author = "Mendon{\c{c}}a, Fernando de",
          affiliation = "{Comiss{\~a}o Nacional de Atividades Espaciais}",
                title = "Ionospheric electron content and variations measured by doppler 
                         shifts in satellite transmissions",
              journal = "Journal of Geophysical Research",
                 year = "1962",
               volume = "67",
               number = "6",
                pages = "2315--2337",
                month = "June",
                 note = "{google Acad{\^e}mico: 68} and {Web of Scince: 11}",
             abstract = "A method is derived for calculating ionospheric electron content 
                         by comparison of the Doppler shifts imparted to two harmonically 
                         related frequencies transmitted from a satellite. This Doppler 
                         method is applied in the analysis of many passages of the 
                         satellite Transit 2-A (1960\η1) during the months of July 
                         through October 1960. The observations were made at Stanford, 
                         California, on the frequencies of 54 Mc/s and its sixth harmonic. 
                         Differences in the electron content of 25 per cent between two 
                         subionospheric points separated by as little as 1000 km were 
                         observed on several passages during magnetically quiet days. On 
                         some magnetically disturbed days these differences increased to 
                         over 50 per cent for the same separation. A very strong magnetic 
                         storm is shown to decrease the early-afternoon electron content to 
                         almost a normal nighttime value over the range of latitudes 
                         surveyed. Other less intense storms are observed to decrease the 
                         electron content to the north and to increase it to the south of 
                         the observer. The day-to-day variations of electron content at a 
                         given latitude on magnetically quiet days are observed to be about 
                         ▒15 per cent from the mean; however, less frequently, variations 
                         as large as ▒50 per cent were observed. Unlike the variations on 
                         the magnetically disturbed days, these variations did not seem to 
                         modify the horizontal gradients normally found.",
                  doi = "10.1029/JZ067i006p0231",
                  url = "http://dx.doi.org/10.1029/JZ067i006p0231",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
        urlaccessdate = "14 ago. 2020"