CUAD: Constellation for Upper Atmosphere Dynamics
Abstract
The dynamical coupling of lower to upper atmosphere has become an intense research topic. It is now quite clear that the lower atmosphere continuously imprints its dynamical state onto the upper atmosphere in the form of winds and waves. This signature from the dense lower atmosphere dynamically expands into the thin upper atmosphere like tsunamis coming ashore. The resulting waves and winds, if adequately observed, could be used not only to reveal their effects on the upper atmosphere, but to help monitor and forecast the evolution of lower atmosphere weather. This would require global observation from orbit, quite a challenge due to the required space and time resolution. Until now, such observations have been limited to Earth limb sensors (ex: GPS-RO and thermal imagers), which have an intrinsic horizontal resolution of 100 to 200 km. As a result, wave field measurements are smeared in time and space to the point of limited value for forecasting. But, if these upper atmosphere signatures could be resolved, it has been shown by a variety of groups that those wave and wind fields would act as powerful boundary conditions on forecast models. We show that new and enabling technologies, and a novel observation technique (gas filtered Doppler scanning, see Gordley and Marshall 2011), now make it possible to observe these parameters at resolutions required to fill this measurement deficiency. The proposed Constellation for Upper Atmosphere Dynamics (CUAD) could observe the upper atmosphere on a global scale at a resolution sufficient to resolve the dynamical connection of lower to upper atmosphere. This can now be accomplished with four types of simple static broadband emission imagers, two of which are gas filtered. The first sensor is a gas filtered broadband nadir emission imager, HATS (High Altitude Thermal Sounder). The second is a simple broadband limb emission radiometer LCER (Limb CO2 Emission Radiometer). The third is a gas filtered limb emission radiometer, DWTS (Doppler Wind and Temperature Sounder). The fourth is a star field limb imager, TStar (Temperature sounder using Star field images). These 4 imagers have a unique synergistic connection that eliminates the need for on-board calibration systems. Plus, each sensor technique, though new in its implementation, has space heritage. Finally, we show results of rigorous performance estimates, and describe how modern detector FPAs, satellite bus ADCS, processor power and downlink bandwidth have come together to enable a complete system calibration anchored to the refractive index of air. This dramatically simplifies the hardware, and insures reliable observation of long-term trends. The talk will conclude with a list of major CUAD challenges and research needed for their solutions. Gordley, L. L., Benjamin T. Marshall, "Doppler Wind and Temperature Sounder: A new approach using gas filter correlation radiometry", JARS, Vol 5, 2011.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E1255G