Orbiter ion mass spectrometer measurements, as available in the UADS d
ata files are used to study the response of dayside Venus ions at vari
ous altitudes to solar wind dynamic pressure, P-SW. Ion densities belo
w about 200 km are not affected by changes in P-SW. At altitudes above
200 km the ions get abruptly depleted with increase in P-SW, and this
abrupt depletion occurs at lower altitudes when P-SW is high. At lowe
r P-SW, the depletion occurs at higher altitudes. The effect is simila
r for all ions. These results are also compared with the empirical rel
ationship observed by Brace et al. (1980) between the ionopause altitu
de and P-SW from electron density measurements on orbiter electron tem
perature probe.