  Horizontal currents in the Bay of Bengal were measured on eight cruises
covering a total of 8600 $km$ using a 300 $kHz$ Acoustic Doppler Current
Profiler (ADCP). The cruises are distributed over multiple seasons and regions
of the Bay. Horizontal wavenumber spectra of these currents over depths of
12--54 m and wavelengths from 2--400 km were decomposed into vortical and
divergent components assuming isotropy. An average of across and along track
spectra over all cruises shows that the spectral slope of horizontal kinetic
energy for wavelengths of 10--80 $km$ scales with an exponent of $-1.7 \pm
0.05$, which transitions to steeper scaling for wavelengths above 80 $km$. The
rotational component is significantly larger than the divergent component at
scales greater than 80 $km$, while the two are comparable for smaller
wavelengths. The measurements show a fair amount of variability and spectral
levels vary between cruises by about a factor of 5 over 10--100 $km$. Velocity
differences over 10--80 $km$ show probability density functions and structure
functions with stretched exponential behavior and anomalous scaling.
Comparisons with the Garrett-Munk internal wave spectrum indicate that
inertia-gravity waves account for only a small fraction of the kinetic energy
except at the smallest scales. These constraints suggest that the near-surface
flow in the Bay is primarily balanced and follows a forward enstrophy transfer
quasigeostrophic regime for wavelengths greater than approximately 80 km, with
a larger role for unbalanced rotating stratified turbulence and internal waves
at smaller scales.
