The turbulent structure of the lake breeze penetration and subsequent development of the thermal internal boundary layer (TIBL) was observed using a kytoon-mounted ultrasonic anemometer-thermometer. The lake breeze penetrated with an upward rolling motion associated with the upward flow near the lake breeze front. After the lake breeze front passed, the behaviors of the velocity and temperature at the top of the lake breeze layer were similar to those found in convective boundary layers (CBL). Comparing %I@, 3 %.lW* and a,,,/~ * between the present observation of TIBL development after the passage of the lake breeze front and CBL data from the literature, the uJBiB* values showed reasonable agreement; however, uJw* and c,Jw* had smaller values in the TIBL than in the CBL at higher altitudes. This is due to the differences in the mean velocity profiles. While the CBL has a uniform velocity profile, the TIBL has a peak at lower elevation due to the lake breeze penetration; the velocity then decreases with height.

A field experiment to measure the turbulent structure ofthe internal boundary layer near the shore was conducted using three instrumented meteorological poles, a kytoon, and a crane-mounted ultrasonic anemometer-thermometer, as well as three reference ultrasonic anemometer-thermometers positioned near the poles. Part 1 of this study gives the explicit details and general characteristics for one run of the experiment. Part 2 (Ohara and Ogawa, 1984) will present a similarity and energy budget analysis. The mean velocity profiles showed that there was wind speed acceleration due to the sea-land temperature difference. In addition, the velocity profiles consisted ofthree distinct regions; the region near the ground had the largest gradient followed by a transition zone which had a small velocity gradient, while above, the profile resembled the oncoming sea breeze. In general, the turbulence was greatest near the shore, gradually decreasing inland. The lowest region had large turbulence intensities and the transition region had some intermittent turbulence characteristics between the lower strong unstable layer and the relatively turbulent-free region above. n nm S(n) u u', w' x z =o 0, 0' I L f )I2 ( 1". ", w frequency (cycle s -') Nomenclature frequency of logarithmic spectral peak (cycle s -') power spectrum (m2 s -* cycle-') mean velocity in the longitudinal direction (m s -') fluctuating wind component in the longitudinal and vertical directions (m shorizontal distance perpendicular to the coast line (m) height above the ground (m) roughness length (m) mean and fluctuating component of potential temperature ("C) wavelength ( = U/n) (m) wavelength corresponding to n,,, ( = V/n,) (m) standard deviation of wind velocity (m s-*) reference value at z = 4.3 m component in the longitudinal, lateral, and vertical directions, respectively. ')