Oded Potchter

Spatial distribution and microscale characteristics of the urban heat island in Tel-Aviv, Israel

Abstract A significant urban heat island (UHI) was identified in Tel-Aviv on a stable winter day. The UHI detection was performed using air temperatures at both the roof and the street levels (using fixed-station and car-traverse measurements) and at the surface level (using an airborne thermal video radiometer [TVR]). Whereas the complex microscale characteristics of the UHI studied by the TVR at the surface level showed variations of up to 10°C, at the street level, air temperature variations of 3–5°C were identified between the city center and the surrounding areas. It was found that during the nighttime, the warm Mediterranean Sea has a moderating effect on the roof-level temperatures, whereas, at the street level, the urban heat island is more pronounced. The combined method of monitoring the UHI from different levels and on different scales for the first time enabled a spatial assessment of the city’s UHI and its diverse thermal coverage characteristics. The thermal differences of neighborhoods, urban activity and urban components were compared. It was demonstrated that the city cover plays an important role in the thermal activity of Tel-Aviv. A similar UHI spatial pattern was obtained using isotherm maps, generated from the air temperatures at street level, and thermal images, generated by the TVR at the surface level. It was concluded that there are differences in the magnitude of the UHI at different levels of the canopy layer and at different times, but the UHI pattern has similar trends.

The impact of an urban park on air pollution and noise levels in the Mediterranean city of Tel-Aviv, Israel.

This study examines the influence of urban parks on air quality and noise in the city of Tel-Aviv, Israel, by investigation of an urban park, an urban square and a street canyon. Simultaneous monitoring of several air pollutants and noise levels were conducted. The results showed that urban parks can reduce NOx, CO and PM10 and increase O3 concentrations and that parks mitigation effect is greater at higher NOx and PM10 levels. During extreme events, mean values of 413 ppb NOx and 80 μG/m3 PM10 were measured in the street while mean values of 89 ppb NOx and 24 μG/m3 PM10 were measured in the park. Whereas summer highest O3 values of 84 ppb were measured in the street, 94 ppb were measured in the park. The benefit of the urban park in reducing NOx and PM10 concentrations is more significant than the disadvantage of increased O3 levels. Furthermore, urban parks can reduce noise by ∼5 dB(A).

Calculated and observed human thermal sensation in an extremely hot and dry climate

Abstract Thermal perception of 36 students has been calculated and observed in a case study on the 10th and 11th of July 2000 at Kibbutz Yotvata under extremely hot and arid climatic conditions. Calculations of thermal sensations were done by energy balance models of Fanger [Thermal Comfort: Analysis and Applications in Environmental Engineering, McGraw-Hill, New York, 1972] and Gagge et al. [ASHRAE Trans. 92 (1986) 709]. Observed and calculated values differed considerably during the daytime under extremely hot conditions, whereas they corresponded well for warm night-time conditions. A temporal development of the differences lead to a theory, which explains the differences according to the factors “short-term thermal adaptation” and “thermal expectation”.

The effects of exposure to environmental factors on Heart Rate Variability: An ecological perspective

The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects.

Human exposure to environmental health concern by types of urban environment: The case of Tel Aviv.

This study classifies urban environments into types characterized by different exposure to environmental risk factors measured by general sense of discomfort and Heart Rate Variability (HRV). We hypothesize that a set of environmental factors (micro-climatic, CO, noise and individual heart rate) that were measured simultaneously in random locations can provide a better understanding of the distribution of human exposure to environmental loads throughout the urban space than results calculated based on measurements from close fixed stations. We measured micro-climatic and thermal load, CO and noise, individual Heart Rate, Subjective Social Load and Sense of Discomfort (SD) were tested by questionnaire survey. The results demonstrate significant differences in exposure to environmental factors among 8 types of urban environments. It appears that noise and social load are the more significant environmental factors to enhance health risks and general sense of discomfort.

Mapping air pollution by biological monitoring in the metropolitan Tel Aviv area

Conventional environmental monitoring is not surrogate of personal exposure. In contrast, biomonitoring provides information on the presence of substances in the human body, making it highly relevant to the assessment of exposure to toxic substances. Induced sputum (IS) is a noninvasive technique for detecting inflammation and reflecting particulate matter content in the airways. In this study, we mapped particulate matter dispersion in metropolitan Tel Aviv by both biomonitoring techniques employing IS samples and by environmental monitoring. All adults referred to the Pulmonary Lab for respiratory symptom evaluation in 2007 and in 2009 were enrolled. Pulmonary function tests were performed by conventional methods. Particulate size distribution in IS was analyzed, and maps of air pollution were created. Biomonitoring was more informative and enabled mapping of wider areas. Integration of biomonitoring and environmental monitoring should be considered in forming public health policy on containment of airborne particles of toxic substances.

Climatic Aspects in the Building of Ancient Urban Settlements in Israel

Abstract The past presents numerous examples of adaptation in urban planning and building design to climatic conditions in different geographical regions. Each historical period developed its own concepts of urbanization and building design, some were unique and others were adapted from period to period. This research will examine to what extent climatic aspects were considered in the building of ancient urban settlements in Israel in the Hellenistic, Roman and Byzantine periods (300 bc – 600 ad ). Thus this research considers Persian, Hauran and Nabatean influences on architecture and city planning.

Climatic aspects in rural settlement development in hot, arid zones: A case study of the Central Jordan Valley

Abstract The characteristics of hot, arid climates include: slight precipitation, high temperature in the summer, low temperature in the winter, low humidity, strong winds and dust storms. These climatic conditions of the hot, arid zones create an uncomfortable environment for man. The state of Israel has performed a major settlement operation in the Jordan Valley in terms of both time and space. The climate of this valley conforms to the above-mentioned desert conditions. The research examined the operation of this settlement development. The methodology of this research was conducted on three levels: a regional level, a local or settlement structure level and the level of building design. On the basis of these conclusions, the research suggests some climate principles for consideration in development of settlement activities and planning in hot, arid zones.

MODIS Summer SUHI Cross-sections Anomalies over the Megacities of the Monsoon Asia Region and Global Trends

RESEARCH ARTICLE MODIS Summer SUHI Cross-sections Anomalies over the Megacities of the Monsoon Asia Region and Global Trends Hofit Itzhak-Ben-Shalom, Pinhas Alpert, Oded Potchter and Rana Samuels The Porter School of Environmental Studies, Tel Aviv University, 69978 Tel Aviv, Israel Department of Geosciences, Tel-Aviv University, P.O. Box 39040, Tel Aviv, Israel Department of Geography and the Human Environment, Tel Aviv University, Tel Aviv, Israel Department of Geography, Beit Berl College, Beit Berl, Israel