Active and passive remote sensing of precipitating storms during CaPE. Part II: Intercomparison of precipitation retrievals over land from AMPR radiometer and CP-2 radar

Summary One of the recent campaigns devoted to precipitation studies using both active and passive microwave remote sensing systems was the Convection and Precipitation/Electrification Experiment (CaPE), which took place in central Florida during the summer of 1991. During CaPE, the airborne Advanced Microwave Precipitation Radiometer (AMPR), having four channels at 10.7, 19.35, 37.1 and 85.5 GHz and the National Center for Atmospheric Research CP-2 multiparameter radar at S-band (3 GHz) and X-band (10 GHz) were operated simultaneously. In this paper, we compare estimated hydrometeor liquid/ice water contents and surface rainrates, both retrieved from the AMPR radiometer and CP-2 radar measurements, for a case study consisting of a heavy precipitating storm over land near Cape Canaveral on August 12, 1991. The multi-frequency radiometer-based retrieval scheme uses a cloud-precipitation dataset generated from a cloud model and extended by a physically-constrained Monte Carlo procedure, along with a discrete-ordinate radiative transfer model and a principal component statistical technique to help formulate non-linear regression equations for the sought-after hydrometeor quantities. By applying linear discriminant analysis, the algorithm is used to estimate column integrated liquid/ice water contents, as well as the vertical profiles of these quantities to within a specified accuracy. Rainfall rates are estimated either by non-linear regression or by a suitable fallout model. The analysis has confined itself to along-track nadir-looking AMPR measuremets to avoid complications with variable polarization mixing and geometric distortion for off-nadir observations. Considering the different model assumptions used in the two types of retrieval algorithms and the diverse geophysical information content within the two types of measurements, substantial agreement between the radar- and radiometer-derived retrievals has been achieved for the columnar liquid/ice water contents and rainrates.With 19 FiguresThe National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation.     

David Mark’s contribution to ethnophysiography research

This article describes Professor David Mark’s considerable contributions over the last 11 years to research in Ethnophysiography, the study of terms used for landscape features in different languages, and toponyms (place-names). His preceding research is briefly discussed to provide a summary of the foundation from which ethnophysiography emerged. This article describes the key stages of development of this new field, including David Mark’s collaborations with Andrew Turk, David Stea, and others. It briefly summarizes the key theories used and the two ethnophysiography case studies undertaken thus far. This article provides an overview of how this collaborative transdisciplinary area of research has developed. It highlights the importance of David Mark’s scholarship in this process and indicates some of the impacts of the research.     

Local characteristics of Postojna Cave climate, air temperature, and pressure monitoring

In Postojna Cave, air temperature and pressure monitoring has been conducted since July 21, 2008. Air pressure in the cave at three monitoring sites fluctuates synchronically with outside air pressure. Temperature data for Postojna 1 and 3 show good correlation with outside climate conditions for the period 2009?C2010. The temperature at Postojna 1 was increasing constantly from March to May 2009, while at Postojna 2, it was decreasing. Postojna 1 has a seasonal trend in accordance with outer trend, while seasonal trend at Postojna 2 is just contrary to outside trend. Microclimate studies at Postojna 2 show local variability, especially in winter, and exhibit special microclimate conditions that may be due to ventilation of unknown passages in the back.     

Impact of peak period visits on the Postojna Cave (Slovenia) microclimate

Cave air temperature, carbon dioxide concentrations in the cave air and external air temperature were analysed at several locations in Postojna Cave over the course of six holiday periods in 2009–2011. The results show that a 1-day increase in visitor numbers from 200 to 3,500 raised the cave air temperature by a maximum of 0.5 °C. The air temperature increases are within the annual range of cave air temperature variations. A fivefold increase in visitor numbers resulted in a carbon dioxide concentration that was at least twice as high as normal. The carbon dioxide concentration increased from 450 to 1,750 ppm (December 2009–January 2010). After 10 days of peak period visits, both the CO₂ concentration and the temperature returned almost to the pre-holiday values. The gradual increase in mean annual air temperature in the cave (2004–2010) is not related to the number of visitors but to outside climate conditions.     

Sensitivity to acidification of subalpine ponds and lakes in north‐western Colorado

Although acidifying deposition in western North America is lower than in many parts of the world, many high‐elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability of ponds and lakes in and near the MZWA were examined to determine their sensitivity to acidification and the effects of acidic deposition during and after snowmelt. Within the areas identified as sensitive to acidification based on bedrock types, there was substantial variability in acid‐neutralizing capacity (ANC), which was related to differences in hydrological flowpaths that control delivery of weathering products to surface waters. Geological and topographic maps were of limited use in predicting acid sensitivity because their spatial resolution was not fine enough to capture the variability of these attributes for lakes and ponds with small catchment areas. Many of the lakes are sensitive to acidification (summer and autumn ANC < 100 µeq L^?1), but none of them appeared to be threatened immediately by episodic or chronic acidification. In contrast, 22 ponds had minimum ANC < 30 µeq L^?1, indicating that they are extremely sensitive to acidic deposition and could be damaged by episodic acidification, although net acidity (ANC < 0) was not measured in any of the ponds during the study. The lowest measured pH value was 5·4, and pH generally remained less than 6·0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition that occurred during the study. The aquatic chemistry of lakes was dominated by atmospheric deposition and biogeochemical processes in soils and shallow ground water, whereas the aquatic chemistry of ponds was also affected by organic acids and biogeochemical processes in the water column and at the sediment–water interface. These results indicate that conceptual and mechanistic acidification models that have been developed for lakes and streams may be inadequate for predicting acidification in less‐understood systems such as ponds. Copyright © 2004 John Wiley & Sons, Ltd.     

The algal community at an ecocline of a cold sulphidic spring (Sovra artesian borehole,Slovenia)

The physicochemical parameters of the sulphide spring water from a 500?m deep artesian borehole in Sovra Valley (Slovenia) are stable, with very little variation: temperature, 9.2 ± 0.0 °C; pH 7.70 ± 0.11; specific electrical conductivity, 777 ± 8 μS/cm; and dissolved oxygen, 0.19 ± 0.11 mg/l. The water from the borehole is hard, rich in sulphates, and has a notable concentration of sulphide, while it is low in chlorides. Communities of phototrophs were analysed at the oxygenic ecocline at the outflow from the borehole, and from further downstream. Caloneis tenuis, Frustulla vulgaris, Gomphonema sp., Navicula radiosa, Oscillatoria sp., and Tribonema vulgare successfully thrive exclusively at the outflow from the borehole under sub-optimum conditions for the majority of phototrophs. Downstream from the borehole, where the hydrogen sulphide degasses, autotrophic biofilms were dominated by different diatoms. The Bray–Curtis similarity index confirms the distinctive phototrophic communities along the oxygenic ecocline downstream from the sulphidic spring. The sulphidic ecocline downstream from the spring is indicative of the composition of phototrophic communities, as some species appear only downstream from the spring. An ecocline downstream from the borehole of the sulphidic spring was reflected also in the bacterial indicator groups. This study brings novel insights to the limited knowledge in the field of oxygenic phototrophy related to sulphidic springs.     

Tracing contingencies: analyzing the political in assemblages of web 2.0 cartographies

Our paper presents a theoretical approach to critical research on web 2.0 cartographies. Within the geoweb, dynamic and collaborative web based maps have become a popular medium for collating and communicating geographic information. Web 2.0 cartographies are often promoted as facilitating public participation and democratizing geographic knowledge. Such claims demand a closer look at the processes through which people do engage in these cartographic projects and the multiple actors, institutions, norms and technologies at work. In the context of ‘theorizing the geoweb’, here we propose conceptual tools for analyzing these myriad interactions within web 2.0 cartographies. We understand web 2.0 cartographies as assemblages of subjects, materialities and practices, or ‘actor networks’. Yet explorations of actor‐networks describe existing relations and as a consequence tend to overlook what has been excluded or lies outside of such assemblages. In order to overcome this blindness we suggest bringing together actor‐network theory with the concepts of hegemonic discourses, contingency and the political from Chantal Mouffe and Ernesto Laclau. These two political theorists stress the idea that specific social realities become fixed, sedimented and perceived as natural while other possible social realities become marginalized. Using the example of the dynamic ‘Palestine Crisis Map’ (an Ushahidi Crowdmap) we demonstrate a methodology that emphasizes sensitivity towards moments of exclusion and struggle, where the political unfolds. Theorizing the political in this way extends the processual approach within Critical Cartography and offers a conceptual basis for critical research on the social dimensions of web 2.0 cartographies and geoweb practices.     

Organotin compounds in seawater and Mytilus galloprovincialis mussels along the Croatian Adriatic Coast

In this work, data on the level of organotin compounds (OTCs) in seawater and mussels collected along the entire Croatian Adriatic Coast are presented. The samples were collected in 2009 and 2010 at 48 locations representing different levels of maritime activities, including marinas, ports and reference sites. Butyltins (BuTs) were found in all analyzed samples, representing >97% of OTCs, and ranged from 0.46 to 27.98 ng Sn L(-1) in seawater and from <6 to 1675 ng Sn g(-1) in mussels. The results indicate a recent input of TBT, with the highest concentrations of BuTs found in the marinas. It appears that the Adriatic coast is still polluted with TBT despite the fact that TBT-containing antifouling paints have been banned in Croatia since 2008. It is questionable how much TBT pollution decreased since 2005, when a high incidence of imposex was established in the same area.     

Emission sources and health risk assessment of polycyclic aromatic hydrocarbons in ambient air during heating and non-heating periods in the city of Novi Sad,Serbia

The paper presents the assessment of emission sources and health risk of 16 PAHs in the city of Novi Sad, Serbia, with developed oil, food, chemical and cement industry. Although the observed region has been previously studied with regard to the occurrence of PAHs in ambient air, the sources of emission and health risk using multivariate statistical methods have never been studied before. The research was conducted during the heating and non-heating periods at three sampling sites located in industrial, residential and high-traffic area. The samples were collected by high-volume air sampler and analysed using the GC/MS system. The data were processed using the positive matrix factorization (PMF) and cluster analysis. To assess the cancer-risk of PAHs, potency equivalency factor approach was used. The results of PMF analysis have indicated that significant sources of PAH emissions are industrial processes and diesel combustion during the non-heating, and coal combustion, heating plants and diesel combustion during the heating season. Cluster analysis of experimental data has confirmed the results obtained using the PMF method. Estimated values of lifetime lung cancer risk were higher than those set by the World Health Organization and US Environmental Protection Agency which indicates that cancer risk due to exposure to PAHs in ambient air exists in both time periods on the territory of Novi Sad.