Dissertations / Theses on the topic 'Tropics'

Thesis (Ph.D.)--George Mason University, 2008.
Vita: p. 160. Thesis director: Ben P. Kirtman. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Climate Dynamics. Title from PDF t.p. (viewed July 18, 2008). Includes bibliographical references (p. 152-159). Also issued in print.

This dissertation examines psychoanalysis in a colonial context, tracing its history in early to mid-twentieth century India. A rich, neglected archive of diaries, letters, administrative documents, as well as psychoanalytical and literary writing in Bengali and English, are drawn on to offer an account of the Indian Psychoanalytical Society (est. 1921), and the anthropologists, doctors, army officers and political figures who were in different ways intimately involved with psychoanalysis. Reconstructing these narratives, and by means of a close reading of texts by Freud, I suggest that the understandings of temporality, sexuality and authority in Freudian psychoanalysis resist colonial discourses of progress and civilisation, notably in relation to the category of the 'primitive', thus frustrating attempts to appropriate the theory for colonial endeavours. In this thesis, psychoanalysis is both an object of historical study, and a form of questioning, part of colonial history and a body of writing and theory available for contested readings. I discuss writing by two colonial psychoanalysts, Lt. Colonel Claud Daly, and Owen A.R. Berkeley Hill, which combines an investment in psychoanalysis with commitment to Empire, based on a desire for all-knowing psychic and political mastery. In contrast, the memoirs of renowned psychoanalyst Wilfred Bion, recounting his childhood in India, are read for their more complex psychic register and anti-colonial strain. Records left by dream-collecting colonial administrators in the Naga Hills, and documents relating to the trial and 'insanity plea' of revolutionary nationalist Gopinath Saha, show us the historical operations of psychoanalysis in collective life. In addition, literary writing by the modernist poet H.D., Temsula Ao, Bankimcandra Chatterji, and Rabindranath Tagore, offers another template for examining the issues raised by both the historical and psychoanalytical writing.

Understanding the unequal distribution of life on earth is a fundamental goal of ecology and evolutionary biology. Past efforts to explain large-scale patterns in diversity have tended to focus on two broad classes of explanation, one invoking the importance of abiotic factors (i.e. climate and vegetation) and the other biotic (i.e. competition); but neither has proven entirely adequate. Parasites are a major but poorly understood component of life that may offer some answers. Yet despite widespread theoretical support and some empirical evidence, the role of parasites in explaining patterns in the diversity, distribution, and abundance of species remains largely untested in natural communities. In this thesis I use a mega-diverse elevation gradient of birds as a model system to study the role of avian malaria in explaining these macroecological patterns. In the first data chapter I tested the extent to which patterns of infection across species is predictable. I found that the effects of host ecology and environment were weakly related to infection prevalence and were not consistent across different malaria lineages. Instead, I show that hosts coexisting with many close phylogenetic relatives consistently experience higher infection than evolutionarily distinct host species. In the second chapter I tested if parasite sharing may help explain these observed relationships and show that parasite sharing among host pairs declines with the time since divergence. Spatial contiguity between host pairs was also positively associated with parasite sharing. In the third chapter I tested how infection prevalence varies across species ranges in accordance with expected variation in host abundance. I show that birds are more likely to be infected at the centre of their elevation range, where host abundance is expected to be highest. Intriguingly, I also found that the incidence of host infection is unrelated to the position within the geographic range of the parasite. In the fourth data chapter, I tested whether parasites may regulate diversity by limiting geographic ranges of their hosts through ‘apparent competition’ in which a non-lethal parasite in a primary host, may be lethal in a secondary host. In support of this, I found that more observed bird ranges end at parasite infection zones than would be expected by chance. Taken together, my results suggest that parasites may play a major role in shaping patterns in the distribution and diversity of species, over both ecological and evolutionary scales. This is likely to arise and be maintained by host parasite interactions in which distantly related hosts are less likely to be infected by local parasites than close relatives, thus promoting the build up of diversity locally. On the basis of my analyses, I conclude that across montane elevation gradients in birds, and across diversity gradients more generally, parasites are likely to play a crucial role in the origin and maintenance of high biological diversity.

In tropical areas, the high rainfall induces severe-and pervasive weathering, producing a thick soil cover. The lithologies underneath may b~ recognised using geochemical mapping, which is based on certain elements that have the ability to differentiate between various lithologic units. Elements that are independent of the weathering process are normally selected for this purpose. The chemistry of mobility of base metals is an important factor to take into account when evaluating the mobility and distribution of these elements in a soil profile. Factors such as pH, Eh, organic material, clay minerals, Fe and Mn oxides are normally key aspects to be considered. When iron-rich rocks undergo deep weathering, lateritic profiles are developed. These are widespread in a belt bordering the equatorial zone, including the Brazilian shield, West and East Africa, parts of India and Northern Australia. In these profiles, the high rainfall promotes intense leaching of the different horizons. Where the pre-existing profiles are mostly preserved, the base metals are distributed throughout the profile: in the upper ferruginous horizon, goethite and hematite can adsorb large amounts of Mo, resulting in large dispersion halo. Other base metals such as Cu and Zn are less resistant in these freely-drained profiles and, therefore, they may be partly leached from the profile. In the lower horizons, Cu, ,zn, Ni and Co are retained, hosted in kaolinite and smectite, and thus, a high geochemical contrast will be identified in this horizon at the expense of a decline in the size of the dispersion haloes. The pre-existing profiles can be truncated, with a thin stone line developing at the contact between the lateritic profile and the recent soil. The conditions in these environments favour the retention of most of the pathfinder and target elements in all soil horizons, with the B horizon showing the highest contrast. If the primary rock is rich in AI, a bauxitic profile will be developed. The world distribution of bauxites closely resembles that of laterites. The behaviour of Co and Ni is very similar to that of iron during the bauxitization. Furthermore, the factors that induce residual enrichment of Al with removal of Fe in the soil profile will cause significant depletion of Co and Ni in these profiles. These metals are then concentrated at the base of the profile because of precipitation from downward percolating solutions. Many karst bauxite deposits in Southern Europe are enriched with Ni and Co in the basal horizon. Such horizon is mined as nickel ore in the bauxites of the Lokris region in Greece. Copper and molybdenum are strongly enriched.in bauxitic profiles. Concentration ratios are 8 and 3.2 for Cu and Mo respectively. Molybdenum is closely related to goethite and hematite, and therefore, the high concentration of Mo in a bauxitic profile will be consistent with the horizon where iron is concentrated. Copper concentrates at the base of the iron rich-horizon but also appears enriched in the saprolite together with Co. When sulphide bodies occur, in this environment, deep and penetrative weathering has resulted in considerable near-surface mobilization of iron and silica. The supergene alteration commonly obscures the identity of the primary sulphides at the surface. In this case, geochemical assessment of the resulting gossan has proved to be crucial in mineral exploration. A search in the secondary mineral assemblage, volatile and precious metals may lead to the information on the composition of the primary sulphide assemblage. The conclusion that will be reached is that if the geochemical properties (mobility, affinities with Fe or Mn oxides and/or clay minerals) of each of the base metals are understood, an appropriate sampling (optimum size-depth combination) will then be done. In such cases, a subdued, weak, but significant, geochemical response will be identified in the surface horizon.

The breeding behaviour of the Blue-throated Bee-eater was studied at two colonies in Peninsula Malaysia during 3 breeding seasons, with particular emphasis on pair behaviour, mixed reproductive strategies and nestling competition. This is the first study of vertebrate social behaviour and ecology to contain the documentation of a relational database. This was designed to store and manipulate all data obtained from regular captures and biometric measurements of adults and nestlings and from observations of adults. DNA fingerprinting was used to establish the true genetic relationships between nestlings and their social parents: most nestlings were genetic offspring (72%). Nestlings were classified as illegitimate offspring using 95% confidence intervals of the band sharing coefficient and number of unexplained nestling bands as criteria. Very few if any nestlings were sired by an extra-pair male (fewer than 5%). Behavioural evidence of strong cooperation between pair members throughout the breeding season supports the DNA fingerprinting results of no confirmed case of offspring fathered by extra-pair males (extra-pair offspring; EPO). The Blue-throated Bee-eater probably has a near monogamous mating system. Most illegitimate nestlings had been 'dumped'. They were either the result of intra-specific nest parasitism (INP; 7%) or of 'quasi' parasitism (the offspring of the pair-male and an extra-pair female; 7-12%). INP by relatives of the hosts could have explained some intermediate band sharing coefficients. Anti-INP behaviour was demonstrated when experimentally 'dumped' eggs were almost always expelled before the onset of laying, but never afterwards. DNA fingerprinting showed that relatives may roost together and that related males may nest close together. Compared with other colonial Bee-eaters, M. viridis had low levels of helping-at-the-nest and EPO, but similar or higher levels of INP. The high nestling mortality in Blue-throated Bee-eaters was explained by a combination of three hypotheses, some of which were tested by experiment. (1) Insurance: extra-eggs are needed to counter hatch failure. (2) Brood reduction (including resource tracking): in times of food constraint, the laterhatched nestlings in asynchrously hatched broods starve. (3) Anti-INP hypothesis: these later-hatched nestlings are eliminated because they are likely to be illegitimate. Hatching failure was about 1 in 3 eggs overall. Help from the male allows an early onset of incubation which results in asynchronous hatching. Nestling hunger was shown to be a proximate factor affecting runt mortality both directly through competition and indirectly through nestling aggression. The demise of runts was delayed when conditions improved. Blue-throated Bee-eater broods are severely limited by food. Under this severe brood size constraint, breeding females may increase reproductive output by 'dumping' their last egg. This leads to the high frequency of INP observed in Blue-throated Bee-eaters. An early onset of incubation also gives the first-laid egg(s) a temporal developmental advantage over subsequently 'dumped' parasitic eggs. The 'dumped' nestlings are eliminated by starvation and siblicide, which may itself be an adaptation to INP to eliminate of unrelated nestlings.

The Tropical Pacific Warm Pool International Cloud Experiment (TWP-ICE) took place in Darwin, Australia in early 2006. C-band radar data from this experiment were used to characterize tropical anvil areal coverage, height, and thickness during the month-long field campaign. The morphology, evolution, and longevity of the anvil were analyzed as well as the relationship of the anvil to the rest of the precipitating system. In addition, idealized in-cloud radiative heating profiles were created based on the anvil observations. The anvil was separated into mixed (i.e., echo base below 6 km) and ice only categories. The experiment areal average coverage for both types of anvil was between 4-5% of the radar grid. Ice anvil thickness averaged 2.8 km and mixed anvil thickness averaged 6.7 km. No consistent diurnal signal was seen in the anvil, implying that the life cycle of the parent convection was of first order importance in determining the anvil height, thickness, and area. Areal peaks show that mixed anvil typically formed out of the stratiform region. Peak production in ice anvil usually followed the mixed anvil peak by 1-3 hr. Anvil typically lasted 4-10 hr after the initial convective rain area peak. The TWP-ICE experienced three distinct regimes: the active monsoon, dry monsoon, and break periods. During the entire experiment (except the active monsoon period) there was a strong negative correlation between ice anvil thickness and ice anvil height, a strong positive correlation between ice anvil area and thickness, and a greater variance in ice anvil bottom than ice anvil top. Anvil produced during the active regime had the most dramatic in-cloud radiative response with a maximum cooling of 0.45° K day-1 at 12 km, a maximum heating of 3° K day-1 at 9 km, and a secondary maximum heating of 1.2° K day-1 at 5 km.

This study examines the global tropical cyclones (TC) patterns and distributions from 2001-2010. The objective of the study was to find out the possible relationship between the TC activities between different oceans. The TC track record was obtained from the Hurricane Data Centre at Unisys Weather webpage and it has been plotted and transferred to a spread sheet format. By combining the data with the oceanic maps from General Bathymetric Chart of the Oceans (GEBCO) digital Atlas, we could conclude the trend and distributions of the TC in each year. Various data were also collected from the National Oceanic and Atmospheric Administration (NOAA), Climate Prediction Center and Bureau of Meteorology (BOM) so as to further explain the TC relationships in different regions. It is concluded that the TC distributions has no significant relationship between oceans in the same hemisphere but it shows certain pattern throughout the ten years record.
published_or_final_version
Applied Geosciences
Master
Master of Science

Studies were carried out in a lowland evergreen rain forest (LERF), on an ultisol, in the 'Reserva da Campina', 45 km north of Manaus, and in two facies of the highly distinct formation called heath forest, on spodosols. The spodosols had a layer of mor humus of thickness varying from nil in some parts in the smaller facies of heath forest (SHF) to 35 cm in the taller facies (THF). The overall aim was to investigate the forest soil biota and its role in nutrient turnover by comparing the SHF, THF and LERF. Microbial biomass, soil respiration and nitrogen transformation rates were measured in the three forest types in both wet and dry seasons. Field and laboratory fertilization experiments were made to investigate potential limiting nutrients for microorganisms and plants. The role of fine roots in decomposition and litter animal colonization was assessed in litter bag studies. SHF soils have a small microbial population with no net nitrification in any season. THF soils showed a variable microbial population adapted to high acidity, which immobilises nitrogen during the wet season, but which allows a net release during the dry season. LERF showed the most diverse population which causes mineralization and nitrification in both seasons. A bioassay with nutrient addition showed that the low pH, and nitrogen and sulphur supply were likely to be limiting nitrogen dynamics in all forest types, but especially in THF and LERF. The ingrowth bags showed that despite the lower values of fine root growth in the SHF (particularly when the white sand of the spodosol was used as the substrate), the roots showed in all plots an increased production with added calcium as carbonate or sulphate. In the decomposition bioassay to evaluate the role of roots in the nutrient turnover it was shown that in all forest types there was no effect of roots on the mass loss of Clitoria leaves but there was a significant effect on concentrations of some nutrients. In general, roots contributed to the accumulation of aluminium and iron and to a faster release and uptake of calcium, magnesium and zinc. A survey of the mycorrhizal associations in all forest types showed that both VAM and ECM fungi with some unknown VAM fungal species are common. VAM and ECM adaptation to low pH and high phenolic compounds in the soils may be important in the maintenance of these ecosystems.

Lake deposits are widespread throughout the Phanerozoic rock record and have long intrigued geologists and paleobiologists in search of natural resources or fossil biota. Low-energy lacustrine depositional environments, characterized by relatively rapid sediment influx rates and shallow zones of bioturbation, likewise produce highly-resolved archives of climate and ecosystems evolution. This dissertation describes four studies that use lake sediments for Quaternary environmental analysis. In East Africa, many decades of prior study provided the critical framework necessary for in-depth paleoenvironmental research at Lake Tanganyika (3° - 9°S). Seismic stratigraphic analysis integrated with radiocarbon-dated sediment cores from the Kalya horst and platform document a dramatic lake level lowstand prior to ~106 ka and a minor, short-lived regression during the Last Glacial Maximum (32 - 14 ka). Paleobathymetric maps reveal that Lake Tanganyika remains a large, connected water body even during episodes of extreme drought, which has implications for local and regional fauna. Over shorter timescales, geochronological, taphonomic and sedimentological analyses of shell beds around Kigoma (central Lake Tanganyika) document three distinct facies-types that are time-averaged over the latest Holocene. Lake level fluctuations associated with the termination of the Little Ice Age (~ 16th century CE) and subsequent encrustation played a key role in shell bed formation and persistence along high-energy littoral platforms, which has implications for structuring specialized communities of benthic fauna. In central South America (18° - 22°S), we studied the limnogeology of small lakes in the Puna and the Pantanal. Analyses of these sites were undertaken to: 1) ascertain how the lakes act as depositional basins; 2) assess sedimentation rates; and 3) construct limnogeological databases to guide future interpretations of ancient sediment cores. At Laguna de los Pozuelos (Argentine Puna), linear sedimentation rates approach 0.14 cm*y⁻¹ in the playa-lake center, and litho- and organo-facies development are dominantly controlled by basin hydrology, climate and biological feedbacks (both nutrient cycling and bioturbation) from waterbirds. At Lagoas Gaíva, Mandioré and Vermelha (Brazilian Pantanal), short-lived radioisotopes indicate uninterrupted depositional rates of 0.11 - 0.24 cm*y⁻¹, and hydrochemical and depositional patterns respond sensitively to changes in the seasonal flooding cycle of the Upper Paraguay River.

The recent elevated North Atlantic hurricane activity has generated considerable interests in the interaction between tropical cyclones (TCs) and climate change. The possible connection between TCs and the changing climate has been indicated by observational studies based on historical TC records; they indicate emerging trends in TC frequency and intensity in some TC basins, but the detection of trends has been hotly debated due to TC track data issues. Dynamical climate modeling has also been applied to the problem, but brings its own set of limitations owing to limited model resolution and uncertainties. The final goal of this study is to project the future changes of North Atlantic TC behavior with global warming for the next 50 years using the Nested Regional Climate Model (NRCM). Throughout the course of reaching this goal, various uncertainties and limitations in simulating TCs by the NRCM are identified and explored. First we examine the TC tracking algorithm to detect and track simulated TCs from model output. The criteria and thresholds used in the tracking algorithm control the simulated TC climatology, making it difficult to objectively assess the model's ability in simulating TC climatology. Existing tracking algorithms used by previous studies are surveyed and it is found that the criteria and thresholds are very diverse. Sensitivity of varying criteria and thresholds in TC tracking algorithm to simulated TC climatology is very high, especially with the intensity and duration thresholds. It is found that the commonly used criteria may not be strict enough to filter out intense extratropical systems and hybrid systems. We propose that a better distinction between TCs and other low-pressure systems can be achieved by adding the Cyclone Phase technique. Two sets of NRCM simulations are presented in this dissertation: One in the hindcasting mode, and the other with forcing from the Community Climate System Model (CCSM) to project into the future with global warming. Both of these simulations are assessed using the tracking algorithm with cyclone phase technique. The NRCM is run in a hindcasting mode for the global tropics in order to assess its ability to simulate the current observed TC climatology. It is found that the NRCM is capable of capturing the general spatial and temporal distributions of TCs, but tends to overproduce TCs particularly in the Northwest Pacific. The overpredction of TCs is associated with the overall convective tendency in the model added with an outstanding theory of wave energy accumulation leading to TC genesis. On the other hand, TC frequency in the tropical North Atlantic is under predicted due to the lack of moist African Easterly Waves. The importance of high-resolution is shown with the additional simulation with two-way nesting. The NRCM is then forced by the CCSM to project the future changes in North Atlantic TCs. An El Nino-like SST bias in the CCSM induced a high vertical wind shear in tropical North Atlantic, preventing TCs from forming in this region. A simple bias correction method is applied to remove this bias. The model projected an increase both in TC frequency and intensity owing to enhanced TC genesis in the main development region, where the model projects an increased favorability of large-scale environment for TC genesis. However, the model is not capable of explicitly simulating intense (Category 3-5) storms due to the limited model resolution. To extrapolate the prediction to intense storms, we propose a hybrid approach that combines the model results and a statistical modeling using extreme value theory. Specifically, the current observed TC intensity is statistically modeled with the General Pareto distribution, and the simulated intensity changes from the NRCM are applied to the statistical model to project the changes in intense storms. The results suggest that the occurrence of Category 5 storms may be increased by approximately 50% by 2055.

The Sardinilla plantation is a long-term facility for studying the links between tree species diversity and ecosystem function. Six native tree species were planted in 2001 in plots containing 1, 3 or 6 species. Soil respiration (SR) measurements were conducted from March to December 2004 on tree pairs. ANOVAs with repeated measure on days were used to test the main effects of species (monocultures), pair (single and two-species pairs), plot (pairs in monoculture, three-, and six-species plots), and season (dry vs. early wet season). ANCOVAs were run for each effect to determine possible biotic and abiotic covariates, including root, tree, and microbial biomass, soil moisture, surface temperature, and bulk density. Significant season and pair effects accounted for 89% and 2% of the variability in SR. Driven by soil moisture, SR increased seven fold during the seasonal transition. In the dry and wet season monocultures had significantly higher SR than two-species pairs.

Thesis (M.S. in Meteorology)--Naval Postgraduate School, June 2006.
Thesis Advisor(s): Patrick Harr, Tom Murphree. "June 2006." Includes bibliographical references (p.77-79). Also available in print.

Thesis (M.S.)--University of Missouri-Columbia, 2005.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (December 19, 2006) Includes bibliographical references.

A faithful depiction of the tropical atmosphere requires three-dimensional sets of observations. Despite the increasing amount of observations presently available, these will hardly ever encompass the entire atmosphere and, in addition, observations have errors. Additional (background) information will always be required to complete the picture. Valuable added information comes from the physical laws governing the flow, usually mediated via a numerical weather prediction (NWP) model. These models are, however, never going to be error-free, why a reliable estimate of their errors poses a real challenge since the whole truth will never be within our grasp.

The present thesis addresses the question of improving the analysis procedures for NWP in the tropics. Improvements are sought by addressing the following issues:

- the efficiency of the internal model adjustment,

- the potential of the reliable background-error information, as compared to observations,

- the impact of a new, space-borne line-of-sight wind measurements, and

- the usefulness of multivariate relationships for data assimilation in the tropics.

Most NWP assimilation schemes are effectively univariate near the equator. In this thesis, a multivariate formulation of the variational data assimilation in the tropics has been developed. The proposed background-error model supports the mass-wind coupling based on convectively-coupled equatorial waves. The resulting assimilation model produces balanced analysis increments and hereby increases the efficiency of all types of observations.

Idealized adjustment and multivariate analysis experiments highlight the importance of direct wind measurements in the tropics. In particular, the presented results confirm the superiority of wind observations compared to mass data, in spite of the exact multivariate relationships available from the background information. The internal model adjustment is also more efficient for wind observations than for mass data.

In accordance with these findings, new satellite wind observations are expected to contribute towards the improvement of NWP and climate modeling in the tropics. Although incomplete, the new wind-field information has the potential to reduce uncertainties in the tropical dynamical fields, if used together with the existing satellite mass-field measurements.

The results obtained by applying the new background-error representation to the tropical short-range forecast errors of a state-of-art NWP model suggest that achieving useful tropical multivariate relationships may be feasible within an operational NWP environment.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第16147号
農博第1883号
新制||農||991(附属図書館)
学位論文||H23||N4617(農学部図書室)
28726
京都大学大学院農学研究科応用生物科学専攻
(主査)教授 廣岡 博之, 教授 祝前 博明, 教授 松井 徹
学位規則第4条第1項該当

This thesis consists of three distinct parts of CAST, CONTRAST and ATTREX, which were aircraft and field campaigns in the West Pacific in January-March 2014. The first section comprises of ozonesonde measurements from Manus Island, Papua New Guinea. A contamination issue affected the first 14 ozonesondes, and so particular care was required to characterize the background current, and as a result, a 'hybrid' background current correction was developed, which combines a constant correction with a pressure dependent correction. Collocated measurements with the CONTRAST aircraft - the NCAR Gulfsteam V - suggests the new hybrid correction produces better ozonesonde profiles than the other corrections that are found in the literature. The results of the ozonesonde measurements revealed a low-ozone event, with minimum ozone concentrations of ~12 ppbv, which was coincident with an easterly jet, and traced back to an area of deep convection: clean marine boundary layer air was uplifted into the tropical tropopause layer (TTL) and then advected in the easterly jet across to Manus Island. The second section attempted to find more examples of low-ozone conditions in the TTL from the aircraft data. The ATTREX aircraft - the NASA Northrop Grumman Global Hawk - observed ozone concentrations of ~10 ppbv in the Southern Hemisphere in proximity of tropical storm Lusi. Whole air samples from all three aircraft suggests the low-ozone air had recently encountered the boundary layer, with enhanced concentrations of surface-generated very short lived substances (VSLSs) compared to air with higher ozone concentrations. No low-ozone events were found in the Northern Hemisphere, even in the vicinity of tropical cyclone Faxai. The third section explores the low-ozone events in the WRF-Chem (Weather Research and Forecasting - with chemistry) in order to see whether the model was capable of recreating the low-ozone event measured by the ozonesondes on 21-23 February as a case study. The WRF-Chem simulation did correctly reproduce the large convective storm in a similar area to that observed by satellites, and surface tracers were uplifted in large quantities as hypothesized. However, no evidence of injection of air into the stratosphere was found in the simulation, and, rather than uplift directly from the surface, mixing of air in the boundary layer followed by uplift into the TTL was the main mechanism for producing the low-ozone event.

The vertical profile of diabatic heating associated with convection is vitally important to the largescale tropical circulation. Systematic errors in diabatic heating distributions in models are considered to be a primary cause in their errors in representing the large-scale mean circulation and tropical variability in the Tropics. Much attention has been given to the vertical heating structure of the Madden-Julian Oscillation (MJO) in recent years to understand the fundamental physics of the MJO and why many general circulation models struggle to simulate a robust MJO. In this thesis, estimates of vertical diabatic heating structures from reanalysis datasets and Tropical Rainfall Measuring Mission (TRMM) latent heating algorithms are used to understand how variations in the detailed structure of the heating influence the structure in the dynamical response in the Tropics. As pan of this study, the role of the vertical structure of the heating of the MJO to the dynamical response is investigated by integrating a primitive equations model with vertical anomalous diabatic heating structures associated with the MJO. In particular, the role of a vertical tilt in the heating, which has been identified in three reanalysis datasets. is investigated in relation to the moisture convergence and energetics. An eastward phase shift of the moisture convergence of approximately 1 day directly associated with the vertical anomalous heating structure of the MJO was found for each of the reanalysis heatings. As a consequence of this phase shift, a surplus of moisture convergence over the anomalous heating was generated in regions ahead of the MIO convection centre indicating a pre-moistening of tlle atmosphere prior to deep convection. It was demonstrated that both a leading mid to shallow congestus heating and a lagging stratiform heating relative to the main MJO convection were important in contributing to the phase shift in the moisture convergence. Both these vertical heating structures may therefore be critical to the maintenance of the MJO through the warm pool region. The response to the two the heatings from the TRMM products showed no phase shift in the moisture convergence relating to the vertical heating structure of the MJO. This was due to no observable vertical tilt in the heating structure. There is increased generation of eddy entropic potential energy and conversion of that energy into eddy kinetic energy through the MJO cycle associated with the vertical anomalous heating structure of the MIO. This was related to stronger heating in the mid-troposphere generating stronger eddy potential energy (EPE) between 600 and 400 hPa, which exceeded the rcduction in generation of EPE in the planetary boundary layer (PBL).

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.
Includes bibliographical references (leaves 227-234).
by Zhongxiang Wu.
Ph.D.

FundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
Objetivou-se com esse trabalho avaliar os efeitos da intensificaÃÃo da produÃÃo de leite, via nÃveis de intensificaÃÃo do sistema, em pastagens de capim-mombaÃa (Panicum maximum Jacq. cv. MombaÃa) no trÃpico Ãmido, durante o perÃodo das Ãguas. Os tratamentos consistiram de quatro nÃveis de intensificaÃÃo, determinados pela combinaÃÃo de nÃveis de adubaÃÃo e nÃvel de produÃÃo dos animais. Foram eles, na sequÃncia crescente de intensificaÃÃo: 1  adubaÃÃo com 400 kg de NÃha-1Ãano-1, com vacas de baixa produÃÃo; 2 adubaÃÃo com 800 kg de NÃha-1Ãano-1, com vacas de baixa produÃÃo; 3 adubaÃÃo com 400 kg de NÃha-1Ãano-1, com vacas de alta produÃÃo; 4 adubaÃÃo com 800 kg de NÃha-1Ãano-1, com vacas de alta produÃÃo. As vacas eram sem raÃas definidas, em mÃdia de terceira cria, com partos ocorridos em outubro/novembro de 2009. No inÃcio das avaliaÃÃes de produÃÃo de leite, encontravam-se com aproximadamente 110 dias de lactaÃÃo. O perÃodo experimental foi de 24 de dezembro de 2009 a 10 de maio de 2010. Para as medidas relacionadas à morfogÃnese e estrutura, foi utilizado o delineamento inteiramente casualizado, com medida repetida no tempo. Quatro tratamentos, com quatro ciclos e quatro repetiÃÃes (piquetes), avaliando a interaÃÃo entre tratamentos e ciclos. Para a avaliaÃÃo do comportamento dos animais, foi utilizado o delineamento inteiramente casualizado, com quatro tratamentos, oito perÃodos e quatro repetiÃÃes (animais), avaliando a interaÃÃo entre tratamentos e perÃodos. Na avaliaÃÃo da distribuiÃÃo de fezes, foi utilizada a anÃlise geoestatÃstica, com quatro tratamentos e trÃs repetiÃÃes (piquetes). Nas anÃlises de produÃÃo dos animais, foi utilizado delineamento inteiramente casualizado simples (placas de fezes, total de fezes, consumo de forragem e consumo total), com medidas repetidas no tempo (escore de condiÃÃo corporal e peso vivo) e com medidas repetidas no tempo, sendo o tempo medida de controle local (produÃÃo de leite por vaca, peso vivo, taxa de lotaÃÃo e produÃÃo de leite por hectare). O perÃodo de descanso utilizado foi o necessÃrio para que fosse possÃvel a expansÃo de 2,5 novas folhas e o resÃduo equivalente ao IAF residual 2,0. O maior fornecimento de nitrogÃnio nÃo proporcionou elevaÃÃo nas variÃveis TAlF, TAlH, TSFant e TSFpost. NÃo foram observadas diferenÃas entre tratamentos em funÃÃo dos tipos de animais. A TAlF segue, em parte, a disponibilidade de Ãgua oriunda da precipitaÃÃo. NÃo houve diferenÃa na TAlH em funÃÃo dos tratamentos. Esse efeito, sendo reflexo do perÃodo de descanso adotado (2,5 novas folhas à perfilho-1), reduziu o nÃvel de interceptaÃÃo da radiaÃÃo fotossinteticamente ativa para valores inferiores a 95%. A intensificaÃÃo apresenta pouco reflexo nas variÃveis estudadas (MSFT, MSFV, MSLV e MSCV). A altura prÃ-pastejo apresentou crescimento do primeiro para o segundo ciclo e posterior declÃnio atà o Ãltimo ciclo, sendo esse o que apresentou os menores valores, para todos os tratamentos. A elevaÃÃo da oferta de nitrogÃnio proporcionou maiores nÃveis de produÃÃo em determinados momentos, quando da oferta de Ãgua em nÃveis adequados. A disponibilidade de Ãgua influenciou a resposta da produÃÃo das pastagens ao longo dos ciclos. Houve relaÃÃo do teor de matÃria orgÃnica do solo e o desempenho produtivo das pastagens. Quanto ao comportamento dos animais, foi observado interaÃÃo entre os tratamentos e os perÃodos do dia, com exceÃÃo do âcomportamento urinandoâ que sà apresentou efeito de perÃodo. A adubaÃÃo influenciou positivamente no âcomportamento pastejandoâ, elevando o tempo gasto na expressÃo do mesmo. Para Outras atividades, o efeito foi negativo, diminuindo o tempo de deslocamento dos animais. A adubaÃÃo e a interaÃÃo a adubaÃÃo à suplemento proporcionaram maior tempo de utilizaÃÃo de sombra pelos animais. A utilizaÃÃo de alimento concentrado elevou o nÃmero de defecaÃÃes, com concentraÃÃo durante os perÃodos de maior permanÃncia no pasto. O perÃodo do dia influenciou o âcomportamento bebendoâ, causando maior consumo de Ãgua nos perÃodos de maiores temperaturas, assim como os tratamentos intermediÃrios apresentaram maiores consumos. No que se refere à distribuiÃÃo de fezes, os dados apresentaram coeficientes de assimetria positiva e de curtose platicÃrtica. Para o coeficiente de variaÃÃo verificou-se uma elevaÃÃo acentuada, com as Ãreas de descanso, apresentando maiores valores e piquetes com maior nÃvel de adubaÃÃo e menores valores. Os fatores climÃticos radiaÃÃo, temperatura e umidade relativa influenciaram significativamente na dispersÃo e localizaÃÃo das fezes. No que se refere ao grau de dependÃncia espacial (GDE), foi verificado classificaÃÃo, variando de moderado a forte. O alcance foi de 14,0 e 12,7 m para as Ãreas de descanso e piquetes, respectivamente. A adubaÃÃo e o fornecimento de concentrado influenciaram a deposiÃÃo e a perda de nitrogÃnio via fezes, elevando seus valores na medida em que se elevou o aporte nutricional. Observou-se heterogeneidade na deposiÃÃo das fezes, ocorrendo zonas de maior concentraÃÃo, como sombra, entrada de piquetes e malhadouro, mostrando picos de deposiÃÃo que chegaram a 1.051,2 kg de N à ha- à ano- e mÃdia variando de 148,8 a 210,7 kg de N à ha- à ano-Â. Houve crescimento das produÃÃes diÃrias e por Ãrea de leite, na medida em que intensificou o sistema. Com a intensificaÃÃo houve maior persistÃncia da lactaÃÃo, observado por meio da relaÃÃo obtida pela divisÃo do coeficiente angular pelo intercepto, resultando em percentual diÃrio de diminuiÃÃo da lactaÃÃo. A persistÃncia da produÃÃo dos animais respondeu diretamente à intensificaÃÃo do sistema, como reflexo da maior intensificaÃÃo (melhoria da dieta). A produÃÃo por Ãrea respondeu mais fortemente ao nÃvel de produÃÃo individual diÃria e segue comportamento quadrÃtico, de acordo com a distribuiÃÃo das chuvas. A produÃÃo fecal cresceu no sentido do maior nÃvel de intensificaÃÃo, resultando em maiores estimativas de consumo. O maior aporte de nutrientes (mais intensivo) possibilitou elevar os nÃveis de produtividade por animal, por Ãrea, em relaÃÃo à mÃo-de-obra e à produÃÃo total diÃria. A maior intensificaÃÃo possibilitou elevar as receitas, todavia elevou os custos totais mensais, apresentando melhor relaÃÃo nos nÃveis intermediÃrios de intensificaÃÃo. Na medida em que se elevou a Ãrea utilizada, o nÃvel menos intensivo apresentou margem bruta positiva. Os custos operacionais efetivos elevaram-se com a intensificaÃÃo dos sistemas. Jà os custos operacionais totais diminuÃram com a intensificaÃÃo, voltando a crescer no nÃvel mais intensivo. A alimentaÃÃo representou por volta de 70% dos custos operacionais efetivos. Os sistemas apresentaram-se inviÃveis no mÃdio-longo prazo, e no curto prazo, foram menos atrativos que o observado na amostra de produtores utilizada nesse estudo.
This study aimed at analyzing the intensification effects via different enhancement levels of the system of milk production in Mombasa grass pastures (Panicum maximum Jacq. cv. MombaÃa) in the humid tropics, during the water period. Treatments consisted of four enhancement levels, determined by combining fertilization levels and production level of the animals. Treatments were in increasing sequence of fertilization, as follow: 1Â Â fertilization with 400 kg of NÃha-1Ãyear-1, with low yield dairy cows; 2ÂÂ fertilization with 800 kg of NÃha-1Ãyear-1, with low yield dairy cows; 3ÂÂ fertilization with 400 kg of NÃha-1Ãyear-1, with high yield dairy cows; 4ÂÂ fertilization with 800 kg of NÃha-1Ãyear-1, with high yield dairy cows. It was used mixed breed cows, on average of third calving, and the births had occurred in October/November 2009. At the beginning of the evaluation of milk production, the cows had around 110 days of lactation. The experiment was conducted between December 24th, 2009 and May 10th, 2010. For the measures related to the morphogenesis and structure, we used a completely randomized design with repeated measurements over time. Four treatments, with four cycles, and four replicates (paddocks) were used to assess the interaction between treatments and cycles. To evaluate the behavior of the animals, we used a completely randomized design, with four treatments, eight periods and four replicates (animals) to evaluate the interaction between treatments and periods. In the evaluation of the distribution of feces, a geostatistical analysis was applied, with four treatments and three replicates (paddocks). In the analysis of animal production, a simple completely randomized design (feces patches, total feces, forage intake and total consumption), with repeated measures over time (body condition score and live weight) and with repeated measures over time; the time considered the measure of local control (milk yield per cow, live weight, stocking rate, and milk production per hectare). The rest period was the necessary to enable the expansion of 2.5 new leaves and the residue equivalent to the residual leaf area index 2.0 (residual LAI 2.0). The greater supply of nitrogen has not provided increase in the following variables: leaf elongation rate (TAlF), stem elongation rate (TAlH), anterior leaf senescence rate (TSFant) and posterior leaf senescence rate (TSFpost). There was no difference among treatments as a function of the type of animals. The TAlF partly had followed the availability of water from the rainfall. It was observed a variation in the organic matter content throughout the area, reflected in the ability to store water and nutrients, which influenced their availability to the pastures. No difference was detected in TAlH in function of treatments. This effect was a result of the rest period adopted (2.5 new leavesÃtiller-1), reducing the capture level of photosynthetically active radiation to values below 95%. The intensification has little consequence on studied variables (total forage dry mass, green forage dry mass, green leaf blade dry mass, and green stem dry mass). The pre-grazing height presented growth from the first to the second cycle and a subsequent decline until the last cycle, considering that this had the lowest values for all treatments. The increase in nitrogen availability promoted higher yield levels at certain moments, when water was supplied at suitable levels. Water availability influenced the yield response of pasture over the cycles. A relationship was verified between the soil organic matter content and yield performance of pastures. Regarding the animals behavior, it was registered interaction between treatments and day periods, except for urinating behavior that was only affected by the period. The fertilization had positive influence on the grazing behavior, increasing the time spent to expressing it. For the other activities the effect was negative, reducing the displacement time of animals. The fertilization and the interaction fertilization x supplement provided a longer use of shading by the animals. The use of concentrate feed increased the number of defecations, especially during the periods of longer permanence in the pasture. Day period influenced the drinking behavior, leading to a higher consumption of water in the periods with higher temperatures, as well as intermediate treatments presented higher consumption. In relation to the feces distribution, the data had coefficients of positive skewness and platicÃrtica kurtosis. For the coefficient of variation, we verified a great variation, with the rest areas presenting higher values, and paddocks with higher fertilization level presenting the lowest values. Climatic factors radiation, temperature and relative humidity have significantly influenced the dispersal and location of the feces. Regarding the degree of spatial dependence (GDE) it was verified classification ranging from moderate to strong, with higher proportion of GDE. The range was between 14.0 and 12.7m for rest areas and paddocks, respectively. The fertilization and supply of concentrate influenced the deposition and loss of nitrogen via feces, increasing its values to the extent that it increased the nutrient input. We observed heterogeneity in deposition of feces, with areas of higher concentration, as shadow, entrance of paddocks, and rest area, presenting peaks of deposition reaching 1,051.2kg NÃha-ÂÃyear-Â, and average varying between 148.8 and 210.7 NÃha-ÂÃyear-Â. There was increase in milk daily production and per area, as it intensified the system, via enhancement. With the intensification there was a greater persistence of lactation, observed through the relationship obtained by dividing the slope per intercept, resulting in a daily percentage of decrease in lactations. The persistence of animalsâ production responded directly to the system intensification, as a consequence of higher enhancement (improved diet). The production per area responded more strongly to the level of individual daily production and followed a quadratic trend, accompanying the rainfall distribution. The fecal production increased towards the highest level of enhancement, resulting in higher estimates of consumption. The greater input of nutrients (more intensive) allowed elevating the productivity levels per animal, per area, in relation to the labor and total daily production. The increase in area used for production improves the investment/production ratio, decreasing as enlarges the area. The greater enhancement enabled raising the revenues, but also raised the total monthly costs, presenting better relationship the intermediate levels of enhancement. To the extent that it has increased the area used, the lowest intensive level had a positive gross margin. The actual operating costs increased as the systems had been intensified. But the total operating costs decreased with the intensification, increasing again at the most intensive level. The feed represented around 70% of actual operating costs. Systems were unfeasible at medium-long terms, and at short term they were less attractive than observed in the sample of producers used in this study.

Despite the vast scholarship on war writing and trauma, a focused study on the connection between individual and collective war traumatic affect and their representation in literature has not been written. This study close-reads and analyzes war writing between 1916 and 2006 in order to trace the narrative tropes that are recurrent in war narratives of that era. The exposition of these tropes is informed by Hayden White’s study Tropics of Discourse, Mikhail Bakhtin’s account of the ‘chronotope’ in The Dialogic Imagination, Julia Kristeva’s theory of abjection, and Cathy Caruth’s writings on trauma theory. The narratives examined are Stratis Myrivilis’s novel Life in the Tomb (1923), Chimamanda Ngozi Adichie’s Half of a Yellow Sun (2006), Thomas Pynchon’s Gravity’s Rainbow (1973), Kurt Vonnegut’s Slaughterhouse-5 (1969), Joseph Heller’s Catch-22 (1961), Joy Kogawa’s Obasan (1981), and Anna Kavan’s collection of short stories I am Lazarus (1945). The analysis of these seven narratives yields the identification of a range of tropes which underpin the representation of war traumatic affect. The identified tropes include the synecdochical relationships between body and nation, the chronotopic connection between traumatized body and warscape, the traumatized mind and the repetitive narration, as well as the proleptic anticipation of traumatic future. In turn, it will be argued, these tropes form assemblages between the individual and the collective and operate on a textual continuum sustained by the representation of past, present, and future war traumas.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 227-251).
The spatiotemporal variability of water vapor near the Equator remains poorly understood because convective organization simultaneously spans the cloud scale (~ 10km) and the planetary scale (~ 10, 000km). Spatiotemporal variability of tropical water vapor may result from internal instabilities of the atmosphere, arising from the interaction between water vapor, radiation and convection. The present work leverages the instability of radiative-convective equilibrium, the most fundamental state of the tropical atmosphere, to connect convective organization in cloud-permitting models with the observed variability of water vapor through common physical mechanisms. First, we propose a simple theory that explains when instability of radiative-convective equilibrium may occur: If the total atmospheric cooling decreases with column water vapor, then radiative-convective equilibrium may be unstable to the growth of moist and dry perturbations.
Secondly, we combine a linear response framework with the weak temperature gradient approximation to analyze the interaction between convection, radiation and water vapor at each level of the atmosphere. We find that convection may interact with radiation to trigger the growth of mid-tropospheric water vapor anomalies by transporting water vapor to the upper troposphere, where it can prevent lower-tropospheric water vapor from radiatively cooling to space. Thirdly, we turn to the spatial organization of water vapor anomalies and relate the evolution of the size of moist and dry regions to diabatic fluxes in twenty cloud-permitting simulations on large domains. Longwave radiation from ice clouds aggregates convection at larger scales, shortwave radiation aggregates convection at smaller scales, and surface enthalpy fluxes smooth out water vapor anomalies through their enthalpy disequilibrium component.
Finally, we relate the transient zonal variability of precipitable water to convective-aggregation mechanisms in realistic models and observations of the atmosphere. Radiative fluxes generate transient water vapor structures of planetary scales, while surface enthalpy fluxes and horizontal energy transport act to smooth out these structures, suggesting parallels between observations and idealized simulations of aggregated convection.
by Tom Beucler.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences

Groundwater ecosystems can moderate the concentrations of agricultural contaminants that discharge into marine zones like the Great Barrier Reef. However, the analysis of microorganisms in our wet-tropics groundwater aquifers has received little attention. This study monitored seasonal changes in groundwater chemistry in aquifers underlying sugarcane in north Queensland and identified microorganisms that inhabit the groundwater and soil. The results indicate a strong connectivity between agricultural soil ecosystems and groundwater aquifers. There was spatial variability in groundwater chemistry due to the heterogeneous nature of the groundwater aquifer alluvium.

Although studies on stable-carbon isotopes in trees from temperate zones provide abundant paleoclimatic data, tropical trees are still understudied in this context. Therefore this study examined the variability of intra- and inter-annual stable-carbon isotopic pattern in several tree species from various tropical climates. The 𝛿¹³C values of samples of 12 broadleaved trees (seven species) from various paleotropical and neotropical sites along a climatic moisture gradient were investigated. The inter-annual variability between species and sites was studied. Further the relationship between 𝛿¹³C and precipitation time series was analyzed. Results show that tropical tree species show a similar variability in carbon isotopic composition as temperate tree species. Significant correlations between annual precipitation and tree-ring 𝛿¹³C time series were negative. Successful crossdating of a tree-ring 𝛿¹³C time series highlights the potential of carbon isotope measurements for tropical tree-ring analytical studies. Tropical broadleaved trees are able to capture a carbon isotopic signal in their annual rings even under everwet conditions and show good potential for paleoclimatic research.

Thesis (Ph. D.)--University of California, San Diego, 2008.
Title from first page of PDF file (viewed July 22, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 203-220).

The tropical seascape is herein defined as a landscape made up of five ecosystems: coastal terrestrial forests, mangrove forests, seagrass beds, coral reefs and the deep sea. Previous studies have shown that men and women use the tropical seascape in different ways. If the seascape was to change as a result of anthropogenic climate change, then men and women could potentially be affected differently by those changes. The seascape is particularly vulnerable to the predicted rise in sea-level and ocean warming, but the coastal terrestrial forests and mangrove forests are in addition vulnerable to the increased storms and hurricanes a warmer climate is predicted to lead to. While men and women utilizes these ecosystems in many different ways, this study found, based on the literature reviewed, that in a worst-case scenario all parts of the seascape could potentially be destroyed and none of the activities performed there today could be performed in the future. The deep sea would not be destroyed, but the fish living there would move to higher latitudes and deeper waters, effectively ending the fishing practices in the tropical waters. To save the tropical seascape anthropogenic climate change would have to stop on a global scale, since the problem cannot be solved on a local or regional level.

A adubação nitrogenada é uma estratégia utilizada para melhorar produção e composição bromatológica de forragens. Em pastagens manejadas intensivamente o uso contínuo de fertilizantes cria condições específicas no sistema onde a planta pode alterar sua responsividade ao nitrogênio. Dessa forma, o objetivo deste trabalho foi verificar a curva de resposta ao nitrogênio de pastagens manejadas intensivamente e mensurar a fração N orgânico mineralizável através do método Illinois Soil Nitrogen Test (ISNT) como possível preditor da resposta a adubação. Foram escolhidas 5 áreas com pastos do gênero Megathyrsus syn Panicum com diferentes tempos de manejo intensivo. Em cada área foi implantado um experimento de curva de resposta ao N utilizando o fonte do nutriente o fertilizante nitrato de amônio nas doses de 0, 50, 100 e 200 kg ha-1 de N corte-1 da forragem. O período de crescimento entre as coletas foi de 28 dias, sendo realizadas 3 amostragens da parte área da pastagem. Amostras de solo foram coletas no pré e pós tratamento. Os teores de ISNT encontrados no pré tratamento foram mais altos do que os normalmente relatados para outras culturas nos trópicos. As áreas com maior tempo de intensificação apresentaram teores de ISNT > 291mg kg-1. A produção de massa seca, teor foliar de N, índice SPAD e NDVI tiveram aumento crescente quando se usou doses mais elevadas de N. As áreas com maior tempo de intensificação tiveram redução da produção de massa seca quando se usou a maior dose do fertilizante nitrogenado. Os teores de PB variaram de 15-22% e estão muito acima dos encontrados na literatura para pastagens do gênero Megathyrsus syn Panicum. Os índices de eficiência de uso do nitrogênio foram baixos, caracterizando a dependência do nitrogênio oriundo do solo para esses cenários de manejo de pastagens. Dentre as áreas avaliadas não se encontrou ausência de resposta à adubação nitrogenada. O ISNT e N mineral presentes no solo foram inversamente relacionados à resposta produtiva dos pastos. Esse estudo mostra potencial em utilizar índices de nitrogênio do solo para o manejo da adubação nitrogenada de pastagens intensivas.
Nitrogen fertilization is a strategy used to improve the production and bromatological composition of forages. In intensively managed pastures the continuous use of fertilizers creates specific conditions in the system where the plant can change its responsiveness to nitrogen. Thus, the objective of this work was to verify the nitrogen response curve of intensively managed pastures and to measure the mineralizable organic N fraction through the Illinois Soil Nitrogen Test (ISNT) as a possible predictor of the fertilization response. Five pasture areas of the genus Megathyrsus syn Panicum were selected with different times of intensive management. In each area an N response curve experiment was implemented using the nutrient source the ammonium nitrate fertilizer at doses of 0, 50, 100 and 200 kg ha-1 of N cut-1 of the forage. The period of growth between the collections was of 28 days, being realized 3 samplings of the part of the pasture. Soil samples were collected in pre and post treatment. The ISNT levels found in pretreatment were higher than those normally reported for other crops in the tropics. The areas with the greatest intensification time presented NPH levels> 291 mg kg-1. Dry mass, N content, SPAD index and NDVI index increased with higher N doses. Areas with higher intensification times had a reduction in dry mass production when the highest nitrogen fertilizer dose was used. Crude protein levels varied from 15-22% and are well above those found in the literature for pastures of the genus Megathyrsus syn Panicum. Nitrogen use efficiency indexes were low, characterizing soil nitrogen dependence for these pasture management scenarios. Among the evaluated areas there was no absence of response to nitrogen fertilization. The ISNT and mineral N present in the soil were inversely related to the productive response of the pastures. This study shows the potential of using soil nitrogen rates to manage the nitrogen fertilization of intensive pastures.