Combined wind measurements by two different lidar instruments in the Arctic middle atmosphere

Abstract

Abstract. During a joint campaign in January 2009, the Rayleigh/Mie/Raman (RMR) lidar and the sodium lidar at the ALOMAR Observatory (69 • N, 16 • E) in Northern Norway were operated simultaneously for more than 40 h, collecting data for wind measurements in the middle atmosphere from 30 up to 110 km altitude. As both lidars share the same receiving telescopes, the upper altitude range of the RMR lidar and the lower altitude range of the sodium lidar overlap in the altitude region of ≈ 80-85 km. For this overlap region we are thus able to present the first simultaneous wind measurements derived from two different lidar instruments. The comparison of winds derived by RMR and sodium lidar is excellent for long integration times of 10 h as well as shorter ones of 1 h. Combination of data from both lidars allows identifying wavy structures between 30 and 110 km altitude, whose amplitudes increase with height. We have also performed vertical wind measurements and measurements of the same horizontal wind component using two independent lasers and telescopes of the RMR lidar and show how to use this data to calibrate and validate the wind retrieval. For the latter configuration we found a good agreement of the results but also identified inhomogeneities in the horizontal wind at about 55 km altitude of up to 20 ms −1 for an integration time of nearly 4 h. Such small-scale inhomogeneities in the horizontal wind field are an essential challenge when comparing data from different instruments.

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region

“…Hooper et al, 2008;Lee et al, 2014) provide additional coverage over 0-20 km. Under clear-sky conditions the Rayleigh-Mie-Raman (RMR) lidar (Baumgarten, 2010;Hildebrand et al, 2012) measures winds throughout the middle atmosphere above Andenes, northern Norway but requires complex laser transmission and detection equipment and is not portable. Ground-based Doppler lidars measure tropospheric and lower stratospheric winds (Gentry et al, 2000), with possible extension up to 50 km (Souprayen et al, 1999) and sodium lidars cover the altitude range 85-100 km (Williams et al, 2004).…”

Simultaneous and co-located wind measurements in the middle atmosphere by lidar and rocket-borne techniques

“…DoRIS is part of the Rayleigh/Mie/Raman (RMR) lidar of the ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research) observatory in Northern Norway (69 • N), which actually consists of a double lidar system and allows temperatures and winds to be measured in two directions simultaneously (von Zahn et al, 2000). A first comparison of winds measured by DoRIS and by a sodium lidar, also located at ALOMAR, showed good agreement in the limited height region of overlapping measurements around 80-85 km (Hildebrand et al, 2012). ALOMAR is located very close to the Andøya Space Center (ASC), which offers the unique opportunity to compare winds from DoRIS with in situ measurements applying rocket-borne techniques.…”

Validation of middle-atmospheric wind in observations and models

“…Validations of the method for nighttime observations have been presented by Hildebrand et al (2012) andLübken et al (2016). Measurements of temperatures and wind during day and night are presented in Baumgarten et al (2015).…”

“…In addition to the improvement of the tropospheric forecast skills of the 15 weather predictions, the higher model lids made available re-analysis data for the stratosphere and mesosphere which are widely used in the research community. However, up to now, only few comparisons between wind observations and models exist: Kishore Kumar et al (2015) analysed the correspondence of fortnightly rocket wind soundings with the MERRA reanalysis and Hildebrand et al (2012Hildebrand et al ( , 2017 showed comparisons between January nighttime lidar measurements and ECMWF operational analysis and forecast data. The present study will show for the first long-term intercomparisons between wind 20 observations and state-of-the-art models and re-analyses (ERA5, ECMWF forecasts, MERRA2, SD-WACCM) by using the 11 months quasi-continuous data set recorded by the microwave radiometer WIRA.…”

“…Injection-seeding of the power laser by a highly frequency-stable continuous wave laser, real-time monitoring of the wavelength transmitted to the atmosphere as well as regular calibrations of the frequency dependence of the transmission through the receiver optics and the iodine vapour cell assure the accuracy of the wind observations. Moreover, the exactitude of the calibration is optimised by performing 1 hour of vertical wind observations at the beginning of each 10 measurement run (for details see Baumgarten, 2010;Hildebrand et al, 2012).…”