Summer Andwinter Research Articles

Estimation of OH in urban plumes using TROPOMI-inferred NO2 ∕ CO

Abstract. A new method is presented for estimating urban hydroxyl radical (OH) concentrations using the downwind decay of the ratio of nitrogen dioxide over carbon monoxide column-mixing ratios (XNO2/XCO) retrieved from the Tropospheric Monitoring Instrument (TROPOMI). The method makes use of plumes simulated by the Weather Research and Forecast model (WRF-Chem) using passive-tracer transport, instead of the encoded chemistry, in combination with auxiliary input variables such as Copernicus Atmospheric Monitoring Service (CAMS) OH, Emission Database for Global Atmospheric Research v4.3.2 (EDGAR) NOx and CO emissions, and National Center for Environmental Protection (NCEP)-based meteorological data. NO2 and CO mixing ratios from the CAMS reanalysis are used as initial and lateral boundary conditions. WRF overestimates NO2 plumes close to the center of the city by 15 % to 30 % in summer and 40 % to 50 % in winter compared to TROPOMI observations over Riyadh. WRF-simulated CO plumes differ by 10 % with TROPOMI in both seasons. The differences between WRF and TROPOMI are used to optimize the OH concentration, NOx, CO emissions and their backgrounds using an iterative least-squares method. To estimate OH, WRF is optimized using (a) TROPOMI XNO2/XCO and (b) TROPOMI-derived XNO2 only. For summer, both the NO2/CO ratio optimization and the XNO2 optimization increase the prior OH from CAMS by 32 ± 5.3 % and 28.3 ± 3.9 %, respectively. EDGAR NOx and CO emissions over Riyadh are increased by 42.1 ± 8.4 % and 101 ± 21 %, respectively, in summer. In winter, the optimization method doubles the CO emissions while increasing OH by ∼ 52 ± 14 % and reducing NOx emissions by 15.5 ± 4.1 %. TROPOMI-derived OH concentrations and the pre-existing exponentially modified Gaussian function fit (EMG) method differ by 10 % in summer and winter, confirming that urban OH concentrations can be reliably estimated using the TROPOMI-observed NO2/CO ratio. Additionally, our method can be applied to a single TROPOMI overpass, allowing one to analyze day-to-day variability in OH, NOx and CO emission.

Inter-comparison of online and offline methods for measuring ambient heavy and trace elements and water-soluble inorganic ions (NO<sub>3</sub><sup>−</sup>, SO<sub>4</sub><sup>2−</sup>, NH<sub>4</sub><sup>+</sup>, and Cl<sup>−</sup>) in PM<sub>2.5</sub> over a heavily polluted megacity, Delhi

Abstract. Characterizing the chemical composition of ambient particulate matter (PM) provides valuable information on the concentration of secondary species and toxic metals and assists in the validation of abatement techniques. The chemical components of PM can be measured by sampling on filters and analyzing them in the laboratory or using real-time measurements of the species. It is important for the accuracy of the PM monitoring networks that measurements from the offline and online methods are comparable and biases are known. The concentrations of water-soluble inorganic ions (NO3−, SO42−, NH4+, and Cl−) in PM2.5 measured from 24 h filter samples using ion chromatography (IC) were compared with the online measurements of inorganics from an aerosol mass spectrometer (AMS) with a frequency of 2 min. Also, the concentrations of heavy and trace elements determined from 24 h filter samples using inductively coupled plasma mass spectroscopy (ICP-MS) were compared with the online measurements of half-hourly heavy and trace metal concentrations from an Xact 625i ambient metal mass monitor. The comparison was performed over two seasons (summer and winter) and at two sites (Indian Institute of Technology Delhi (IITD) and Indian Institute of Tropical Meteorology, Delhi (IITMD)) which are located in the Delhi National Capital Region (NCR), India, one of the most heavily polluted urban areas in the world. Collocated deployments of the instruments helped to quantify the differences between online and offline measurements and evaluate the possible reasons for positive and negative biases. The slopes for SO42− and NH4+ were closer to the 1:1 line during winter and decreased during summer at both sites. The higher concentrations on the filters were due to the formation of particulate (NH4)2SO4. Filter-based NO3− measurements were lower than online NO3− during summer at IITD and winter at IITMD due to the volatile nature of NO3− from the filter substrate. Offline-measured Cl− was consistently higher than AMS-derived Cl− during summer and winter at both sites. Based on their comparability characteristics, elements were grouped into three categories. The online element data were highly correlated (R2>0.8) with the offline measurements for Al, K, Ca, Ti, Zn, Mn, Fe, Ba, and Pb during summer at IITD and winter at both the sites. The higher correlation coefficient demonstrated the precision of the measurements of these elements by both the Xact 625i and ICP-MS. Some of these elements showed higher Xact 625i elemental concentrations than ICP-MS measurements by an average of 10 %–40 % depending on the season and site. The reasons for the differences in the concentration of the elements could be the distance between two inlets for the two methods, line interference between two elements in Xact measurements, the sampling strategy, variable concentrations of elements in blank filters, and the digestion protocol for ICP-MS measurements.

Full flowering phenology of apple tree (<i>Malus domestica</i>) in Pūre orchard, Latvia from 1959 to 2019

Abstract. The Pūre orchard is one of the oldest apple orchards in the Baltic, where thousands of varieties of fruit trees from throughout the world are grown and tested. Over time, a huge knowledge base has been accumulated, but most of the observational data are stored in archives in paper format. We have digitized a small part of the full flowering phenological data of apple trees (Malus domestica) over the period of 1959 to 2019 for 17 varieties of apple trees, a significant step for horticulture and agricultural economics in Latvia. Climate change has led to significant changes in the phenology of apple trees as all varieties, autumn, summer and winter, have begun to flower earlier: from 2002 to 2019, on average full flowering was recorded to have taken place around 21 May, whereas for the period 1959–1967 it occurred around 27–28 May. To develop better-quality phenological predictions and to take account of the fragmentary nature of phenological data, in our study we assessed the performance of three meteorological data sets – gridded observation data from E-OBS, ERA5-Land reanalysis data and direct observations from a distant meteorological station – in simple phenological degree-day models. In the first approximation, the gridded E-OBS data set performs best in our phenological model.

Total column water vapour retrieval from S-5P/TROPOMI in the visible blue spectral range

Abstract. Total column water vapour has been retrieved from TROPOMI measurements in the visible blue spectral range and compared to a variety of different reference data sets for clear-sky conditions during boreal summer and winter. The retrieval consists of the common two-step DOAS approach: first the spectral analysis is performed within a linearized scheme and then the retrieved slant column densities are converted to vertical columns using an iterative scheme for the water vapour a priori profile shape, which is based on an empirical parameterization of the water vapour scale height. Moreover, a modified albedo map was used combining the OMI LER albedo and scaled MODIS albedo map. The use of the alternative albedo is especially important over regions with very low albedo and high probability of clouds like the Amazon region. The errors of the total column water vapour (TCWV) retrieval have been theoretically estimated considering the contribution of a variety of different uncertainty sources. For observations during clear-sky conditions, over ocean surface, and at low solar zenith angles the error typically is around values of 10 %–20 %, and during cloudy-sky conditions, over land surface, and at high solar zenith angles it reaches values around 20 %–50 %. In the framework of a validation study the retrieval demonstrates that it can well capture the global water vapour distribution: the retrieved H2O vertical column densities (VCDs) show very good agreement with the reference data sets over ocean for boreal summer and winter whereby the modified albedo map substantially improves the retrieval's consistency to the reference data sets, in particular over tropical land masses. However, over land the retrieval underestimates the VCD by about 10 %, particularly during summertime. Our investigations show that this underestimation is likely caused by uncertainties within the surface albedo and the cloud input data: low-level clouds cause an underestimation, but for mid- to high-level clouds good agreement is found. In addition, our investigations indicate that these biases can probably be further reduced by the use of improved cloud input data. For the general purpose we recommend only using VCDs with cloud fraction <20 % and AMF >0.1, which represents a good compromise between spatial coverage and retrieval accuracy. The TCWV retrieval can be easily applied to further satellite sensors (e.g. GOME-2 or OMI) for creating uniform, long-term measurement data sets, which is particularly interesting for climate and trend studies of water vapour.

Acrylic acid and related dimethylated sulfur compounds in the Bohai and Yellow seas during summer and winter

Abstract. Spatiotemporal distributions of dissolved acrylic acid (AAd) and related biogenic sulfur compounds including dimethylsulfide (DMS) and dissolved and total dimethylsulfoniopropionate (DMSPd and DMSPt) were investigated in the Bohai Sea (BS) and Yellow Sea (YS) during summer and winter. AAd and DMS production from DMSPd degradation and AAd degradation were analyzed. Significant seasonal variations in AAd and DMS(P) were observed. AAd exhibited similar distributions during summer and winter; i.e., relatively high values of AAd occurred in the BS and the northern YS, and the concentrations decreased from inshore to offshore areas in the southern YS. Due to strong biological production from DMSP and abundant terrestrial inputs from rivers in summer, the AAd concentrations in the surface seawater during summer (30.01 nmol L−1) were significantly higher than those during winter (14.98 nmol L−1). The average concentration sequence along the transects during summer (AAd > DMSPt > DMS > DMSPd) showed that particulate DMSP (DMSPp) acted as a DMS producer and that terrestrial sources of AAd were present; in contrast, the sequence in winter was AAd > DMSPt > DMSPd > DMS. High values of AAd and DMS(P) were mostly observed in the upper layers, with occasional high values at the bottom. High AAd concentrations in the porewater, which could be transported to the bottom water, might result from the cleavage of intracellular DMSP and reduce bacterial metabolism in sediments. In addition, the production and degradation rates of biogenic sulfur compounds were significantly higher in summer than in winter, and the removal of AAd was primarily attributed to microbial consumption. Other sources of AAd existed aside from the production from DMSPd.

Temperature and humidity characteristics of residential buildings in northern China

Buildings are one of the typical underlying surfaces of cities, but the study of hydrological effects of buildings is a weak link in urban hydrological research. Indoor temperature and humidity are important embodiments of the hydrological effect of building water activity. Beijing, as the capital of China, is selected as the representative research area in north China. The variation characteristics of temperature and humidity of residential buildings, as well astheir relationship with each other, are analyzed through experimental monitoring. The result showsthat human water use activities in buildings will increase indoor humidity. The indoor humidity is higher than the outdoor humidity in the sunny days of spring, summer andwinter, while it is lower than the outdoor humidity through rainy days and the whole autumn. Both indoor and outdoor humidityreach peak and nearly the same at night, but the difference between the indoor and outdoor humidity is obvious during the daytime. Based on the results we can draw the conclusion that (1) indoor water use activities canproduce obvious water vapor diffusion; (2) In northern China, the indoor humidity of the residential buildings is higher than the outdoor humidity, and will flow to outdoors during most sunny days; (3) among all the types of the rooms in the resendital building, bathroom is the largest contributor to water vapor dissipation. We suggest that water vapor dissipation in buildings should be taken into account in the study of evaporation in urban areas since it may profoundly affect the urban hydrological cycle.

Spatial and temporal variability of turbulence dissipation rate in complex terrain

Abstract. To improve parameterizations of the turbulence dissipation rate (ϵ) in numerical weather prediction models, the temporal and spatial variability of ϵ must be assessed. In this study, we explore influences on the variability of ϵ at various scales in the Columbia River Gorge during the WFIP2 field experiment between 2015 and 2017. We calculate ϵ from five sonic anemometers all deployed in a ∼4 km2 area as well as from two scanning Doppler lidars and four profiling Doppler lidars, whose locations span a ∼300 km wide region. We retrieve ϵ from the sonic anemometers using the second-order structure function method, from the scanning lidars with the azimuth structure function approach, and from the profiling lidars with a novel technique using the variance of the line-of-sight velocity. The turbulence dissipation rate shows large spatial variability, even at the microscale, especially during nighttime stable conditions. Orographic features have a strong impact on the variability of ϵ, with the correlation between ϵ at different stations being highly influenced by terrain. ϵ shows larger values in sites located downwind of complex orographic structures or in wind farm wakes. A clear diurnal cycle in ϵ is found, with daytime convective conditions determining values over an order of magnitude higher than nighttime stable conditions. ϵ also shows a distinct seasonal cycle, with differences greater than an order of magnitude between average ϵ values in summer and winter.

Health hazards due to the exposure to radon in schools of the Cappadocia region

This study presents the results of a survey of radon concentrations in schools (kindergartens, primary schools, secondary schools, high schools, colleges, and one faculty) located in the province of Nevsehir which is the center of the Cappadocia region. Radon measurements covered two consecutive 6-month periods in the ground floor classrooms inside the school buildings and they were performed using a continuous active radon detector (AlphaGUARD PQ2000 PRO). Data distribution is well fitted by a log-normal curve. The arithmetic average value of the radon concentrations measured in summer and winter was found as 75 ? 12 Bqm-3 and 67 ? 10 Bqm-3, respectively. From the measured results, the effective doses from radon exposures in summer and winter were estimated as 0.27 and 0.40 mSv and 0.24 and 0.36 mSv for students and teachers, respectively. The results showed that radon concentration measured in schools does not pose significant health hazards for students and teachers.

Araneofauna (Arachnida: Araneae) de suelo en bosques nativos, exóticos y pajonales del Parque General San Martín, Entre Ríos Argentina

Ground aracnofauna (Araneae: Araneae) in native and exotic Forest and grasslands of San Martin Park, Entre Rios, Argentina. The Exotic plant species invasion in the Argentine Espinal region causes a changein the appearance of the landscape, altering the environment and producing a significant loss of biodiversity. We studied the composition of ground spiders in Parque General San Martin, Entre Rios, during the summerand winter seasons of 2012. Three areas were selected: pajonal (P), native forest (BN) and exotic forest (BE), pitfalls were used for sampling. A total of 1398 spiders (26 families and 120 species/morphospecies) werecollected. The most abundant families in the different areas were Lycosidae (n=574; 41.06%), Tetragnathiidae (n=223; 15.95%) and Linyphiidae (n=137; 9.80%). The guild category “ground hunters” (n=632) “sheet webweavers” (n=262) and “orb webs weavers” (n=244) were highly represented in all sampling areas. Diversity indices showed that BN was more diverse than P and BE. Complementarity values obtained between P andBE and BN were higher than 71%, while BE and BN showed values of 63%. This study constitutes the first record of the spider´s community of Parque General San Martin.

Infrastructure development and urbanisation in pastoralist Amdo (a research report)

Abstract The past two decades have seen massive investments in infrastructure development in China's western regions. Formerly hard to access, the remote grasslands of the Amdo region in Sichuan Province are today incorporated into an ever-growing road network, which connects dispersed summer and winter pastures with township centres and outlying townships with county towns, prefecture towns and, by extension, with provincial capitals and the national transportation system. Infrastructural development impacts on economic development not only in terms of access to markets, but also the basic mobility patterns of pastoralists. This paper elucidates the interrelationships between transportation infrastructure development, motorisation and urbanisation. I argue that motorisation plays an important role in the incorporation of nomads into the newly constructed settlements and the urban spaces of Amdo. The motorisation of pastoralist households, which developed alongside road construction, has produced new mobility patterns and facilitated novel types of movement. Pastoralists use motorised vehicles to maintain communication with townspeople and to access public spaces in urban centres. Accounts of urbanisation processes in pastoral regions cannot ignore the pastoralists who still live outside urban centres, but for whom motorisation and construction of roads has facilitated a wholly different level of access to urban areas that are, in multiple ways, inscribing urban forms onto the nomads' lands.

Economic Evaluation of Switchgrass Feedstock Production Systems Tested in Potassium-Deficient Soils

Limited information is available about the economic benefits and costs associated with managing switchgrass (Panicum virgatum L.) produced for bioenergy feedstock in the K-deficient soils common in the southern Great Plains. The objectives of this study were to determine the most economical production system for harvesting and managing N and K fertilizations on switchgrass stands and to determine how sensitive the results are to various feedstock and fertilizer market price scenarios. A 4-year agronomic field experiment was conducted on a K-deficient site in South Central Oklahoma; the treatments included two harvest systems (summer and winter (SW) and winter only (W)), two N rates (0 and 135 kg ha−1), and two K rates (0 and 67 kg ha−1). Enterprise budgeting techniques and mixed ANOVA models were used to determine and compare the effects of eight harvest/N/K systems on yield, total cost, revenue, and net return. The harvest/N/K systems evaluated included SW/0/0, SW/0/67, SW/135/0, SW/135/67, W/0/0, W/0/67, W/135/0, and W/135/67. Results revealed the SW/135/67 system produced significantly (P > 0.0001) greater average yield compared to the other systems; however, the SW/0/0 system was the most (P > 0.0001) economical, realizing an average net return of $415 ha−1. Compared to the base–case net return of the SW/0/0 system, the value of the additional yield generated with the SW/135/67 system was less than the costs associated with the extra nutrients and additional harvest activity. For feedstock prices greater than $110 Mg−1, the most economical system shifted from the SW/0/0 to favor the SW/135/67 system.

ANÁLISE DA ESTABILIDADE DA PRODUÇÃO DE LEITE NO MUNICÍPIO DE SANTO ÂNGELO - RS

The main objective of this research is to analyze the stability of the milkproduction series throughout the use of statistical process control techniquesin a way to offer to the companies, which receive the product innatura an estimative of the periods of bigger and smaller milk production.To accomplish the main purpose, a sample was collated of somesmall producers in Santo Ângelo city. The sample was composed by fiftyweeks from July 20th, 2009 toJuly 12th, 2010. Firstly, the series behaviorwas analyzed graphically and aftera SARIMA(2,1,0)(1,0,1)7model wasfound.A control charts was established in the original variable and inthe residues data from the SARIMA model, as a way to understand theautocorrelation effect in the control chart. Making a comparison amongthese control charts is possible to understand the autocorrelation effectpresent in the original data. Based on the original charts it is possibleto verify that the series has a seasonal period represented by summerand winter months. Comparing the control charts, the original data presentedmore out-of-control sample points besides control limits than the residual series of the math model. It is necessary to emphasize thatthe producers should create alternative methods in order to maintain aminimum stock of cattle feed. In the summer is necessary to maintainan enough level of water to the cattle and to irrigate the pasture. Besidesthese factors the sanitary conditions must be maintained.

Klimawandel: Anpassungsstrategien im Alpentourismus. Ergebnisse einer alpenweiten Delphi-Befragung

Zusammenfassung Die Auswirkungen des Klimawandels sind von großer Bedeutung für die Zukunft des Alpentourismus. Neben der Vermeidung der Klimaänderung geht es darum, geeignete Anpassungsstrategien für die alpinen Tourismusdestinationen zu entwickeln. Unter Beteiligung von Tourismus- und Klimaexperten aus sechs Alpenländern beschäftigte sich eine Delphi-Analyse mit Anpassungsstrategien im alpinen Sommer- und Wintertourismus. Im Zentrum der Analyse stand die Frage nach der Reaktion der Gäste auf die Folgen der Klimaänderung, nach den verschiedenen Formen von Anpassungsstrategien und nach der Rolle der einzelnen Akteure im Anpassungsprozess. Als Ergebnis der Studie werden elf Aktionsfelder dargestellt und maßgebliche Akteursgruppen benannt.

C-reactive protein and particulate matter predict plasma fibrinogen levels

Inflammation and thrombosis play crucial roles in the pathogenesis of athero-thrombotic vascular disease. Amassing evidence points to a cross-link between these two systems. For instance, while some studies have shown that inflammation can activate coagulation, others demonstrate that coagulation can induce inflammation [1]. Seasonal variations in cardiovascular disease risk have previously been observed and are postulated to be explained, at least in part, by elevated wintertime fibrinogen levels [2]. However, details pertaining to the causeof seasonalvariations infibrinogen levelshaveyet tobeelucidated. C-reactive protein (CRP) is proposed to be an emerging, but reliable cardiovascular risk factor [3, 4]. In a study of healthy middleaged women, the highest CVD risk was found among those with elevated levels of both fibrinogen and CRP [3]. Further, a recent review identified both fibrinogen and CRP as important and evidence-based markers of CVD risk [4]. Exposure to particulate matter (PM) air pollution is also associated with increased levels of blood inflammation markers and coagulation parameters [5, 6]. In addition, the cause of elevated mortality rates in winter season has been attributed to virus infections, especially influenza [7]. However, there exists limited information of the prospective effects of environmental factors (including antibody titer of influenza and PM) on seasonal variations of plasma fibrinogen levels and its determinants. From July to September 2002, 155 office employees whoworked in a petrochemical company based in the Taipei and who participated in a cardiovascular health promotion program were recruited for a second blood sampling for CRP and fibrinogen during the wintertime (January–February 2003). Overnight fasting blood samples for lipids and glucose levels were assayed in the central laboratory. Serum highsensitivity CRP (hs-CRP) was measured using a chemiluminescent enzyme-labeled immunometric assay (Diagnostic Products Co., Los Angeles). Plasma fibrinogen was measured using the clotting method of Clauss (Diagnostica Stago, France). Antibody titer of influenza A and B was measured via a commercial anti-influenza A and B virus ELISA IgG kit (EUROIMMUN, Lubeck, Germany). A Particulate Matter Supersite monitoring station (Supersite), located in the center of the Taipei metropolitan area monitored the environmental conditions. Concentrations of PM10, temperature and humidity level were measured on an hourly basis [5, 6]. The participants had a mean age of 56.26±5.00 years and were predominantly male (85.53%). Analysis of seasonal variations in levels of plasma fibrinogen, serum hs-CRP and other covariates are illustrated in Table 1. The mean summer plasma fibrinogen level was 9.45±2.36 μmol/L and increased significantly to 9.89±1.58 μmol/L during the winter. A similar wintertime increase in PM10 was also noted. However, mean hs-CRP levels did not differ according to season. After controlling for potential confounders, multiple linear regression analyses revealed serumhs-CRP levels tobe thebest correlate of summer andwinter plasma fibrinogen levels. One day prior exposure to PM10 levels in summer and winter–summer difference were also significantly associatedwith the correspondingplasmafibrinogen levels (Table 2). The positive correlation of seasonal differences between each participant's hs-CRP and fibrinogen levels is demonstrated in Fig. 1. This study in middle-aged office workers demonstrates a clear seasonal variation of fibrinogen levels that is strongly correlated with hs-CRP levels. This finding suggests a major role of inflammation in association with the seasonal variation of fibrinogen levels. In addition, PM air pollution was identified as another independent determinant of plasma fibrinogen during the summer, as well as its seasonal variation. Indeed, numerous studies have consistently reported that ambient air pollution, especially PM, is associated with cardiovascular morbidity and mortality [8, 9]. This study also supports the notion that CRP levels are stable across different seasons and are thus suitable for assessment in epidemiological and clinical applications [10]. A prior study suggested that the cause of the winter increase in US mortality was likely explained solely by increased rates of influenza [7]. However, we found no relationship between influenza A and B and fibrinogen levels in our study. This indicates that the relationship between fibrinogen levels and mild subclinical inflammation, as represented by CRP levels, was independent of influenza A and B. Plasma fibrinogen levels are correlated with the basal subclinical inflammation, implying that the activation of coagulation is determined by the basal inflammation status. Thus, therapies aimed at reducing inflammatory status, such as HMG-Co A reductase inhibitors (statins) and aspirin, may readily reduce cardiovascular events, even among patients without overt hyperlipidemia [11]. In conclusion, our findings support the hypothesis that the seasonal rhythm of fibrinogen is correlated with the basal

Análisis comparativo del estado nutricional de vitamina D y de los hábitos de exposición solar de las participantes españolas (adolescentes y de edad avanzada) del Estudio de los Cinco Países (Proyecto OPTIFORD)

Introduction: Vitamin D deficiency is known to be very common in adolescent girls and elderly women. Aim: To analyze vitamin D status, vitamin D intake and solar exposure of Spanish participants in The Five Countries Study of Optiford Project. Methods: Questionnaires approved and validated of lifestyle and food consumption frequency applied. The biochemical analysis of 25-hidroxivitamin D and PTH and the evaluation of the solar exposure (dosymeter UV VioSpor) were carried out. Results: The average solar exposure of adolescent girls (1,519 J/m2) was double than elderly women (740 J/m2). The vitamin D status of adolescent girls in summer and winter was better than elderly women. Conclusions: Solar exposure habits are different between the two age groups. This fact, jointly to the lower body’s capacity to synthesize Vitamin D through exposure to the sun in the elderly, may justify the worse vitamin D status in this age group.

Infrared remote sensing of Earth degassing - Ground study

Geodynamical processes e.g., volcanoes, often cause degassing at the Earth surface. The geogas emanates via mineral springs, water mofettes, or dry mofettes. It is assumed that the emerging gas influences the temperature of the spring or mofette water, respectively and the surface temperature of the soil at and around the dry gas vents. This causes a thermal anomaly in comparison to the close vicinity. Under specific conditions this effect should be extractable from remotely acquired infrared images allowing detection, mapping and monitoring of gas vents/springs within large areas and short times. This article describes preparatory investigations for which emanating Earth gas was simulated by leading compressed air into the ground and releasing it in some depth via a metal lance. The thermal effect at the surface was observed from a nearby thermovision camera in summer and winter under varying meteorological conditions. A procedure was developed to reliably identify gas release areas within the recorded thermal images of the scene. The investigations are aiming at studies to be performed later in the Western Bohemia (Czech Republic) earthquake swarm region where especially CO2 of magmatic origin from European SubContinental Mantle (ESCM) emanates.

Precipitation magnitude and timing differentially affect species richness and plant density in the sotol grassland of the Chihuahuan Desert

Arid and semi-arid environments are dynamic ecosystems with highly variable precipitation, resulting in diverse plant communities. Changes in the timing and magnitude of precipitation due to global climate change may further alter plant community composition in desert regions. In this study, we assessed changes in species richness and plant density at the community, functional group, and species level in response to variation in the magnitude of natural seasonal precipitation and 25% increases in seasonal precipitation [e.g., supplemental watering in summer, winter, or summer and winter (SW)] over a 5-year period in a sotol grassland in the Chihuahuan Desert. Community species richness was higher with increasing winter precipitation while community plant density increased with greater amounts of winter and summer precipitation, suggesting winter precipitation was important for species recruitment and summer precipitation promoted growth of existing species. Herb and grass density increased with increasing winter and summer precipitation, but only grass density showed a significant response to supplemental watering treatments (SW treatment plots had higher grass density). Shrubs and succulents did not exhibit changes in richness or density in response to natural or supplemental precipitation. In this 5-year study, changes in community species richness and density were driven by responses of herb and grass species that favored more frequent small precipitation events, shorter inter-pulse duration, and higher soil moisture. However, due to the long life spans of the shrub and succulent species within this community, 5 years may be insufficient to accurately evaluate their response to variable timing and magnitude of precipitation in this mid-elevation grassland.

Economic Impact of Climate Change on Crop Production in Ethiopia: Evidence from Cross-section Measures

This study used the Ricardian approach that captures farmer adaptations to varying environmental factors to analyze the impact of climate change on cropfarminginEthiopia. Bycollectingdatafromfarmhouseholdsindifferent agro-ecological zones of the county, net crop revenue perhectarewas regressed on climate, household and soil variables. The results show that these variables have a significant impact on the net crop revenue per hectare of farmers under Ethiopian conditions. The seasonal marginal impact analysis indicates that marginally increasing temperature during summerand winter would significantly reduce crop net revenue per hectare whereas marginally increasing precipitation during spring would significantly increase net crop revenue per hectare. Moreover, the net crop revenue impact of predicted climate scenarios from three models (CGM2, HaDCM3 and PCM) for the years 2050 and 2100 indicated that there would be a reduction in crop net revenue per hectare bytheyears2050and2100.Moreover,thereductioninnetrevenueperhectare bytheyear2100wouldbemorethanthereductionbytheyear2050indicating the damage that climate change would pose increases with time unless this negative impact is abated through adaptation. Additionally, results indicate that the net revenue impact of climate change is not uniformly distributed across the different agro-ecological zones of Ethiopia.

Trace Metal Content Trend of Mussel Perna Perna (Linnaeus, 1758) from the Atlantic Coast of Southern Brazil

The concentration assessment of Hg, Pb, Cd, Cu, Zn, Cr, Mnand Fe in marine mussels Perna perna, sampled at 15stations along the 800 km Southern Brazilian Coast, has beencarried out. Samplings were taken twice, in summer andwinter of 2000. The concentrations found were lower thansimilar studies carried out along the Central Coast of Brazil andlower than the maximum limits permitted in bivalve molluscsdesignated for human consumption (Brazilian, Spanish andLuxembourg legislation sets). The data also showed lowervalues compared with other regions of the world. Thecomparison of present data with the data obtained 10 years agoat the same stations did not show significant differences,consequently the concentrations found could be used asbaseline values.

Pup growth and maternal attendance patterns in Subantarctic fur seals

Samples of pups from the expanding populations of Subantarctic fur seals (Arctocephalus tropicalis) atMarion and Gough islands were weighed at specific ages between birth and weaning in the period 1993-2000. Growth was estimated and compared between years, sexes, sites of different density, and populations. Pups of comparable age were consistently heavier at Marion Island than at Gough Island, probably reflecting relative prey resource abundance. No changes in pupgrowth rates were apparent over the study period, nor was there any evidence that growth was affected by ENSO events. Measures of pup growth at Marion Island were complemented by measures of maternal attendance behaviour during three summer andwinter seasons. More years of data are required to determine patterns between attendance, growth, resource conditions and population abundance trends.