Local Climate Zone in Xi’an City: A Novel Classification Approach Employing Spatial Indicators and Supervised Classification

The Local Climate Zone (LCZ), as a foundational element of urban climate zone classification proposed by Oke and Stewart, categorizes urban surface types based on 10 influential parameters affecting the urban heat island effect, such as building density, surface reflectivity, sky view factor, and surface roughness length. This method divides cities into 17 different Local Climate Zones (LCZs) to standardize climate observations and promote global climate research exchange, offering valuable insights for heat island studies. In this study, we enhance the existing local climate zones spatial classification approach by focusing on Xi’an city’s urban layout and architectural features. By using urban spatial indicators and employing a supervised classification approach and a spatial clustering method with land parcels as statistical units, we investigate typical urban areas and classify Xi’an’s land parcels into 17 or 15 distinct local climate zones. Subsequently, through the evaluation of two distinct classification methods, the most suitable urban microclimate zoning method for Xi’an city was selected. This optimization of the local climate zoning representation introduces a spatial classification method tailored to urban climate planning and control, utilizing urban spatial indicators and remote sensing data. The resulting urban climate zoning map not only supports sample selection for urban heat environment parameter observation but also aids urban planners in identifying spatial distribution patterns for climate zoning

Expert Consultation on Market Information Systems and Agricultural Commodity: Exchanges: Strengthening Market Signals and Institutions. Proceedings of an expert meeting held in Amsterdam, The Netherlands, 28–30 November 2005

The Expert Consultation on Market Information Systems and Agricultural Commodity Exchanges: Strengthening Market Signals and Institutions was convened to review CTA’s investments in MIS and ACEs within a broad perspective to determine which are the more successful systems, what conditions have enabled them to function well, and how they are being used by farmers’ organisations, traders and other development partners..

Characterisation of communal rangeland degradation and evaluation of vegetation restoration techniques in the Eastern Cape, South Africa

This study assessed the social factors influencing poor communal rangeland management, which are assumed to result in rangeland degradation. This was followed by, examination of biophysical characteristics of rangeland degradation in communal areas. To relate social factors featuring in communal rangeland management with rangeland degradation, biophysical factors influencing livestock grazing distribution patterns were studied. To establish the solution to communal rangeland degradation, rangeland restoration techniques were evaluated. The study was conducted at Amakhuze Tribal Authority (ATA) (S32o 38´, E26o56, 763 - 1500 m.a.s.l) composed of six villages and Phandulwazi Agricultural High School (S32o 39´ and E26o 55´, 747 m.a.s.l). Focus group discussions were conducted in six villages and questionnaire surveys in four randomly selected villages to assess social factors influencing communal rangeland degradation. Communal rangeland degradation biophysical characteristics were assessed. Biophysical factors affecting livestock grazing distribution pattern were examined through direct field observations for 12 months. Restoration techniques were evaluated on 26 plots. The social factors influencing communal rangeland management include lack of skills on rangeland management for farmers, lack of individual/community obligation on grazing management, lack of effective policies and/or poor enforcement accompanied by lack of effective institutions governing rangeland utilisation and management. Communal rangelands were more (χ 2 = 2612.07, df = 26, p < 0.01) degraded compared with controlled grazing areas. Within the communal rangelands, land degradation was higher at the low-lying areas, compared to foothills, midslopes, and mountaintop (crest). Rangeland degradation in communal areas was characterised by poor forage productivity and poor vegetation cover , higher soil unconfined compressive strength (UCS) (4.5 kg/cm2) with low hydraulic conductivity (5.21 x 10-3) and physical soil loss characteristics such presence of terracettes, pedestals, rills and gullies. Grazing distribution was higher at valley bottom (r2 = 0.404, p < 0.001), low altitude (r2 = -0.007, p < 0.001), closer to water points (r2 = -0.001, p < 0.001), and on grassland vegetation (r2 = 0.620, p < 0.001). Introduction of seedlings with microcatchment combined with brushpack promoted (p < 0.05) higher number of tillers (13), leaves (42) and reduced seedling mortality (10.4percent). T. triandra produced higher (p < 0.05) number of tillers (12) and leaves (39) but low number of inflorescence (0.7) with higher mortality rates (25.3percent) compared to P. dilatatum. Where plant propagules were introduced as seeds, use of microcatchment promoted higher seed germination (F = 38.84, p < 0.05) and maintained higher plant density (F = 37.43, p < 0.05). E. curvula seeds attained higher germination rate and maintained higher plant density compared to D. eriantha and P. Maximum. Use of microcatchment, brushpack, and water spreading system promoted soil water retention. It is important that any interventions aimed at improving communal rangeland management, controlling rangeland degradation in the communal areas, or restoring degraded rangelands to consider the social factors driving rangeland management and biophysical factors influencing grazing distribution pattern. Rangeland restoration techniques for communal areas should be centred on their ability to collect and retain water to promote restoration performance of introduced plant propagules.Thesis (PhD) -- Faculty of Science and Agriculture, 201