Multivariate Objective Analysis of Wind and Height Fields in the Tropics

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CBDR&RC in a regime applicable to all

The principle of common, but differentiated, responsibilities and respective capabilities (CBDR&RC) is fundamental to the UNFCCC. Some options for a nuanced model of differentiation that addresses both responsibility and capability in a changing world are explored, such as new categories of countries, and some of the political issues that such a model might face are considered. The strengths and limitations of options for graduation based on ‘objective’ criteria such that countries could move between categories or ‘graduate’ – an option provided by the UNFCCC – are discussed. Countries could also choose to join another club (e.g. the G20), self-elect into categories or differentiate among themselves implicitly by accepting different commitments and actions. CBDR&RC will form part of the overall legally binding agreement, and must apply symmetry in some respects and differentiation in others to the commitments and actions contained therein. Some possible characteristics of CBDR&RC of relevance in a regime ‘applicable to all’ are outlined. These include promoting climate action and using mechanisms available in the UNFCCC to instil dynamism. Differentiation on mitigation must consider the distinctions between absolute and relative reductions, as well as commitments to outcomes and implementation. CBDR&RC should be applied to mitigation, adaptation, and the means of implementation.

Policy relevance

In Durban, Parties agreed to negotiate a regime ‘applicable to all’, which sent a political signal that there should be greater symmetry between nations. The world has changed since the UNFCCC was negotiated in 1992. It is now less helpful to think only in terms of two groups of countries (e.g. Annex I and non-Annex I), and evident that there are significant differences between member states. This requires a more nuanced interpretation of the principles of equity and CBDR&RC, which is an integral part of the UNFCCC. The options for the different approaches outlined in this article might help in the construction of a more nuanced model. All must do more, while some must do more still than others. To achieve this, some defining characteristics of CBDR&RC in a regime applicable to all are suggested.     

REE geochemistry of ore zones in the archean auriferous schist belts of the eastern Dharwar Craton, south India

The eastern Dharwar Craton of southern India includes at least three ∼ 2700Ma supracrustal belts (schist belts) which have mesothermal, quartz-carbonate vein gold mineralization emplaced within the sheared metabasalts. In the Hutti and the Kolar schist belts, the host rocks are amphibolites and the ore veins have been flanked by only a thin zone of biotitic alteration; in the Ramagiri belt, however, the host rocks to the veins have been affected by more extensive but lower temperature alteration by fluids. The rare earth element (REE) geochemistry of the host metabasalts, alteration zones, ore veins and the bulk sulfides separated from the ore veins and the alteration zones suggest that

SATELLITE-OBSERVED RADIATIVE ENERGY BUDGET DURING ONSET PHASE OF SUMMER MONSOON

In this paper satellite-derived radiative energy budget such as shortwave radiative heating,longwaveradiative heating and net radiation balance have been studied for the onset phase of summer monsoon1979. Since cloud play an important role in determining diabatic heating field as well as being a reflectionof status of the monsoon itself, the day to day evolution of clouds from TIROS-N satellite has beenmade. Satellite-derived radiative heating rates from surface to 100 hPa were computed for each 100 hPathickness layer. These heating rates were then compared with the observed latitudinal distribution of total radintive heating rates over the domain of the study. From the results of our study it was found thatthe characteristic features such as net radiative heating rates of the order of 0.2℃/day at upper tropospheric level(100-200 hPa)and cooling throughout the lower tropospheric layers with relatively lesscooling between 500-700 hPa layer observed.in a case of satellitexierived radiative energy budget agreewell with the characteristic features of observational radiative energy budget over the domain of thestudy. Therefore, it is suggested that radiative energy budget derived from satellite observati0ns be usedwith great potential and confidence for the evolution of complete life cycle of monsoon over the Indianregion for different years.     

Petrogenesis and source characteristics of metatholeiites from the Archean Ramagiri schist belt, eastern part of Dharwar craton, India

The N–S trending, 2–4 km wide Ramagiri schist belt is made up of three blocks dominated by metavolcanic rocks, separated and surrounded by granitic rocks of distinct characteristics. The metavolcanic rocks are tholeiitic in composition and are very similar in their major element composition as well as in their abundances of some trace elements. However, the rare earth elements (REE) require distinct sources. The rocks of the amphibolite facies eastern block have LREE depleted REE patterns ([Ce/Yb] = 0.7–0.9), requiring derivation from depleted mantle-like sources. The greenschist facies metatholeiitic rocks of the central block have LREE enriched REE patterns ([Ce/Yb] = 3–6), reflecting the nature of their source(s). The Nd isotopic data require that the LREE enriched nature could not have been attained significantly prior to its melting. The fine-grained, upper greenschist facies metatholeiites of the western block have flat to slightly LREE depleted patterns ([Ce/Yb] = 0.8–0.95). Minor fractional crystallization of rock forming minerals may relate a few samples to each other among samples from each of the three blocks. Different extents of partial melting of distinct mantle sources have played a dominant role in the generation of the parent magmas to the central versus eastern and western block metatholeiites. The geochemical data suggest that the mantle sources were non-lherzolitic, and that these sources may have seen previous episodes of melt addition and extraction prior to melting that gave rise to the parent melts to the rocks ∼2750 Ma ago. The REE data indicate that while the sources of the eastern and western block rocks were similar to depleted mantle (ɛ_{Nd( i )} about +2), the source of the central block rocks (ɛ_{Nd( i )} about +3.5) were enriched in large ion lithophile element (LILE)-rich fluids/melts probably derived from subducting oceanic crust. This and other trace element signatures point to magma extraction in tectonic settings similar to modern island arcs. Subsequent to magma emplacement and crystallization, all the three suites of rocks were affected by interaction with low-temperature, crustal derived fluids (ɛ_{Nd 2750Ma} of about −8 to −12), probably during the accretion of the three blocks of the belt in the present form. The inferred source characteristics, tectonic setting of magma generation and the crustal fluid processes seem to suggest that Phanerozoic-style tectonic processes may have been important in the generation of Archean crust in the Dharwar craton. Received: 31 July 1995 / Accepted: 12 May 1997     

Geochemistry and origin of ferruginous nodules in weathered granodioritic gneisses, Mysore Plateau, Southern India

Fe-nodules occur within saprolites formed from weathering of granodioritic gneisses in the rain-shadow region of the Mysore Plateau adjacent to the Sahyadri Mountains in Southern India. These nodules and their host saprolites were studied for their geochemistry, including chemical speciation, to understand nodule formation and chemical redistribution processes during rock weathering. From their mode of occurrence, and mineralogical and geochemical data, we infer that the nodules originated by a two-stage process in which the initial extensive weathering of gneisses likely facilitated subsequent ferrolysis weathering and nodule formation. Nodules originated by precipitation of goethite, hematite and gibbsite along with several amorphous phases within the matrix of weathered gneisses. This is possible only under hydromorphic conditions, suggesting that parts of the plateau must have gone through a humid phase prior to the present aridity. In the saprolites, Al, Fe, and Ti become enriched because of the removal of Si, Ca, Na, and K. However within the nodule, Fe, Ti, Cr, and Ni are deposited after their chemical transport from the saprolite. Titanium, known for its immobile nature, was also mobilized and concentrated under the conditions of nodule formation. The most important elements in the nodule constitution are Fe, Al, Ti, and Mn, each having both crystalline and amorphous phases. Fe-Ti and Mn oxyhydroxides grain coatings in the saprolites and discrete amorphous Mn and Ti phases in the nodules seem to have scavenged trace elements from the weathering profile. REE were mobilized during weathering and nodule genesis in which Ce and Ti show a strong geochemical coherence. The enrichment of only HREE in saprolite, and both HREE and LREE with significant Ce in the nodule, indicate the control of evolving secondary minerals in the REE redistribution during rock weathering. Strong enrichment of Ce in the weathering profile and in nodules has important implications to the REE chemistry of river waters.     

On the impact of divergent part of the wind computed from INSAT OLR data on global analysis and forecast fields

Summary In this paper, a procedure for the computation of the divergent part of wind from Outgoing Longwave Radiation (OLR) data is described. This divergent part is included in the global analysis scheme and its impact is studied by computing the vertical velocity, velocity potential etc., using the analysed fields with and without modifying the divergent part and also making 24 hr and 48 hr rainfall forecasts.Results show that magnitudes of vertical velocity were increased when the divergent part was modified in the wind analysis. There were also changes observed in the analysed wind field over convective regions and the changes over the oceanic regions were higher, suggesting that the impact of divergent part is more pronounced over data sparse regions. Marginal increase was observed in 24 hr and 48 hr rainfall forecast over the Indian region. The area averaged rainfall forecast at each time step in the first 6 hours of model integration was also higher in the case when the wind field contained the divergent part.To sum up, it can be stated that the inclusion of the divergent part from OLR data in the initial wind field has brought out positive impact on the wind analyses and rainfall forecast.With 12 Figures     

Analysis—Prediction experiments over Indian region using primitive equation barotropic model

The impact of initial guess and grid resolutions on the analysis and prediction has been investigated over the In-dian region. For this purpose, an univariate objective analysis scheme and a primitive equation barotropic model have been used. The impact of initial guess and the resolutions on analysis and prediction is discussed.     

An efficient optimum interpolation scheme for objective analysis over Indian region

In the optimum interpolation scheme, the weights for the observations are computed by solving a set of linear equations for every grid point. As the number of observations increases particularly over data-rich regions, the matrix dimension increases and the computer time required to solve these equations to determine weights increases considerably. In order to reduce the computer time for computing the weights, Tanguay and Robert suggested schemes in which the gaussian function representing the autocorrelation function has been approximated by a second-order and also by a fourth-order Taylor series expansion. This resulted in the solution of matrices of order 4 or 9 respectively to obtain weighting functions irrespective of the number of observations used in the analysis. In the present study, the analyses of mean sea level pressure and geopotential height at 700 mbar level have been carried out for five days using the above two schemes and the regular OI scheme. The analyses are found to be similar in all the three cases suggesting that a lot of computer time could be saved without sacrificing the analysis accuracy by using the modified scheme in which the second-order approximation is utilized.     

Impact of Monex-79 data on the objective analysis of the wind field over the Indian region

The monsoon sub-programme of FGGE deployed a variety of observing systems such as research aircraft, research vessels, floating ballooms, and a geostationary satellite, etc. during the special observational period of Monex-79, with a view to making the best possible data set available for studies on various aspects of the monsoon circulation. Whether the data obtained from the various observational platorms improve the representation of the monsson systems, flow patterns, etc. in the analysis is the basis of this study. For this, the objective analyses of the wind field were made with different data sets, first using only the data from conventional observation platforms, subsequently including the data from aircraft and ships and then finally including the data from the satellite. These analyses were compared with carefully made subjective analyses.It is inferred that the addition of data has a positive impact on the objective analysis and the improvement in the analysis is more marked in the data-void region like the Arabian Sea compared to the region where observational stations are distributed fairly stisfactorily. It is also inferred that the impact of the aircraft/ship data on the analysis is more consistent than the data from the satellite.