Correction to “PMCs and the water frost point in the Arctic summer mesosphere” by M. H. Stevens et al.

2002 ◽  
Vol 29 (16) ◽  
pp. 44-1-44-1
Author(s):  
M. H. Stevens ◽  
R. R. Conway ◽  
C. R. Englert ◽  
M. E. Summers ◽  
K. U. Grossman ◽  
...  
Keyword(s):  
The Arctic ◽  
Frost Point ◽  
Arctic Summer

scholarly journals PMCs and the water frost point in the Arctic summer mesosphere

2001 ◽  
Vol 28 (23) ◽  
pp. 4449-4452 ◽  
Author(s):  
Michael H. Stevens ◽  
Robert R. Conway ◽  
Christoph R. Englert ◽  
Michael E. Summers ◽  
Klaus U. Grossmann ◽  
...  
Keyword(s):  
The Arctic ◽  
Frost Point ◽  
Arctic Summer

scholarly journals Polar Stratospheric Cloud evolution and chlorine activation measured by CALIPSO and MLS, and modelled by ATLAS

2015 ◽  
Vol 15 (16) ◽  
pp. 22141-22182
Author(s):  
H. Nakajima ◽  
I. Wohltmann ◽  
T. Wegner ◽  
M. Takeda ◽  
M. C. Pitts ◽  
...  
Keyword(s):  
The Arctic ◽  
Temperature History ◽  
Threshold Temperature ◽  
Limiting Factor ◽  
Temperature Decrease ◽  
Air Mass ◽  
Frost Point ◽  
Rapid Temperature ◽  
Cloud Evolution ◽  
Stratospheric Clouds

Abstract. We examined observations of polar stratospheric clouds (PSCs) by CALIPSO and of HCl, ClO and HNO3 by MLS along air mass trajectories to investigate the dependence of the inferred PSC composition on the temperature history of the air parcels, and the dependence of the level of chlorine activation on PSC composition. Several case studies based on individual trajectories from the Arctic winter 2009/10 were conducted, with the trajectories chosen such that the first processing of the air mass by PSCs in this winter occurred on the trajectory. Transitions of PSC composition classes were observed to be highly dependent on the temperature history. In cases of a gradual temperature decrease, nitric acid trihydrate (NAT) and super-cooled ternary solution (STS) mixture clouds were observed. In cases of rapid temperature decrease, STS clouds were first observed, followed by NAT/STS mixture clouds. When temperatures dropped below the frost point, ice clouds formed, and then transformed into NAT/STS mixture clouds when temperature increased above the frost point. The threshold temperature for rapid chlorine activation on PSCs is approximately 4 K below the NAT existence temperature, TNAT. Furthermore, simulations of the ATLAS chemistry and transport box model along the trajectories were used to corroborate the measurements and show good agreement with the observations. Rapid chlorine activation was observed when an airmass encountered PSCs. The observed and modelled dependence of the rate of chlorine activation on the PSC composition class was small. Usually, chlorine activation was limited by the amount of available ClONO2. Where ClONO2 was not the limiting factor, a large dependence on temperature was evident.

scholarly journals Composition analysis of liquid particles in the Arctic stratosphere under synoptic conditions

2006 ◽  
Vol 6 (3) ◽  
pp. 689-696 ◽  
Author(s):  
C. Weisser ◽  
K. Mauersberger ◽  
J. Schreiner ◽  
N. Larsen ◽  
F. Cairo ◽  
...  
Keyword(s):  
Equilibrium Temperature ◽  
Solid Particles ◽  
The Arctic ◽  
Composition Analysis ◽  
Molar Ratios ◽  
Frost Point ◽  
Synoptic Conditions ◽  
Lee Waves ◽  
Stratospheric Clouds ◽  
First Time

Abstract. Synoptic scale polar stratospheric clouds (PSCs) that formed without the presence of mountain lee waves were observed in early December 2002 from Kiruna/Sweden using balloon-borne instruments. The physical, chemical, and optical properties of the particles were measured. Within the PSC solid particles existed whenever the temperature was below the equilibrium temperature for nitric acid trihydrate and liquid particles appeared when the temperature fell below an even lower threshold about 3 K above the frost point with solid particles still present. The correlation of liquid supercooled ternary solution aerosols with local temperatures is a pronounced feature observed during this flight; average molar ratios H2O/HNO3 were somewhat higher than predicted by models. In addition HCl has been measured for the first time in liquid aerosols. The chlorine isotope signature served as a unique tool to identify unambiguously HCl dissolved in STS particles. Within a narrow temperature range of about three degrees above the frost point, the measured average amount of HCl in liquid particles is below 1 weight%.

On small particles in the Arctic summer boundary layer: observations at two different heights near Ny-Ålesund, Svalbard

Tellus B ◽  
2009 ◽  
Vol 61 (2) ◽  
pp. 473-482 ◽  
Author(s):  
JOHAN STRÖM ◽  
ANN-CHRISTINE ENGVALL ◽  
FRANK DELBART ◽  
RADOVAN KREJCI ◽  
RENATE TREFFEISEN
Keyword(s):  
Boundary Layer ◽  
The Arctic ◽  
Small Particles ◽  
Arctic Summer

Black carbon radiative forcing over the Indian Arctic station, Himadri during the Arctic Summer of 2012

2015 ◽  
Vol 157 ◽  
pp. 29-36 ◽  
Author(s):  
M.P. Raju ◽  
P.D. Safai ◽  
S.M. Sonbawne ◽  
C.V. Naidu
Keyword(s):  
Black Carbon ◽  
Radiative Forcing ◽  
The Arctic ◽  
Arctic Summer

Total sea ice concentration retrieval from the SSM/I 85.5 GHz channels during the arctic summer

1997 ◽  
Vol 62 (1) ◽  
pp. 63-76 ◽  
Author(s):  
Dan Lubin ◽  
Caren Garrity ◽  
RenéO. Ramseier ◽  
Robert H. Whritner
Keyword(s):  
Sea Ice ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
Arctic Summer

scholarly journals The Arctic Summer Cloud Ocean Study (ASCOS): overview and experimental design

2014 ◽  
Vol 14 (6) ◽  
pp. 2823-2869 ◽  
Author(s):  
M. Tjernström ◽  
C. Leck ◽  
C. E. Birch ◽  
J. W. Bottenheim ◽  
B. J. Brooks ◽  
...  
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Surface Energy Balance ◽  
Cloud Condensation Nuclei ◽  
The Arctic ◽  
Data Set ◽  
Arctic Clouds ◽  
Pack Ice ◽  
Ocean Study ◽  
Arctic Summer

Abstract. The climate in the Arctic is changing faster than anywhere else on earth. Poorly understood feedback processes relating to Arctic clouds and aerosol–cloud interactions contribute to a poor understanding of the present changes in the Arctic climate system, and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Improved formulations in climate models require such observations, which can only come from measurements in situ in this difficult-to-reach region with logistically demanding environmental conditions. The Arctic Summer Cloud Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year (IPY) 2007–2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August and returned on 9 September 2008. In transit into and out of the pack ice, four short research stations were undertaken in the Fram Strait: two in open water and two in the marginal ice zone. After traversing the pack ice northward, an ice camp was set up on 12 August at 87°21' N, 01°29' W and remained in operation through 1 September, drifting with the ice. During this time, extensive measurements were taken of atmospheric gas and particle chemistry and physics, mesoscale and boundary-layer meteorology, marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing of new hypotheses on cloud processes, their interactions with the sea ice and ocean and associated physical, chemical, and biological processes and interactions. For example, the first-ever quantitative observation of bubbles in Arctic leads, combined with the unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggests the possibility of primary marine organically derived cloud condensation nuclei in Arctic stratocumulus clouds. Direct observations of surface fluxes of aerosols could, however, not explain observed variability in aerosol concentrations, and the balance between local and remote aerosols sources remains open. Lack of cloud condensation nuclei (CCN) was at times a controlling factor in low-level cloud formation, and hence for the impact of clouds on the surface energy budget. ASCOS provided detailed measurements of the surface energy balance from late summer melt into the initial autumn freeze-up, and documented the effects of clouds and storms on the surface energy balance during this transition. In addition to such process-level studies, the unique, independent ASCOS data set can and is being used for validation of satellite retrievals, operational models, and reanalysis data sets.

scholarly journals The Impact of Arctic Winter Infrared Radiation on Early Summer Sea Ice

2015 ◽  
Vol 28 (15) ◽  
pp. 6281-6296 ◽  
Author(s):  
Hyo-Seok Park ◽  
Sukyoung Lee ◽  
Yu Kosaka ◽  
Seok-Woo Son ◽  
Sang-Woo Kim
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Interannual Variability ◽  
Radiative Forcing ◽  
Heat Content ◽  
The Arctic ◽  
Upper Ocean ◽  
Upper Ocean Heat Content ◽  
The Arctic Ocean ◽  
Arctic Summer

Abstract The Arctic summer sea ice area has been rapidly decreasing in recent decades. In addition to this trend, substantial interannual variability is present, as is highlighted by the recovery in sea ice area in 2013 following the record minimum in 2012. This interannual variability of the Arctic summer sea ice area has been attributed to the springtime weather disturbances. Here, by utilizing reanalysis- and satellite-based sea ice data, this study shows that summers with unusually small sea ice area are preceded by winters with anomalously strong downward longwave radiation over the Eurasian sector of the Arctic Ocean. This anomalous wintertime radiative forcing at the surface is up to 10–15 W m−2, which is about twice as strong than that during the spring. During the same winters, the poleward moisture and warm-air intrusions into the Eurasian sector of the Arctic Ocean are anomalously strong and the resulting moisture convergence field closely resembles positive anomalies in column-integrated water vapor and tropospheric temperature. Climate model simulations support the above-mentioned findings and further show that the anomalously strong wintertime radiative forcing can decrease sea ice thickness over wide areas of the Arctic Ocean, especially over the Eurasian sector. During the winters preceding the anomalously small summer sea ice area, the upper ocean of the model is anomalously warm over the Barents Sea, indicating that the upper-ocean heat content contributes to winter sea ice thinning. Finally, mass divergence by ice drift in the preceding winter and spring contributes to the thinning of sea ice over the East Siberian and Chukchi Seas, where radiative forcing and upper-ocean heat content anomalies are relatively weak.

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