Suborbital Research in the Mesosphere and Lower Thermosphere a New Window on the Turbopause Region

Transcription

1 Suborbital Research in the Mesosphere and Lower Thermosphere a New Window on the Turbopause Region Michael E. Summers George Mason University Mesosphere-Lower Thermosphere (MLT) Next-Gen Reusable Suborbital Access to MLT Opportunities and Challenges 1

2 The Mesosphere/Lower Thermosphere The Mesosphere/Lower Thermosphere region (~ km) of the atmosphere is perhaps the least sampled and most poorly understood region of the Earth s atmosphere. The MLT is above the region sampled by aircraft and balloons, and below that sampled by satellites. 2

3 The Mesosphere-Lower Thermosphere 3

4 In a Big Picture Sense the MLT encompasses: The transition region from turbulent control to diffusive control, i.e., the turbopause, The region where solar UV variability has its largest impact, The region where gravity waves dissipate momentum, and Earth s highest clouds (Polar Mesospheric Clouds). The MLT is a VERY complex region. 4

5 Noctilucent Clouds Noctilucent clouds, are tenuous water ice clouds that are observed in twilight most commonly at latitudes between 50 and 70 (north and south). They are the highest clouds in the Earth's atmosphere, located at km altitude. 5

6 Polar Mesospheric Clouds This image of Polar Mesospheric Clouds (PMC) is from the Aeronomy of Ice in the Mesosphere Cloud Imaging and Particle Size (AIM-CIPS) instrument on July 14, 2009 in the northern polar region. AIM Satellite View of PMCs The North Pole (90N) is in the center. Latitude bands of 80N, 70N, and 60N are also indicated by the light blue circles. Credit: Cloud Imaging and Particle Size Experiment data processing team at the University of Colorado s Laboratory for Atmospheric and Space Physics. 6

7 Polar Mesospheric Clouds PMCs manifest horizontal structure on scales of 1000s of km down to that of only a few km. These structures represent variability in either temperature or water vapor, or more likely both. This variability suggests that the Mesosphere exhibits weather driven by dynamical sources such as gravity waves and their breaking. But there may be dynamical instabilities as well. The observed horizontal variability in PMCs should be accompanied by variations in odd-hydrogen chemistry, and in particular O 3, at least on the larger scales. 7

8 Aeronomy of Ice in the Mesosphere (AIM) SOFIE & Model O 3 vs. Temperature!

9 What s needed to improve our understanding of the MLT High vertical resolution coincident mesospheric important chemically active trace gases such as H2O, O3, CO2, NO, etc., over a range of latitudes, seasons, and time of day. Better observational characterization of the dynamical structure of the mesosphere vertical and horizontal wind fields. With these types of observations we could improve our quantitative understanding of the interaction between the mesosphere and lower thermosphere. 9

10 Blue Origin and Projected Flight Paths 10

11 Virgin Galactic Spaceship 2

12 In situ Isotope Sampling (O 2, CO 2, CH 4, H 2 O, H 2, etc.) Fine-scale in situ sampling of mesospheric air, with a range of trace gases and respective isotope fractionation measurements, can provide information on the history of both the chemistry and transport of the air sample. This would be a new opportunity for the mesosphere! 12

13 Oxygen Isotopic Fractionation is Indicative of Source Regions 13

14 Advantages of MLT Observations from Suborbital Vehicles (1) Flight paths right through the middle of the MLT. (2) In situ sampling: key chemical trace gases, meteoritic dust, isotopes of elements in important trace gases, water vapor, sulfates, CO 2, etc. (3) Frequent flights: The MLT region is highly variable. The MLT has multiple-scale structures (water layers, turbulent regions and cells, polar vortex boundary structures, etc) in addition to seasonal and diurnal variation. 14

15 Opportunities, but Challenges as well. Technical issues: Pointing Accuracy, Control, Knowledge Vehicle Windows Ports for sampling Tourists Now is an important time for researchers to work with vehicle designers to develop requirements for needed observations. 15

16 Reusable Suborbital Research and Education Missions New window on the MLT! destinations/suborbit/conceptual%20feathered %20SpaceShipTwo%20flightsmall.jpg 16

17 Backup Slides 17

18 Factors Influencing PMC Formation Processes Affecting PMCs Ionization Sources Cosmic Dust Influx H 2 O / H 2 SO 4 Crystals hυ NO e - Nucleation Region Ablation 88 km Idealized H 2 O Mixing Ratio Profile with and without PMC Presence Visible Cloud Ice Crystal Growth 83 km Processes depicted with arrows are incorporated into models used in AIM analysis. NRL 2-D Model Sedimentation Sublimation Temperature Profile CARMA Microphysical Model H 2 O Gravity Waves Upwelling Due to their close connection to water and temperature, PMCs are thought to be climate indicators. 18

19 Game Changing Aspects Of Next-Gen Suborbital High Flight Rates. Extremely Low Cost. Researchers Can Fly With Their Gear.