Giampiero Maracchi

Weather-Related Changes in 24-Hour Blood Pressure Profile. Effects of Age and Implications for Hypertension Management

A downward titration of antihypertensive drug regimens in summertime is often performed on the basis of seasonal variations of clinic blood pressure (BP). However, little is known about the actual interaction between outdoor air temperature and the effects of antihypertensive treatment on ambulatory BP. The combined effects of aging, treatment, and daily mean temperature on clinic and ambulatory BP were investigated in 6404 subjects referred to our units between October 1999 and December 2003. Office and mean 24-hour systolic BP, as well as morning pressure surge, were significantly lower in hot (>90th percentiles of air temperature; 136±19, 130±14, and 33.3±16.1 mm Hg; P<0.05 for all), and higher in cold (<10th percentiles) days (141±12, 133±11, and 37.3±9.5 mm Hg; at least P<0.05 for all) when compared with intermediate days (138±18, 132±14, and 35.3±15.4 mm Hg). At regression analysis, 24-hour and daytime systolic pressure were inversely related to temperature (P<0.01 for all). Conversely, nighttime systolic pressure was positively related to temperature (P<0.02), with hot days being associated with higher nighttime pressure. Air temperature was identified as an independent predictor of nighttime systolic pressure increase in the group of elderly treated hypertensive subjects only. No significant relationship was found between air temperature and heart rate. Our results show for the first time that hot weather is associated with an increase in systolic pressure at night in treated elderly hypertensive subjects. This may be because of a nocturnal BP escape from the effects of a lighter summertime drug regimen and may have important implications for seasonal modulation of antihypertensive treatment.

A synoptic approach to weather conditions discloses a relationship with ambulatory blood pressure in hypertensives.

BACKGROUND Higher blood pressure (BP) values in cold than in hot months has been documented in hypertensives. These changes may potentially contribute to the observed excess winter cardiovascular mortality. However, the association with weather has always been investigated by considering the relationship with a single variable rather than considering the combination of ground weather variables characterizing a specific weather pattern (air mass (AM)). METHODS We retrospectively investigate in Florence (Italy) the relationship between BP and specific AMs in hypertensive subjects (n = 540) referred to our Hypertension Unit for 24-h ambulatory BP monitoring during the period of the year characterized by the highest weather variability (winter). Five different winter daily AMs were classified according to the combination of ground weather data (air temperature, cloud cover, relative humidity, atmospheric pressure, wind speed, and direction). RESULTS Multiple variable analysis selected the AM as a significant predictor of mean 24-h BP (P < 0.01 for diastolic BP (DBP) and P < 0.05 for systolic BP (SBP)), daytime DBP (P < 0.001) and nighttime BP (P < 0.01 for both SBP and DBP), with higher BP values observed in cyclonic (unstable, cloudy, and mild weather) than in anticyclonic (settled, cloudless, and cold weather) days. When the association with 2-day sequences of AMs was considered, an increase in ambulatory BP followed a sudden day-to-day change of weather pattern going from anticyclonic to cyclonic days. CONCLUSIONS The weather considered as a combination of different weather variables may affect BP. The forecast of a sudden change of AM could provide important information helpful for hypertensives during winter.

The impact of built-up surfaces on land surface temperatures in Italian urban areas

Urban areas are characterized by the very high degree of soil sealing and continuous built-up areas: Italy is one of the European countries with the highest artificial land cover rate, which causes a substantial spatial variation in the land surface temperature (LST), modifying the urban microclimate and contributing to the urban heat island effect. Nevertheless, quantitative data regarding the contribution of different densities of built-up surfaces in determining urban spatial LST changes is currently lacking in Italy. This study, which aimed to provide clear and quantitative city-specific information on annual and seasonal spatial LST modifications resulting from increased urban built-up coverage, was conducted generally throughout the whole year, and specifically in two different periods (cool/cold and warm/hot periods). Four cities (Milan, Rome, Bologna and Florence) were included in the study. The LST layer and the built-up-surface indicator were obtained via use of MODIS remote sensing data products (1km) and a very high-resolution map (5m) of built-up surfaces recently developed by the Italian National Institute for Environmental Protection and Research. The relationships between the dependent (mean daily, daytime and nighttime LST values) and independent (built-up surfaces) variables were investigated through linear regression analyses, and comprehensive built-up-surface-related LST maps were also developed. Statistically significant linear relationships (p<0.001) between built-up surfaces and spatial LST variations were observed in all the cities studied, with a higher impact during the warm/hot period than in the cool/cold ones. Daytime and nighttime LST slope patterns depend on the city size and relative urban morphology. If implemented in the existing city plan, the urban maps of built-up-surface-related LST developed in this study might be able to support more sustainable urban land management practices by identifying the critical areas (Hot-Spots) that would benefit most from mitigation actions by local authorities, land-use decision makers, and urban planners.

The ontogenesis of wheat under scenarios of increased air temperature in Italy : a simulation study

Abstract Simulations of wheat development were used to evaluate the duration and variability of wheat development phases under current and future climates in Italy. The adaptation of different varieties to scenarios of increased temperature and potential changes in management were explored and assessment was made of the effect induced by climate change upon the workdays of the most important crop husbandry practices. The sensitivity of wheat development to arbitrary changes in temperature (+ 2 °C, + 4 °C) was considered in the first instance. The results obtained showed that an arbitrary increase in temperature reduced the duration of the phenological phases. Analyses made using composite time-dependent scenarios showed an increase in agricultural risk and a more pronounced reduction in the length of the development phases in southern and central Italy than in the northern part of the country. Development predictions, based on equilibrium 2 x CO 2 scenarios, gave similar results but there were significant differences between the 2 x CO 2 scenario results. Management analyses suggested that slow developing varieties are likely to be better suited than fast ones to a warming climate in northern and central Italy, while the opposite is likely to occur in the south. The combination of an increase in wheat development rate and a change in the amount of precipitation is likely to cause a general reduction in the number of days suitable for agricultural operations in northern Italy.

A biometeorological procedure for weather forecast to assess the optimal outdoor clothing insulation

Clothing insulation represents an important parameter strongly dependent on climate/weather variability and directly involved in the assessment of the human energy balance. Few studies tried to explore the influence of climate changes on the optimal clothing insulation for outdoor spaces. For this reason, the aim of this work was to investigate mainly the optimal outdoor minimum clothing insulation value required to reach the thermal neutrality (min_clo) related to climate change on a seasonal basis. Subsequently, we developed an example of operational biometeorological procedure to provide 72-hour forecast maps concerning the min_clo. Hourly meteorological data were provided by three Italian weather stations located in Turin, Rome and Palermo, for the period 1951–1995. Environmental variables and subjective characteristics referred to an average adult young male at rest and at a very high metabolic rate were used as input variables to calculate the min_clo by using a thermal index based on the human energy balance. Trends of min_clo were assessed by a non-parametric statistical method. Results showed a lower magnitude of trends in a subject at a very high metabolic rate than at rest. Turin always showed a decrease of min_clo during the study period and prevalently negative trends were also observed in Palermo. On the other hand, an opposite situation was observed in Rome, especially during the morning in all seasons. The development of a daily operational procedure to forecast customized min_clo could provide useful information for the outdoor clothing fitting that might help to reduce the weather-related human health risk.

Water management in a semi-arid region: an analogue algorithm approach for rainfall seasonal forecasting

Methods and results of this recent branch of atmospheric sciences must be the most simple and accessible as possible. For this reason, the Institute of Biometeorology, (part of the National Research Council, http://www.ibimet.cnr.it), has developed a physically — based statistical approach to obtain seasonal forecasts, regarding rainfall precipitation, over Sahel region.

Weather and climate monitoring for food risk management

Food insecurity represents one of the main indicators of the poverty level of a country and can breed a strong dependence on foreign aid with a strong slowdown of the national economy. African arid and semi-arid areas are characterised by food precariousness and their agricultural activity is strongly dependent on the extreme climatic conditions that affect the available water supply. This situation has led to the need to develop new tools for the prediction and the management of crisis. The characterisation of climate and the identification of anomalies, the monitoring of weather conditions and their influence on crops, short and medium range weather forecasts and long-term climate predictions are among the most powerful tools to predict, in as short a time as possible, crises due to the absence or delay of rainfall season. Meteorological information can also be used as an input to agrometeorological models applied for crisis prevention or for its management during the growing season when the crops are already present. In this paper, a review of these tools is made and some operational products presented. Copyright

Seasonal Predictions and Monitoring for Sahel Region

Although seasonal forecast applications are still in an early stage of development there is now enough collective experience from research efforts around the world to induce some meaningful considerations.