scholarly journals Spectroscopic evidence for NAT, STS, and ice in MIPAS infrared limb emission measurements of polar stratospheric clouds

2006 ◽  
Vol 6 (5) ◽  
pp. 1201-1219 ◽  
Author(s):  
M. Höpfner ◽  
B. P. Luo ◽  
P. Massoli ◽  
F. Cairo ◽  
R. Spang ◽  
...  
Keyword(s):  
Spectral Band ◽  
Michelson Interferometer ◽  
Polar Stratospheric Clouds ◽  
Density Profiles ◽  
Ice Clouds ◽  
Spectroscopic Evidence ◽  
Cloud Optical Thickness ◽  
Stratospheric Clouds ◽  
The Antarctic ◽  
Lidar Observations

Abstract. We have analyzed mid-infrared limb-emission measurements of polar stratospheric clouds (PSCs) by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) during the Antarctic winter 2003 with respect to PSC composition. Coincident Lidar observations from McMurdo were used for comparison with PSC types 1a, 1b and 2. Application of new refractive index data of β-NAT have allowed to accurately simulate the prominent spectral band at 820 cm-1 observed by MIPAS at the location where the Lidar instrument observed type 1a PSCs. Broadband spectral fits covering the range from 780 to 960 cm-1 and from 1220 to 1490 cm-1 showed best agreement with the MIPAS measurements when spectroscopic data of NAT were used to simulate the MIPAS spectra. MIPAS measurements collocated with Lidar observations of Type 1b and Type 2 PSCs could only be reproduced by assuming a composition of supercooled ternary H2SO4/HNO3/H2O solution (STS) and of ice, respectively. Particle radius and number density profiles derived from MIPAS were generally consistent with the Lidar observations. Only in the case of ice clouds, PSC volumes are partly underestimated by MIPAS due to large cloud optical thickness in the limb-direction. A comparison of MIPAS cloud composition and Lidar PSC-type determination based on all available MIPAS-Lidar coincident measurements revealed good agreement between PSC-types 1a, 1b and 2, and NAT, STS and ice, respectively. We could not find spectroscopic evidence for the presence of nitric acid dihydrate (NAD) from MIPAS observations of PSCs over Antarctica in 2003.

scholarly journals Spectroscopic evidence for β-NAT, STS, and ice in MIPAS infrared limb emission measurements of polar stratospheric clouds

2005 ◽  
Vol 5 (5) ◽  
pp. 10685-10721 ◽  
Author(s):  
M. Höpfner ◽  
B. P. Luo ◽  
P. Massoli ◽  
F. Cairo ◽  
R. Spang ◽  
...  
Keyword(s):  
Michelson Interferometer ◽  
Spectral Signature ◽  
Polar Stratospheric Clouds ◽  
Density Profiles ◽  
Ice Clouds ◽  
Spectroscopic Evidence ◽  
Cloud Optical Thickness ◽  
Stratospheric Clouds ◽  
The Antarctic ◽  
Lidar Observations

Abstract. We have analyzed mid-infrared limb-emission measurements of polar stratospheric clouds (PSCs) by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) during the Antarctic winter 2003 with respect to PSC composition. Coincident lidar observations from McMurdo were used for comparison with PSC types 1a, 1b and 2. By application of new refractive index data we could prove that a spectral signature at 820 cm−1 as observed by MIPAS near to the observation of a type 1a PSC is due to a composition of β-NAT. MIPAS infrared spectra collocated with Lidar observations of Type 1b and Type 2 PSCs could only be reproduced by assuming a composition of supercooled ternary H2SO4/HNO3/H2O solution (STS) and of ice, respectively. Particle radius and number density profiles derived from MIPAS were generally consistent with the lidar observations. Only in the case of ice clouds, PSC volumes are underestimated due to large cloud optical thickness in the limb-direction. A comparison of MIPAS cloud composition and lidar PSC-type determination based on all available MIPAS-lidar coincident measurements revealed good agreement between PSC-types 1a, 1b and 2, and NAT, STS and ice, respectively. We could not find any spectroscopic evidence for the presence of nitric acid dihydrate (NAD) from any MIPAS observation of PSCs over Antarctica in 2003.

scholarly journals Accuracy and precision of polar lower stratospheric temperatures from reanalyses evaluated from A-Train CALIOP and MLS, COSMIC GPS RO, and the equilibrium thermodynamics of supercooled ternary solutions and ice clouds

2018 ◽  
Vol 18 (3) ◽  
pp. 1945-1975 ◽  
Author(s):  
Alyn Lambert ◽  
Michelle L. Santee
Keyword(s):  
Pressure Range ◽  
Equilibrium Thermodynamics ◽  
Polar Stratospheric Clouds ◽  
Ice Clouds ◽  
Warm Bias ◽  
Frost Point ◽  
Ternary Solutions ◽  
Accuracy And Precision ◽  
Temperature Reference ◽  
Stratospheric Clouds

Abstract. We investigate the accuracy and precision of polar lower stratospheric temperatures (100–10 hPa during 2008–2013) reported in several contemporary reanalysis datasets comprising two versions of the Modern-Era Retrospective analysis for Research and Applications (MERRA and MERRA-2), the Japanese 55-year Reanalysis (JRA-55), the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-I), and the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (NCEP-CFSR). We also include the Goddard Earth Observing System model version 5.9.1 near-real-time analysis (GEOS-5.9.1). Comparisons of these datasets are made with respect to retrieved temperatures from the Aura Microwave Limb Sounder (MLS), Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) temperatures, and independent absolute temperature references defined by the equilibrium thermodynamics of supercooled ternary solutions (STSs) and ice clouds. Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations of polar stratospheric clouds are used to determine the cloud particle types within the Aura MLS geometric field of view. The thermodynamic calculations for STS and the ice frost point use the colocated MLS gas-phase measurements of HNO3 and H2O. The estimated bias and precision for the STS temperature reference, over the 68 to 21 hPa pressure range, are 0.6–1.5 and 0.3–0.6 K, respectively; for the ice temperature reference, they are 0.4 and 0.3 K, respectively. These uncertainties are smaller than those estimated for the retrieved MLS temperatures and also comparable to GPS RO uncertainties (bias  <  0.2 K, precision  >  0.7 K) in the same pressure range. We examine a case study of the time-varying temperature structure associated with layered ice clouds formed by orographic gravity waves forced by flow over the Palmer Peninsula and compare how the wave amplitudes are reproduced by each reanalysis dataset. We find that the spatial and temporal distribution of temperatures below the ice frost point, and hence the potential to form ice polar stratospheric clouds (PSCs) in model studies driven by the reanalyses, varies significantly because of the underlying differences in the representation of mountain wave activity. High-accuracy COSMIC temperatures are used as a common reference to intercompare the reanalysis temperatures. Over the 68–21 hPa pressure range, the biases of the reanalyses with respect to COSMIC temperatures for both polar regions fall within the narrow range of −0.6 K to +0.5 K. GEOS-5.9.1, MERRA, MERRA-2, and JRA-55 have predominantly cold biases, whereas ERA-I has a predominantly warm bias. NCEP-CFSR has a warm bias in the Arctic but becomes substantially colder in the Antarctic. Reanalysis temperatures are also compared with the PSC reference temperatures. Over the 68–21 hPa pressure range, the reanalysis temperature biases are in the range −1.6 to −0.3 K with standard deviations  ∼  0.6 K for the CALIOP STS reference, and in the range −0.9 to +0.1 K with standard deviations  ∼  0.7 K for the CALIOP ice reference. Comparisons of MLS temperatures with the PSC reference temperatures reveal vertical oscillations in the MLS temperatures and a significant low bias in MLS temperatures of up to 3 K.

scholarly journals Can gravity waves significantly impact PSC occurrence in the Antarctic?

2009 ◽  
Vol 9 (22) ◽  
pp. 8825-8840 ◽  
Author(s):  
A. J. McDonald ◽  
S. E. George ◽  
R. M. Woollands
Keyword(s):  
Antarctic Peninsula ◽  
Gravity Waves ◽  
Clustering Algorithm ◽  
Small Scale ◽  
Temperature Threshold ◽  
Aerosol Extinction ◽  
Polar Stratospheric Clouds ◽  
Mountain Wave ◽  
Stratospheric Clouds ◽  
The Antarctic

Abstract. A combination of POAM III aerosol extinction and CHAMP RO temperature measurements are used to examine the role of atmospheric gravity waves in the formation of Antarctic Polar Stratospheric Clouds (PSCs). POAM III aerosol extinction observations and quality flag information are used to identify Polar Stratospheric Clouds using an unsupervised clustering algorithm. A PSC proxy, derived by thresholding Met Office temperature analyses with the PSC Type Ia formation temperature (TNAT), shows general agreement with the results of the POAM III analysis. However, in June the POAM III observations of PSC are more abundant than expected from temperature threshold crossings in five out of the eight years examined. In addition, September and October PSC identified using temperature thresholding is often significantly higher than that derived from POAM III; this observation probably being due to dehydration and denitrification. Comparison of the Met Office temperature analyses with corresponding CHAMP observations also suggests a small warm bias in the Met Office data in June. However, this bias cannot fully explain the differences observed. Analysis of CHAMP data indicates that temperature perturbations associated with gravity waves may partially explain the enhanced PSC incidence observed in June (relative to the Met Office analyses). For this month, approximately 40% of the temperature threshold crossings observed using CHAMP RO data are associated with small-scale perturbations. Examination of the distribution of temperatures relative to TNAT shows a large proportion of June data to be close to this threshold, potentially enhancing the importance of gravity wave induced temperature perturbations. Inspection of the longitudinal structure of PSC occurrence in June 2005 also shows that regions of enhancement are geographically associated with the Antarctic Peninsula; a known mountain wave "hotspot". The latitudinal variation of POAM III observations means that we only observe this region in June–July, and thus the true pattern of enhanced PSC production may continue operating into later months. The analysis has shown that early in the Antarctic winter stratospheric background temperatures are close to the TNAT threshold (and PSC formation), and are thus sensitive to temperature perturbations associated with mountain wave activity near the Antarctic peninsula (40% of PSC formation). Later in the season, and at latitudes away from the peninsula, temperature perturbations associated with gravity waves contribute to about 15% of the observed PSC (a value which corresponds well to several previous studies). This lower value is likely to be due to colder background temperatures already achieving the TNAT threshold unaided. Additionally, there is a reduction in the magnitude of gravity waves perturbations observed as POAM III samples poleward of the peninsula.

Aircraft lidar observations of an enhanced type Ia polar stratospheric clouds during APE-POLECAT

1999 ◽  
Vol 104 (D19) ◽  
pp. 23961-23969 ◽  
Author(s):  
A. Tsias ◽  
M. Wirth ◽  
K. S. Carslaw ◽  
J. Biele ◽  
H. Mehrtens ◽  
...  
Keyword(s):  
Polar Stratospheric Clouds ◽  
Type Ia ◽  
Stratospheric Clouds ◽  
Lidar Observations

scholarly journals Lidar observations of polar stratospheric clouds at the South Pole: 2. Stratospheric perturbed conditions, 1992 and 1993

1997 ◽  
Vol 102 (D11) ◽  
pp. 12945-12955 ◽  
Author(s):  
Marco Cacciani ◽  
Paola Colagrande ◽  
Alcide di Sarra ◽  
Daniele Fuà ◽  
Paolo Di Girolamo ◽  
...  
Keyword(s):  
South Pole ◽  
The South ◽  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Lidar Observations

Lidar Observations of Polar Stratospheric Clouds Above Spitsbergen

1997 ◽  
pp. 509-512 ◽  
Author(s):  
K. Stebel ◽  
R. Neuber ◽  
G. Beyerle ◽  
J. Biele ◽  
P. Scheuch ◽  
...  
Keyword(s):  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Lidar Observations

Lidar observations of polar stratospheric clouds at Andøya, Norway, in January 1992

1994 ◽  
Vol 21 (13) ◽  
pp. 1307-1310 ◽  
Author(s):  
H. J. Schäfer ◽  
P. Scheuch ◽  
M. Langer ◽  
K. H. Fricke ◽  
U. von Zahn ◽  
...  
Keyword(s):  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Lidar Observations

scholarly journals Polar Stratospheric Clouds: Satellite Observations, Processes, and Role in Ozone Depletion

2021 ◽  
Author(s):  
Ines Tritscher ◽  
Michael C. Pitts ◽  
Lamont R. Poole ◽  
Thomas Peter ◽  
Keyword(s):  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Michelson Interferometer ◽  
Orthogonal Polarization ◽  
Polar Stratospheric Clouds ◽  
Spatial And Temporal Distributions ◽  
Stratospheric Clouds ◽  
Polar Ozone ◽  
Made In

&lt;p&gt;The important role of polar stratospheric clouds (PSCs) in stratospheric ozone depletion during winter and spring at high latitudes has been known since the 1980s. However, contemporary observations by the spaceborne instruments MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), MLS (Microwave Limb Sounder), and CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) have brought about a comprehensive and clearer understanding of PSC spatial and temporal distributions, their conditions of existence, and the processes through which they impact polar ozone. Within the SPARC (Stratosphere-troposphere Processes And their Role in Climate) PSC initiative (PSCi), those datasets have been synthesized and discussed in depth with the result of a new vortex-wide climatology of PSC occurrence and composition. We will present our results within this vPICO together with a review of the significant progress that has been made in our understanding of PSC nucleation, related dynamical processes, and heterogeneous chlorine activation. Moreover, we have compiled different techniques for parameterizing PSCs and we will show their effects in global models.&lt;/p&gt;

scholarly journals Quasi-coincident observations of polar stratospheric clouds by ground-based lidar and CALIOP at Concordia (Dome C, Antarctica) from 2014 to 2018

2021 ◽  
Vol 21 (3) ◽  
pp. 2165-2178
Author(s):  
Marcel Snels ◽  
Francesco Colao ◽  
Francesco Cairo ◽  
Ilir Shuli ◽  
Andrea Scoccione ◽  
...  
Keyword(s):  
Orthogonal Polarization ◽  
Data Sampling ◽  
Polar Stratospheric Clouds ◽  
Air Masses ◽  
Ground Based Lidar ◽  
Stratospheric Clouds ◽  
Observation Geometry ◽  
The Antarctic ◽  
Seasonal And Interannual Variations ◽  
Good Agreement

Abstract. Polar stratospheric clouds (PSCs) have been observed from 2014 to 2018 from the lidar observatory at the Antarctic Concordia station (Dome C), included as a primary station in the NDACC (Network for Detection of Atmospheric Climate Change). Many of these measurements have been performed in coincidence with overpasses of the satellite-borne CALIOP (Cloud Aerosol Lidar with Orthogonal Polarization) lidar, in order to perform a comparison in terms of PSC detection and composition classification. Good agreement has been obtained, despite intrinsic differences in observation geometry and data sampling. This study reports, to our knowledge, the most extensive comparison of PSC observations by ground-based and satellite-borne lidars. The PSCs observed by the ground-based lidar and CALIOP form a complementary and congruent dataset and allow us to study the seasonal and interannual variations in PSC occurrences at Dome C. Moreover, a strong correlation with the formation temperature of NAT (nitric acid trihydrate), TNAT, calculated from local temperature, pressure, and H2O and HNO3 concentrations is shown. PSCs appear at Dome C at the beginning of June up to 26 km and start to disappear in the second half of August, when the local temperatures start to rise above TNAT. Rare PSC observations in September coincide with colder air masses below 18 km.

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