The Colorado Lee Wave Program

Abstract

The National Center for Atmospheric Research has, for the last two winters, undertaken investigations of lee waves and orographic wind phenomena in the Front Range of the Rocky Mountains near Boulder, Colorado. During February 1968 the observational program was conducted in cooperation with the Air Force HI-CAT Program, the Canadian National Research Council, ESSA, The Explorer’s Research Corporation and the White Sands Missile Range. All of these agencies contributed aircraft and personnel for operation of a joint flight program aimed at obtaining, for the first time, synchronous quantitative data on lee waves and associated turbulence phenomena from the surface to 70,000 feet above representative Rocky Mountain topography. To an extent the program was successful, in that several cases of moderate amplitude lee waves were observed with 3 or 4 aircraft. Two of these have been partially analyzed and some results are presented. The most significant result of the 1968 program was the large amplitude of both standing gravity waves and turbulence in the stratospheric levels sampled by the HI-CAT U-2. No complete explanation of these effects is offered, but a relation recently proposed by Scorer appears relevant.