[en] The daily rainfall data collected in the second half of the last century at 31 climatic stations in Lazio, Italy, have been subjected to statistical analysis in order to describe the pluviometric regime of the whole area on a multi-decadal time scale. The stations, for their geographical distribution within the region under study, are apt to represent different climatic zones, namely, a coastal, a rural, a suburban and an urban zone. The data have been treated both as time series and as geographical statistical variates with the double aim, first, to verify if in the area under study any changes in the yearly precipitation rate, frequency and its distribution over different classes of rain intensity, have occurred in the last 50 years; second, to evidence a possible correlation between the intensity of precipitation and any of some environmental variables such as altitude, distance from the coastline and distance from the urban site. As for the first issue, it can be concluded that the precipitations over the Roman area in the period 1951-2000 show no significant trend; in particular, no trend is visible in any of the single classes of rain intensity, both absolute and percentile-based, considering either their frequency or their percent contribution to the total. As for the second issue, significant correlations have been found in the spatial distribution of rainfall with any of the relevant environmental variables mentioned above. The results of the analysis also show that in the urban area a less amount of rain seem to fall than in the surroundings zones, a result that seems rather anomalous in consideration of the several known factors that favour the intensification of the rainfall in the city with respect to its surroundings. A detailed statistical characterization of all the single 31 stations over the whole period is also given via a separate study of the durations of droughts and of the statistics of rainy days, using best fits based on the Weibull probability distribution

[en] Highlights: • A new methodology is proposed to estimate the rainfall aggressiveness risk. • This methodology is based on daily rainfall records. • A new synthesis parameter based on Modified Fournier and Oliver's indices is used. • It is calibrated with respect to the erosivity R factor for a simultaneity period. • The SW of Iberian Peninsula has been selected to test its regional application. The temporal irregularity of rainfall, characteristic of a Mediterranean climate, corresponds to the irregularity of the environmental effects on soil. We used aggressiveness as an indicator to quantify the potential environmental impact of rainfall. However, quantifying rainfall aggressiveness is conditioned by the lack of sub-hourly frequency records on which intensity models are based. On the other hand, volume models are characterized by a lack of precision in the treatment of heavy rainfall events because they are based on monthly series. Therefore, in this study, we propose a new methodology for estimating rainfall aggressiveness risk. A new synthesis parameter based on reformulation using daily data of the Modified Fournier and Oliver's Precipitation Concentration indices is defined. The weighting of both indices for calculating the aggressiveness risk is established by multiple regression with respect to the local erosion R factor estimated in the last decades. We concluded that the proposed methodology overcomes the previously mentioned limitations of the traditional intensity and volume models and provides accurate information; therefore, it is appropriate for determining potential rainfall impact over long time periods. Specifically, we applied this methodology to the daily rainfall time series from the San Fernando Observatory (1870–2010) in southwest Europe. An interannual aggressiveness risk series was generated, which allowed analysis of its evolution and determination of the temporal variability. The results imply that environmental management can use data from long-term historical series as a reference for decision making.

[en] The high rate of deforestation of the Brazilian Amazon over the past two decades has jeopardized genetic diversity, contributed to regional and global climate change, caused erosion and flooding, destroyed forest resources, spread disease, and increased poverty. This book presents a selection of papers from an international conference that explored alternatives to deforestation of tropical forests. The alternatives described include natural forest management, agroforestry systems, and forest reestablishment on degraded pastures. The book should be useful to scientists, regional planners, and the broad scientific audience

No abstract available

[en] The Tibetan Plateau (TP), with an average elevation of over 4000 m asl and an area of approximately 2.5 x 10⁶ km², is the highest and most extensive highland in the world and has been called the 'Third Pole'. The TP exerts a huge influence on regional and global climate through thermal and mechanical forcing mechanisms. Because the TP has the largest cryospheric extent outside the polar region and is the source region of all the large rivers in Asia, it is widely recognized to be the driving force for both regional environmental change and amplification of environmental changes on a global scale. Within China it is recognized as the 'Asian water tower'. In this letter, we summarize the recent changes observed in climate elements and cryospheric indicators on the plateau before discussing current unresolved issues concerning climate change in the TP, including the temporal and spatial components of this change, and the consistency of change as represented by different data sources. Based on meteorological station data, reanalyses and remote sensing, the TP has shown significant warming during the last decades and will continue to warm in the future. While the warming is predominantly caused by increased greenhouse gas emissions, changes in cloud amount, snow-albedo feedback, the Asian brown clouds and land use changes also partly contribute. The cryosphere in the TP is undergoing rapid change, including glacier retreat, inconsistent snow cover change, increasing permafrost temperatures and degradation, and thickening of the active layer. Hydrological processes impacted by glacial retreat have received much attention in recent years. Future attention should be paid to additional perspectives on climate change in the TP, such as the variations of climate extremes, the reliability of reanalyses and more detailed comparisons of reanalyses with surface observations. Spatial issues include the identification of whether an elevational dependency and weekend effect exist, and the identification of spatial contrasts in temperature change, along with their causes. These issues are uncertain because of a lack of reliable data above 5000 m asl.

[en] Soil moisture observations in sites with natural vegetation were made for several decades in the former Soviet Union at hundreds of stations. In this paper, the authors use data from six of these stations from different climatic regimes, along with ancillary meteorological and actinometric data, to demonstrate a method to validate soil moisture simulations with biosphere and bucket models. Some early and current general circulation models (GCMs) use bucket models for soil hydrology calculations. More recently, the Simple Biosphere Model (SiB) was developed to incorporate the effects of vegetation on fluxes of moisture, momentum, and energy at the earth's surface into soil hydrology models. Until now, the bucket and SiB have been verified by comparison with actual soil moisture data only on a limited basis. In this study, a Simplified SiB (SSiB) soil hydrology model and a 15-cm bucket model are forced by observed meteorological and actinometric data every 3 h for 6-yr simulations at the six stations. The model calculations of soil moisture are compared to observations of soil moisture, literally 'ground truth,' snow cover, surface albedo, and net radiation, and with each other. For three of the stations, the SSiB and 15-cm bucket models produce good simulations of seasonal cycles and interannual variations of soil moisture. For the other three stations, there are large errors in the simulations by both models. Inconsistencies in specification of field capacity may be partly responsible. There is no evidence that the SSiB simulations are superior in simulating soil moisture variations. In fact, the models are quite similar since SSiB implicitly has a bucket embedded in it. One of the main differences between the models is in the treatment of runoff due to melting snow in the spring-SSiB incorrectly puts all the snowmelt into runoff. While producing similar soil moisture simulations, the models produce very different surface latent and sensible heat fluxes, which would

No abstract available

[en] A multitemporal analysis on the Mount Disgrazia glaciers was performed by using the 1975, 1978 and 1980 MSS Landsat images. On these images the glaciers were completely described in their boundaries and surface features. Fixed structures were used along their boundaries as fiducial points of the ground control table for the multitemporal comparison of the glaciers. This makes it possible to estimate the galcier surface changes due to frontal displacements as well as the changes in the snow-covered area due to the displacements of the snow transient line. The procedure is possible since the recordings of Landsat satellites are continuous in space and time. It gives completeness to the individual data on the glaciers as provided by the field measurements and it makes the management of the water resources possible

[en] A discussion of studies detailing the damaging effects of acid precipitation in North America and Europe is followed by a commentary on the controversial political and economic issues associated with forestalling deterioration of the environment. A comprehensive bibliography is included

[en] The general pattern of rain falling on the earth and reacting with the materials of the lithosphere (the weathering reactions so familiar to every beginning geology student) began soon after the earth was formed and has continued to the present. Anthropogenic additions to the natural acidic components of the atmosphere have increased since the time of the industrial revolution until they now rival or exceed those of the natural system. The severity of the environmental perturbations caused by these anthropogenic additions to the atmosphere has become a hotly debated topic in scientific forums and in the political arena. The six chapters in this book address various aspects of the acid deposition phenomenon from a geological perspective. It is hoped that the geological approach will be useful in bringing the problem more clearly into focus and may shed light on the geochemical processes that modify the chemical composition of acid deposition after it encounters and reacts with the materials of the lithosphere