IHOP Update

IHOP, an NCAR-led experiment, took place in May and June over the Southern Great Plains. In one of the largest-ever field experiments in North America, scientists from the U.S. and several foreign countries teamed to improve characterization of the four-dimensional distribution of water vapor and its application to improving the understanding and prediction of thunderstorms. Airflow, temperature, and humidity data were collected with a large armada of aircraft and ground-based mobile sensors and fixed-base remote and in-situ sensors. NSSL's contribution to the armada included a SMART Radar, a mobile CLASS ballooning vehicle, a camera vehicle, 9 mobile mesonets, an NSSL field coordination vehicle, an NSSL scout vehicle, and a technicians vehicle to provide in-field maintenance.

NSSL's ground-based platforms focused on mesoscale boundaries and convection initiation on a total of 12 mission days. Of these 12 cases, cumulonimbus clouds developed within the intensive observing region along a boundary on 2 days, towering cumuli on 5 days, and no significant convection on 5 days. An additional 3 days were spent sampling boundary layer evolution from sunrise to early afternoon around a cluster of fixed IHOP sensors in the Oklahoma Panhandle. The 24 May case featured the first known observed evolution of a dryline, cold front, and their triple point intersection using highresolution mobile sensors. Valuable data were also collected on sharply defined drylines, slow moving cold fronts, and the triple point intersection of an outflow boundary and a convergence line.

by Conrad Ziegler