Combined interplay of the Atlantic multidecadal oscillation and the interdecadal Pacific oscillation on rainfall and its extremes over Indian subcontinent

2014 ◽  
Vol 44 (11-12) ◽  
pp. 3339-3359 ◽  
Author(s):  
Manish K. Joshi ◽  
Archana Rai
2018 ◽  
Vol 31 (3) ◽  
pp. 1227-1244 ◽  
Author(s):  
Zeyuan Hu ◽  
Aixue Hu ◽  
Yongyun Hu

Abstract Regional sea surface temperature (SST) mode variabilities, especially the La Niña–like Pacific Ocean temperature pattern known as the negative phase of the interdecadal Pacific oscillation (IPO) and the associated heat redistribution within the ocean, are the leading mechanisms explaining the recent global warming hiatus. Here version 1 of the Community Earth System Model (CESM) is used to examine how different phases of two leading decadal time scale SST modes, namely the IPO and the Atlantic multidecadal oscillation (AMO), contribute to heat redistribution in the global ocean in the absence of time-evolving external forcings. The results show that both the IPO and AMO contribute a similar magnitude to global mean surface temperature and ocean heat redistribution. Both modes contribute warmer surface temperature and higher upper ocean heat content in their positive phase, and the reverse in their negative phase. Regionally, patterns of ocean heat distribution in the upper few hundred meters of the tropical and subtropical Pacific Ocean depend highly on the IPO phase via the IPO-associated changes in the subtropical cell. In the Atlantic, ocean heat content is primarily associated with the state of the AMO. The interconnections between the IPO, AMO, and global ocean heat distribution are established through the atmospheric bridge and the Atlantic meridional overturning circulation. An in-phase variant of the IPO and AMO can lead to much higher surface temperatures and heat content changes than an out-of-phase variation. This result suggests that changes in the IPO and AMO are potentially capable of modulating externally forced SST and heat content trends.


2016 ◽  
Author(s):  
Tianjun Zhou ◽  
Andrew Turner ◽  
James Kinter ◽  
Bin Wang ◽  
Yun Qian ◽  
...  

Abstract. The Global Monsoons Model Inter-comparison Project (GMMIP) has been endorsed by the panel of Coupled Model Inter-comparison Project (CMIP) as one of the participating MIPs in the sixth phase of CMIP (CMIP6). The focus of GMMIP is on monsoon climatology, variability, prediction and projection, which is relevant to four of the "Grand Challenges" proposed by the World Climate Research Programme. At present, 21 international modelling groups are committed to joining GMMIP. This overview paper introduces the motivation behind GMMIP and the scientific questions it intends to answer. Three tiers of experiments, of decreasing priority, are designed to examine: (a) model skill in simulating the climatology and interannual-to-multidecadal variability of global monsoons during SST-forced experiments of the historical climate period; (b) the roles of the Interdecadal Pacific Oscillation and Atlantic Multidecadal Oscillation in driving variations of the global and regional monsoons; and (c) the effects of large orographic terrain on the establishment of the monsoons. The outputs of the CMIP6 DECK, "historical" simulation and other MIPs will also be used in the diagnostic analysis of GMMIP to give a comprehensive understanding of the roles played by different external forcings, potential improvements in the simulation of monsoon rainfall at high resolution and predictability at decadal time scales. The implementation of GMMIP will improve our understanding of the fundamental physics of changes in the global and regional monsoons over the past 140 years and ultimately benefit monsoon prediction and projection in the current century.


2019 ◽  
Vol 26 (3) ◽  
pp. 251-266 ◽  
Author(s):  
Jürgen Kurths ◽  
Ankit Agarwal ◽  
Roopam Shukla ◽  
Norbert Marwan ◽  
Maheswaran Rathinasamy ◽  
...  

Abstract. A better understanding of precipitation dynamics in the Indian subcontinent is required since India's society depends heavily on reliable monsoon forecasts. We introduce a non-linear, multiscale approach, based on wavelets and event synchronization, for unravelling teleconnection influences on precipitation. We consider those climate patterns with the highest relevance for Indian precipitation. Our results suggest significant influences which are not well captured by only the wavelet coherence analysis, the state-of-the-art method in understanding linkages at multiple timescales. We find substantial variation across India and across timescales. In particular, El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) mainly influence precipitation in the south-east at interannual and decadal scales, respectively, whereas the North Atlantic Oscillation (NAO) has a strong connection to precipitation, particularly in the northern regions. The effect of the Pacific Decadal Oscillation (PDO) stretches across the whole country, whereas the Atlantic Multidecadal Oscillation (AMO) influences precipitation particularly in the central arid and semi-arid regions. The proposed method provides a powerful approach for capturing the dynamics of precipitation and, hence, helps improve precipitation forecasting.


Crisis ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 73-77 ◽  
Author(s):  
Dinesh Bhugra

Abstract. Sati as an act of ritual suicide has been reported from the Indian subcontinent, especially among the Hindus, for several centuries. Although legally proscribed, these acts occur even now in modern India. The principle behind such acts has been put forward as the principle of good wife. There is little evidence to suggest that women who commit this act suffer from a formal mental illness. Cultural factors and gender role expectations play a significant role in the act and its consequences. Using recent examples, this paper illustrates the cultural factors, which may be seen as contributing to the act of suicide. Other factors embedded in the act also emphasize that not all suicides have underlying psychiatric disorders and clinicians must take social causation into account while preparing any prevention strategies.


Crisis ◽  
2002 ◽  
Vol 23 (3) ◽  
pp. 104-107 ◽  
Author(s):  
Murad M. Khan

Summary: The Indian subcontinent comprises eight countries (India, Pakistan, Bangladesh, Nepal, Sri Lanka, Afghanistan, Bhutan, and the Maldives) and a collective population of more than 1.3 billion people. 10% of the world's suicides (more than 100,000 people) take place in just three of these countries, viz. India, Sri Lanka, and Pakistan. There is very little information on suicides from the other four countries. Some differences from suicides in Western countries include the high use of organophosphate insecticides, larger numbers of married women, fewer elderly subjects, and interpersonal relationship problems and life events as important causative factors. There is need for more and better information regarding suicide in the countries of the Indian subcontinent. In particular, studies must address culture-specific risk factors associated with suicide in these countries. The prevention of this important public health problem in an area of the world with myriad socio-economic problems, meager resources, and stigmatization of mental illness poses a formidable challenge to mental health professionals, policy makers, and governments of these countries.


2017 ◽  
Vol 3 (4) ◽  
pp. 383-391
Author(s):  
Mohd Asif Khan ◽  
Shashi Bhooshan Tiwari ◽  
Himanshu Gupta ◽  
Huma Noor

Since ancient time, herbal drugs were highly used in the prevention and cure of various human illnesses. In India, Azadirachta indica being commonly known as Neem or Margosa is one of the multi-functional trees; belonging to Meliaceae family. In 1992, the US National Academy of Sciences was published a report entitled ‘Neem- a tree for solving global problems’. It is still considered as ‘village dispensary’ throughout the India. There are two species of Azadirachta which have been investigated; Azadirachta indica that is found in the Indian subcontinent and Azadirachta excelsa Kack that is homegrown to Indonesia and Philippines. A large number of pharmacologically active substances have been identified and isolated from the different parts of neem including azadirachtin, meliacin, gedunin, salanin, nimbin, valassin and various other components which are derived from these main compounds. Many different studies have been evaluated and authenticated for its various traditional and pharmacological activities like itching, leprosy, wound healing, spermicidal, anti-inflammatory, insecticidal, antidiabetic and analgesic etc. In the beginning of 1979, patenting on neem was started by CSIR to separate the active compounds from neem oil. Its great implantation fights with soil erosion, global warming, deforestations and desertification world-wide. In 2002, World Neem Conference raised the neem tree as an industrial or commercial plant. This review is going to explore comprehensively; traditional, pharmacological potential along with patenting, environmental & industrial significant of various parts of neem tree with safety concerns.


Author(s):  
Harimohan Garg ◽  
Haritej Anand Khirawari ◽  
Sona Priyadarshi

Background: Pancytopenia is diagnosed when there is a reduction in all three hematopoietic cell lines. Till date there is limited number of studies on the frequency of various causes of pancytopenia. Of these some have been reported from the Indian subcontinent. There appears to be a changing spectrum of pancytopenia over the past two decades. The objective was to study the etiopathological spectrum of adult patients with pancytopenia over a period of one and half year. Methods: The Prospective and retrospective observational study was conducted in the Department of Family Medicine, Batra Hospital and Medical Research Centre, New Delhi.  A total of 120 Patients were included in the study. All patients gave their consent to take part in the study and were subjected to a questionnaire regarding symptoms, past relevant history, lifestyle and detailed clinical examination and investigations as mentioned in materials and methods. Results: Six broad diagnostic groups could be identified in adults with pancytopenia. Megaloblastic anemia (D1) was the largest group comprising 57.5% of all patients. 11.7% of patients with pancytopenia were diagnosed as Aplastic anemia (D2).11.7% of patients with pancytopenia were diagnosed as leukemia/lymphoma (D3) such as lymphoma (1), metastatic anaplastic carcinoma (1), acute leukemia (11), and metastatic gastric carcinoma (1). 15% of patients with pancytopenia were diagnosed with infections (D4) such as complicated malaria cases (7), HIV (5), disseminated tuberculosis (4), viral (2). We also encountered (D5) 0.8% was Myelophthisis/Storage disorder as myelodysplastic syndrome (1) and 3.3% were other (D6) as reactive marrow (4). Conclusion: Pancytopenia is not a disease itself. It is a hematological feature of varying etiology with slight male preponderance. Megaloblastic anemia along with mixed nutritional anemia is leading cause of pancytopenia in India followed by infections being second and aplastic anemia and acute leukemia being third common causes. Keyword: Pancytopenia, Megaloblastic anemia, Nutritional anemia.


2020 ◽  
Vol 650 ◽  
pp. 269-287
Author(s):  
WC Thaxton ◽  
JC Taylor ◽  
RG Asch

As the effects of climate change become more pronounced, variation in the direction and magnitude of shifts in species occurrence in space and time may disrupt interspecific interactions in ecological communities. In this study, we examined how the fall and winter ichthyoplankton community in the Newport River Estuary located inshore of Pamlico Sound in the southeastern United States has responded to environmental variability over the last 27 yr. We relate the timing of estuarine ingress of 10 larval fish species to changes in sea surface temperature (SST), the Atlantic Multidecadal Oscillation, the North Atlantic Oscillation, wind strength and phenology, and tidal height. We also examined whether any species exhibited trends in ingress phenology over the last 3 decades. Species varied in the magnitude of their responses to all of the environmental variables studied, but most shared a common direction of change. SST and northerly wind strength had the largest impact on estuarine ingress phenology, with most species ingressing earlier during warm years and delaying ingress during years with strong northerly winds. As SST warms in the coming decades, the average date of ingress of some species (Atlantic croaker Micropogonias undulatus, summer flounder Paralichthys dentatus, pinfish Lagodon rhomboides) is projected to advance on the order of weeks to months, assuming temperatures do not exceed a threshold at which species can no longer respond through changes in phenology. These shifts in ingress could affect larval survival and growth since environmental conditions in the estuarine and pelagic nursery habitats of fishes also vary seasonally.


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