Response of Atomic Hydrogen and Oxygen to Solar Radiation Changes: Measurements and Simulations.
Prof. Martin Riese
Dr. Martin Kaufmann
The scientific objective of this proposal is the analysis of the energy budget of the upper mesosphere - lower thermosphere (UMLT) region. The solar UV-forcing in this region is highly variable (e.g. about 27% for Lyman-α and 7% for the Schumann- Runge-continuum during the 27-day solar cycle). This implies that the variability of the UMLT region is significantly in uenced by solar variability. The basis of this analysis will be the global and temporal distribution of atomic oxygen and hydrogen derived from various instruments onboard the ENVISAT satellite. Daytime atomic oxygen and hydrogen will be derived using O2(1Δ) and OH(v) Meinel bands measured by the SCIAMACHY instrument. During the night atomic oxygen data will be derived from SCIAMACHY OH(v) and O(1S) data. A novelty will be the derivation of atomic hydrogen at nighttime from the combination of GOMOS O3 and SCIAMACHY OH(v) data. This method is applied to satellite data for the first time and will yield global elds of atomic hydrogen with unprecedented signal-to-noise ratio. With this dataset we will calculate chemical heating rates on a global scale and for the varying solar activity. This data will be used to verify and to improve the elds of the 3-d interactive chemical dynamical model ROSE [Smith et al., 2003].