This research is an attempt to investigate the blocking systems over the Atlantic Ocean and especially over the Mediterranean sea, which leads to surface cyclogenesis in the east of the Mediterranean Sea, and the influence of their effects over the Iranian region. At the first step of study, Mediterranean topography, local Mediterranean winds and cyclogenesis have studied; then structure and types of existing blocking systems on the synoptic weather maps have been introduced with figures.In the second step of the study, all of the blocking systems that were formed over the Atlantic Ocean were identified from 1989 to 1997, the results of which are shown in the table included in the paper. Of course this part of the work was done with the help of Prof. Colucci from USA and data are given from NCEP.Atmospheric blocking systems can lead to a stagnation of weather patterns where the patterns remain for several days or even weeks at the same location during the blocking system. This case can lead to flooding, drought, above normal temperatures, below normal temperatures and other weather extremes. Therefore, it is important to recognize a blocking pattern in its initial development. With this awareness, one can forecast up to several days in advance with a high degree of accuracy.

This study was conducted during summer and winter of 2018- 2019 in the agricultural research field of Shahid Chamran University. Experimental design was split- plot based on RCBD with three replications. The main plot was the type of agricultural system in three levels including conventional (Conv), organic (Org) and sustainable (Sust) (integrated between Conv and Org) and sup- plot was the type of pre- cultivated crop in sequence with wheat including cultivation of mung bean (M- W), corn (C- W), sesame (S- W) and fallow (F- W). Yield quantity (yield and its component) and quality (grain protein), an estimate of photosynthesis matter transfer index of wheat and soil organic carbon (SOC) after one double-cropping were measured. The result showed that the highest (545.04 g/m2) and the lowest (409.28 g/m2) seed yields were obtained in Conv and Org respectively. In contract, with the changing type of system from Conv to Org, grain protein was increased significantly (from 8.3 to 9.6 %). In addition, the highest (535.47 g/m2) yield of wheat was obtained from M- W double cropping. On the other hands the highest remobilization and current photosynthesis matter were obtained in the organic agricultural system with M- W and conventional with M- W double cropping. The situation of SOC showed that the highest (33.18 mg/g) SOC was obtained in the organic agricultural system with C- W double cropping. The reason for improving SOC in the organic and sustainable agricultural system was application of organic matter (compost and vermicompost) and crop residue management. Totally, from the crop ecology point of view, sustainable agricultural method with a sequence of M- W was the most desirable system.

blocking event can lead to economic losses at the macro level and be effective on health on a large scale. blocking is one of the Mid-latitude systems and Iran due to the situation is affected by this phenomenon. In order to investigate the blocking systems affecting the climate of Iran, daily geopotential heights of 500 hPa of grid points within the 0-90N and 90W-100E windows were extracted from the NCEP reanalysis data for the 1953-2012 period at 2.5 degrees resolution. By using the two dimensional index, the blocking systems were defined within these geopotential data. The whole process was programmed and modeled in the MATLAB environment. In the second step the characteristics of blocking systems such as central location, intensity, spatial structure, and duration were extracted.The results showed that the most frequent occurring place for these systems is the area between 10W to 20E; while Iran was the second center for these events. The developing location of the most blockings affecting the climate of Iran is the Scandinavian Peninsula. The medium blockings were frequent and the mean duration of these systems was 6 days. The application of the non-parametric Mann-Kendal test revealed no significant trend of the frequencies of blocking systems over the study period.

The purpose of this study was to investigate and identify the effect of blocking systems on Iran's poisoning during the period 1975-2015 using the blocking numerical index. The results showed that in the cold seasons most of the blockades affecting the atmosphere of Iran were in the northern Atlas. Also, the study of the severity of effective blockades affecting Iran's climate showed that the strong blocking is moderate in terms of the highest number after the blocking, indicating that Iran was more affected by moderate blocking (74. 6%) and then strong (21. 1%). The number of weak blocking is very low (4. 3%). Due to the frequency of occurrence of blocking also was found wet Iran in months. Cold, the core of the blocking in between longitude 30 ° west and 30 ° East over the Atlantic formed and as the warm season approaching, the core the land was transferred to the regions dominated by positive changes in parameters affect precipitation. Also, in Bandal's review in different seasons, it was revealed that in winter, with the retreat of the adjacent high pressure and the strength of the polar vertex, along with the occurrence of strong and long blockades, the average rainfall is more than the other seasons.

Today, many navigation systems come into contest with Global Positioning System (GPS). Some of these systems are GLONASS, Galileo and Beidou.The best way for incresing the number of satellites in user view is to combine these systems. Likewise, since it is possible for GPS or GLONASS satellites to be blocked by intentional or unintentional interventions, combining becomes more efficacious way against this kind of happening. In this paper, in addition to discussing about GPS and GLONASS combination effects on positioning accuracy improvement, we will propose a method against GPS satellites blocking using GLONASS integration. Though high accuracy of proposed method, it has real-time positioning ability and low implementation complexity. It also has abitity to deal with intentional blocking. As Kalman filter is one of the cheapest and applicable tool that can be be implemented on chip precessors. The real data used for implementation in this paper is collected by a GPS and GLONASS receiver and simulation results has been successfully shown accurcy improvement in proposed method.