Upgrades implemented over a number of years in an open source version of the Eta model, posted at the CPTEC web site http://etamodel.cptec.inpe.br/, are summarized and examples of benefits are shown. The version originates from the NCEP's Workstation Eta code posted on the NCEP web site http://www.emc.ncep.noaa.gov/ mmb/wrkstn_eta, which differs from the NCEP's latest operational Eta by having the WRF-NMM nonhydrostatic option included. Most of the upgrades made resulted from attention paid to less than satisfactory performance noted in several Eta results, and identification of the reasons for the problem. Others came from simple expectation that including a feature that is physically justified but is missing in the code should help. The most notable of the upgrades are the introduction of the so-called sloping steps, or discretized shaved cells topography; piecewise-linear finitevolume vertical advection of dynamic variables; vapor and hydrometeor loading in the hydrostatic equation, and changes aimed at refining the convection schemes available in the Eta. Several other modifications have to do with the calculation of exchange coefficients, conservation in the vertical diffusion, and diagnostic calculation of 10-m winds. Several examples showing improved performance resulting from the dynamics changes are given. One includes a case of unrealistically low temperatures in several mountain basins generated by a centered vertical advection difference scheme's unphysical advection from below ground, removed by its replacement with a finitevolume scheme. Another is that of increased katabatic winds in the Terra Nova Bay Antarctica region. Successful forecast of the severe downslope zonda wind case in the lee of the highest peaks of the Andes is also shown, and some of the recent successful verification results of the use of the upgraded model are pointed out. The code is used at numerous places, and along with setup information it is available for outside users at the CPTEC Eta web site given above.

O(3), NO(2), SO(2), CO and PM(10) concentrations, simultaneously determined for the first time in Belgrade urban area in the autumnal period of 2005, are presented. The obtained results display similar behaviour of SO(2), NO(2), CO, PM(10) opposite from that of O(3). The weekend effect was also investigated showing diminution of average daily concentrations of SO(2), NO(2), PM(10) and CO for 72, 40, 37 and 42% respectively, and increase of the average daily concentration of O(3) for 56%. Influence of meteorological conditions on observed concentration levels was studied, too. The observed influence of wind speed on the O(3) nightly concentration levels was analyzed pointing to the phenomena of O(3) transport during episodic measurements. To make an identification of possible pollution sources and analyse the influence of meteorological parameters on pollution levels, air back trajectories for high level concentrations episodes were calculated and analysed. A multivariate receptor modelling (Principal Component Analysis, Cluster Analysis) has been applied to a set of data in order to determine the contribution of different sources. It was found that the main principal components, extracted from the air pollution data, were related to gasoline combustion, oil combustion and ozone transport.

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A technology assessment of the future potential of hail suppression and all its possible ramifications in the United States in future years has included an attempt to define the current status of hail suppression. Hail suppression is at a stage in which the socioeconomic impacts of its use and the means to optimize its future utilization can be adequately treated. The estimation of a wide range of future suppression capabilities was based on the current status, which was defined after inspecting three sources of information: 1) results from preliminary evaluations of six recent projects, 2) findings on four published assessments of weather modification, and 3) results from two opinion surveys. This investigation indicates: 1) scientific beliefs about existing capabilities are widely different, with the majority of experts believing there is no capability; 2) the published reviews are optimistic but largely nondefinitive; and 3) the results of five of six recent suppression projects show suppression levels of 20-50%, but the results are largely not significant at the 5% level. This difference between average beliefs of experts and the results of recent projects suggests the need for an extensive investigation of the data and results of these recent projects.

This paper explores wetland-based tourism in four Ramsar sites in northern Serbian province Vojvodina, as well as a connection between tourism and nature protection. These regions are of great importance for Vojvodina, especially from the point of view of ecosystem services, because 83.3% of its territory are agricultural areas. Explored Ramsar sites were designated in period from 2004 to 2008 and they have been included in many plans as important areas for tourism development. However, the level of tourism development in these sites is not uniform because it depends on variety of factors such as touristic attractions value, engagement of nature protection managers in tourism development, and level of nature degradation and protection. The main objective of this paper is to determine the interconnection between nature degradation, nature protection and tourism development in selected Ramsar areas of Vojvodina, based on the Internal data of protected area managers,Report on the state of the environment and the scope of tourism development (infrastructure, services, development plans).

ABSTRACT:The development of tourism in protected areas is a particular challenge for the tourism business and the activity of nature conservation. The leading criteria for sustainable tourism in protected areas emphasize the importance of the adoption of certain principles of care, long-term planning and management that integrates nature protection and tourism. In this respect, the paper analyzes their importance in the case of Special Nature Reserve »Gornje Podunavlje« in Vojvodina. After acquiring the status of a special nature reserve, talk about the importance of this area to the tourism of Sombor and Apatin, where it is located, has increased. This trend follows the design of educational and tourist tracks, starting and running events as well as starting tourism businesses in rural households. There could be multiple benefits of this for the local communities.