1,720,966 research outputs found
Evaluation of three new surface irrigation parameterizations in the WRF-ARW v3.8.1 model: The Po Valley (Italy) case study
Full text linkIrrigation is a method of land management that can affect the local climate. Recent literature shows that it affects mostly the near-surface variables and it is associated with an irrigation cooling effect. However, there is no common parameterization that also accounts for a realistic water amount, and this factor could ascribe one cause to the different impacts found in previous studies. This work aims to introduce three new surface irrigation parameterizations within the WRF-ARW model (v3.8.1) that consider different evaporative processes. The parameterizations are tested on one of the regions where global studies disagree on the signal of irrigation: the Mediterranean area and in particular the Po Valley. Three sets of experiments are performed using the same irrigation water amount of 5.7 mm d-1, derived from Eurostat data. Two complementary validations are performed for July 2015: monthly mean, minimum, and maximum temperature with ground stations and potential evapotranspiration with the MODIS product. All tests show that for both mean and maximum temperature, as well as potential evapotranspiration simulated fields approximate observation-based values better when using the irrigation parameterizations. This study addresses the sensitivity of the results to human-decision assumptions of the parameterizations: start time, length, and frequency. The main impact of irrigation on surface variables such as soil moisture is due to the parameterization choice itself affecting evaporation, rather than the timing. Moreover, on average, the atmosphere and soil variables are not very sensitive to the parameterization assumptions for realistic timing and length
Irrigation impact on precipitation during a heatwave event using WRF-ARW: The summer 2015 Po Valley case
No full textIrrigation is crucial in sustaining food production and it is found to have a cooling effect. Changes at the surface affect both the circulation and the precipitation. The magnitude depends on the model used, the irrigation description and the water amount, as well as the region. The study focuses on northern Italy (the Po Valley) due to its vulnerability to heatwaves and dependency on local water sources. This study is performed with the Weather Research and Forecasting (WRF) model and newly developed irrigation parameterizations defined by different evaporative processes. The model runs at a 3 km convection-permitting resolution, starting in May 2015 and analyzing July. An irrigation amount of 5.7 mm is applied daily at 5 UTC for 3 h, starting from May 15. A set of convection-parameterized sensitivity simulations is used to investigate the results' dependency on timing. Using a convection-parameterized set of experiments, it is assessed that irrigation increases the precipitation accumulated over the region. While irrigation modifies the air mass properties, convection-permitting runs show that afternoon events are inhibited due to an increase in convection inhibition and decrease in boundary layer height. This happens despite the increase in the convective available potential energy (CAPE) and a decrease in both the lifting condensation level and level of free convection. For the nighttime event, irrigation increases significantly both boundary layer moisture and CAPE, increasing the precipitation. All cases are compared against the national radar composite accumulated over two hours, finding that the irrigated runs perform better than the control
Regional climate impacts of irrigation in northern Italy using a high resolution model
Full text linkIrrigation is crucial for sustaining agriculture in certain regions; however, there are effects on the local climate. Previous studies discussed that the irrigation signal might depend on the geographical region as well as the synoptic and climatic conditions. The work presented here aims to investigate the mechanisms behind changes in the irrigation impact on the local conditions depending on synoptic changes. Different to previous works, this employs convection-permitting simulations. Irrigation processes are parameterized in three different ways depending on the evaporative loss. The region of focus is in northern Italy (Po Valley), which is of interest for both the soil-atmosphere coupling strength and widely used irrigation. The simulation period is Summer 2015 (May-July), which includes a heatwave month (July) and an average month (June). The results show how irrigation prevented the drying out of the soil layers during the heatwave. This influences the surface flux partition differently, by increasing moisture flux and decreasing the sensible heat flux. In general, the irrigation impact magnitude, with respect to the control simulation, is more than double in July compared to June. This study discusses climate implications for the region, such as the impact of widespread irrigation on the vegetation health, the heatwave feedback mechanism, atmospheric pollution, and human heat discomfort
Assessment of air quality and microclimate in EU selected cities pre-infrastructural solutions
No full textThe objective of this deliverable is to produce a quantitative assessment of current climate and air quality conditions in iSCAPE cities (“baseline scenario”). This fulfils the objective of providing a synthesis of climatic conditions and air quality pre-intervention of PCSs in each city. Mean meteorological conditions are obtained by calculating the annual average from hourly recordings over 5 years for wind speed and wind direction, and 10 years of hourly air temperature and daily precipitation. All the considered monitoring stations in each city belong to the governmental agencies and, therefore, they follow the acquisition and dissemination standard of the European legislation. Mean conditions are represented with graphs and histograms to provide an immediate snapshot of climatic conditions and to serve as background for the interpretation of the distribution of PM10, PM2.5, NO2 or/and NOX as well as ozone. Those compounds are presented as concentration maps with high resolution maps generated for each site. The combination of meteorological data and concentration maps furnish a baseline for the PCS interventions at each site. The year of reference is different for each site, reflecting what is currently available at our best knowledge. Mutual results show pollution concentrations are directly associated to the presence of anthropogenic activities and filtered by atmospheric circulation. In Bologna, Guildford and Vantaa it is evident that the primary contribution to pollution distribution is at roads and junctions, which is also valid for Bottrop Motorways junction stands out as one of the most polluted points and influences pollutant distributions. Dublin and Vantaa perceive both wet (precipitations) and dry (winds) pollutant removal, while low pollutant concentrations in Hasselt are solely a consequence of wet removal. This report also provides novel information regarding heat waves and urban heat island (UHI) for the two larger sites within iSCAPE i.e. Dublin and Bologna. Those two large cities are affected as noted in iSCAPE D1.4 by UHI phenomenon which during summer may exacerbate climatic conditions when a heat wave is occurring. To better tailor iSCAPE PCS interventions it is crucial to consider the behavior of air temperature distribution under heat wave conditions. To this end novel numerical simulations are validated and used to illustrate the “expected” spatial distribution of air temperature within the city and relative UHI quantified. Despite Dublin being much larger than Bologna, the effect of building density and built thermal properties is such that Bologna’s UHI is much larger and show stronger diurnal variation. This indicates clearly that southern European cities may consider larger employment of PCSs to mitigate both air quality and climate
Future impacts of the Reforestation Policy on the amospheric parameters: a sensitivity study over Ireland
Full text linkThe increase of temperature attributed to anthropogenic emissions is projected to continue in future climate scenarios. Several protocols and policies are being put in place in several European countries to reduce both emissions and impact of human activities. The Irish Reforestation policy is a good example of such protocols. Nevertheless often contemplated policies do not take into account their potential effects on the atmospheric variables. This study aims to assess the influence of the increase of vegetation cover over Ireland, with respect to the surface temperature and the livestock heat comfort, using the Weather Research Forecast (WRF) model. Two main multi-scale numerical simulations are performed: (i) a control scenario with no change in vegetation cover and (ii) a scenario with increased tree cover based on the suggested Irish Reforestation policy. The vegetation change increases the temperature over the simulated domain and moreover, it enhances the livestock heat discomfort during the day-time, with different magnitude all over the domain. It is concluded that the reforestation policy, which is introduced to mitigate the greenhouse emissions, causes a further increase in the temperature and livestock heat discomfort
Future impacts of the reforestation policy on the atmospheric parameters in Ireland: a sensitivity study including heat discomfort impacts on humans and livestock
No full textThe increase of temperature attributed to anthropogenic emissions is projected to continue in future climate scenarios. Protocols and policies are being put in place in several European countries to reduce both emissions and impact of human activities on climate. The Irish Reforestation policy is a good example of such protocols. Nevertheless, often contemplated policies do not take into account their potential effects on the atmospheric variables. This study aims to assess the influence of the increase of vegetation cover over Ireland, on surface temperature, livestock, and human heat comfort, using the Weather Research Forecast (WRF-ARW 3.7.1) model. Multi-scale numerical simulations are performed under two scenarios: (i) a “control scenario” considering no change in vegetation cover with respect to the prescribed one and (ii) a “green scenario” with increased tree cover based on the introduced Irish Reforestation policy. To simulate this policy, the cropland and vegetative mosaic is substituted with evergreen broad-leaf forest, increasing the total forest area from 19.7 to 36.2% of the land in the analyzed domain. This change in vegetation cover increases the temperature over the simulated domain up to (Formula presented.)C and, moreover, it enhances both human and livestock heat discomfort during the daytime, with different magnitude all over the domain. It is concluded that the reforestation policy, which is introduced to mitigate the climate warming and greenhouse gas emissions, causes a further increase in temperature along with heat discomfort to both human and livestoc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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