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>

Poleward moisture transport and its influence on precipitation in the Arctic: From case studies to long-term statistics

2020 ◽  
Author(s):  
Melanie Lauer ◽  
Annette Rinke ◽  
Irina Gorodetskaya ◽  
Susanne Crewell
Keyword(s):  
Sea Ice ◽  
Case Studies ◽  
Water Vapour ◽  
Moisture Transport ◽  
Longwave Radiation ◽  
The Arctic ◽  
Vapour Transport ◽  
Water Vapour Transport ◽  
Downward Longwave Radiation

<p>There are many factors which could contribute to the Arctic warming: feedback processes like the lapse rate and ice-albedo feedback, the increasing downward longwave radiation caused by clouds and water vapour, and the reduction of sea ice in summer that leads to absorption of solar radiation and increase in local evaporation and more clouds. But also the atmospheric moisture transport from the lower latitudes can contribute to the surface warming in high-latitudes. This poleward moisture transport is mostly accomplished by extra-tropical cyclones, with especially strong contribution by the Atmospheric Rivers (ARs). ARs are long, narrow bands of enhanced water vapour transport which are responsible for over 90% of the poleward water vapour transport in and across mid-latitudes. Furthermore, they are responsible for producing significant levels of rain and snow. In addition, the greenhouse effect of water vapour and the formation of clouds increase the downward longwave radiation which can cause a thinning and melting of Arctic sea ice and snow.</p><p>In this study, we investigate the contribution of ARs to Arctic precipitation. Firstly, we look into different case studies for which observational data from the campaigns within the Collaborative Research Center “Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback Mechanisms (AC)<sup>3</sup>” exist. The data include enhanced observations at/around Svalbard performed during the ACLOUD and the AFLUX campaigns.</p><p>Previous studies have shown that ARs reaching into the Arctic have different origins, including the Atlantic and the Pacific pathways and also Siberia. Here we examine which pathway is more common and which one transports more moisture into the Arctic for these case studies by using existing AR catalogues from global and polar-specific algorithms. Furthermore, the variability of precipitation influences the surface mass and energy balance of polar sea ice and ice sheets. Therefore, we will analyse the influence of ARs on precipitation in terms of frequency, intensity, and type of precipitation (rain or snow) for the different case studies. For this purpose, we will use reanalyses and observational data for the water vapour transport, total precipitation, rain and snow profiles.The occurrence of ARs and its influence on precipitation will be extended from case studies to the long-term statistics (for at least 10 years).</p>

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 Moisture fluxes derived from EOS aqua satellite data for the north water polynya over 2003-2009

2012 ◽  
Vol 117 (D6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Linette N. Boisvert ◽  
Thorsten Markus ◽  
Claire L. Parkinson ◽  
Timo Vihma
Keyword(s):  
Satellite Data ◽  
The North ◽  
North Water Polynya ◽  
Moisture Fluxes ◽  
North Water ◽  
Aqua Satellite

High-Latitude Atmospheric River Cross-Sections over the North Atlantic: Assessing Optimized Airborne Sounding Strategies

2021 ◽  
Author(s):  
Henning Dorff ◽  
Heike Konow ◽  
Vera Schemann ◽  
Felix Ament
Keyword(s):  
High Resolution ◽  
Water Vapour ◽  
Cross Sections ◽  
North Atlantic ◽  
High Latitude ◽  
Vapour Transport ◽  
The North ◽  
Water Vapour Transport ◽  
Low Level Jet ◽  
The North Atlantic

<p>Regarding arctic amplification, meridional transports of moisture and heat from subpolar regions represent a crucial phenomenon. Among such intrusions, Atmospheric Rivers (ARs) are characterized by narrow and transient moisture flows, which are responsible for up to 90% of vertical integrated water vapour transport (IVT) into the Arctic. Moreover, they are relevant for meridional air mass transformations and precipitation events. To identify local sources and sinks of moisture associated with such AR pathways, the accurate determination of total IVT along the AR cross-sections is indispensable. However, since ARs primarily occur over ocean basins, e.g. the North Atlantic, there is a lack of measurements inside ARs. Spaceborne sensors struggle to profile the interior of AR cores, leading to a blind zone where the majority of water vapour is located.</p><p>Conversely, airborne released dropsondes currently provide the most detailed insights on ARs. The frequency of dropsonde releases is, however, technically limited, so that uncertainties in the calculated total IVT of the AR transect may be significant. In particular, when the IVT within the AR core has high lateral variability, unresolved AR-IVT characteristics can constrain the moisture budget analysis. During the North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX), conducted in autumn 2016, the High Altitude and LOng- Range research aircraft (HALO) performed several flight segments along high-latitude AR cross-sections. From these North Atlantic ARs associated with strong meridional water vapour transport, we exemplarily present high-resolution measurements and sounding profiles in the interior of AR cross-sections. We focus on a polar case (research flight RF10, 13<sup>th</sup> October 2016) and include simulations from the cloud-resolving model ICON-2km, to investigate the lateral AR-IVT variability.  </p><p>Comparing dropsonde IVT values with the simulations from ICON-2km, the model shows a valid representation of the AR. Therefore, we use the high-resolution simulations to generate additional synthetic observations. They allow us to identify major sources of error for observational representation of IVT variability in AR cross-sections. Analysing the vertical profile of water vapour transport, we find that specific humidity and wind speed contribute to lateral IVT variability at different heights. With regard to the total cross-section IVT, we derive across-track sounding resolutions required for typical arctic AR-IVT characteristics. The considered AR shows the presence of a low-level jet, a pre-cold-frontal strong wind corridor below 1000 m, resulting from the temperature gradient across the cold front. Since maximum values and increasing lateral variability of IVT appear close to this low-level jet, our results emphasize the need of high-resolution, i.e frequent sonde releases, around the low-level jet to calculate the cross-section total IVT. Our findings aim at optimizing observational airborne strategies for future campaigns, e.g. HALO-AC³ in 2022, in order to lower the uncertainties of IVT in high-latitude and arctic ARs.</p>

Stanowiska reliktowego gatunku Betula humilis (Betulaceae) w Dolinie Górnego Nurca na Nizinie Północnopodlaskiej

2019 ◽  
pp. 161-168
Author(s):  
Aleksander Kołos
Keyword(s):  
Drainage Ditches ◽  
North West ◽  
Hay Meadows ◽  
The North ◽  
South West ◽  
North Eastern ◽  
New Localities ◽  
Western Border ◽  
Betula Humilis ◽  
Trees And Shrubs

Betula humilis Schrank (shrubby birch) is among the most endangered shrub species in Poland. All localities are in the eastern and northern parts of the country, where the species reaches the western border of its geographical range in Europe. Betula humilis is disappearing in Poland due to wetland melioration and shrub succession. Over 80% of the localities described in Poland have not been confirmed in the last 20 years. Five new localities of B. humilis in the North Podlasie Lowland were recorded from 2008 to 2019 in the Upper Nurzec Valley (Fig. 1): 1–1.5 km south-west of Pawlinowo village (in the ATPOL GC7146 plot) and 1.5–2 km north-west of Żuki village (ATPOL GC7155, GC156 and GC166). The population near Pawlinowo (locality 1) is currently composed of ~80 individuals (101 individuals were noted in 2010) and is one of the largest populations in north-eastern Poland. Betula humilis grows there within patches dominated by Salix rosmarinifolia and megaforbs. The population at locality 5 is composed of 18 individuals. At the remaining localities, only 1–4 individuals were found, scattered along drainage ditches surrounded by hay meadows. At some of these localities the species is threatened with extinction. It is suggested to remove competitive trees and shrubs (mainly Populus tremula, Betula pubescens and Salix cinerea) in order to maintain the local populations.

scholarly journals Reproductive health among Venezuelan migrant women at the north western border of Brazil: A qualitative study

2021 ◽  
pp. 100060
Author(s):  
Maria Y. Makuch ◽  
Maria Jose D. Osis ◽  
Cinthia Brasil ◽  
Helder S.F. de Amorim ◽  
Luis Bahamondes
Keyword(s):  
Reproductive Health ◽  
Qualitative Study ◽  
Migrant Women ◽  
The North ◽  
Western Border ◽  
North Western

scholarly journals Three generations of stars: a possible case of triggered star formation

2020 ◽  
Vol 496 (1) ◽  
pp. 870-874
Author(s):  
M B Areal ◽  
A Buccino ◽  
S Paron ◽  
C Fariña ◽  
M E Ortega
Keyword(s):  
Star Formation ◽  
Young Stellar Objects ◽  
H Ii Regions ◽  
Stellar Objects ◽  
Three Generations ◽  
The North ◽  
Western Border ◽  
H Ii Region ◽  
New Generation ◽  
North Western

ABSTRACT Evidence for triggered star formation linking three generations of stars is difficult to assemble, as it requires convincingly associating evolved massive stars with H ii regions that, in turn, would need to present signs of active star formation. We present observational evidence for triggered star formation relating three generations of stars in the neighbourhood of the star LS II +26 8. We carried out new spectroscopic observations of LS II +26 8, revealing that it is a B0 III-type star. We note that LS II +26 8 is located exactly at the geometric centre of a semi-shell-like H ii region complex. The most conspicuous component of this complex is the H ii region Sh2-90, which is probably triggering a new generation of stars. The distances to LS II +26 8 and to Sh2-90 are in agreement (between 2.6 and 3 kpc). Analysis of the interstellar medium on a larger spatial scale shows that the H ii region complex lies on the north-western border of an extended H2 shell. The radius of this molecular shell is about 13 pc, which is in agreement with what an O9 V star (the probable initial spectral type of LS II +26 8 as inferred from evolutive tracks) can generate through its winds in the molecular environment. In conclusion, the spatial and temporal correspondences derived in our analysis enable us to propose a probable triggered star formation scenario initiated by the evolved massive star LS II +26 8 during its main-sequence stage, followed by stars exciting the H ii region complex formed in the molecular shell, and culminating in the birth of young stellar objects around Sh2-90.

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