In the current research, tropical cyclone Haiyan (TCH) was focused and some meteorological parameters in the LOWER- and upper-levels of TROPOSPHERE have been investigated. For this aim, five datasets including re-analysis and observational data have been used and some parameters including sea surface temperature, relative humidity, potential temperature, relative vorticity, vertical wind shear, geo-potential height, temperature and wind vector have been analyzed, based on latitude- ongitude distributions, vertical profiles and time series plots. Results indicated that all focused parameters in the LOWER levels of TROPOSPHERE were disturbed from the beginning of TCH lifetime and also contributed in TCH intensification and weakening. owever, variation of the selected parameters at the upper part of TROPOSPHERE started with a delay of about 2-3 days, they affect TCH intensification and weakening. Conclusively, it can be claimed that both LOWER- and upperlevels of TROPOSPHERE have been changed during TCH and their positive interaction helped TCH to be intensified to category 5.

Ozone trends in the Upper TROPOSPHERE and LOWER Stratosphere over the Indian region are investigated using three satellite data sets namely Halogen Occultation Experiment (1993-2005), Stratospheric Aerosol and Gas Experiment (1993-2005) II, and Aura Microwave Limb Sounder (MLS, 2005-2011). Estimated ozone trends using multi-variate regression analysis are compared with trends at two Indian ozonesonde stations (Delhi, 28oN, 77oE and Pune, 18oN, 73oE), and a 3-D Chemical Transport Model (CTM, SLIMCAT) for the 1993-2005 time period. Overall, all the observational data sets and model simulations indicate significant increasing trend in the upper TROPOSPHERE (0-2.5%/year). In the LOWER stratosphere, estimated trends are slightly positive up to 30 mb and are negative between 30 and 10 mb. Increasing trends in the upper TROPOSPHERE is probably due to increasing trends in the tropospheric ozone precursor gases (e.g. CO, NO x, NMHCs). Here, we argue that these contrasting ozone-trend profiles might be partially responsible for insignificant long-term trends in the tropical total column ozone. On seasonal scale, positive trends are observed during all the seasons in the upper TROPOSPHERE while structure of trend profile varies in LOWER stratosphere. Seasonal variations of ozone trends and its linkages with stratospheric intrusions and increasing trends in lightning flashes in the TROPOSPHERE are also discussed.

This project studies the relationship of rainfall with a thickness of the LOWER layer of the TROPOSPHERE. Area between latitude 32.5 and 37 N in the Zagros Mountains in the central west of Iran was studied. Study of the long term period of rainfall elucidated seven synoptic stations of the central west of Iran. Two years of High rainfall and low rainfall and pervasive rainfall days of LOWER (up to 5 mm), medium (5 to 10 mm) and higher (more than 10 mm) for above months were selected from those years. Anomaly investigation on the average thickness of the atmosphere in Iran during this period to the long-term 66-yearold indicated that the annual average thickness has been more about 1.5 meters in the central west region in Iran. So the layer thickness (850-1000), temperature and specific humidity at the LOWER layer of the TROPOSPHERE thickness in selected rainfall days in the central west region, it was shown that there was a thickness reduction at the rainfall day in 11 cases, thickness increment in 7 cases and no changes in 2 cases which remains constant. The amount of atmospheric thickness changes in the LOWER layer of the TROPOSPHERE has not followed any specific trend and its changes and amount varied in different months. Also, the correlation of rainfall with the atmosphere thickness in the LOWER layer of TROPOSPHERE in different seasons has not followed any specific trend and other conditions would be examined.

Inertia– gravity waves (IGWs) play an important role in transporting energy and momentum, in making and shaping turbulence and mixing, and in influencing the mean circulation and thermal structure of the atmosphere. They cause perturbations in the main dynamical fields, such as pressure, temperature and wind. Therefore, knowledge of their sources and analysis of their characteristics are very important. Given that there has been no study to identify and simulate IGWs that may have occurred over Tehran during the last few decades, the current research aims to investigate IGWs in the LOWER TROPOSPHERE based on the long-term data of Mehr-Abad meteorological station during the period from 1960 to 2015. One method for detecting IGWs is checking the large amplitude hourly surface pressure changes. At first, hourly surface pressure observations for Tehran in a 55-yr period have been used to find the distribution of large hourly pressure changes defined as falls or rises in excess of 3 hPa per hour. After making careful checks, 101 cases were identified as potential candidates of IGWs occurrences. In the second part of the paper, we constructed composite maps of mean sea level pressure, 1000-500 hPa thickness, 500 hPa geopotential height, and 850 hPa, 500 hPa and 200 hPa wind. The cyclone-related IGW composite showed that the IGW events clustered poleward of the estimated position of the surface warm front, northeastward of the surface cyclone center, downstream and within the poleward exit region of a jet streak that was upstream of a ridge. By analyzing the synoptic-scale environments in which IGWs evolve, the probable candidates for IGWs were reduced to 17, among which 13 events were associated with convection and 4 events were related to cyclone development. In order to evaluate our analysis and to obtain the IGWs characteristics, the Weather Research and Forecasting (WRF) model was used. We determined the position of wave packets and their propagation during the time evolution by drawing the horizontal velocity divergence. The horizontal and vertical wavelength, intrinsic frequency, the period, horizontal and vertical velocity and the group velocity were determined by drawing the cross sections of horizontal velocity divergence and making use of the dispersion relation for hydrostatic waves, as well as the relations for the horizontal and vertical components of group velocity and the intrinsic phase speed. Then we drew time series of the horizontal velocity divergence and sea level pressure, and evaluated the correlation between these two quantities. By checking the horizontal velocity divergence at 800 hPa which is near the surface of the earth, it was observed that negative/positive divergence is associated with pressure rise/fall. On the other hand, the strength or weakness of wave’ s amplitude was investigated by using the time series of horizontal divergence at different pressure levels. The numerical simulation results not only confirmed the validity of the method employed to analyze and identify IGWs, but also determined the connection between the IGWs sources, their propagation as well as their effects on meteorological fields such as pressure, temperature and wind over Tehran, especially at Mehr-Abad meteorological station.

One of the main challenges in tracking radio occultation (RO) signals of open loop approach is the excess Doppler estimation accuracy in LOWER TROPOSPHERE. Propagation of RO signals through the LOWER TROPOSPHERE with severe refractivity gradient results in high phase acceleration and low signal to noise ratio (SNR) signal. Because of the high refractivity in the LOWER moist TROPOSPHERE, the received RO signals by global navigation satellite system (GNSS) receivers can have large excess Doppler which may vary rapidly. Due to limitation on bandwidth and transmitted information to post processing, we can' t use very high sampling rate at GNSS receivers at LEO satellite. Therefore, try to enhance the accuracy of the Doppler predicted models in the satellite makes the GNSS-RO receivers by using efficiently frequency estimation method at GNSS receivers. In this regard, we investigate the event of RO signal and then the various frequency estimation methods to improve the estimates of the Doppler frequency in post processing are evaluated. The various frequency estimation methods are investigated from performance and computational complexity perspective. Via simulation, the excess Doppler estimation accuracy in post processing for different frequency estimation methods are compared by its root mean squared error. Based on simulation results, it is seen that both ESPRIT and Jacobsen with Bias schemes have the better performance and the estimation error of them are less than that of other methods.

Decreased precipitation and water scarcity are some of the important challenges in most parts of Iran in recent years and need a cost-effective solution based on high technical knowledge and equipment,To improve the meteorological conditions with modern technologies, one can use the high voltage injection air ionization equipment. The result efficiently can increase cloud-water vapor concentration nuclei due to generate duplex clouds. Recent theoretical and experimental work suggests that a charged atmosphere will have a LOWER nucleation barrier and will also help stabilize embryonic particles. This allows nucleation to occur at LOWER vapor concentrations and demonstrates that charged particle and molecular clusters, condensing around natural air ions can grow significantly faster than corresponding neutral clusters. The theoretical dynamic locating of the injection model also indicates that the nucleation rate of particles in the non-charged regions (without injection) is limited by the ion production rate from other sources such as cosmic rays. Thus, stable charged particle concentration by injection resulting from condensation and growth can survive long after ion injection and ionization. Theoretical study of dynamic locating of injection model establishes a relationship between the dynamic locating electromagnetic region of changing point ionization and precipitation microphysics. Mechanism TROPOSPHERE ionization and the Earth electromagnetic field properties cannot be excluded and there are established electrical effects on precipitation microphysics. Building on the relationship between changing points and ion injection the observations are extended to the realm of electromagnetic field microphysics by exploring this model. The injection produces positive /negative ions and free electrons. Many of these ions will be quickly lost to ion-ion recombination. Some of the ions escape recombination or reduced ion concentrations because the ionization produced by the electric field often is decreased because of the dust storm or wind that are generated in fixed changing points. As we presented in this article, dynamic locating of injection in the TROPOSPHERE is very important to provide additive effects increasing cloud concentrations and generating precipitation, which is the main achievement of this analytical-simulation work. In this analytical-simulation study, which is based on real and experimental data taken from the western and southwestern regions of Iran, we first review the background of the results obtained from the injection process and the effect of generating clouds in the TROPOSPHERE. Then we obtain the results of the same data with the theoretical effect of dynamic locating and simulation with injection at the electromagnetic changing points. The results of the previous data assuming maximization of utility have been recalculated and compared. The injection results are optimized by a dynamic locating technique that affects utility indices of maximum electromagnetic changing field between TROPOSPHERE-ground the earth thickness. Due to the increased generation of rainy clouds and maximization of their concentrations and increased local precipitation by the dynamic locating method at the injection site and the optimal operation of the equipment is investigated. The theoretical model that is presented shows that the theoretical dynamic locating of injection model by increasing in ionizing effect leads to a 15-20% increase in precipitation, decrease of 11% in temperature, increase of 10% in humidity.

Background and Aims: Various methods are used for treatment of open bite. The objective of this study was to investigate the effects of LOWER Anterior High Pull Headgear (LAHPH) appliance in Class I subjects with moderate open bite and high LOWER lip line.Materials and Methods: The study group was composed of 10 subjects with a mean age of 15.8±2.5 years and 3.05±0.07 mm moderate open bite. All the patients rejected or thognathic surgery. The treatment included extraction of upper and LOWER second premolars followed by leveling, banding, bonding, posterior space closure, and anterior retraction. After these procedures, the open bite was reduced to 2.04±1.17 mm. afterwards; LAHPH was applied for 18 hours per day for 8±2 months. LAHPH appliance was composed of High Pull Headgear and two hooks mounted on its inner bow. Two elastics (1.8, light, Dentaurum) connected the upper hooks on the inner bow to the LOWER hooks on the mandibular canines vertically. The forces produced by the prescribed elastics were 10 and 60 g during mouth closing and opening, respectively. Paired T-test was used to evaluate pre-and post-treatment outcomes.Results: The pre-and post-treatment cephalometric evaluations showed that the LAHPH reduced effectively the open bite of the patients to 0.15±1.7 mm (P<0.001).Conclusion: This appliance can be used as an acceptable method for closing the open bite in Class I subjects.

in this research, their effects on the flight of airplanes were investigated. The study area is the country of Iran, and the flight routes of Kermanshah, Ahvaz and BandarAbbas to Tehran. The research data includes maps of the Vertical Transect (profile) of the jet stream, the daily average of the Zonal wind (U-Wind) and meridional wind (V-Wind) components for the winter period of 2018 through NOAA/NCEP environmental databases. Also, flight route information was received from FlightRadar24 and Flightaware systems. First, by using Vertical Transect maps, the days containing strong U-Wind were extracted, and the average position of the core of the Jet Streams in the Zonal and meridional wind components, the Tropospheric level of 200 HP was detected. The list of flights was prepared, and the Zonal Wind maps were produced. Finally, the height of the flights was compared with the level of the currents of the Jet Streams, and the influence or lack of influence of the Jet Streams on the flights was studied. According to the results of the research, all the Jet Streams caused turbulence for all flights, and they caused a decrease in the speed of flights between Ahvaz and BandarAbbas to Tehran and an increase in the speed of flights between Kermanshah and Tehran according to the direction and type of Jet Streams. It was also found that all the Jet Streams had a speed of more than 90 knots, so the capacity to create tension and turbulence such as CAT was seen in them