Balloon borne observations of backscatter, frost point and ozone in polar stratospheric clouds at the South Pole

1991 ◽  
Vol 18 (2) ◽  
pp. 171-174 ◽  
Author(s):  
James M. Rosen ◽  
Norman T. Kjome ◽  
Samuel J. Oltmans
Keyword(s):  
South Pole ◽  
The South ◽  
Polar Stratospheric Clouds ◽  
Frost Point ◽  
Stratospheric Clouds

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 at the South Pole: 1. Stratospheric unperturbed conditions, 1990

1997 ◽  
Vol 102 (D11) ◽  
pp. 12937-12943 ◽  
Author(s):  
Marco Cacciani ◽  
Giorgio Fiocco ◽  
Paola Colagrande ◽  
Paolo Di Girolamo ◽  
Alcide di Sarra ◽  
...  
Keyword(s):  
South Pole ◽  
The South ◽  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Lidar Observations

Continuous Lidar Monitoring of Polar Stratospheric Clouds at the South Pole

2009 ◽  
Vol 90 (5) ◽  
pp. 613-618 ◽  
Author(s):  
James R. Campbell ◽  
Ellsworth J. Welton ◽  
James D. Spinhirne
Keyword(s):  
South Pole ◽  
The South ◽  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds

Polar stratospheric clouds at the South Pole in 1990: Lidar observations and analysis

1993 ◽  
Vol 98 (D1) ◽  
pp. 1001-1010 ◽  
Author(s):  
Richard L. Collins ◽  
Kenneth P. Bowman ◽  
Chester S. Gardner
Keyword(s):  
South Pole ◽  
The South ◽  
Polar Stratospheric Clouds ◽  
Stratospheric Clouds ◽  
Lidar Observations

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 A-train CALIOP and MLS observations of early winter antarctic polar stratospheric clouds and nitric acid in 2008

2011 ◽  
Vol 11 (10) ◽  
pp. 29283-29356
Author(s):  
A. Lambert ◽  
M. L. Santee ◽  
D. L. Wu ◽  
J. H. Chae
Keyword(s):  
Nitric Acid ◽  
Gas Phase ◽  
Wave Activity ◽  
Equilibrium Curve ◽  
Polar Stratospheric Clouds ◽  
Frost Point ◽  
Time Histories ◽  
Stratospheric Clouds ◽  
The Antarctic ◽  
Temperature Time

Abstract. A-train Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Microwave Limb Sounder (MLS) observations are used to investigate the development of polar stratospheric clouds (PSCs) and the gas phase nitric acid distribution in the early 2008 Antarctic winter. Observational evidence of gravity-wave activity is provided by Atmospheric Infrared Sounder (AIRS) radiances and infrared spectroscopic detection of nitric acid trihydrate (NAT) in PSCs is obtained from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). Goddard Earth Observing System Data Assimilation System (GEOS-5 DAS) analyses are used to derive Lagrangian trajectories and to determine temperature-time histories of air parcels. We use CALIOP backscatter and depolarization measurements to classify PSCs and the MLS measurements to determine the corresponding gas phase HNO3 as a function of temperature. For liquid PSCs the uptake of HNO3 follows the theoretical equilibrium curve for supercooled ternary solutions (STS), but at temperatures about 1 K lower as determined from GEOS-5. In the presence of solid phase PSCs, above the ice frost-point, the HNO3 depletion occurs over a wider range of temperatures (+2 to −7 K) distributed about the NAT equilibrium curve. Rapid gas phase HNO3 depletion is first seen by MLS from from 23–25 May 2008, consisting of a decrease in the volume mixing ratio (parts per billion by volume) from 14 ppbv to 7 ppbv on the 46–32 hPa (hectopascal) pressure levels and accompanied by a 2–3 ppbv increase by renitrification at the 68 hPa pressure level. Temperature-time histories of air parcels demonstrate that the depleted HNO3 region is more clearly correlated with prior low temperature exposure of a few kelvin above the frost-point than with either the region bounded by the NAT existence temperature threshold or the region of minimum temperatures. From the combined data we infer the presence of large-size NAT particles with effective radii >5–7 μm and low NAT number densities <1×10−3 cm−3. This denitrification event is observed close to the pole in the Antarctic vortex before synoptic temperatures first fall below the ice frost point and before the widespread occurrence of large-scale NAT PSCs at altitudes 18–26 km in a polar freezing belt. The NAT outbreak is similar to an event previously reported from MIPAS observations in mid-June 2003 and is again linked to NAT formation via ice-seeding following an episode of mountain wave activity detected by AIRS. Subsequent wave-ice formation in the rapid cooling phases over the Antarctic Peninsula and Ellsworth Mountains is detected here by CALIOP and MIPAS. The NAT clouds appear to be composed of relatively small particles with estimated effective radii of around 1 μm and high NAT number densities >0.2 cm−3.

scholarly journals A-train CALIOP and MLS observations of early winter Antarctic polar stratospheric clouds and nitric acid in 2008

2012 ◽  
Vol 12 (6) ◽  
pp. 2899-2931 ◽  
Author(s):  
A. Lambert ◽  
M. L. Santee ◽  
D. L. Wu ◽  
J. H. Chae
Keyword(s):  
Nitric Acid ◽  
Gas Phase ◽  
Wave Activity ◽  
Equilibrium Curve ◽  
Polar Stratospheric Clouds ◽  
Frost Point ◽  
Time Histories ◽  
Stratospheric Clouds ◽  
The Antarctic ◽  
Temperature Time

Abstract. A-train Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Microwave Limb Sounder (MLS) observations are used to investigate the development of polar stratospheric clouds (PSCs) and the gas-phase nitric acid distribution in the early 2008 Antarctic winter. Observational evidence of gravity-wave activity is provided by Atmospheric Infrared Sounder (AIRS) radiances and infrared spectroscopic detection of nitric acid trihydrate (NAT) in PSCs is obtained from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). Goddard Earth Observing System Data Assimilation System (GEOS-5 DAS) analyses are used to derive Lagrangian trajectories and to determine temperature-time histories of air parcels. We use CALIOP backscatter and depolarization measurements to classify PSCs and the MLS measurements to determine the corresponding gas-phase HNO3 as a function of temperature. For liquid PSCs the uptake of HNO3 follows the theoretical equilibrium curve for supercooled ternary solutions (STS), but at temperatures about 1 K lower as determined from GEOS-5. In the presence of solid phase PSCs, above the ice frost-point, the HNO3 depletion occurs over a wider range of temperatures (+2 to −7 K) distributed about the NAT equilibrium curve. Rapid gas-phase HNO3 depletion is first seen by MLS from from 23–25 May 2008, consisting of a decrease in the volume mixing ratio from 14 ppbv (parts per billion by volume) to 7 ppbv on the 46–32 hPa (hectopascal) pressure levels and accompanied by a 2–3 ppbv increase by renitrification at the 68 hPa pressure level. The observed region of depleted HNO3 is substantially smaller than the region bounded by the NAT existence temperature threshold. Temperature-time histories of air parcels demonstrate that the depletion is more clearly correlated with prior exposure to temperatures a few kelvin above the frost-point. From the combined data we infer the presence of large-size NAT particles with effective radii >5–7 μm and low NAT number densities <1 × 10−3 cm−3. This denitrification event is observed close to the pole in the Antarctic vortex before synoptic temperatures first fall below the ice frost point and before the widespread occurrence of large-scale NAT PSCs. An episode of mountain wave activity detected by AIRS on 28 May 2008 led to wave-ice formation in the rapid cooling phases over the Antarctic Peninsula and Ellsworth Mountains, seeding an outbreak of NAT PSCs that were detected by CALIOP and MIPAS. The NAT clouds formed at altitudes of 18–26 km in a polar freezing belt and appear to be composed of relatively small particles with estimated effective radii of around 1 μm and high NAT number densities >0.2 cm−3. This NAT outbreak is similar to an event previously reported from MIPAS observations in mid-June 2003.

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