)
- A Carla Staver
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA.
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74
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Wu R, Yang S, Liu S, Sun L, Lian Y, Gao Z. Northeast China summer temperature and North Atlantic SST. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015779] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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75
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Wang SY, Davies RE, Huang WR, Gillies RR. Pakistan's two-stage monsoon and links with the recent climate change. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jd015760] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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76
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Kelly P, Mapes B. Zonal mean wind, the Indian monsoon, and July drying in the western Atlantic subtropics. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jd015405] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Patrick Kelly
- Division of Meteorology and Physical Oceanography, Rosenstiel School of Marine and Atmospheric Science; University of Miami; Miami Florida USA
| | - Brian Mapes
- Division of Meteorology and Physical Oceanography, Rosenstiel School of Marine and Atmospheric Science; University of Miami; Miami Florida USA
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77
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Wu R, Yang S, Liu S, Sun L, Lian Y, Gao Z. Changes in the relationship between Northeast China summer temperature and ENSO. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2010jd014422] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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78
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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]
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79
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Wahl ER, Morrill C. Climate change. Toward understanding and predicting monsoon patterns. Science 2010; 328:437-8. [PMID: 20413481 DOI: 10.1126/science.1188926] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Eugene R Wahl
- NOAA-National Climatic Data Center-Paleoclimatology Branch, World Data Center for Paleoclimatology, 325 Broadway, Boulder, CO 80305, USA.
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80
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81
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Zhang Z, Cazelles B, Tian H, Stige LC, Bräuning A, Stenseth NC. Periodic temperature-associated drought/flood drives locust plagues in China. Proc Biol Sci 2009; 276:823-31. [PMID: 19033144 DOI: 10.1098/rspb.2008.1284] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Global warming is currently of great concern. Yet the ecological effects of low-frequency climate variations remain largely unknown. Recent analyses of interdecadal variability in population abundance of the Oriental migratory locust (Locusta migratoria manilensis) in China have revealed negative associations with temperature and positive associations with Yangtze drought and flood frequencies during the past millennium (AD 957-1956). In order to shed new light on the causal relationships between locust abundance, floods, droughts and temperature in ancient China, we used wavelet analysis to explore how the coherencies between the different variables at different frequencies have been changed during the past millennium. We find consistent in-phase coherencies between locusts and drought/flood frequencies, and out-of-phase coherencies between locusts and temperature and between drought/flood and temperature at period components of 160-170 years. Similar results are obtained when historical data of drought/flood frequencies of the Yangtze Delta region are used, despite flood data showing a weak and somewhat inconsistent association with other factors. We suggest that previously unreported periodic cooling of 160-170-year intervals dominate climatic variability in China through the past millennium, the cooling events promoting locust plagues by enhancing temperature-associated drought/flood events. Our results signify a rare example of possible benign effects of global warming on the regional risk of natural disasters such as flood/drought events and outbreaks of pest insects.
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Affiliation(s)
- Zhibin Zhang
- Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
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82
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Maity R, Kashid SS. HYDROCLIMATOLOGICAL APPROACH FOR MONTHLY STREAMFLOW PREDICTION USING GENETIC PROGRAMMING. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/09715010.2009.10514943] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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83
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Wang B, Yang J, Zhou T, Wang B. Interdecadal Changes in the Major Modes of Asian–Australian Monsoon Variability: Strengthening Relationship with ENSO since the Late 1970s*. JOURNAL OF CLIMATE 2008; 21:1771-1789. [DOI: 10.1175/2007jcli1981.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
The present paper develops an integral view of the year-to-year variability across the entire Asian–Australian monsoon (A–AM) system, which covers one-third of the global tropics between 40° and 160°E. Using season-reliant empirical orthogonal function (S-EOF) analysis, the authors identified two major modes of variability for the period 1956–2004. The first exhibits a prominent biennial tendency and concurs with the turnabout of El Niño–Southern Oscillation (ENSO), providing a new perspective of the seasonally evolving spatiotemporal structure for tropospheric biennial oscillation. The second mode leads ENSO by one year. The remote El Niño forcing, the monsoon–warm pool ocean interaction, and the influence of the annual cycle are three fundamental factors for understanding the behavior of the first mode. The monsoon–ocean interaction is characterized by a positive feedback between the off-equatorial convectively coupled Rossby waves and the underlying sea surface temperature (SST) “dipole” anomalies.
Since the late 1970s the overall coupling between the A–AM system and ENSO has become strengthened. The relationships between ENSO and the western North Pacific, East Asian, and Indonesian monsoons have all become enhanced during ENSO’s developing, mature, and decaying phases, overriding the weakening of the Indian monsoon–ENSO anticorrelation during the developing phase. Prior to the late 1970s (1956–79), the first mode shows a strong biennial tendency, and the second mode does not lead ENSO. After 1980, the first mode shows a weakening biennial tendency, and the second mode provides a strong precursory signal for ENSO. These interdecadal changes are attributed to increased magnitude and periodicity of ENSO and the strengthened monsoon–ocean interaction.
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Affiliation(s)
- Bin Wang
- Department of Meteorology, and International Pacific Research Center, University of Hawaii at Manoa, Honolulu, Hawaii
| | - Jing Yang
- Department of Meteorology, and International Pacific Research Center, University of Hawaii at Manoa, Honolulu, Hawaii, and LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Tianjun Zhou
- LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Bin Wang
- LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
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84
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Comprehensive analysis of the impact of climatic changes on Chinese terrestrial net primary productivity. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11434-007-0521-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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85
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Weinstock EM, Pittman JV, Sayres DS, Smith JB, Anderson JG, Wofsy SC, Xueref I, Gerbig C, Daube BC, Pfister L, Richard EC, Ridley BA, Weinheimer AJ, Jost HJ, Lopez JP, Loewenstein M, Thompson TL. Quantifying the impact of the North American monsoon and deep midlatitude convection on the subtropical lowermost stratosphere using in situ measurements. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007jd008554] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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86
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Stager JC, Ruzmaikin A, Conway D, Verburg P, Mason PJ. Sunspots, El Niño, and the levels of Lake Victoria, East Africa. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2006jd008362] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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87
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Marchant R, Mumbi C, Behera S, Yamagata T. The Indian Ocean dipole ? the unsung driver of climatic variability in East Africa. Afr J Ecol 2007. [DOI: 10.1111/j.1365-2028.2006.00707.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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88
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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.
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Affiliation(s)
- Nerilie J Abram
- Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.
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89
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Yancheva G, Nowaczyk NR, Mingram J, Dulski P, Schettler G, Negendank JFW, Liu J, Sigman DM, Peterson LC, Haug GH. Influence of the intertropical convergence zone on the East Asian monsoon. Nature 2007; 445:74-7. [PMID: 17203059 DOI: 10.1038/nature05431] [Citation(s) in RCA: 657] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 11/06/2006] [Indexed: 11/09/2022]
Abstract
The Asian-Australian monsoon is an important component of the Earth's climate system that influences the societal and economic activity of roughly half the world's population. The past strength of the rain-bearing East Asian summer monsoon can be reconstructed with archives such as cave deposits, but the winter monsoon has no such signature in the hydrological cycle and has thus proved difficult to reconstruct. Here we present high-resolution records of the magnetic properties and the titanium content of the sediments of Lake Huguang Maar in coastal southeast China over the past 16,000 years, which we use as proxies for the strength of the winter monsoon winds. We find evidence for stronger winter monsoon winds before the Bølling-Allerød warming, during the Younger Dryas episode and during the middle and late Holocene, when cave stalagmites suggest weaker summer monsoons. We conclude that this anticorrelation is best explained by migrations in the intertropical convergence zone. Similar migrations of the intertropical convergence zone have been observed in Central America for the period ad 700 to 900 (refs 4-6), suggesting global climatic changes at that time. From the coincidence in timing, we suggest that these migrations in the tropical rain belt could have contributed to the declines of both the Tang dynasty in China and the Classic Maya in Central America.
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Affiliation(s)
- Gergana Yancheva
- GeoForschungsZentrum (GFZ), Section 3.3, Telegrafenberg, Potsdam D-14473, Germany
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90
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Maity R, Kumar DN, Nanjundiah RS. REVIEW OF HYDROCLIMATIC TELECONNECTION BETWEEN HYDROLOGIC VARIABLES AND LARGE-SCALE ATMOSPHERIC CIRCULATION PATTERNS WITH INDIAN PERSPECTIVE. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/09715010.2007.10514859] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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91
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Yang H, Jia X, Li C. The tropical Pacific-Indian Ocean temperature anomaly mode and its effect. CHINESE SCIENCE BULLETIN-CHINESE 2006. [DOI: 10.1007/s11434-006-2199-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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92
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Kumar KK, Rajagopalan B, Hoerling M, Bates G, Cane M. Unraveling the Mystery of Indian Monsoon Failure During El Nino. Science 2006; 314:115-9. [PMID: 16959975 DOI: 10.1126/science.1131152] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The 132-year historical rainfall record reveals that severe droughts in India have always been accompanied by El Niño events. Yet El Niño events have not always produced severe droughts. We show that El Niño events with the warmest sea surface temperature (SST) anomalies in the central equatorial Pacific are more effective in focusing drought-producing subsidence over India than events with the warmest SSTs in the eastern equatorial Pacific. The physical basis for such different impacts is established using atmospheric general circulation model experiments forced with idealized tropical Pacific warmings. These findings have important implications for Indian monsoon forecasting.
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Affiliation(s)
- K Krishna Kumar
- Indian Institute of Tropical Meteorology, Pune, 411008, India
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93
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Hong B, Lin Q, Hong Y. Interconnections between the Asian monsoon, ENSO, and high northern latitude climate during the Holocene. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/s11434-006-2112-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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94
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Dore MHI. Climate change and changes in global precipitation patterns: what do we know? ENVIRONMENT INTERNATIONAL 2005; 31:1167-81. [PMID: 15922449 DOI: 10.1016/j.envint.2005.03.004] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2004] [Accepted: 03/10/2005] [Indexed: 05/02/2023]
Abstract
The objective of this paper is to synthesize the large literature recording changing patterns of precipitation in the observed data, thus indicating that climate change is already a reality. Such a synthesis is required not only for environmental researchers but also for policy makers. The key question is the broad picture at major regional and continental levels. Some interesting conclusions for this survey are emerging. For example, the review shows increased variance of precipitation everywhere. Consistent with this finding, we observe that wet areas become wetter, and dry and arid areas become more so. In addition, the following general changing pattern is emerging: (a) increased precipitation in high latitudes (Northern Hemisphere); (b) reductions in precipitation in China, Australia and the Small Island States in the Pacific; and (c) increased variance in equatorial regions. The changes in the major ocean currents also appear to be affecting precipitation patterns. For example, increased intensity and frequency of El Niño and ENSO seem associated with evidence of an observed "dipole" pattern affecting Africa and Asia, although this time series is too short so far. But the changing pattern calls for renewed efforts at adaptation to climate change, as the changing precipitation pattern will also affect the regional availability of food supply.
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Affiliation(s)
- Mohammed H I Dore
- Climate Change Laboratory, Brock University, St Catharines, ON, Canada L2S 3A1.
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95
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Goes JI, Thoppil PG, Gomes HDR, Fasullo JT. Warming of the Eurasian Landmass Is Making the Arabian Sea More Productive. Science 2005; 308:545-7. [PMID: 15845852 DOI: 10.1126/science.1106610] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The recent trend of declining winter and spring snow cover over Eurasia is causing a land-ocean thermal gradient that is particularly favorable to stronger southwest (summer) monsoon winds. Since 1997, sea surface winds have been strengthening over the western Arabian Sea. This escalation in the intensity of summer monsoon winds, accompanied by enhanced upwelling and an increase of more than 350% in average summertime phytoplankton biomass along the coast and over 300% offshore, raises the possibility that the current warming trend of the Eurasian landmass is making the Arabian Sea more productive.
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Affiliation(s)
- Joaquim I Goes
- Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, ME 04575, USA.
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96
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Challinor AJ, Wheeler TR, Slingo JM, Craufurd PQ, Grimes DIF. Simulation of Crop Yields Using ERA-40: Limits to Skill and Nonstationarity in Weather–Yield Relationships. ACTA ACUST UNITED AC 2005. [DOI: 10.1175/jam2212.1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Reanalysis data provide an excellent test bed for impacts prediction systems, because they represent an upper limit on the skill of climate models. Indian groundnut (Arachis hypogaea L.) yields have been simulated using the General Large-Area Model (GLAM) for annual crops and the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-yr reanalysis (ERA-40). The ability of ERA-40 to represent the Indian summer monsoon has been examined. The ability of GLAM, when driven with daily ERA-40 data, to model both observed yields and observed relationships between subseasonal weather and yield has been assessed. Mean yields were simulated well across much of India. Correlations between observed and modeled yields, where these are significant, are comparable to correlations between observed yields and ERA-40 rainfall. Uncertainties due to the input planting window, crop duration, and weather data have been examined. A reduction in the root-mean-square error of simulated yields was achieved by applying bias correction techniques to the precipitation. The stability of the relationship between weather and yield over time has been examined. Weather–yield correlations vary on decadal time scales, and this has direct implications for the accuracy of yield simulations. Analysis of the skewness of both detrended yields and precipitation suggest that nonclimatic factors are partly responsible for this nonstationarity. Evidence from other studies, including data on cereal and pulse yields, indicates that this result is not particular to groundnut yield. The detection and modeling of nonstationary weather–yield relationships emerges from this study as an important part of the process of understanding and predicting the impacts of climate variability and change on crop yields.
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Affiliation(s)
- A. J. Challinor
- Centre for Global Atmospheric Modelling, Department of Meteorology, and Department of Agriculture, The University of Reading, Reading, United Kingdom
| | - T. R. Wheeler
- Department of Agriculture, The University of Reading, Reading, United Kingdom
| | - J. M. Slingo
- Centre for Global Atmospheric Modelling, Department of Meteorology, The University of Reading, Reading, United Kingdom
| | - P. Q. Craufurd
- Department of Agriculture, The University of Reading, Reading, United Kingdom
| | - D. I. F. Grimes
- Department of Meteorology, The University of Reading, Reading, United Kingdom
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97
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Zinke J, Pfeiffer M, Timm O, Dullo WC, Davies GR. Atmosphere-ocean dynamics in the Western Indian Ocean recorded in corals. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2005; 363:121-142. [PMID: 15598627 DOI: 10.1098/rsta.2004.1482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present a set of Porites coral oxygen isotope records from the tropical and subtropical Western Indian Ocean covering the past 120-336 years. All records were thoroughly validated for proxy response to regional climate factors and their relation to large-scale climate modes. The records show markedly different imprints of regional climate factors. At the same time, all coral records show clear teleconnections between the Western Indian Ocean and the El Nino-Southern Oscillation (ENSO). The multi-proxy site analysis enables the detection of the covariance structure between individual records and climate modes such as ENSO. This method unravels shifts in ENSO teleconnectivity of the Western and Central Indian Ocean on multi-decadal time-scales (after 1976). The Seychelles record shows a stationary correlation with ENSO, Chagos corals show evidence for non-stationary delta18O/ENSO relationships and the Southwestern Indian Ocean corals show a strong relationship with ENSO when the forcing is strong (1880-1920, 1970 to present). Our results indicate that the coral delta18O, in combination with other proxies, can be used to monitor temporal and spatial variations in the sea-surface temperature and the fresh water balance within the Indian Ocean on interannual to interdecadal time-scales.
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Affiliation(s)
- J Zinke
- Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
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98
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Goswami BN, Xavier PK. Dynamics of “internal” interannual variability of the Indian summer monsoon in a GCM. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jd006042] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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99
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Vuille M, Werner M, Bradley RS, Keimig F. Stable isotopes in precipitation in the Asian monsoon region. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005jd006022] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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100
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Singh J. Spring precipitation variations over the western Himalaya, India, since A.D. 1731 as deduced from tree rings. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jd004855] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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