Dealing with displacement: Can “social protection” facilitate long-term adaptation to climate change?     

Craig A. Johnson  Krishna Krishnamurthy 《Global Environmental Change》2010,20(4):648-655

This article explores the possibilities of using social protection to manage and reduce the risks of forced displacement resulting from climate change. It reviews the relevant literature on migration, disasters and climate change, and constructs a model through which international policies may be used to encourage resettlement options that support the capabilities and entitlements of poor and vulnerable populations. By distinguishing between rapid-onset disasters and long-term environmental change, it explores the ways in which cash transfers, asset transfers and conditional cash transfers may be used to break the cycle of vulnerability, destitution and distress migration that can occur during times of severe environmental stress. An important distinction is made between “economic migration,” which implies that households have at their disposal an opportunity to engage in forward-looking analysis about the ways in which they will invest household resources and “distress migration,” which implies that household decisions about investment and migration are largely ad hoc responses to external environmental processes and events. The article reviews recent discussions about the prospects of revising the international refugee regime, and identifies the opportunities and challenges of using social protection to support household decisions that can facilitate economic migration over the long-term.  相似文献   

Seasonal persistence and propagation of intraseasonal patterns over the Indian monsoon region   总被引：1，自引：0，他引：1  

V. Krishnamurthy  J. Shukla 《Climate Dynamics》2008,30(4):353-369

The space-time evolution of convection over the monsoon region containing the Indian subcontinent, the Indian Ocean and the West Pacific has been studied. A multi-channel singular spectrum analysis of the daily outgoing longwave radiation has yielded two intraseasonal oscillatory patterns and two large-scale standing patterns as the most dominant modes of intraseasonal variability. The oscillatory modes vary on time scales of about 45 and 28 days and their average cycles of variability are shown to correspond to the life cycles of active and break periods of monsoon rainfall over India. During an active (break) cycle, a convection (dry) anomaly zone first appears in the equatorial Indian Ocean, subsequently expands to cover the Indian subcontinent and finally contracts to disappear in the northern part of India. Some eastward and northward movements are found to be associated with both oscillatory modes, while westward movement may also be associated with the 28-day mode. The oscillatory modes are shown to have a large spatial scale extending to the West Pacific. One of the standing modes has anomalies of uniform sign covering the entire region and is related to El Niño and southern oscillation (ENSO) pattern. The other standing mode has a dipole structure in the equatorial Indian Ocean associated with large-scale anomalies over India with the same sign as those over the western part of the dipole. These two standing modes persist throughout the monsoon season, each maintaining its respective pattern. The seasonal mean monsoon is mainly determined by the two standing patterns, without much contribution from the oscillatory modes. The relative role of the standing patterns (ENSO mode and dipole mode) seems to be important in determining the seasonal mean during certain years.  相似文献   

Daily atmospheric variability in the South American monsoon system   总被引：1，自引：1，他引：0  

V. Krishnamurthy  Vasubandhu Misra 《Climate Dynamics》2011,37(3-4):803-819

The space–time structure of the daily atmospheric variability in the South American monsoon system has been studied using multichannel singular spectrum analysis of daily outgoing longwave radiation. The three leading eigenmodes are found to have low-frequency variability while four other modes form higher frequency oscillations. The first mode has the same time variability as that of El Nino-Southern Oscillation (ENSO) and exhibits strong correlation with the Pacific sea surface temperature (SST). The second mode varies on a decadal time scale with significant correlation with the Atlantic SST suggesting an association with the Atlantic multidecadal oscillation (AMO). The third mode also has decadal variability but shows an association with the SST of the Pacific decadal oscillation (PDO). The fourth and fifth modes describe an oscillation that has a period of about 165 days and is associated with the North Atlantic oscillation (NAO). The sixth and seventh modes describe an intraseasonal oscillation with a period of 52 days which shows strong relation with the Madden-Julian oscillation. There exists an important difference in the variability of convection between Amazon River Basin (ARB) and central-east South America (CESA). Both regions have similar variations due to ENSO though with higher magnitude in ARB. The AMO-related mode has almost identical variations in the two regions, whereas the PDO-related mode has opposite variations. The interseasonal NAO-related mode also has variations of opposite sign with comparable magnitudes in the two regions. The intraseasonal variability over the CESA is robust while it is very weak over the ARB region. The relative contributions from the low-frequency modes mainly determine the interannual variability of the seasonal mean monsoon although the interseasonal oscillation may contribute in a subtle way during certain years. The intraseasonal variability does not seem to influence the interannual variability in either region.  相似文献   

Launching of a new journal from China     

P. Krishnamurthy 《Journal of the Geological Society of India》2011,77(2):204-204

  相似文献   

Sub-daily variations observed in Tropical Easterly Jet (TEJ) streams     

M. Venkat Ratnam  M. Roja Raman  Sanjay Kumar Mehta  Debashis Nath  B.V. Krishnamurthy  M. Rajeevan  S. Vijaya Bhaskara Rao  D. Narayana Rao 《Journal of Atmospheric and Solar》2011,73(7-8):731-740

To investigate the sub-daily variation in Tropical Easterly Jet (TEJ), a few special experiments have been conducted with mesosphere–stratosphere–troposphere (MST) radar located at Gadanki(13.5°N, 79.2°E) under Study on Atmospheric Forcing and Responses (SAFAR) campaign during 2008–2009. Large sub-daily changes in the TEJ characteristics are observed within a day in addition to day-to-day changes. Based on this observational study, three possible mechanisms for the sub-daily variations are proposed i.e., (1) motion of TEJ core, (2) large updrafts and downdrafts, and (3) strong wave activity. Interestingly, TEJ peak altitude is seen above the Cold Point Tropopause altitude for about 42% of the days.  相似文献   

Redox evolution in glacial drift aquifers: role of diamicton units in reduction of Fe(III)     

Nathaniel A. Barnes  Alan E. Kehew  R. V. Krishnamurthy  Carla M. Koretsky 《Environmental Earth Sciences》2011,62(5):1027-1038

High iron concentrations create water quality problems for municipal use in glacial drift aquifer units. The chemical evolution of oxic groundwater in shallow aquifer units to anoxic groundwater in deeper aquifer units, in which soluble Fe(II) is stable, is attributed to coupled reduction of Fe(III) on aquifer solids with oxidation of organic carbon. The objective of this study was to characterize the distribution of organic carbon in aquifer and aquitard sediments to determine the availability of potential electron donors to drive these reactions. To do this, four complete rotasonic cores in a glacial aquifer/aquitard system were sampled at close intervals for analyses of grain-size distribution and organic carbon content. The results indicate significantly higher organic carbon concentrations in diamicton (till) units that function as aquitards, relative to coarse-grained aquifer units. In addition, readily reducible iron content in the diamicton units and lower aquifer unit materials is sufficient to produce far more dissolved iron than is present in the aquifer. Groundwater evolves to the level of iron reduction as a terminal electron-accepting process as it moves downward through aquitard units along flow paths from upland recharge areas to downgradient discharge areas. Deeper aquifer units are therefore unlikely to contain groundwater with low iron concentration.  相似文献   

Birth Centenary Celebrations of B. P. Radhakrishna     

P. Krishnamurthy 《Journal of the Geological Society of India》2018,92(1):122-124

  相似文献   

Groundwater resources development in hard rock terrain - an approach using remote sensing and GIS techniques     

Jagannathan Krishnamurthy  Arul Mani  Venkatakrishnan Jayaraman  M Manivel 《International Journal of Applied Earth Observation and Geoinformation》2000,2(3-4)

To demonstrate the capabilities of remote sensing and Geographic Information System (GIS) techniques for groundwater resources development in hard rock terrains, specifically for the demarcation of suitable sites for artificial recharge of groundwater aquifers, a study was carried out in the Kallar Basin, which is located in parts of the Salem and Tiruchirapalli districts, Tamil Nadu, India. Thematic maps defining lithology, lineaments, landforms, landuse, drainage density, thickness of weathered zone, thickness of fractured zone, hydrological soils, and well yield were prepared from data collected by the Indian Remote Sensing Satellite (IRS) -1C and by conventional methods. All the thematic layers were integrated using a GIS-based model developed specifically for this purpose, enabling a map showing artificial recharge zones to be generated. The exact type of artificial recharge structure, eg, check dam, nallabund, gully plugging and percolation pond, suitable for replenishing groundwater was identified by superposing a drainage network map over an artificial recharge zones map. The GIS-based demarcation of artificial zones developed in the study was based on logical conditions and reasoning, so that the same techniques (with appropriate modifications) could be adopted elsewhere, especially in hard rock terrain, where the occurrence of groundwater is restricted and subject to greater complexity.  相似文献   

Investigating landfill‐impacted groundwater seepage into headwater streams using stable carbon isotopes     

E. A. Atekwana  R. V. Krishnamurthy 《水文研究》2004,18(10):1915-1926

The impact of landfill contaminated groundwater along a reach of a small stream adjacent to a municipal landfill was investigated using stable carbon isotopes as a tracer. Groundwater below the stream channel, groundwater seeping into the stream, groundwater from the stream banks and stream water were sampled and analysed for dissolved inorganic carbon (DIC) and the isotope ratio of DIC (δ¹³C_DIC). Representative samples of groundwater seeping into the stream were collected using a device (a ‘seepage well’) specifically designed for collecting samples of groundwater seeping into shallow streams with soft sediments. The DIC and δ¹³C_DIC of water samples ranged from 52 to 205 mg C/L and ?16·9 to +5·7‰ relative to VPDB standard, respectively. Groundwater from the stream bank adjacent to the landfill and some samples of groundwater below the stream channel and seepage into the stream showed evidence of δ¹³C enriched DIC (δ¹³C_DIC = ?2·3 to +5·7‰), which we attribute to landfill impact. Stream water and groundwater from the stream bank opposite the landfill did not show evidence of landfill carbon (δ¹³C_DIC = ?10·0 to ?16·9‰). A simple mixing model using DIC and δ¹³C_DIC showed that groundwater below the stream and groundwater seeping into the stream could be described as a mixture of groundwater with a landfill carbon signature and uncontaminated groundwater. This study suggests that the hyporheic zone at the stream–groundwater interface probably was impacted by landfill contaminated groundwater and may have significant ecological implications for this ecotone. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Mangrove (Avicennia marina subsp. australasica) litter production and decomposition in a temperate estuary     

RV Gladstone-Gallagher  CJ Lundquist  CA Pilditch 《新西兰海洋与淡水研究杂志》2013,47(1):24-37

Mangrove forests can provide important cross-boundary subsidies of organic matter to adjacent habitats through the production, export, decomposition and assimilation of litter. We quantified two of these components in a temperate mangrove forest in Whangamata Harbour, New Zealand: 1) litter production; and 2) decomposition rates as a function of tidal elevation, sediment type and burial depth. Litter traps sampled monthly for a year measured an annual detrital input of 3.24–5.38 t DW ha^?1, of which 77% occurred in summer. Decomposition rates depended on litter type, with leaves decomposing faster (63 d to decay by 50%) than pneumatophore and wood material (316 and 460 d, respectively). Buried leaf and wood litter decomposed 1.3–1.4 times slower than litter on the sediment surface; however, tidal elevation and sediment type (mud vs. sand) had no effect. The slow decay of litter (an order of magnitude slower than tropical mangrove litter) suggests that its incorporation into temperate marine food webs may be relatively slow.  相似文献