Statistical analysis of the Madrid urban heat island

Multi-Temporal Land Surface Temperature and Vegetation Greenness in Urban Green Spaces of Puebla, Mexico

The urban heat island (UHI) effect is a global problem that is likely to grow as a result of urban population expansion. Multiple studies conclude that green spaces and waterbodies can reduce urban heat islands. However, previous studies often treat urban green spaces (UGSs) as static or limit the number of green spaces investigated within a city. Cognizant of these shortcomings, Landsat derived vegetation and land surface temperature (LST) metrics for 80 urban green spaces in Puebla, Mexico, over a 34-year (1986–2019) and a 20-year (2000–2019) period were studied. To create a photo library, 73 of these green spaces were visited and the available land cover types were recorded. Green spaces with Indian laurel were found to be much greener and vegetation index values remained relatively stable compared to green spaces with mixed vegetation cover. Similarly, green spaces with large waterbodies were cooler than those without water. These results show that larger green spaces were significantly cooler (p < 0.01) and that size can explain almost 30% of temperature variability. Furthermore, green spaces with higher vegetation index values were significantly cooler (p < 0.01), and the relationship between greenness and temperature strengthened over time.

Evaluation of the Impact of the Envelope System on Thermal Energy Demand in Hospital Buildings

Construction materials and systems for the thermal building envelope have played a key role in the improvement of energy efficiency in buildings. Urban heat islands together with the upcoming rising global temperature demand construction solutions that are adapted to the specific microclimate conditions. These circumstances are even more dramatic in the case of healthcare buildings where the need to preserve constant indoor temperatures is a priority for the proper recovery of patients. A new neonatal hospital, located in Madrid (Spain), has been monitored, and building energy simulations were performed to evaluate the effect of the building envelope on the energy demand. Based on the simulation results, the design of the building envelope was found to be insufficiently optimised to properly protect the building from the external heat flow. This is supported by the monitored results of the indoor temperatures, which went over the standard limit for about 50% of the hours, achieving up to 27 °C in June and July, and 28 °C in August. The results showed, on one hand, that solar radiation gains transmitted through the façade have an important impact on the indoor temperature in the analysed rooms. Heat gains through the opaque envelope showed an average of 8.37 kWh/day, followed by heat gains through the glazing with an average value of 5.29 kWh/day; while heat gains from lighting and occupancy were 5.21 kWh/day and 4.47 kWh/day, respectively. Moreover, it was shown that a design of the envelope characterised by large glass surfaces and without solar protection systems, resulted in excessive internal thermal loads that the conditioning system was not able to overcome.

Application of a short term air quality action plan in Madrid (Spain) under a high-pollution episode - Part I: Diagnostic and analysis from observations

Exceedances of NO₂ hourly limit value (200 μg·m^-3) imply the need to implement short term action plans to avoid adverse effects on human health in urban areas. The Madrid City Council applied the stage 3 of the NO₂ protocol during a high-pollution episode under stable meteorological conditions on December 2016 for the first time. This included road traffic access restrictions to the city centre (50% of conventional private vehicles based on plate numbers). In this contribution we analyse different meteorological and air quality observations, including non-standard parameters (such as number of ultrafine particles and remote sensing techniques MAXDOAS) for a better understanding of the effectivity of short-term emission abatement measures under real conditions and to identify options to improve the NO₂ protocol in the future. According to our results, the inversion base height computed from vertical temperature soundings is a meaningful index to anticipate very unfavourable conditions and trigger the actions included in the protocol. The analysis of the concentration levels of the main pollutants from the Madrid air quality monitoring network indicate that only stage 3 of the protocol had a significant effect on NO₂ maximum concentrations. The restrictions applied may have prevented NO₂ concentrations to further increase in the city centre (up to 15%) although pollution levels in the city outskirts, outside the area directly affected by the traffic restrictions, remained unchanged or may have been slightly increased. Nonetheless, further studies are needed to estimate more precisely the effect of the measures taken and to assess potential trade-offs. Our results suggest that emissions play an important role also under very strong stability conditions although drastic measures are needed to achieve a significant impact. This highlights the importance of an appropriate timing for short-term actions and the need of permanent abatement measures related to air quality plans and policies.

Prevalence of heartworm in dogs and cats of Madrid, Spain

BACKGROUND

Dirofilaria immitis causes heartworm disease, a chronic and potentially fatal cardiopulmonary disease which mainly affects dogs and cats. It is present in most of Spain, due to favourable climatic factors. Madrid, located in the centre of the Iberian Peninsula, is the most highly populated city in the country. There is a lack of current data on canine heartworm and there are no published epidemiological data regarding feline heartworm in this region, therefore the aim of this study was to assess the prevalence and current distribution of canine and feline dirofilariosis in the province of Madrid.

METHODS

Serum samples from 1716 dogs and 531 cats, from animals living in the metropolitan area of Madrid and adjacent areas, were studied. All the samples, either from cats and dogs, were tested for circulating D. immitis antigens using a commercial immunochromatographic test kit. Furthermore, to establish the seroprevalence of heartworm infection in cats, serological techniques for anti-D. immitis and anti-Wolbachia antibody detection were used.

RESULTS

Prevalence of D. immitis in the canine population of Madrid was 3%, showing an increase in comparison to previous data. The presence of heartworm in the city centre could be influenced by the presence of Urban Heat Islands, while the positive dogs from metropolitan and adjacent areas were mainly located under the influence of rivers. Regarding cats, 0.2% were positive to the antigens test and 7.3% were seropositive to both anti-D. immitis and Wolbachia surface protein antibodies, which demonstrate the presence of feline heartworm in Madrid. Seropositive cats were present in the same areas where positive dogs were found. Indoor/outdoor cats showed the highest seroprevalence whereas the lowest corresponded to indoor cats, demonstrating that prophylactic treatments should be carried out regardless of lifestyle. Infection was found in 2.2% of dogs and 6.7% of the cats < 1 year-old, which indicates that early preventive campaigns in puppies and kittens should be implemented.

CONCLUSIONS

The results point to the need for adequate prophylactic measures through the administration of macrocyclic lactones in animals living in Madrid. Veterinarians should be aware of the presence of this disease and include heartworm in the differential diagnosis when a pet presents with symptoms compatible with D. immitis.

Analyzing the heat island magnitude and characteristics in one hundred Asian and Australian cities and regions

Urban heat island is the more documented phenomenon of climate change. Information on the magnitude and the characteristics of the canopy layer urban heat island measured in 101 cities and regions of Asia and Australia and collected through 88 scientific articles, are compiled, evaluated and presented. Data are classified in several clusters according to the experimental protocol used and the type of statistical information reported regarding the magnitude of the urban heat island. Results and detailed analysis are given for each defined cluster. Very significant differences on the UHI intensity are found between the clusters and analyzed in detail. The detailed impact of the main weather parameters and conditions on the magnitude of the UHI is also investigated. The specific influence of anthropogenic thermal fluxes as well as of the urban morphological and construction characteristics to UHI is thoroughly examined. The relation between the UHI intensity and the city size is assessed and global relationships of UHI as a function of the urban population are proposed. The seasonal and diurnal variability of the UHI is analyzed and discussed while specific features and conditions like the urban heat island characteristics in coastal cities and the existence of daytime cool islands are explored. Finally, the impact of the selected reference station and its characteristics is considered.

Spatial and Temporal Structure of the Urban Heat Island in Seoul

The spatial and temporal structure of the urban heat island in Seoul, Korea, is investigated using near-surface temperature data measured at 31 automatic weather stations (AWSs) in the Seoul metropolitan area for the 1-yr period from March 2001 to February 2002. The urban heat island in Seoul deviates considerably from an idealized, concentric heat island structure, mainly because of the location of the main commercial and industrial sectors and the local topography. Relatively warm regions extend in the east–west direction and relatively cold regions are located near the northern and southern mountains. Several warm cores are observed whose intensity, size, and location are found to vary seasonally and diurnally. Similar to previous studies, the urban heat island in Seoul is stronger in the nighttime than in the daytime and decreases with increasing wind speed and cloud cover, but it is least developed in summer. The average maximum urban heat island intensity is 2.2°C over the 1-yr period and it is 3.4°C at 0300 local standard time (LST) and 0.6°C at 1500 LST. The reversed urban heat island is occasionally observed in the afternoon, but its intensity is very weak. An empirical orthogonal function (EOF) analysis is performed to find the dominant modes of variability in the Seoul urban heat island. In the analysis using temperature data that are averaged for each hour of the 1-yr period, the first EOF explains 80.6% of the total variance and is a major diurnal mode. The second EOF, whose horizontal structure is positive in the eastern part of Seoul and is negative in the western part, explains 16.0% of the total variance. This mode is related to the land use type and the diurnal pattern of anthropogenic heat release. In the analysis using temperature data at 0300 LST, the leading four modes explain 72.4% of the total variance. The first EOF reflects that the weakest urban heat island intensity is in summer. It is found that the urban heat island in Seoul is stronger on weekdays than weekends.