Polar thermosphere-stratosphere photochemical coupling experiment: Two rocket measurements in polar winter at 69°N

Abstract

Two rocket experiments were carried out just before and after the polar night at Andoya (69°N), Norway to investigate transport of nitric oxide produced by auroral processes into the middle atmosphere and its influence on the ozone chemistry. Nitric oxide densities of (2-5) × 10 8 cm -3 found in the 70-90 km region are one to two orders of magnitude larger than those at middle latitudes. The measured density profiles appear to agree semiquantitatively with model simulations which includes auroral processes. The influence on ozone densities in the 70-90 km region due to such enhanced nitric oxide abundance is found to be still insignificant as compared to that due to transport in the middle of February, one month after the end of polar night and one month before the spring equinox. The larger ozone densities found in February (in spite of longer sunlit duration) than in November in the 40-60 km region again support predominance of transport over photochemical destruction.

Measurements of meteor smoke particles during the ECOMA-2006 campaign: 2. Results

“…This shows that our derived NO-number densities are larger than the corresponding results from the HALOE-climatology by a factor of 6. However, a large variability of NO with time, particularly at high latitudes, was reported by different authors and is well known (Ackerman, 1979;Iwagami et al, 1998;Vitt et al, 2000).…”

Measurement of Negative Ions in the Lower Ionosphere (D-Layer) in the Polar Region.

“…On the other hand, the dip of ozone density which appears around 76-78 km measured at Pocker Flat, Alaska, before sunrise (Green et al,1986) coincides rather well with the upper end height ofthe negative ion layer in the D-region at Andoya. The ozone density measured by Rikkyo University group by a sensor on board the same rockethas indicated a clear depletion of ozone density around 78 km (Iwagami et al, 1994).These facts would be related to the situation inside open geomagnetic field where high energetic electrons are rich while negative ions are deficient. In such a situation, the reactions (2), (15)-(23), which favor the ozone protection, are not effective but the reactions (4), (24)-{30) which proceed the ozone destruction can be applied.…”

“…The one of the objectives of the present observation in the arctic region was to prove the effect of NO created by high energetic particles at h > 90 km in the polar region (Iwagami et al, 1994). In the winter time of arctic region, NO cannot be dissociated by solar light and falls down to the ozone layer (Solomon and Garcia, 1984) and destroy ozone there.…”

Mesospheric Ozone Density Profile in the Polar Region.

“…A brief explanation of the instruments on board the rockets has been presented elsewhere (Iwagami et al, 1994).…”