Because the U.S. landscape is becoming increasingly urban, it is desirable to better understand the processes of turbulent momentum and scalar transport over urban terrain. In an attempt to better characterize the detailed physical mechanisms of momentum and scalar variance transport in an urban roughness sublayer (URSL), synchronized hot-wire and photo-ionization detector measurements were taken near the center of the grid of simulated buildings at the Mock Urban Setting Test (MUST) conducted at the Dugway Proving Ground, UT (September 2001).  The test site consisted of an unstaggered 12 x 10 array of 12.2 m x 2.6 m x 2.6 m shipping containers (l_p=0.13, l_f1=0.11, l_f2=0.03). The surrounding terrain consisted of a flat surface with a low, nearly uniform covering of sagebrush.  The shipping containers were arranged such that an aligned wind angle produced an isolated roughness flow regime, while off-angle winds generated a wake interference regime.  Spatially and temporally resolved turbulence measurements were taken near the center of the array at 0.5H above the building height, H, i.e., within a well-developed roughness sublayer.  These measurements were acquired using the Scalar Transport Probe (STP) designed and built by Metzger and Klewicki (1999).  The STP consists of a compact array of four hot-wire sensors surrounding two photo-ionization detectors.  This arrangement allows high-resolution measurements of u (axial velocity), w (surface normal velocity), and c (concentration), as well as the gradients of these quantities in the z direction.  These measurements make it possible to obtain time series data of several terms in the axial stress transport equation,

and scalar variance transport equation,

shown here for 2-D (in the mean), statistically stationary flow.  In addition to the STP measurements, background URSL turbulence data were acquired using an array of three-dimensional sonic anemometers mounted on a 5m tower located nearby within the array.  Mean wind profiles of the surface layer flow approaching the array were acquired with a minisodar.  Results are presented for a near-neutral and stably stratified surface layer, and for a range of incident flow angles.  Turbulence results include long time statistics of the axial, normal and Reynolds shear stresses and their spectra, as well a number of the terms in the above equations.  Owing to the likely effect of the building wakes on the turbulent length scales within the URSL flow, particular attention is paid to the spectra of the vertical transport terms and their comparison to similar spectra taken in an undisturbed ASL over homogeneous terrain.