IHOP horizontal convective rolls open cells morning transition boundary layer evolution
Abstract:
Despite research that has detailed the characteristics of nocturnal boundary layers
and convective boundary layers, the morning transition from the nocturnal to
the convective is still not well understood. This transition process often involves
the development of two- and three-dimensional convective structures, with three-
dimensional convection replacing two-dimensional, linear convection. Both this
transition, and the nature of the three-dimensional convective structures over land,
have not received a great deal of attention previously. The 21 June 2002 case
from the International H2 O Pro ject (IHOP 2002)was selected because of its lack of
strong synoptic and mesoscale forcings. Multiple instrument platforms, including
S-band and X-band radars, a 915 MHz wind profiler, rawinsondes, and aircraft,
were deployed to measure kinematic, thermodynamic, and moisture fields over a
limited domain. The data are analyzed to present a picture of the transition from
the nocturnal to the convective boundary layer, and the evolution from linear
convection to a mixture of disorganized and cellular convection.
