The quality of pressure distribution over the atmosphere of the sea level and geopotential altitude at different atmosphere layers affect on many climate and meteorology phenomena of the earth surface. One of the important meteorology phenomenon is the occurrence of frost phenomenon especially late spring frost. In this surrey, occurring late spring frost days and minimum temperature during the...

Global warming is increasing permanently, because the concentration of CO2 in the atmosphere is rising continuously. According to National Oceanographic and Atmospheric Administration, the concentration of CO2 in the atmosphere was 407 ppm in June 2016 and 413 ppm in April 2017 as a last record for now. If the effects of other greenhouse gases, such as CH4, N<su...

tetrahedrane is most strained and the smallest cage compound. it attracts organic chemists because ofits unusual bonding nature and highly symmetrical structure. however, many efforts to isolate theparent tetrahedrane have been unsuccessful because of the high reactivity and very short lifetimecaused by the strain in this molecule. modeling of molecules for determination of structuralproperties...

particulate matters commonly found dispersed in the atmosphere are composed of a large variety of substances. dustfall is the usual index of particles in the size range greater than 10 m. two semi automated so2 sampling units were installed in tehran university campus (from 21 january 1973 to 22 dec. 1974) and gheitarieh area (from 23 august to 23 oct. 1974) hydrogen peroxide method was used fo...

Long-baseline interferometry at optical and near-infrared wavelengths is an emerging technology which is quickly becoming a useful tool to investigate stellar atmospheres and to compare observations with models. Stellar atmosphere models have so far mainly been constrained by comparisons with stellar spectra which are integrated over the stellar disks. Interferometric observations provide spati...

a watershed management program is usually based on the results of watershed modeling. accurate modeling results are decided by the appropriate parameters and input data. precipitation is the most important input for watershed modeling. precipitation characteristics usually exhibit significant spatial variation, even within small watersheds. therefore, properly describing the spatial variation o...

Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphe...

A new approach for the study of the pollution of operating theatre atmospheres by volatile anaesthetic agents is described. Disadvantages of earlier work are discussed together with ways in which they may be overcome. Some pitfalls in analysis, sampling and standardization are indicated and some hazards of incorrect data interpretation are shown. The need for a cautious and critical attitude is...