Direct cloud water recovery by inertial impaction: Implications for large scale water supply in the Cape Verde Islands

Summary In this study, we explore the idea of harvesting cloud water in mountainous areas of the drought prone Cape Verde Islands as a year-round fresh water resource based on three cloud water collection experiments in the islands. Cloud water was collected by impaction on a commercially available, plastic, agricultural shade cloth at Serra Malagueta, Santiago, and at Monte Verde, São Vicente. This shade screen possesses superior properties to other reported materials for cloud water collection, including an impact-efficient mesh shape, high tensile strength and durability, tear resistance, and excellent water drainage characteristics. Collection efficiency of monofilament knitted shade screen varied with the mesh density (50% or 70% shading) and height of the screens, but for Monte Verde all screens above 3 m collected greater than 6 lm^–2 day^–1 on average for 315 days of measurement. Dry season collection for the most effective panel, a double layer of 50% shading screen, ranged from 1.3 lm^–2 day^–1 in December, 1988, to 7.8 and 7.7 lm^–2 day^–1 in November and April, 1988 respectively. Based on these measurements, we discuss a logical next phase for implementation of a large scale cloud water catchment system.With 3 Figures     

Simultaneous measurements of ozone and its precursors on a diurnal scale at a semi urban site in India

Simultaneous observations of surface ozone (O₃) with its precursors namely, carbon monoxide (CO) and oxides of nitrogen (NO_x) have been taken on diurnal scale from a tropical semi-urban site, Pune (18.54°N, 73.81°E) in India. We present the data for one year (2003–2004) period to study the salient features of these trace gases. The peak in amplitude of ozone is found during the noontime whereas in CO and NO_X it is observed in the morning hours between 0800 and 0900 H. The concentration of these pollutants drop down considerably during southwest monsoon months and the diurnal pattern also become very weak. The diurnal trends of these gases are found to be different for different seasons, which are specific to the receptor site. Model simulations using 3-D chemical-transport model with regional emission inventories and observed winds have also been carried out. The comparison of model results with observations, on seasonal basis yielded a reasonable qualitative agreement. The relative role of local emissions and long range transport in the diurnal pattern for different seasons has been outlined, which reveals that the ozone is highly influenced by regional/long range transport in this region. The effect of precursor amounts in the morning on afternoon ozone peak levels has been investigated using the lag correlation study, which reveals that a time lag of 5–7 h is required for most of these precursor gases to photo-chemically produce ozone to its maximum potential. Results are discussed in the light of available topographic and meteorological conditions.     

Estimation of precipitable water at different locations using surface dew-point

Summary The Reitan (1963) regression equation of the form lnw =a +bT _d has been examined and tested to estimate precipitable water vapor content from the surface dew point temperature at different locations. The results of this study indicate that the slopeb of the above equation has a constant value of 0.0681, while the intercepta changes rapidly with latitude. The use of the variable intercept technique can improve the estimated result by about 2%.With 6 Figures     

Rainfall rate distribution in a local scale: The case of Barcelona city

Summary Convective rainfall rate distribution is not very uniform even at a local scale. In order to make an evaluation of it in the urban area of Barcelona, a dense rain gauge network has been stablished in this city. The gauges are of high resolution tilting bucket type. In this paper, preliminary results are presented. The distributions obtained show a strong variation of the rainfall rate for the several parts of the city. The intensity-duration curves for severe storms have been made in the various points of measure together with the areal reduction factors of rainfall. The analysis of raincell movement gives E-W as a predominant direction and a speed in the 3–12 m/s range.With 9 Figures     

Effects of local drought condition on public opinions about water supply and future climate change

A growing body of research indicates that opinions about long-term climate change and other natural resource issues can be significantly affected by current weather conditions (e.g., outside air temperature) and other highly contingent environmental cues. Although increased severity and frequency of droughts is regarded as a likely consequence of anthropogenic climate change, little previous research has attempted to relate the experience of drought with public attitudes about water supply or water-related climate change issues. For this study, a large set (n?=?3,163) of public survey data collected across nine states of the southern United States was spatio-temporally linked with records of short-term (~12 weeks) and long-term (~5 years) drought condition at the level of each respondent’s zip code. Multivariate ordinal logistic regression models that included numerous other independent variables (environmental ideology, age, gender, education, community size, residency duration, and local annual precipitation) indicated highly significant interactions with long-term drought condition, but showed no significant effect from short-term drought condition. Conversely, attitudes about water-related climate change showed highly significant interactions with short-term drought, with weaker to no effects from long-term drought. While the finding of significant effects from short-term drought condition on opinions about future drought is broadly consistent with previous public opinion research on climate change, the finding of water supply attitudes being more responsive to longer term drought condition is, to our knowledge, a novel result. This study more generally demonstrates the methodological feasibility and applied importance of accounting for local drought condition when public opinion information is used to evaluate outreach programs for water conservation and climate change.     

A hybrid approach to improving the skills of seasonal climate outlook at the regional scale

A hybrid seasonal forecasting approach was generated by the National Centers for Environmental Prediction operational Climate Forecast System (CFS) and its nesting Climate extension of Weather Research and Forecasting (CWRF) model to improve forecasting skill over the United States. Skills for the three summers of 2011–2013 were evaluated regarding location, timing, magnitude, and frequency. Higher spatial pattern correlation coefficients showed that the hybrid approach substantially improved summer mean precipitation and 2-m temperature geographical distributions compared with the results of the CFS and CWRF models. The area mean temporal correlation coefficients demonstrated that the hybrid approach also consistently improved the timing prediction skills for both variables. In general, the smaller root mean square errors indicated that the hybrid approach reduced the magnitude of the biases for both precipitation and temperature. The greatest improvements were achieved when the individual models had similar skills. The comparison with a North American multi-model ensemble further proved the feasibility of improving real-time seasonal forecast skill by using the hybrid approach, especially for heavy rain forecasting. Based on the complementary advantages of CFS the global model and CWRF the nesting regional model, the hybrid approach showed a substantial enhancement over CFS real-time forecasts during the summer. Future works are needed for further improving the quality of the hybrid approach through CWRF’s optimized physics ensemble, which has been proven to be feasible and reliable.     

Evaluation of the impact of climate changes on water storage and groundwater recharge at the watershed scale

 The increase of concentration of carbon dioxide and other greenhouse gases in the atmosphere will certainly affect hydrological regimes. Global warning is thus expected to have major implications on water resources management. Our objective is to present a general approach to evaluate the effect of potential climate changes on groundwater resources. In the current stage of knowledge, large-scale global climate models are probably the best available tools to provide estimates of the effects of raising greenhouse gases on rainfall and evaporation patterns through a continuous, three dimensional simulation of atmospheric, oceanic and cryospheric processes. However their spatial resolution (generally some thousands of square kilometers) is not compatible with that of watershed hydrologic models. The main purpose of this study is to evaluate the impact of potential climate changes upon groundwater resources. A general methodology is proposed in order to disaggregate outputs of large-scale models and thus to make information directly usable by hydrologic models. As an illustration, this method is applied to a CO₂-doubling scenario through the development of a local weather generator, although many uncertainties are not yet assessed about the results of climate models. Two important hydrological variables: rainfall and potential evapotranspiration are thus generated. They are then used by coupling with a physically based hydrological model to estimate the effects of climate changes on groundwater recharge and soil moisture in the root zone. Received: 17 April 1998 / Accepted: 29 September 1998     

An assessment of the climate change impacts on groundwater recharge at a continental scale using a probabilistic approach with an ensemble of GCMs

This study used 16 Global Climate Models and three global warming scenarios to make projections of recharge under a 2050 climate for the entire Australian continent at a 0.05° grid resolution. The results from these 48 future climate variants have been fitted to a probability distribution to enable the results to be summarised and uncertainty quantified. The median results project a reduction in recharge across the west, centre and south of Australia and an increase in recharge across the north and a small area in the east of the continent. The range of results is quite large and for large parts of the continent encompasses both increases and decreases in recharge. This makes it difficult to utilise for water resources management so the results have been analysed with a risk analysis framework; this enables the future projections for groundwater recharge to be communicated to water managers in terms of likelihood and consequence of a reduction in recharge. This highlights an important message for water resource managers that in most areas of Australia they will be making decisions on water allocations under considerable uncertainty as to the direction and magnitude of recharge change under a future climate and that this uncertainty may be irreducible.     

城市热岛效应热点问题研究进展

概述了国内外城市热岛效应研究热点及不足,探讨了时空替代性、评价指标合理性、模拟空间尺度适宜性及理论与应用研究相结合等问题,指出未来城市热岛效应研究应注重新方法与新思路的集成、城市群热岛效应监测、城市热岛与全球异常环境要素间的生态关联性、缓解城市热岛效应的生态途径与技术方法。     

Some implications of a new approach to the water vapour feedback

The water vapour feedback is the largest physical climate feedback. It also gives the second-largest contribution to the range of uncertainty in climate sensitivity in General Circulation Models (GCMs). Tracing these differences back to their physical causes in the hope of constraining climate sensitivity requires an appropriate quantification. Yet the Intergovernmental Panel on Climate Change judge that the conventional diagnosis of a “water vapour feedback” and a “lapse rate feedback” provides little insight into differences between GCMs’ climate sensitivities. We show that the conventionally diagnosed water vapour feedback is in fact formally useless for investigating differences between GCMs’ climate sensitivities—the anticorrelation between conventional “water vapour feedback” and “lapse rate feedback” makes the correlation between the “water vapour feedback” and their sum insignificant: i.e. statistically, knowing this “feedback” allows one to conclude nothing about the sum and thence about climate sensitivity. This follows primarily from how little relative humidity (RH) changes with climate change in GCMs. A more detailed physical analysis concludes that the overall mean decrease of RH on warming seen in GCMs is robustly physically based. This and other physical arguments then suggest that the stronger the positive “water vapour feedback”, the less sensitive climate can be expected to be. A diagnosis based on the “partly-Simpsonian” model of water vapour feedback avoids these problems. On the conventional view of the water vapour feedback, naive extrapolation of variations within present-day climate suggests that parts of our planet are close to locally reaching conditions that would allow a run-away water vapour greenhouse effect once they were extensive enough. Of course this has never occurred in geological history, and is not seen in Earth-like GCMs. Again, the “partly-Simpsonian” approach provides a simple qualitative explanation, by showing that the water vapour feedback can only cancel part of the basic Planck’s Law negative feedback.     

Perceptions of climate change: Linking local and global perceptions through a cultural knowledge approach

Understanding public perceptions of climate change is fundamental to both climate science and policy because it defines local and global socio-political contexts within which policy makers and scientists operate. To date, most studies addressing climate change perceptions have been place-based. While such research is informative, comparative studies across sites are important for building generalized theory around why and how people understand and interpret climate change and associated risks. This paper presents a cross-sectional study from six different country contexts to illustrate a novel comparative approach to unraveling the complexities of local vs global perceptions around climate change. We extract and compare ‘cultural knowledge’ regarding climate change using the theory of ‘culture as consensus’. To demonstrate the value of this approach, we examine cross-national data to see if people within specific and diverse places share ideas about global climate change. Findings show that although data was collected using ethnographically derived items collected through place-based methods we still find evidence of a shared cultural model of climate change which spans the diverse sites in the six countries. Moreover, there are specific signs of climate change which appear to be recognized cross-culturally. In addition, results show that being female and having a higher education are both likely to have a positive effect on global cultural competency of individuals. We discuss these result in the context of literature on environmental perceptions and propose that people with higher education are more likely to share common perceptions about climate change across cultures and tentatively suggest that we appear to see the emergence of a ‘global’, cross-cultural mental model around climate change and its potential impacts which in itself is linked to higher education.     

Evaluation of MM5 mesoscale model at local scale for air quality applications over the Swedish west coast: Influence of PBL and LSM parameterizations

Summary The performance of MM5 mesoscale model (Version 3.6.3) using different planetary boundary layer (PBL) and land surface model (LSM) parameterizations is evaluated and compared using high temporal and spatial resolution G?TE2001 campaign data at local scale (a few kilometers) over the Greater G?teborg area along the Swedish west coast during 7–20 May 2001. The focus is on impact of PBL and LSM parameterizations on simulated meteorological variables important for air quality applications such as global radiation, diurnal cycle of near-surface air temperature and wind, diurnal cycle intensity, near-surface vertical temperature gradient, nocturnal temperature inversion, boundary layer height, and low-level jet (LLJ). The model performance for daytime and nighttime and under different weather conditions is also discussed. The purpose is to examine the performance of the model using different PBL and LSM parameterizations at local scale in this area for its potential applications in air quality modeling. The results indicate that the influence of PBL and LSM parameterizations on simulated global radiation, diurnal cycle of near-surface air temperature and wind speed, diurnal cycle intensity, vertical temperature gradient, nocturnal temperature inversion and PBL heights, which are critical parameters for air quality applications, is evident. Moreover, the intensity and location of LLJ are simulated well by all schemes, but there also exist some differences between simulated results by using different PBL and LSM schemes. Therefore, the choice of PBL and LSM parameterizations is important for MM5 applications to air quality studies. Correspondence: Junfeng Miao, Department of Earth Sciences, G?teborg University, P.O. Box 460, 405 30 G?teborg, Sweden     

Experimental study of the transfer velocity for urban surfaces with a water evaporation method

A major problem in urban climate modelling is determining how the heat fluxes from various canyon surfaces are affected by canyon flow. To address this problem, we developed a water evaporation method involving filter paper to study the distribution of the convective transfer velocity in urban street canyons. In this method, filter paper is pasted onto a building model and the evaporation rate from the paper is measured with an electric balance. The method was tested on 2D (two-dimensional) street canyon models and 3D model arrangements. Moreover, in this technique, it is easy to restrict the flux within an arbitrary surface in question. That is, the evaporation distribution on a surface can be studied by using several small pieces of filter paper. In the 2D case, the wall transfer velocity was strongly dependent on the canyon aspect ratio for perpendicular wind directions and it varied widely with height within both windward and leeward wall surfaces. For 3D cubic arrays, the relation to canyon aspect ratio was largely different from that of the 2D canyon. And, as a case study, the variation of wind direction was investigated for a city-like setting. The area-averaged transfer velocity was insensitive to wind direction but its local deviation was significant. Finally, we measured the transfer velocity for a clustered block array surrounded by relatively wide streets. The effect of spatial heterogeneity on the transfer velocity was significant. Moreover, for a fixed total building volume, the transfer velocity was considerably larger when the building height varied than when it was uniform. Therefore, the water evaporation method with filter paper is expected to be useful for studying the transfer velocity and ventilation rates in urban areas with various canyon shapes.     

Estimation of water balance components in the Black Sea

Presented are the estimates of precipitation amount and evaporation for the Black Sea basin based on the data of numerical regional reanalysis. The spatial distribution of considered variables is compared with the results obtained before using the method of extrapolation of measurements at the coastal meteorological stations. The computed water balance components of the Black Sea compared with the available literature data are used for obtaining the estimate of the mean water discharge in the Bosphorus.     

Incorporating resilience into sustainability indicators: An example for the urban water sector

The development and use of indicators is common practice in efforts to promote urban sustainability. Indicators used to measure urban sustainability tend to focus narrowly on describing the current state of the urban system. Although a time series analysis using these indicators may lend insights into trends towards or away from certain ‘sustainability’ goals, existing indicators of urban sustainability do not provide information on the ability or the likelihood that the current system state can be maintained or improved over time. Indicators that incorporate a measure of system resilience would provide useful information on system sustainability. Through development of a new indicator, Water Provision Resilience (WPR), we provide an example of how measures of resilience could be incorporated into sustainability indicators. The new indicator adds six color codings to the existing indicator ‘percent of the population with access to safe water.’ Each color coding represents a measure of the ability of the water system to maintain or improve the current percent of the population with access to safe water in key areas of the water provision sector: supply, infrastructure, service provision, finances, water quality and governance. The metric is then applied to three cities. The goal in developing this metric is to provide a starting point for re-thinking the metrics used to measure progress and sustainability in order to incorporate the ability to absorb and adapt to stresses into sustainability analysis.     

Estimation of the rate of water renewal in the ocean conveyor

The imitating numerical model of the turbulent exchange between the ocean conveyor belt and the surrounding waters is proposed. The water particle exchange through the belt surface of the given size during its movement along the deep conveyor branch is considered. The length of the turbulent jump is parameterized with the aid of coefficients of vertical and horizontal turbulent diffusion and its direction is simulated using the Monte Carlo method. By means of the computation of trajectories of 10⁶ separate particles, their spatial distribution is determined for different time intervals after the deep water formation. It is demonstrated that due to the lateral exchange, the water in the given part of the belt is renewed by 60% during 25 years and by 75% during 75 years. A comparison with the computations based on the usual method is carried out for the vertical exchange: it is revealed that in both cases the considerable renewal of water in the conveyor belt occurs during the time period of about 10⁴ years.     

Improving the quality of drinking water supply in the Northwest of Russia

Described is the geoinformational model of the multilevel information system for the control and management of drinking water quality. The system includes the common centralized archive of geographic, ecological, analytical, and normative data, the models of objects, and the system of the analysis and reception of information in organizations referred to different administrations. The system is tested using the analysis of drinking water supply quality in the Arkhangelsk oblast. The system was created in the framework of the TACIS program “Improving the Qualtty of Drinking Water in the Northwest Region of Russia.”     

Preliminary evaluation of the benefits of a participatory regional integrated assessment software

This paper provides a preliminary evaluation of the Regional Impact Simulator—a user-friendly, PC-based tool designed with stakeholders for stakeholders wishing to assess the effects of climate and/or socio-economic change on the important sectors and resources in the UK at a regional scale, in particular, impacts to coastal and river flooding, agriculture, water resources and biodiversity. While integrated assessments are relatively new, simulators that help stakeholders visualize and think about potential changes in the environment or society at a regional scale are very new. An earlier project, RegIS1, was the first local/regional integrated assessment conducted in the UK. It developed a method for engaging stakeholders in a “stakeholder-led” integrated assessment process. The RegIS2 project developed a simulation tool and followed the same “stakeholder-led” principle in designing and testing the tool. The role of stakeholders in informing the design of the simulator is discussed here, as is a stakeholder evaluation survey on its success in meeting its objectives. We also reflect on the need and desire of stakeholders to have such a tool. And because the Steering Committee – made up of stakeholders – was so invaluable in ensuring the usefulness of research outputs, a series of Steering Committee ‘rules’ is proposed intending to maximise the benefits of this valuable resource. Finally, we outline how our experience with the ‘Regional Impact Simulator’ serves as a test-bed for further studies of stakeholder-led, regional, integrated assessment.     

The economics of climate change impacts and policy benefits at city scale: a conceptual framework

Cities are particularly vulnerable to climate change and climate extremes in part because they concentrate many activities, people and wealth in limited areas. As a result they represent an important scale for assessment and understanding of climate change impacts. This paper provides a conceptual and methodological framework for urban economic impact assessment of climate change. The focus of the paper is on model-based analysis of future scenarios, including a framing of uncertainty for these projections, as one valuable input into the decision-making process. The paper highlights the main assessment difficulties, methods and tools, and selected examples across these areas. A number of challenges are unique to climate change impact assessment and others are unique to the problem of working at local scales. The paper also identifies the need for additional research, including the need for more integrated and systemic approaches to address climate change as a part of the urban development challenge as well as the need to assess the economic impacts of climate change and response policy at local scale.