Mixed But Nothing Mixing: Multiple Layers as Detected by Doppler LiDAR and High Resolution Soundings in New York State

Analysis of several years’ worth of high resolution soundings and LiDAR observations made at Albany NY and at other profiler sites of the New York State Mesonet (NYSM) show active and passive convective boundary layers (CBLs) evolving over the diurnal cycle. The complexity of this BL lifecycle is illustrated in Figure 1, which shows the presence and persistence of multiple layers over the course of a diurnal cycle. Such layers of speed and directional shear are evident throughout the day, beginning with the evening transition, persisting overnight (as residual BLs) atop the (at times intermittent) stable BL, and continuing through an evolving daytime CBL. We show that this fine structure of the lower atmosphere is not captured by operational or experimental numerical weather prediction models, and is frequently present (and detectable by NYSM profilers) in the valley regions of New York State. The crucial question is: what maintains the multiple-layer structure and how/when is the surface linked to these elevated layers? NYSM profiter and surface flux data are interrogated to examine the connection between the surface and the passive/active mixed layers.