IHOP, an NCAR-led experiment and one of the largest-ever field experiments in North America, took place in May and June 2002 over the Southern Great Plains. 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 up to 6 aircraft and 20 ground-based mobile sensors. Many fixed-base remote and in-situ measurements were also obtained.
NSSL's contribution to the armada included a SMART radar (SR-1), a mobile CLASS ballooning vehicle, 9 mobile mesonets, and a camera vehicle. In tight coordination with all of IHOP's other mobile assets, NSSL's ground-based platforms focused on mesoscale boundaries and convection initiation (CI) on a total of 12 mission days during IHOP. Of these 12 CI cases, cumulonimbus clouds developed within the intensive observing region (IOR) along a boundary on 2 days. In five other CI cases, the deepest clouds to develop in the IOR were towering cumuli. The five remaining CI missions were spent studying boundaries that did not produce significant convection. 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 high resolution mobile sensors. Valuable data were also collected on sharply defined drylines, slow moving cold fronts, and the triple point interesection of an outflow boundary and a horizontal convective roll.