Lidars With Narrow FOV for Daylight Measurements

Eixmann, Ronald; Gerding, M.; Höffner, J.; Kopp, M.

doi:10.1109/tgrs.2015.2401333

Cited by 13 publications

(8 citation statements)

References 14 publications

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“…To reduce the effects of tropospheric turbulence on the laser beam propagation and the alignment of laser and telescope FOV, an active beam stabilization based on a Piezo‐coupled mirror is used [ Eixmann et al , ]. This method was first developed for the mobile IAP iron lidar by Höffner and Lautenbach [].…”

Section: Instrumentation and Datamentioning

confidence: 99%

Seasonal variation of gravity wave parameters using different filter methods with daylight lidar measurements at midlatitudes

2017

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The daylight‐capable Rayleigh‐Mie‐Raman (RMR) lidar at the midlatitude station in Kühlungsborn (54°N, 12°E) is in operation since 2010. The RMR lidar system is used to investigate different fractions of atmospheric waves, like gravity waves (GW) and thermal tides (with diurnal, semidiurnal, and terdiurnal components) at day and night. About 6150 h of data have been acquired until 2015. The general challenge for GW observations is the separation of different wave contributions from the observed superposition of GW, tides, or even longer periodic waves. Unfiltered lidar data always include such a superposition. We applied a Butterworth filter to separate GW and tides by vertical wavelength with a cutoff wavelength of 15 km and by observed periods with a cutoff period of 8 h. GW activity and characteristics are derived in an altitude range between 30 and 70 km. The retrieved vertically filtered temperature deviations contain GW with small vertical wavelengths over a broad range of periods, while only a small range of periods is included in the temporally filtered temperature deviations. We observe an annual variation of the wave activity for unfiltered and vertically filtered data, which is caused from tides and inertia gravity waves. In contrast to that, filtering in time leads to a weak semiannual variation for gravity waves with periods of 4–8 h, especially in higher altitudes. During summer, these waves have the half of the total amount of the potential energy budget compared to the unfiltered data. This shows the importance of waves with periods smaller than 8 h.

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Section: Instrumentation and Datamentioning

confidence: 99%

Seasonal variation of gravity wave parameters using different filter methods with daylight lidar measurements at midlatitudes

2017

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“…Two steering mirrors and one fixed mirror are used to guide the light into the atmosphere, co-axially with the receiving telescope. The first of these steering mirrors is Piezo-mounted and used for beam stabilization (Eixmann et al, 2015). By computer-controlled beam stabilization the beam axis is fixed to the optical axis of the telescope on a single pulse basis to overcome the effects of, e.g., atmospheric turbulence on the geometrical overlap of beam and telescope.…”

Section: Instrumental Setup Of the New Iap Rmr Lidarmentioning

confidence: 99%

Mesospheric temperature soundings with the new, daylight-capable IAP RMR lidar

Gerding¹,

Kopp²,

Höffner³

et al. 2016

Preprint

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Abstract. Temperature measurements by lidar are an important tool for the understanding of the mean state of the atmosphere as well as the propagation of gravity waves and thermal tides. Though, mesospheric lidar soundings are often limited to nighttime conditions (e.g., solar zenith angle >96°) due to the low signal-to-noise ratio during the day. By this, examination of long-period gravity waves and tides is inhibited, as well as soundings in summer at polar latitudes. We developed a new daylight-capable RMR lidar at our site in Kühlungsborn/Germany (54° N, 12° E) that is in routine operation since 2010 for temperature soundings up to 90 km or ~75 km (night or day) and soundings of noctilucent clouds (NLC). Here we describe the setup of the system with special emphasis on the daylight suppression methods like spatial and spectral filtering. The narrowband Fabry-Pérot etalons for spectral filtering of the received signal induce an altitude dependant transmission of the detector. As a result, the signal is no longer proportional to the air density and the hydrostatic integration of the profile results in systematic temperature errors of up to 4 K. We demonstrate a correction method and the validity of correction by comparison with data obtained by our co-located, nighttime-only RMR-lidar where no etalon is installed. As a further example a time series of temperature profiles between 20 and 80 km is presented for day and night of 9/10 March 2014. Together with the other data of March 2014 these profiles are used to calculate tidal amplitudes. It is found that tidal amplitudes vary between ~1 and 5 K depending on altitude.

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“…The laser is emitted co-axially with the receiving telescope by means of different steerable mirrors. A beam-stabilization based on a Piezo-coupled mirror is used to keep the laser beam within the 62 µrad field of view of the telescope [7]. Input for beam-stabilization is provided by a CCD camera observing the beam in real-time through the same telescope and a 90:10 beam splitter.…”

Section: Methodsmentioning

confidence: 99%

Lidar Soundings Between 30 and 100 km Altitude During Day and Night for Observation of Temperatures, Gravity Waves and Tides

Gerding

Baumgarten

Höffner

et al. 2016

EPJ Web of Conferences

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Ground-based temperature measurements by lidar are an important tool for the understanding of long-term temperature changes as well as the propagation of gravity waves and tides. Though, mesospheric soundings are often limited to nighttime conditions due to the low signal-tonoise ratio during the day. We developed a daylight-capable RMR lidar for temperature soundings in the middle atmosphere. The influences of the narrowband detector on the calculated hydrostatic temperatures as well as their correction are described. The RMR lidar is complemented by a co-located resonance lidar. We present an example for tidal analyses and short-term variability of tidal amplitudes.

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Lidars With Narrow FOV for Daylight Measurements

Cited by 13 publications

References 14 publications

Seasonal variation of gravity wave parameters using different filter methods with daylight lidar measurements at midlatitudes

Seasonal variation of gravity wave parameters using different filter methods with daylight lidar measurements at midlatitudes

Mesospheric temperature soundings with the new, daylight-capable IAP RMR lidar

Lidar Soundings Between 30 and 100 km Altitude During Day and Night for Observation of Temperatures, Gravity Waves and Tides

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