scholarly journals Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

2011 ◽  
Vol 11 (18) ◽  
pp. 9865-9885 ◽  
Author(s):  
A. Gabriel ◽  
H. Körnich ◽  
S. Lossow ◽  
D. H. W. Peters ◽  
J. Urban ◽  
...  
Keyword(s):  
Water Vapour ◽  
Satellite Data ◽  
Stationary Wave ◽  
Atmospheric Ozone ◽  
Mixing Processes ◽  
Linear Solution ◽  
Mean Values ◽  
Double Peak Structure ◽  
The North ◽  
Wave Patterns

Abstract. Stationary wave patterns in middle atmospheric ozone (O3) and water vapour (H2O) are an important factor in the atmospheric circulation, but there is a strong gap in diagnosing and understanding their configuration and origin. Based on Odin satellite data from 2001 to 2010 we investigate the stationary wave patterns in O3 and H2O as indicated by the seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means). At mid- and polar latitudes we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20 % of the zonal mean values. During winter, the wave one in O3* shows a maximum over the North Pacific/Aleutians and a minimum over the North Atlantic/Northern Europe and a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from the lower stratosphere to the upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave patterns occur mainly during southern spring. By comparing the observed wave patterns in O3* and H2O* with a linear solution of a steady-state transport equation for a zonally asymmetric tracer component we find that these wave patterns are primarily due to zonally asymmetric transport by geostrophically balanced winds, which are derived from observed temperature profiles. In addition temperature-dependent photochemistry contributes substantially to the spatial structure of the wave pattern in O3* . Further influences, e.g., zonal asymmetries in eddy mixing processes, are discussed.

scholarly journals Zonal asymmetries in middle atmospheric ozone and water vapour derived from Odin satellite data 2001–2010

2011 ◽  
Vol 11 (2) ◽  
pp. 4167-4198 ◽  
Author(s):  
A. Gabriel ◽  
H. Körnich ◽  
S. Lossow ◽  
D. H. W. Peters ◽  
J. Urban ◽  
...  
Keyword(s):  
Water Vapour ◽  
Southern Hemisphere ◽  
Satellite Data ◽  
Stationary Wave ◽  
Atmospheric Ozone ◽  
Tracer Transport ◽  
Meridional Transport ◽  
Mixing Processes ◽  
Double Peak Structure ◽  
Wave Patterns

Abstract. Based on Odin satellite data 2001–2010 we investigate stationary wave patterns in middle atmospheric ozone (O3) and water vapour (H2O) as indicated by their seasonal long-term means of the zonally asymmetric components O3* = O3-[O3] and H2O* = H2O-[H2O] ([O3], [H2O]: zonal means). At mid- and polar latitudes of Northern and Southern Hemisphere, we find a pronounced wave one pattern in both constituents. In the Northern Hemisphere, the wave one patterns increase during autumn, maintain their strength during winter and decay during spring, with maximum amplitudes of about 10–20% of zonal mean values. During winter, the wave one in stratospheric O3* is characterized by a maximum over North Pacific/Aleutians and a minimum over North Atlantic/Northern Europe and by a double-peak structure with enhanced amplitude in the lower and in the upper stratosphere. The wave one in H2O* extends from lower stratosphere to upper mesosphere with a westward shift in phase with increasing height including a jump in phase at upper stratosphere altitudes. In the Southern Hemisphere, similar wave one patterns occur during southern spring when the polar vortex breaks down. Based on a simplified tracer transport approach we explain these wave patterns as a first-order result of zonal asymmetries in mean meridional transport by geostrophically balanced winds, which were derived from combined temperature profiles of Odin, and ECMWF (European Centre of Medium-Range Weather Forecasts) Reanalysis data (ERA Interim). Further influences which may contribute to the stationary wave patterns, e.g. eddy mixing processes or temperature-dependent chemistry, are discussed.

scholarly journals QUASI-STATIONARY PLANETARY WAVES IN MID-LATITUDE STRATOSPHERE–MESOSPHERE IN WINTER 2011-2020

2021 ◽  
pp. 307-311
Author(s):  
Chenning Zhang ◽  
Oleksandr Evtushevsky ◽  
Gennadi Milinevsky
Keyword(s):  
Surface Pressure ◽  
Satellite Data ◽  
Geopotential Height ◽  
Stationary Wave ◽  
Planetary Waves ◽  
Stationary Waves ◽  
Aleutian Low ◽  
The North ◽  
Pressure Anomaly ◽  
Icelandic Low

The 10-year climatology (2011–2020) of quasi-stationary planetary waves in the mid-latitude stratosphere and mesosphere (40–50N, up to 90 km) has been analyzed. Longitude–altitude sections of geopotential height and ozone have been obtained using the Aura MLS satellite data. It is found that stationary wave 1 propagates into the mesosphere from the North American High and Icelandic Low, which are adjacent surface pressure anomalies in the structure of stationary wave 2. Unexpectedly, the strongest pressure anomaly in the Aleutian Low region does not contribute to the stationary wave 1 formation in the mesosphere. The vertical phase transformations of stationary waves in geopotential height and ozone show inconsistencies that should be studied separately.

scholarly journals Upstream of hydroclimate extremes : maxima of moisture transport

2021 ◽  
Author(s):  
Ambroise Dufour ◽  
Sergey Gulev ◽  
Olga Zolina
Keyword(s):  
Water Vapour ◽  
Satellite Data ◽  
Moisture Transport ◽  
Time Range ◽  
The North ◽  
Water Vapour Transport ◽  
Common Time ◽  
Western Border ◽  
Moisture Fluxes ◽  
Wind Profiles

<p>The prevailing westerly winds provide Europe with an average flow of moisture from the North Atlantic. We document the climatological transport of water vapour across Europe's western border, from the south of the Iberic Peninsula to Northern Scandinavia. Four state-of-the-art reanalyses (NCEP CFSR, JRA 55, MERRA 2 and ERA 5) are confronted to satellite observations (QUIKSCAT and ASCAT) and to radiosoundings (IGRA) from six coastal sites.  Over the datasets' common time range (2000-2011), the agreement is generally good in terms of yearly and monthly fluxes. The satellite products have generally lower values than the rest of the ensemble. Some disparities appear on the vertical. A longer time range (1980-2020) excludes satellite data but allows to detect local increases in moisture transport in the later years.</p><p>Beyond the climatological picture, day to day moisture fluxes present significant fluctuations, both in the dry and wet directions. The variability is consistent between reanalyses and radiosondes but slightly weaker in the satellite data. The fluxes on pressure levels are strongly correlated to their vertically integrated counterpart. We take advantage of the vertical coherence to stratify humidity and wind profiles according to quantiles of integrated moisture transport. The respective role of humidity and wind changes becomes apparent. Wind speed and direction determines the moisture transport more than the humidity field on a short term basis. On the scale of decades, there was no discernable change of circulation. It was moistening that drove the increase in water vapour transport. The effect was disproportionate for higher quantiles as a consequence of the non-linear Clausius-Clapeyron equation.</p>

Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada

2006 ◽  
Vol 80 (2) ◽  
pp. 193-197 ◽  
Author(s):  
R.A. Khan ◽  
C.V. Chandra
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Groups ◽  
Climatic Conditions ◽  
Otter Trawl ◽  
Commercial Fishery ◽  
Metazoan Parasites ◽  
Mean Values ◽  
The North

AbstractA study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotylereflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

scholarly journals Wind forcing of salinity anomalies in the Denmark Strait overflow

Ocean Science ◽  
2011 ◽  
Vol 7 (6) ◽  
pp. 821-834 ◽  
Author(s):  
S. Hall ◽  
S. R. Dye ◽  
K. J. Heywood ◽  
M. R. Wadley
Keyword(s):  
General Circulation ◽  
Thermohaline Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Mixing Processes ◽  
East Greenland ◽  
The North ◽  
East Greenland Current ◽  
Denmark Strait ◽  
Salinity Anomaly

Abstract. The overflow of dense water from the Nordic Seas to the North Atlantic through Denmark Strait is an important part of the global thermohaline circulation. The salinity of the overflow plume has been measured by an array of current meters across the continental slope off the coast of Angmagssalik, southeast Greenland since September 1998. During 2004 the salinity of the overflow plume changed dramatically; the entire width of the array (70 km) freshened between January 2004 and July 2004, with a significant negative salinity anomaly of about 0.06 in May. The event in May represents a fresh anomaly of over 3 standard deviations from the mean since recording began in 1998. The OCCAM 1/12° Ocean General Circulation Model not only reproduces the 2004 freshening event (r=0.96, p<0.01), but also correlates well with salinity observations over a previous 6 year period (r=0.54, p<0.01), despite the inevitable limitations of a z-coordinate model in representing the mixing processes at and downstream of the Denmark Strait sill. Consequently the physical processes causing the 2004 anomaly and prior variability in salinity are investigated using the model output. Our results reject the hypotheses that the anomaly is caused by processes occurring between the overflow sill and the moorings, or by an increase in upstream net freshwater input. Instead, we show that the 2004 salinity anomaly is caused by an increase in volume flux of low salinity water, with a potential density greater than 27.60 kg m−3, flowing towards the Denmark Strait sill in the East Greenland Current. This is caused by an increase in southward wind stress upstream of the sill at around 75° N 20° W four and a half months earlier, and an associated strengthening of the East Greenland Current.

scholarly journals Evaluation of MODIS Water Vapour Products over ALGERIA using Radiosonde Data

2021 ◽  
Vol 44 ◽  
Author(s):  
Houaria Namaoui ◽  
Salem Kahlouche ◽  
Ahmed Hafidh Belbachir
Keyword(s):  
Water Vapour ◽  
Satellite Data ◽  
Correlation Coefficients ◽  
Precipitable Water ◽  
Radiosonde Data ◽  
Precipitable Water Vapour ◽  
Total Precipitable Water ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Remote sensing of atmospheric water vapour using GNSS and Satellite data has become an efficient tool in meteorology and climate research. Many satellite data have been increasingly used to measure the content of water vapour in the atmosphere and to characterize its temporal and spatial variations. In this paper, we have used observations from radiosonde data collected from three stations (Algiers, Bechar and Tamanrasset) in Algeria from January to December 2012 to evaluate Moderate Resolution Imaging Spectroradiometer (MODIS) total precipitable water vapour (PWV) products. Results show strong agreement between the total precipitable water contents estimated based on radiosondes observations and the ones measured by the sensor MODIS with the correlation coefficients in the range 0.69 to 0.95 and a mean bias, which does not exceed 1.5.  

scholarly journals Biochemical parameters variations with season, age, sex, parity and pregnancy in crossbred goats raised in Tiaret, Algeria

2021 ◽  
Vol 8 (1) ◽  
pp. 69-79
Author(s):  
Berrani Abdelkader ◽  
Meliani Samia ◽  
Bourabah Akila
Keyword(s):  
Significant Influence ◽  
Biochemical Parameters ◽  
Physiological State ◽  
Mean Values ◽  
North West ◽  
The North ◽  
Nutritional Conditions ◽  
Physiological Stage ◽  
The Mean ◽  
Calcium And Phosphorus

Abstract The aim of this study was to determine the influence of season, age, sex, parity and gestation status on some biochemical parameters in local cross-bred goats raised in Tiaret, Algeria. Ninety cross bred local goats, from 2019 to 2020, aged between nine and seventy-two months at different physiological stage were used. Animals belong to different farms in Tiaret located at the north-west Algeria (35°22’ N, 1°19’ E). The mean values of triglycerides, creatinine and calcium were significantly (p<0,05) higher in winter than in spring. The physiological state of the goat had a significant influence (p<0,05) on cholesterol, urea, total proteins, calcium and phosphorus, with a high average values in non-pregnant goats, while triglycerides and globulin had significant higher values in postpartum and pregnant femals, respectively. In our work, parity had a significant influence (p<0,05) on cholesterol, calcium and phosphorus, with high average values in young goats and a significant influence (p<0,05) on triglycerides and creatinine with high average values in primiparous ones. Age significantly influenced (p<0,05) cholesterol, triglycerides, total protein, calcium and globulin. The results obtained from this study could serve as reference values for the local goats and other regions or countries with similar climatic and nutritional conditions.

scholarly journals Large-Scale Flow and the Long-Lasting Blocking High over Russia: Summer 2010

2012 ◽  
Vol 140 (9) ◽  
pp. 2967-2981 ◽  
Author(s):  
Andrea Schneidereit ◽  
Silke Schubert ◽  
Pavel Vargin ◽  
Frank Lunkeit ◽  
Xiuhua Zhu ◽  
...  
Keyword(s):  
Heat Wave ◽  
Large Scale ◽  
Wave Structure ◽  
Arctic Region ◽  
Stationary Wave ◽  
Boreal Summer ◽  
Atmospheric Variability ◽  
The North ◽  
Blocking High ◽  
Large Scale Flow

Abstract Several studies show that the anomalous long-lasting Russian heat wave during the summer of 2010, linked to a long-persistent blocking high, appears mainly as a result of natural atmospheric variability. This study analyzes the large-scale flow structure based on the ECMWF Re-Analysis Interim (ERA-Interim) data (1989–2010). The anomalous long-lasting blocking high over western Russia including the heat wave occurs as an overlay of a set of anticyclonic contributions on different time scales. (i) A regime change in ENSO toward La Niña modulates the quasi-stationary wave structure in the boreal summer hemisphere supporting the eastern European blocking. The polar Arctic dipole mode is enhanced and shows a projection on the mean blocking high. (ii) Together with the quasi-stationary wave anomaly, the transient eddies maintain the long-lasting blocking. (iii) Three different pathways of wave action are identified on the intermediate time scale (~10–60 days). One pathway commences over the eastern North Pacific and includes the polar Arctic region; another one runs more southward and crossing the North Atlantic, continues to eastern Europe; a third pathway southeast of the blocking high describes the downstream development over South Asia.

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