1. BAS microwave radiometer deployment at ALOMAR David Newnham david.newnham@bas.ac.uk 19 th March 2011

2. BAS microwave radiometer: ALOMAR project objectives To determine the altitude-dependent sources of NO x in the winter-time Arctic middle atmosphere. –in situ production by energetic electrons and protons versus indirect mechanisms e.g. vertical transport in the polar vortex. To quantify the short- and long-term impact on O 3 in the polar stratosphere and mesosphere of NO x generated by energetic electrons and protons. To determine NO, O 3, and CO volume mixing ratio profiles (40–90 km) over a complete Arctic winter (2011/12).

3. BAS microwave radiometer –Ground-based observations. –SIS mixer/CTS for high sensitivity/high resolution. –Simultaneous profiles of NO and O 3 from 30 km to 80 km (up to 8 km resolution) for all conditions. –Passive, continuous measurements (polar winter/diurnal). Methodology

4. A microwave radiometer for the remote sensing of nitric oxide and ozone in the middle atmosphere, P.J. Espy et al, Proc. SPIE 6362, 63620P-3 (2006) BAS microwave radiometer: Schematic diagram TaTa Antenna Band-pass filter 4-6 GHz IF amplifier SIS mixer V RF V IF Local oscillators (230/250 GHz) Down- Converters Low- pass filters  2.4 GHz Splitter WB CTS Atmospheric emission Amplifier NB CTS

5. ParameterNOOzone LO frequency / GHz255.25992 Down-converter frequency / MHz 3100.003280.00 Spectrometer # channels Centre frequency / GHz Bandwidth / MHz Channel spacing / kHz Narrow-band CTS 4096 1.35 40.35 9.85 Wide-band CTS 7500 2.10 215.07 28.68 Spectral range / GHz250.790 – 250.830249.772 – 249.987 Integration time~22 hrs/day (6 s per record) BAS microwave radiometer: 250 GHz measurements

6. BAS microwave radiometer: NO data inversion using MOLIERE code

7. BAS microwave radiometer: NO observations following a small geomagnetic storm

8. BAS microwave radiometer: O 3 data inversion using ARTS code

9. BAS microwave radiometer: O 3 and NO observations following a moderate geomagnetic storm Moderate Geomagnetic Storm (-79 Dst) – For comparison, Halloween Storm -600 A 30% depletion of O 3 after the storm Impact altitude range: 55 – 80 km Enhanced levels of NO tracking O 3 loss Propagate down to 55 km in 7 days Vertical velocity: 1-3 m/s Caused by particles originating in the radiation belt

10. BAS microwave radiometer: Planned polar deployments ALOMAR, Andøya, Norway (69°N, 16°E) –Summer 2011 - May 2012. –Co-located LIDAR, water vapour radiometer, radar, riometer, and radio- wave propagation observations. –Natural Environment Research Council (NERC, UK) Small Grant NE/I016767/1. –Collaborators: Pat Espy (NTNU), Craig Rodger (U. Otago), Annika Seppälä (FMI). Halley VI station, Antarctica (76°S, 27°W) –2013 – 2015+. –Co-located OH interferometer, sonde, riometer, radar, and radio-wave propagation observations. Halley VI build, February 2011 Halley VI radiometer/LIDAR double caboose arriving at BAS Cambridge, February 2011