Unusual appearance of mother‐of‐pearl clouds above El Calafate, Argentina (50°21′S, 72°16′W)

Dörnbrack, Andreas; Kaifler, Bernd; Kaifler, Natalie; Rapp, Markus; Wildmann, Norman; Garhammer, Markus; Ohlmann, Klaus; Payne, James E.; Sandercock, Morgan; Austin, Elizabeth

doi:10.1002/wea.3863

Cited by 20 publications

(26 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For illustration reasons, we applied a running mean filter to the zonal winds with a width of 10 days and 5 km in time and the vertical, respectively. Clearly, strong temperature disturbances are visible in the winter months, and also a particularly large perturbation is found in mid‐August 2019 just before the extraordinary SH SSW of 2019 occurred (e.g., Dörnbrack et al., 2020; Rapp et al., 2021, and references therein). In order to remove structures other than GWs from

T^{'}

another filtering step is needed.…”

Section: Methodsmentioning

confidence: 99%

High‐Cadence Lidar Observations of Middle Atmospheric Temperature and Gravity Waves at the Southern Andes Hot Spot

Reichert

Kaifler

et al. 2021

JGR Atmospheres

View full text Add to dashboard Cite

The observation of atmospheric gravity waves in the middle atmosphere is a challenging task and calls for highly sophisticated instrumentation. However, the effort is worthwhile as the propagation of gravity waves (GWs) is a key mechanism in coupling all layers of the atmosphere, transferring energy and momentum from their source regions to the locations where they dissipate (e.g., Fritts & Alexander, 2003). To observe properties of GWs at a specific location, a suitable tool is a lidar system because it samples a large altitude range from the lower stratosphere to the lower thermosphere with high temporal and vertical resolutions. This work presents the first high-cadence middle atmospheric lidar temperature data set from a location in the lee of the Southern Andes at the east coast of Argentina for the period November 2017 to October 2020.GWs in the middle atmosphere over the Southern Andes have been the focus of multiple studies (e.g.,

show abstract

T^{'}

another filtering step is needed.…”

Section: Methodsmentioning

confidence: 99%

High‐Cadence Lidar Observations of Middle Atmospheric Temperature and Gravity Waves at the Southern Andes Hot Spot

Reichert

Kaifler

et al. 2021

JGR Atmospheres

View full text Add to dashboard Cite

show abstract

“…In these equations, v HNO 3 is the mean thermal velocity of air molecules (in metres per second), R * stands for the universal constant of an ideal gas in joules per mole per kelvin (J mol −1 K −1 ), ρ NAT is the crystal density of NAT (1.626 × 10 6 g m −3 ; Drdla et al, 1993;van den Broek et al, 2004) and M NAT is the NAT molar mass of 117 g mol −1 . In one of the Eulerian formulations by van den Broek et al (2004), this radius change is applied to particles in size bins, but directly converted into a change in the particle number concentration ("FixedRad" approach).…”

Section: Discussionmentioning

confidence: 99%

“…Particle radius, particle number concentration and particle surface area concentration are used to calculate the heterogeneous reaction rate constants on the surface of PSCs. For NAT and ice, which can grow to relatively large sizes in the order of tens of micrometres, the following equation is used to calculate the heterogeneous reaction rate constant, assum-ing spherical particles (Drdla et al, 1993):…”

Section: Discussionmentioning

confidence: 99%

Mountain-wave-induced polar stratospheric clouds and their representation in the global chemistry model ICON-ART

Weimer

Schröter

Hoffmann³

et al. 2021

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Polar stratospheric clouds (PSCs) are a driver for ozone depletion in the lower polar stratosphere. They provide surface for heterogeneous reactions activating chlorine and bromine reservoir species during the polar night. The large-scale effects of PSCs are represented by means of parameterisations in current global chemistry–climate models, but one process is still a challenge: the representation of PSCs formed locally in conjunction with unresolved mountain waves. In this study, we investigate direct simulations of PSCs formed by mountain waves with the ICOsahedral Nonhydrostatic modelling framework (ICON) with its extension for Aerosols and Reactive Trace gases (ART) including local grid refinements (nesting) with two-way interaction. Here, the nesting is set up around the Antarctic Peninsula, which is a well-known hot spot for the generation of mountain waves in the Southern Hemisphere. We compare our model results with satellite measurements of PSCs from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and gravity wave observations of the Atmospheric Infrared Sounder (AIRS). For a mountain wave event from 19 to 29 July 2008 we find similar structures of PSCs as well as a fairly realistic development of the mountain wave between the satellite data and the ICON-ART simulations in the Antarctic Peninsula nest. We compare a global simulation without nesting with the nested configuration to show the benefits of adding the nesting. Although the mountain waves cannot be resolved explicitly at the global resolution used (about 160 km), their effect from the nested regions (about 80 and 40 km) on the global domain is represented. Thus, we show in this study that the ICON-ART model has the potential to bridge the gap between directly resolved mountain-wave-induced PSCs and their representation and effect on chemistry at coarse global resolutions.

show abstract

“…We execute the temperature retrieval with a time-pyramid approach (Kaifler and Kaifler, 2020): Firstly, the photon count profiles are temporally binned to a nightly mean photon count profile and the respective temperature integration is initialised with the a-priori value 𝑇 𝑖𝑛𝑖𝑡 . The nightly mean photon count profile has the greatest SNR compared to higher temporal resolutions due to the smoothing of the noise.…”

Section: Temperature Retrievalmentioning

confidence: 99%

Estimating the uncertainty of middle-atmospheric temperatures retrieved from airborne Rayleigh lidar measurements

Knobloch

Kaifler

Rapp

2022

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Possible uncertainties of lidar measurements of middle-atmospheric temperatures, measured with the novel airborne Rayleigh lidar system ALIMA, are investigated on the basis of data from the SouthTRAC-GW campaign in September 2019 and corresponding simulations of photon counts of the ALIMA system. We evaluate uncertainties due to the attenuation by Rayleigh extinction and ozone absorption, (signal-induced) photon noise, the photon background, and the nonlinearity of photon counting detectors. Ozone absorption induces an altitude-dependent cold bias in the retrieved temperatures of 2 K between 25 km to 55 km. Rayleigh extinction introduces a similar uncertainty of 2 K below 25 km that can be decreased by a suitable correction. Photon noise can introduce uncertainties of ±25 K at high altitudes (above 70 km) for high temporal resolutions (1 min), but on average the photon noise influences the temperature by only 1 K to 2 K at 70 km and decreases downwards. Uncertainties related to the photon background and the nonlinearity of the detectors, with a dead time correction applied, play a minor role in the temperature uncertainty. The analysis of the photon background in the ALIMA measurements of six research flights of the SouthTRAC-GW campaign proves the assumption of a constant photon background with altitude as well as the Poisson distribution of the photon counts. The airborne operation of ALIMA is advantageous as the high flight altitudes reduce the Rayleigh extinction by up to 17 % and thus result in higher signal levels compared to a ground-based operation. Overall, our analysis reveals that temperatures can be retrieved from ALIMA measurements with a remaining uncertainty of ≤ 1 K if all known biases are corrected.

show abstract

Unusual appearance of mother‐of‐pearl clouds above El Calafate, Argentina (50°21′S, 72°16′W)

Cited by 20 publications

References 27 publications

High‐Cadence Lidar Observations of Middle Atmospheric Temperature and Gravity Waves at the Southern Andes Hot Spot

High‐Cadence Lidar Observations of Middle Atmospheric Temperature and Gravity Waves at the Southern Andes Hot Spot

Mountain-wave-induced polar stratospheric clouds and their representation in the global chemistry model ICON-ART

Estimating the uncertainty of middle-atmospheric temperatures retrieved from airborne Rayleigh lidar measurements

Contact Info

Product

Resources

About