2. Undertake model calculations to assess the importance of NLCs such as sensitivity studies on climate (see e.g., Herman & Goldberg, 1978, p. 243f, in particular the study of Hummel and Olivero (1976) referenced therein). 3. Examine the feasibility of NLC observations by satellites during time of rocket launches, such as the recent Atlas-Centaur launch. If the results of item 2 above show that NLCs have some significance, it is reasonable to consider a broader program, including the following items. 4. Studies of (natural NLCs to determine their origin, composition, microphysics and spatial/temporal characteristics. 5. Investigate ambient mesospheric water vapor concentrations from the standpoint of global morphology and variability, and also the mesospheric circulation, both from the standpoint of correlating or predicting with natural NLCs. In addition, several classes of experiments can be designed relative to the formation of long-lasting contrails or artificial noctilucent clouds: 6. Monitor rocket launches of opportunity for high-altitude cloud formation, contrails, and related phenomena. 7. Execute a mesospheric water release to generate an artificial noctilucent cloud for study. 8. Investigate water vapor condensation in adiabatically expanding rocket plumes, to deduce eventual particle concentrations, size, and momentum. The experimental tools that might be utilized in these studies may be divided into the following categories: 1. Cloud detection and characterization (a) Twilight photography/photometry from the ground. (b) Limb scanning photometry from satellites in place. (c) High resolution spectral and polarization measurement of reflected light (from the ground or from rockets). (d) Rocket sampling of clouds using various collection surfaces/filters to detect solid and volatile materials. (e) Electron microscopy/chemical analysis of NLC samples. (f) In situ optical sizing instruments and condensation nuclei counters. 2. Related atmospheric parameters (a) Air temperatures using rocket grenades (or infrared emissions).
RkJQdWJsaXNoZXIy MTU5NjU0Mg==