scholarly journals On the consistency of HNO<sub>3</sub> and NO<sub>2</sub> in the Aleutian High region from the Nimbus 7 LIMS Version 6 data set

2018 ◽  
Vol 11 (6) ◽  
pp. 3611-3626
Author(s):  
Ellis Remsberg ◽  
Murali Natarajan ◽  
V. Lynn Harvey
Keyword(s):  
Climate Models ◽  
Polar Vortex ◽  
Zonal Distribution ◽  
Data Set ◽  
Model Calculations ◽  
The North ◽  
Low Latitudes ◽  
History Of ◽  
Sulfuric Acid Aerosols ◽  
Short Time

Abstract. This study uses photochemical calculations along kinematic trajectories in conjunction with Limb Infrared Monitor of the Stratosphere (LIMS) observations to examine the changes in HNO3 and NO2 near 30 hPa in the region of the Aleutian High (AH) during the minor warming event of January 1979. An earlier analysis of Version 5 (V5) LIMS data indicated increases in HNO3 without a corresponding decrease in NO2 in that region and a quasi-wave 2 signature in the zonal distribution of HNO3, unlike the wave 1 signal in ozone and other tracers. Version 6 (V6) LIMS also shows an increase of HNO3 in that region, but NO2 is smaller than from V5. The focus here is to convey that V6 HNO3 and NO2 are of good quality, as shown by a re-examination of their mutual changes in the AH region. Photochemical model calculations initialized with LIMS V6 data show increases of about 2 ppbv in HNO3 over 10 days along trajectories terminating in the AH region on 28 January. Those increases are mainly a result of the nighttime heterogeneous conversion of N2O5 on background stratospheric sulfuric acid aerosols. Changes in the composition of the air parcels depend on the extent of exposure to sunlight and, hence, on the dynamically controlled history of the trajectories. Trajectories that begin in low latitudes and traverse to across the North Pole in a short time lead to the low HNO3 in the region separating the anticyclone from the polar vortex, both of which contain higher HNO3. These findings help to explain the observed seasonal evolution and areal extent of both species. V6 HNO3 and NO2 are suitable, within their errors, for the validation of stratospheric chemistry–climate models.

scholarly journals On the consistency of HNO<sub>3</sub> and NO<sub>2</sub> in the Aleutian High reigon from the Nimbus 7 LIMS version 6 dataset

2018 ◽  
Author(s):  
Ellis Remsberg ◽  
Murali Natarajan ◽  
V. Lynn Harvey
Keyword(s):  
Climate Models ◽  
Polar Vortex ◽  
Zonal Distribution ◽  
Model Calculations ◽  
Stratospheric Chemistry ◽  
Low Latitudes ◽  
History Of ◽  
Sulfuric Acid Aerosols ◽  
Short Time ◽  
Time Lead

Abstract. This study uses photochemical calculations along kinematic trajectories in conjunction with Limb Infrared Monitor of the Stratosphere (LIMS) observations to examine the changes in HNO3 and NO2 near 30 hPa in the region of the Aleutian High (AH) during the minor warming event of January 1979. An earlier analysis of Version 5 (V5) LIMS data indicated increases in HNO3 without a corresponding decrease in NO2 in that region and a wave-2 signature in the zonal distribution of HNO3, unlike the wave-1 signal in ozone and other tracers. Version 6 (V6) LIMS also shows an increase of HNO3 in that region, but NO2 is smaller than from V5. The focus here is to convey that both V6 HNO3 and NO2 are of better quality than from V5, as shown here by a re-examination of their mutual changes in the AH region. Photochemical model calculations initialized with LIMS V6 data show increases of about 2 ppbv in HNO3 over 10 days along trajectories terminating in the AH region on 28 January. Those increases are mainly a result of the nighttime heterogeneous conversion of N2O5 on background stratospheric sulfuric acid aerosols. Changes in the composition of the air parcels depend on the extent of exposure to sunlight and, hence, on the dynamically controlled history of the trajectories. Trajectories that begin in low latitudes and traverse to across the Pole in a short time lead to the low HNO3 in the region separating the anticyclone from the polar vortex, both of which contain higher HNO3. These findings help to explain the observed seasonal evolution and areal extent of both species. V6 HNO3 and NO2 are suitable, within their errors, for the validation of stratospheric chemistry/climate models.

scholarly journals Diversity of the Wintertime Arctic Oscillation Pattern among CMIP5 Models: Role of the Stratospheric Polar Vortex

2019 ◽  
Vol 32 (16) ◽  
pp. 5235-5250 ◽  
Author(s):  
Hainan Gong ◽  
Lin Wang ◽  
Wen Chen ◽  
Renguang Wu ◽  
Wen Zhou ◽  
...  
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Arctic Oscillation ◽  
Climate Models ◽  
Polar Vortex ◽  
Cmip5 Models ◽  
Stratospheric Polar Vortex ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific

AbstractThe wintertime Arctic Oscillation (AO) pattern in phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models displays notable differences from the reanalysis. The North Pacific center of the AO pattern is larger in the ensemble mean of 27 models than in the reanalysis, and the magnitude of the North Pacific center of the AO pattern varies largely among the models. This study investigates the plausible sources of the diversity of the AO pattern in the models. Analysis indicates that the amplitude of the North Pacific center is associated with the coupling between the North Pacific and North Atlantic, which in turn is primarily modulated by the strength of the stratospheric polar vortex. A comparative analysis is conducted for the strong polar vortex (SPV) and weak polar vortex (WPV) models. It reveals that a stronger stratospheric polar vortex induces more planetary waves to reflect from the North Pacific to the North Atlantic and more wave activity fluxes to propagate from the North Pacific to the North Atlantic in the SPV models than in the WPV models. Thus, the coupling of atmospheric circulation between the North Pacific and North Atlantic is stronger in the SPV models, which facilitates more North Pacific variability to be involved in the AO variability and induces a stronger North Pacific center in the AO pattern. The increase in vertical resolution may improve the simulation of the stratospheric polar vortex and thereby reduces the model biases in the North Pacific–North Atlantic coupling and thereby the amplitude of the North Pacific center of the AO pattern in models.

The Atlantic jet response to forcing: a regime perspective

2021 ◽  
Author(s):  
Michael Goss ◽  
Aditi Sheshadri ◽  
Erik Lindgren ◽  
Noah Diffenbaugh
Keyword(s):  
Climate Model ◽  
Polar Vortex ◽  
Data Set ◽  
Latitude Range ◽  
Physical Mechanisms ◽  
Zonal Winds ◽  
The North ◽  
Composite Response ◽  
Co2 Forcing

&lt;p&gt;The winter jet stream in the North Atlantic has been shown to preferentially occur at three distinct latitudes [Woolings et al., 2010; Woolings et al., 2018], which we will call the three Atlantic &amp;#8220;jet regimes.&amp;#8221; Distinct physical mechanisms may be responsible for each of the three jet regimes&amp;#8212;for example, the northernmost jet regime is strongly linked to the Greenland tip jet [White et al., 2019]. We seek to investigate the role of stratospheric and CO2 forcing, such as from sudden stratospheric warmings (SSWs), strong polar vortex events (SPVs), and anthropogenic global warming, on the Atlantic jet in the context of these jet regimes.&lt;/p&gt;&lt;p&gt;To do so, we use a &amp;#8220;jet latitude index&amp;#8221; (JLI), which is determined by finding the latitude of the peak zonal winds over some latitude range, averaged over some longitude range, to show that sudden stratospheric warmings (SSWs) impact the likelihood that the Atlantic jet will be in any particular jet regime. These calculations are performed in the ECMWF Interim Reanalysis (ERAI) data set, an in-house 200-year Whole Atmosphere Community Climate Model (WACCM) run, and in a subset of CMIP6 models. We seek to investigate how changes in the composite response of the jet over the Atlantic associated with SSWs, SPVs, and greenhouse gas forcing, are borne out in the context of the three Atlantic jet regimes. We find that, following SSWs, the northern regime becomes less frequent, and the southern regime becomes more frequent, while the jet latitude peaks of the regimes do not notably shift. Following SPVs, the northern regime becomes more frequent, the southern regime becomes less frequent, and again, the peak latitudes do not shift. Under CO2 forcing, we do not find a consistent signal from model to model, and we test whether these differences may be related to model differences in local meridional temperature gradients over the Atlantic.&lt;/p&gt;

The Other Archipelago: Kulak Deportations to the North in 1930

Slavic Review ◽  
2001 ◽  
Vol 60 (4) ◽  
pp. 730-755 ◽  
Author(s):  
Lynne Viola
Keyword(s):  
The State ◽  
The Other ◽  
The North ◽  
Scant Attention ◽  
History Of ◽  
Women And Children ◽  
Short Time

The “other archipelago” of “special setdements” was a cornerstone of the evolving gulag (Glavnoe upravlenie ispravitel’no-trudovykh lagerei) order. Scholars have paid relatively scant attention to the special settlements, which emerged first to isolate and exploit the labor of the dekulakized peasantry and within a short time would house a variety of other state-defined social and ethnic aliens through the course of the Stalin years. This article explores the history of the other archipelago in the year 1930, its founding and perhaps most difficult year, focusing on the NortiV ern Region. It was here that the state chose to send over a quarter of a million peasants, the single largest contingent of dekulakized peasant families in 1930. Against this icy backdrop, the special setders—men, women, and children—built the villages of the other archipelago within the wilderness.

scholarly journals A multi-wavelength classification method for polar stratospheric cloud types using infrared limb spectra

2016 ◽  
Author(s):  
R. Spang ◽  
L. Hoffmann ◽  
M. Höpfner ◽  
S. Griessbach ◽  
R. Müller ◽  
...  
Keyword(s):  
Climate Models ◽  
Polar Vortex ◽  
Bayesian Classifier ◽  
Solid Particles ◽  
Detection Sensitivity ◽  
Radiative Transfer Model ◽  
Ratio Method ◽  
Transfer Model ◽  
Model Calculations ◽  
The Antarctic

Abstract. The MIPAS instrument onboard the ESA Envisat satellite operated from July 2002 until April 2012. The infrared limb emission measurements represent a unique dataset of day and night observations of polar stratospheric clouds (PSCs) up to both poles. Cloud detection sensitivity is comparable to spaceborne lidars, and it is possible to classify different cloud types from the spectral measurements in different atmospheric windows regions. Here we present a new PSC classification scheme based on the combination of a well-established two-colour ratio method and multiple 2D brightness temperature difference probability density functions. The method is a simple probabilistic classifier based on Bayes' theorem with a strong independence assumption. The method has been tested in conjunction with a database of radiative transfer model calculations of realistic PSC particle size distributions, geometries, and composition. The Bayesian classifier distinguishes between solid particles of ice and nitric acid trihydrate (NAT), as well as liquid droplets of super-cooled ternary solution (STS). The classification results are compared to coincident measurements from the space borne lidar CALIOP instrument over the temporal overlap of both satellite missions (June 2006 to March 2012). Both datasets show a good agreement for the specific PSC classes, although the viewing geometries, vertical and horizontal resolution are quite different. Discrepancies are observed for the MIPAS ice class. The Bayesian classifier for MIPAS identifies substantially more ice clouds in the southern hemisphere polar vortex than CALIOP. This disagreement is attributed in parts to the difference in the sensitivity on mixed-type clouds. Ice seems to dominate the spectral behaviour in the limb infrared spectra and may cause an overestimation in ice occurrence compared to the real fraction of ice within the PSC area in the polar vortex. The entire MIPAS measurement period was processed with the new classification approach. Examples like the detection of the Antarctic NAT belt during early winter, and its possible link to mountain wave events over the Antarctic Peninsula, which are observed by the AIRS instrument, are highlighting the importance of a climatology of in total 9 southern and 10 northern hemisphere winters. The new dataset is valuable both for detailed process studies, and for comparisons with and improvements of the PSC parameterisations used in chemistry transport and climate models.

scholarly journals Cultural Continuity in Bospor of the 4th–6th Centuries through the Archaeological Lens

2020 ◽  
pp. 114-123
Author(s):  
Aleksey Klemeshov ◽  
Sergey Gorlanov ◽  
Danila Dryga ◽  
Aleksandr Mochalov
Keyword(s):  
General Idea ◽  
Cultural Continuity ◽  
North Caucasus ◽  
Krasnodar Krai ◽  
Black Sea Region ◽  
The Core ◽  
The North ◽  
History Of ◽  
Short Time ◽  
Archaeological Monument

The paper focuses on the study of the monument that dates back to the Migration Period — Verkhnegostagayevsky settlement (Krasnodar Krai). It describes the core findings of complex archaeological excavations of the fortress on the spurs of the Main Caucasian Range, which allowed not only to get a general idea of the archaeological monument in a fairly short time, but also to evaluate its significance for the history of both the Northern Black Sea region and the North Caucasus at the turn of the two eras. The authors describe the fortification and layout of the site, which was a large political or sacred centre.

scholarly journals Has Stratospheric HCl in the Northern Hemisphere Been Increasing Since 2005?

2020 ◽  
Vol 8 ◽  
Author(s):  
Yuanyuan Han ◽  
Fei Xie ◽  
Jiankai Zhang
Keyword(s):  
Northern Hemisphere ◽  
Climate Models ◽  
Linear Trend ◽  
Polar Vortex ◽  
Joint Effect ◽  
Residual Circulation ◽  
Quasi Biennial Oscillation ◽  
Middle Latitudes ◽  
The North ◽  
Biennial Oscillation

Stratospheric hydrogen chloride (HCl) is the main stratospheric reservoir of chlorine, deriving from the decomposition of chlorine-containing source gases. Its trend has been used as a metric of ozone depletion or recovery. Using the latest satellite observations, it is found that the significant increase of Northern Hemisphere stratospheric HCl during 2010–2011 can mislead the trend of HCl in recent decades. In agreement with previous studies, HCl increased from 2005 to 2011; however, when the large increase of stratospheric HCl during 2010–2011 is removed, the increasing linear trend from 2005 to 2011 becomes weak and insignificant. In addition, the linear trend of Northern Hemisphere stratospheric HCl from 2005 to 2016 is also weak and insignificant. The significant increase of HCl during 2010–2011 is attributed to a strong northern polar vortex and a weakened residual circulation, which slowed down the transport of HCl between the low-mid latitudes and the high latitudes, leading to an accumulation of HCl in the middle latitudes of the stratosphere. In addition, a weakened residual circulation leads to enhance conversion of chlorine-containing source gases of different lifetimes to HCl, thus increasing the levels of HCl. Simulations by both chemistry transport and chemistry-climate models support the result. It is further found that the joint effect of a La Niña event, the west phase of the quasi-biennial oscillation and positive anomalies of sea surface temperature in the North Pacific is responsible for the strong northern polar vortex and a weakened residual circulation.

Regime Behaviour in the Upper Stratosphere as a Precursor of Stratosphere- Troposphere Coupling of the Northern Hemisphere

2021 ◽  
Author(s):  
Hua Lu ◽  
Lesley Gray ◽  
Patrick Martineau ◽  
John King ◽  
Thomas Bracegirlde
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Surf Zone ◽  
Polar Vortex ◽  
Flow Regimes ◽  
Late Winter ◽  
Rossby Wave Breaking ◽  
The North ◽  
Westerly Jet ◽  
Westerly Jets

&lt;p&gt;A flow regime index is constructed based on the November-December standard deviation of the Ertel&amp;#8217;s potential vorticity (EPV) in the northern upper stratosphere at 1500 K (~40 km). The index reveals two flow regimes in both the stratosphere and the troposphere. In the stratosphere, the two flow regimes involve zonally asymmetric variability that is manifested by a modulation of the Aleutian High and distinct early-to-late winter development of the polar vortex. During the wide-jet regime, an anomalously strengthened, upright polar vortex is found in middle winter, which involves an equatorward shift of the surf zone in the middle to upper stratosphere, a poleward movement of the polar vortex axis, and a sharpening of the polar vortex edge, suggesting a dominant effect of Rossby wave breaking. During the narrow-jet regime, the vortex weakens at least a month earlier in association with enhanced large-scale PV mixing.&lt;/p&gt;&lt;p&gt;The upper stratospheric flow regimes also have detectable signal in the vicinity of the tropospheric westerly jets in middle winter. The tropospheric responses are also zonally asymmetric. During the wide-jet regime, the largest response is found over the North Pacific with a weakened, poleward shifted westerly jet over north America. &amp;#160;The circulation anomalies during the narrow-jet regime are most strong over the North Atlantic with a weakened, and equatorward shifted westerly jet there. The flow regimes also differ distinctively in their impacts on high-frequency variability downstream of the westerly jets and associated temperature variability. Given the flow regimes in the upper stratosphere leads the tropospheric response by one to two months, improved representation of upper stratospheric variability in climate models may offer more skillful prediction of long-range surface weather forecasts.&lt;/p&gt;

Ras al Khaimah: further archaeological discoveries

Antiquity ◽  
1976 ◽  
Vol 50 (200) ◽  
pp. 216-222
Author(s):  
Beatrice De Cardi
Keyword(s):  
United Arab Emirates ◽  
The State ◽  
Focused Attention ◽  
North East ◽  
The North ◽  
History Of ◽  
The City

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.

Sequencing Analysis and Phylogenetic Tree of HPV Isolated from Breast Cancer Patients at Thi-Qar Province/Iraq

2020 ◽  
pp. 37-40
Keyword(s):  
Nucleotide Sequence ◽  
Phylogenetic Tree ◽  
Evolutionary Relationship ◽  
Nucleotide Sequencing ◽  
Sequencing Analysis ◽  
Breast Cancer Patients ◽  
The North ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed Paraffin Embedded ◽  
History Of

Genetic variety examination has demonstrated fundamental to the understanding of the epidemiological and developmental history of Papillomavirus (HPV), for the development of accurate diagnostic tests and for efficient vaccine design. The HPV nucleotide diversity has been investigated widely among high-risk HPV types. To make the nucleotide sequence of HPV and do the virus database in Thi-Qar province, and compare sequences of our isolates with previously described isolates from around the world and then draw its phylogenetic tree, this study done. A total of 6 breast formalin-fixed paraffin-embedded (FFPE) of the female patients were included in the study, divided as 4 FFPE malignant tumor and 2 FFPE of benign tumor. The PCR technique was implemented to detect the presence of HPV in breast tissue, and the real-time PCR used to determinant HPV genotypes, then determined a complete nucleotide sequence of HPV of L1 capsid gene, and draw its phylogenetic tree. The nucleotide sequencing finding detects a number of substitution mutation (SNPs) in (L1) gene, which have not been designated before, were identified once in this study population, and revealed that the HPV16 strains have the evolutionary relationship with the South African race, while, the HPV33 and HPV6 showing the evolutionary association with the North American and East Asian race, respectively.

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