Impacts of enhanced CCN on the organization of convection and recent reduced counts of monsoon depressions

Monsoon depressions, that form during the Indian summer monsoon season (June to September) are known to be baroclinic disturbances (horizontal scale 2,000–3,000 km) and are driven by deep convection that carries a very large vertical slope towards cold air aloft in the upper troposphere. Deep convection is nearly always organized around the scale of these depressions. In the maintenance of the monsoon depression the generation of eddy kinetic energy on the scale of the monsoon depression is largely governed by the “in scale” covariance of heating and temperature and of vertical velocity and temperature over the region of the monsoon depression. There are normally about 6–8 monsoon depressions during a summer monsoon season. Recent years 2009, 2010 and 2011 saw very few (around 1, 0 and 1 per season respectively). The best numerical models such as those from ECMWF and US (GFS) carried many false alarms in their 3–5 day forecasts, more like 6–8 disturbances. Even in recent years with fewer observed monsoon depressions a much larger number of depressions is noted in ECMWF forecasts. These are fairly comprehensive models that carry vast data sets (surface and satellite based), detailed data assimilation, and are run at very high resolutions. The monsoon depression is well resolved by these respective horizontal resolutions in these models (at 15 and 35 km). These models carry complete and detailed physical parameterizations. The false alarms in their forecasts leads us to suggest that some additional important ingredient may be missing in these current best state of the art models. This paper addresses the effects of pollution for the enhancement of cloud condensation nuclei and the resulting disruption of the organization of convection in monsoon depressions. Our specific studies make use of a high resolution mesoscale model (WRF/CHEM) to explore the impacts of the first and second aerosol indirect effects proposed by Twomey and Albrecht. We have conducted preliminary studies including examination of the evolution of radar reflectivity (computed inversely from the model hydrometeors) for normal and enhanced CCN effects (arising from enhanced monsoon pollution). The time lapse histories show a major disruption in the organization of convection of the monsoon depressions on the time scale of a week to 10 days in these enhanced CCN scenarios.     

Influences of local weather, large-scale climatic drivers, and the ca. 11 year solar cycle on lake ice breakup dates; 1905–2004

We investigate the temporal patterns in inter-annual variability in ice breakup dates for Lakes Mendota and Monona, Wisconsin, between 1905 and 2004. We analyze the contributions of long-term trends attributed to climate change, local weather, indices of sunspots, and large-scale climatic drivers, such as the North Atlantic Oscillation (NAO) and El Niňo Southern Ocean Index (ENSO) on time series of lake-ice breakup. The relative importance of the aforementioned explanatory variables was assessed using linear regression and variation partitioning models accounting for cyclic temporal dynamics as represented by Moran Eigenvector Maps (MEM). Model results explain an average of 58 % of the variation in ice breakup dates. A combination of the long-term linear trends, rain and snowfall in the month prior to breakup, air temperature in the winter prior to breakup, cyclic dynamics associated with sunspot numbers, ENSO, and for Lake Mendota, NAO, all significantly influence the timing of ice breakup. Significant cycle lengths were 3.5, 9, 11, and 50 years. Despite their proximity, Lakes Mendota and Monona exhibit differences in how and which explanatory variables were incorporated into the models. Our results indicate that lake ice dynamics are complex in both lakes and multiple interacting processes explain the residuals around the linear warming trends that characterize lake ice records.     

Uncertainty, ignorance and ambiguity in crop modelling for African agricultural adaptation

Drawing on social constructivist approaches to interpreting the generation of knowledge, particularly Stirling’s (Local Environ 4(2):111–135, 1999) schema of incomplete knowledge, this paper looks critically at climate-crop modelling, a research discipline of growing importance within African agricultural adaptation policy. A combination of interviews with climate and crop modellers, a meta-analysis survey of crop modelling conducted as part of the CGIAR’s Climate Change Agriculture and Food Security (CCAFS) programme in 2010, and peer-reviewed crop and climate modelling literature are analysed. Using case studies from across the crop model production chain as illustrations it is argued that, whilst increases in investment and growth of the modelling endeavour are undoubtedly improving observational data and reducing ignorance, the future of agriculture remains uncertain and ambiguous. The expansion of methodological options, assumptions about system dynamics, and divergence in model outcomes is increasing the space and need for more deliberative approaches to modelling and policy making. Participatory and deliberative approaches to science-policy are advanced in response. The discussion highlights the problem that, uncertainty and ambiguity become hidden within the growing complexity of conventional climate and crop modelling science, as such, achieving the transparency and accessibility required to democratise climate impact assessments represents a significant challenge. Suggestions are made about how these challenges might be responded to within the climate-crop modelling community.     

Technology transfer by CDM projects

Abstract

Technology development and transfer is an important feature of both the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. Although the Clean Development Mechanism (CDM) does not have an explicit technology transfer mandate, it may contribute to technology transfer by financing emission reduction projects using technologies currently not available in the host countries. This article analyses the claims about technology transfer made by CDM project participants in their project design documents. Roughly one-third of all CDM projects, accounting for almost two-thirds of the annual emission reductions, involve technology transfer. Technology transfer varies widely across project types and is more common for larger projects and projects with foreign participants. Equipment transfer is more common for larger projects, while smaller projects involve transfers of both equipment and knowledge or of knowledge alone. Technology transfer does not appear to be closely related to country size or per-capita GDP, but a host country can influence the extent of technology transfer involved in its CDM projects.     

Solitons and Lie group analysis to an extended quantum Zakharov–Kuznetsov equation

In this paper, complete geometric symmetry of extended quantum Zakharov–Kuznetsov (QZK) equation are investigated. All of the geometric vector fields for the new extended QZK equation are presented. At the same time, a plethora of exact solutions are obtained by the application of the group theorem. In addition, 1-soliton solution of the extended QZK equation with power law nonlinearity is obtained by the aid of traveling wave hypothesis with the necessary constraints in place for the existence of the soliton.     

Mars interplanetary trajectory design via Lagrangian points

With the increase in complexities of interplanetary missions, the main focus has shifted to reducing the total delta-V for the entire mission and hence increasing the payload capacity of the spacecraft. This paper develops a trajectory to Mars using the Lagrangian points of the Sun-Earth system and the Sun-Mars system. The whole trajectory can be broadly divided into three stages: (1) Trajectory from a near-Earth circular parking orbit to a halo orbit around Sun-Earth Lagrangian point L₂. (2) Trajectory from Sun-Earth L₂ halo orbit to Sun-Mars L₁ halo orbit. (3) Sun-Mars L₁ halo orbit to a circular orbit around Mars. The stable and unstable manifolds of the halo orbits are used for halo orbit insertion. The intermediate transfer arcs are designed using two-body Lambert’s problem. The total delta-V for the whole trajectory is computed and found to be lesser than that for the conventional trajectories. For a 480 km Earth parking orbit, the total delta-V is found to be 4.6203 km/s. Another advantage in the present approach is that delta-V does not depend upon the synodic period of Earth with respect to Mars.     

Quasi-terminator orbits near primitive bodies

Quasi-terminator orbits are introduced as a class of quasi-periodic trajectories in the solar radiation pressure (SRP) perturbed Hill dynamics. These orbits offer significant displacements along the Sun-direction without the need for station-keeping maneuvers. Thus, quasi-terminator orbits have application to primitive-body mapping missions, where a variety of observation geometries relative to the Sun (or other directions) can be achieved. This paper describes the characteristics of these orbits as a function of normalized SRP strength and invariant torus frequencies and presents a discussion of mission design considerations for a global surface mapping orbit design.