Diurnal variation in middle atmospheric ozone by ground based microwave radiometry at Ny-Ålesund over 1 year

Abstract

Abstract. We present an analysis of the diurnal ozone cycle from one year of continuous ozone measurements from two ground based microwave radiometers in the Arctic. The instruments GROMOS-C and OZORAM have been located at the AWIPEV research base at Ny-Ålesund, Svalbard (79• E) and gathered a comprehensive time series of middle atmospheric ozone profiles with a high time resolution. An intercomparison was performed with EOS MLS and ozone sonde measurements and simulations with SD-WACCM. The measured datasets were used to study the photochemically induced diurnal cycle of ozone 5 in the stratosphere and mesosphere. Throughout the year the insolation in the Arctic changes drastically from polar night to polar day. Accordingly, the seasonal variations in the diurnal ozone cycle are large. In the stratosphere we found a diurnal cycle throughout the whole period of polar day with the largest amplitude in April. In the mesosphere a diurnal cycle was detected in spring and fall. SD-WACCM has proved to well capture the diurnal cycle and was therefore used to analyse the chemical reaction rates of ozone production and loss at equinox and summer solstice. Furthermore GROMOS-C proofed capable of 10 measuring the tertiary ozone layer above Ny-Ålesund in winter.

Investigation of Arctic middle-atmospheric dynamics using 3 years of H<sub>2</sub>O and O<sub>3</sub> measurements from microwave radiometers at Ny-Ålesund

“…8). In the mesosphere a diurnal cycle was detected in spring and autumn whereas in the stratosphere at 10 hPa the diurnal variation is seen in mid summer during the period of polar day (Schranz et al, 2018).…”

“…Therefore GROMOS-C observes subsequently in the four cardinal directions (N-E-S-W) at 22 • elevation with a sampling time of 4 seconds. At the Arctic location of Ny-Ålesund this allows observations in and outside of the polar vortex if the vortex edge is close to Ny-Ålesund (Schranz et al, 2018). The retrieval of ozone and wind is performed with Qpack (Eriksson et al, 2005) and ARTS2 (Eriksson et al, 2011), using an optimal estimation method (Rodgers, 1976).…”

Interannual Variation of Upper Stratospheric Ozone in the Northern Midlatitudes in Early Winter Caused by Planetary Waves

“…In contrast to many other observation methods, observations by millimeter-wave radiometer (MWR) make it possible to obtain ozone mixing ratios with high temporal resolution (~1 hr) over a wide altitude range from the stratosphere to the lower mesosphere (e.g., Moreira et al, 2016;Parrish et al, 2014;Schranz et al, 2018;Solomonov et al, 2012). The largest positive ozone trend after 2000 was observed around 1 hPa in the Northern midlatitude, owing mainly to a decline in the atmospheric abundance of chlorine (WMO, 2018); however, factors that cause interannual ozone variations at that pressure level have been examined to a lesser degree.…”