Tropospheric Airborne Meteorological Data Reporting (TAMDAR) Sensor Eddy Dissipation Rate Performance in UND Citation II Flight Tests

The Tropospheric Airborne Meteorological Data Reporting (TAMDAR) sensor is designed to measure winds, temperature, humidity, turbulence and icing from regional commercial aircraft. TAMDAR is intended to supply both soundings and en-route data at altitudes and locations that will complement current MDCRS (Meteorological Data Collection and Reporting System) and AMDAR (Aircraft Meteorological Data Report) systems. For data validation purposes, the TAMDAR sensor was installed on the University of North Dakota (UND) Cessna Citation II. NASA Langley Research Center and its research partners from the University of North Dakota (UND) and the National Center for Atmospheric Research (NCAR) are conducting flight tests on the UND Citation II to compare the TAMDAR sensor's eddy dissipation rate (EDR) data with two other sources: calculations of EDR made at NCAR in each wind component using high-rate data from the Citation, and direct EDR measurements from the Citation's on-board EDR system. Both on-board systems (TAMDAR and UND) assume that turbulence is isotropic, and both estimate EDR using an implementation of the MacCready algorithm that is applied to the fluctuating longitudinal component of the wind. A modified TAMDAR sensor with high data-rate outputs has been developed for these tests. This study entails a statistical analysis of EDR for over several separate flights as well as a detailed analysis of significant turbulence encounters.