author = "Li, G. and Ning, B. and Liu, L. and Abdu, Mangalathayil Ali and 
                         Wan, W. and Hu, L.",
          affiliation = "{Chinese Academy of Sciences} and {Chinese Academy of Sciences} 
                         and {Chinese Academy of Sciences} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {} and {Chinese Academy of 
                title = "Shear in the zonal drifts of 3m irregularities inside spread F 
                         plumes observed over Sanya",
              journal = "Journal of Geophysical Research A: Space Physics",
                 year = "2015",
               volume = "120",
               number = "9",
                pages = "8146--8154",
                month = "Sept.",
             keywords = "A vertical shear in zonal drifts of ESF 3 m irregularities is 
                         detected at low latitude, Better knowledge of plasma zonal drift 
                         shear at low latitude are needed, The shear centers at an apex 
                         altitude of 650 km over dip equator.",
             abstract = "Incoherent scatter radars near magnetic equator regularly measured 
                         a vertical shear in zonal drifts of the evening background plasma, 
                         with westward drifts below the equatorial F region peak and 
                         eastward drifts above. We report here observations of a clear 
                         shear structure in the zonal drifts of 3m irregularities inside 
                         spread F (SF) backscatter plumes measured with a 47.5MHz coherent 
                         scatter radar operated at a low-latitude site Sanya (18.4N, 
                         109.6E; dip latitude 12.8N). The radar interferometry analysis on 
                         the zonal drifts of the 3m irregularities yields results 
                         consistent with that estimated from the irregularity echo Doppler 
                         velocity measurements with multiple beams. It is shown that the SF 
                         3m irregularities move westward at the lowest altitudes, while at 
                         higher altitudes in the same SF plume structure, the 3m 
                         irregularities drift eastward. One interesting point is that the 
                         vertical shear of zonal drifts was centered at ~300km altitude 
                         over Sanya, which maps to an apex altitude of ~650km at magnetic 
                         equator and is thus apparently higher than the apex altitudes 
                         250-450km where the zonal velocity shear has usually been 
                         observed. Analysis of the observations suggests that while the 
                         possibility of local generation of the shear flow of the 
                         irregularities can exist, the possibility of a plasma vortex 
                         appearing at relative high altitudes causing the zonal drift shear 
                         of F region 3m irregularities measured over Sanya cannot be 
                         totally ruled out.",
                  doi = "10.1002/2015JA021497",
                  url = "http://dx.doi.org/10.1002/2015JA021497",
                 issn = "2169-9402",
             language = "en",
        urlaccessdate = "27 nov. 2020"