The Structure of Baroclinic Zones Using TIROS-N Temperature Retrievals

Abstract

Case studies are used to examine the horizontal and vertical temperature structure in baroclinic zones for three synoptic situations. The studies compare analyses of 1000?500 mb and 700?300 mb thicknesses made from satellite data only with National Meteorological Center (NMC) analyses made from conventional data. In addition, isentropic cross sections across baroclinic zones are shown using data from each of three sources; radiosondes, satellite soundings, and NMC global analyses. These cross sections demonstrate that the satellite soundings generally represent the baroclinic zones at least as well as the NMC analyses, with thermal wind speed maxima that are comparable with those obtained from either the radiosonde or NMC analysis cross sections. However, the computed speed maxima from the satellite data were achieved because the soundings depicted the frontal zones as being steeper than in the radiosonde versions. That condition, in which the principal horizontal temperature gradients were aligned in a nearly vertical fashion in the satellite data cross sections, thus contributed to the vertical summation of the gradients, even though temperature gradients at individual levels were usually weaker than the corresponding radiosonde gradients.