HAO Colloquium - Cheng Sheng, HAO

Modeling Nitric Oxide in the Upper Atmosphere With TIEGCM

Nitric oxide (NO) is a minor species in the upper atmosphere, but both chemically and radiatively active. NO cooling at 5.3 μm is the primary mechanism regulating the thermosphere during geomagnetic storms. Previous studies based on the TIEGCM have reported that the modeled neutral density recovery after geomagnetic storms was much slower than that derived from satellite measurements. Uncertainty in the modeled NO density is speculated to be one of the main reasons causing the model-data discrepancy since NO plays a major role in thermospheric cooling. This has motivated us to revisit the NO density in TIEGCM simulations. First, I will discuss NO density at low latitudes where NO production is mainly controlled by solar EUV and soft X-rays. Our results show that NO density at and below its peak height is also subject to photolysis and the tidal forcing from below. Second, I will examine storm-time NO enhancements at middle latitudes by utilizing both GUVI measurements and TIEGCM simulations. 

Building:

Room Number: 
2126

Type of event:

Will this event be webcast to the public by NCAR|UCAR?: 
Calendar Timing: 
Wednesday, December 6, 2017 - 1:30pm to 2:30pm