During the spring and spring and summer of 2002, a unique, collaborative effort was made to compare measurements of natural rain made with different types of instruments. The instruments, including several types of disdrometers, a vertically pointing X-band radar (3.2 cm wavelength), the NOAA Aeronomy Laboratory 2835 MHz (10.6 cm wavelength) wind profiler, and an anemometer, were collocated at the Iowa City Municipal Airport in Iowa City, I.A, which is under the umbrella of the National Weather Service WSR-88D in Davenport, IA (KDVN). Much research has focused on the role of horizontal reflectivity variability on radar-rainfall errors and uncertainties. However, the role of vertical variability has received relatively little attention, although previous work has shown that corrections to the vertical profile of reflectivity can markedly improve radar-rainfall estimates. In this work, we focus on comparison of the vertical profiles of reflectivity observed by the 2835 MHz profiler and the KDVN WSR-88D. Since we have nearly continuous observations by the profiler, we consider optimal temporal integration scales for comparison with the WSR-88D. Using second-order moments, we compare the vertical variability of reflectivity as seen by the two instruments.