The imprint of glacial and periglacial erosion processes on fluvial landscape metrics

2020 ◽  
Author(s):  
Moritz Liebl ◽  
Jörg Robl ◽  
David Lundbek Egholm ◽  
Kurt Stüwe ◽  
Gerit Gradwohl
Keyword(s):  
Process Model ◽  
Large Scale ◽  
Eastern Alps ◽  
Cold Climate ◽  
Mountain Range ◽  
Mountain Ranges ◽  
Fluvial Processes ◽  
Erosion Processes ◽  
The Impact ◽  
Topographic Pattern

<p>The emerging Pleistocene glaciations have left a distinct topographic footprint in mountain ranges worldwide. However, it is still unclear how the formation of cirques above (including the potential destruction of peak relief) and the excavation of glacial troughs below the long-term snowline altered to the large-scale topographic pattern of mountain ranges originally conditioned by fluvial processes.</p><p>Some mountain ranges such as the Eastern Alps feature a bimodal topographic pattern characterized by a transition from increasing to decreasing slope with elevation. Bimodality might be an expression of glacial reshaping, as glacial troughs with steepened valley flanks have been formed at low elevations and low relief surfaces at high elevations. On the other hand, bimodality might represent the state of fluvial prematurity as expression of ongoing landscape adjustment to an uplift event in the recent past. Despite their completely different evolution, both hypotheses lead to a bimodal landscape with a similar slope-elevation distribution.</p><p>In this study, we explore the impact of cold climate erosional processes on the mountain range scale topographic pattern. For this, we use synthetically generated and natural mountain range landscapes conditioned by fluvial processes and apply a surface process model for cold climate conditions (iSOSIA). In regions with high glacial impact, we explore an upstream migrating glacial signature represented by two frequency maxima in the slope elevation distribution at lower elevations (i.e. below the snowline, where glacial troughs formed). This is accompanied with an increase in slope on average compared to the initial topography. Above the snow line, bimodality vanishes and mean slope is similar to the initial fluvial topography. Interestingly, in the Eastern Alps, we explore a similar pattern where the transition from increasing to decreasing slope with elevation is located at about 1800 m, which is roughly at the position of the last glacial maximum (LGM) snowline of this region.</p>

Progressive landscape transformation from a fluvial to a glacial topography

2021 ◽  
Author(s):  
Moritz Liebl ◽  
Jörg Robl ◽  
David Egholm ◽  
Günther Prasicek ◽  
Kurt Stüwe ◽  
...  
Keyword(s):  
Landscape Metrics ◽  
Eastern Alps ◽  
Cold Climate ◽  
Mountain Range ◽  
Equilibrium Line Altitude ◽  
Mountain Ranges ◽  
Model Time Series ◽  
Channel Slope ◽  
Spatial Transition ◽  
Glacial Landforms

<p>Mid-latitude mountain ranges such as the Eastern Alps are characterized by a strong topographic imprint of Pleistocene glaciations. The characteristic geometry of glacial landforms has been quantified in various ways, but studies about the evolution of glacial landscape metrics are lacking. However, such information is needed to interpret the evolutionary state of glacial topography.</p><p>By employing a landscape evolution model for cold climate processes, we trace the fluvial-to-glacial transformation of a synthetic landscape. Our simulations inspired by alpine glaciations of mid-latitude mountain ranges with peaks and ridges towering above the glacier network lead to a general increase in relief. This is expressed as the formation of overdeepened valleys with steepened flanks. Overdeepening starts at the glacier front and progressively extends upstream with ongoing glacial erosion.</p><p>The topographic signature of the progressively transforming landscape is characterized by an increase of mean channel slopes and its variance. However, above the steep flanks, the initial fluvial topography is persisting. Whereas the initial fluvial mountain range is characterized by a monotonic increase of channel slope with elevation, a transition from increasing to decreasing channel slope with elevation emerges above the equilibrium line altitude where (tributary-)headwalls transition to ridges and summits. This turning point and a high slope variance becomes progressively distinctive with ongoing glacial occupation.</p><p>By comparing landscape metrics derived from model time series with those of the Eastern Alps, we found that the temporal transition observed in our numerical experiments occur as spatial transition from the fully glaciated western to a minorly glaciated eastern part of the Alps. Thus, slope-elevation plots serve as a diagnostic tool for interpreting the glacial - fluvial influence in mountain landscapes. However, catchments of the unglaciated part of the Eastern Alps show also turning points in their slope-elevation distributions, but the variance of slope is significantly smaller at all elevation levels, when compared to the glaciated part.</p>

scholarly journals Impact of North Atlantic Oscillation on the Snowpack in Iberian Peninsula Mountains

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 105 ◽  
Author(s):  
Esteban Alonso-González ◽  
Juan I. López-Moreno ◽  
Francisco M. Navarro-Serrano ◽  
Jesús Revuelto
Keyword(s):  
North Atlantic Oscillation ◽  
Iberian Peninsula ◽  
Sierra Nevada ◽  
North Atlantic ◽  
Snow Water Equivalent ◽  
Mountain Range ◽  
Winter Climate ◽  
Mountain Ranges ◽  
Iberian Range ◽  
The Impact

The North Atlantic Oscillation (NAO) is considered to be the main atmospheric factor explaining the winter climate and snow evolution over much of the Northern Hemisphere. However, the absence of long-term snow data in mountain regions has prevented full assessment of the impact of the NAO at the regional scales, where data are limited. In this study, we assessed the relationship between the NAO of the winter months (DJFM-NAO) and the snowpack of the Iberian Peninsula. We simulated temperature, precipitation, and snow data for the period 1979–2014 by dynamic downscaling of ERA-Interim reanalysis data, and correlated this with the DJFM-NAO for the five main mountain ranges of the Iberian Peninsula (Cantabrian Range, Central Range, Iberian Range, the Pyrenees, and the Sierra Nevada). The results confirmed that negative DJFM-NAO values generally occur during wet and mild conditions over most of the Iberian Peninsula. Due to the direction of the wet air masses, the NAO has a large influence on snow duration and the annual peak snow water equivalent (peak SWE) in most of the mountain ranges in the study, mostly on the slopes south of the main axis of the ranges. In contrast, the impact of NAO variability is limited on north-facing slopes. Negative (positive) DJFM-NAO values were associated with longer (shorter) duration and higher (lower) peak SWEs in all mountains analyzed in the study. We found marked variability in correlations of the DJFM-NAO with snow indices within each mountain range, even when only the south-facing slopes were considered. The correlations were stronger for higher elevations in the mountain ranges, but geographical longitude also explained the intra-range variability in the majority of the studied mountains.

On the Synergistic Climatic Effects of Covarying Major Mountain Range Topographies

2020 ◽  
Author(s):  
Sebastian G. Mutz ◽  
Todd A. Ehlers
Keyword(s):  
General Circulation ◽  
Atmospheric Transport ◽  
Circulation Model ◽  
Careful Consideration ◽  
Mountain Range ◽  
Earth Surface ◽  
Climatic Effects ◽  
Climate Conditions ◽  
Mountain Ranges ◽  
The Impact

<p>The interpretation of Earth surface archives often requires consideration of distant off-site events. One such event is the surface uplift of Earth’s major mountain ranges, which affects climate and the Earth’s surface globally. In this study, the individual and synergistic climatic effects of topographic changes in major mountain ranges are explored with a series of General Circulation Model (GCM) experiments and analyses of atmospheric teleconnections. The GCM experiments are forced with different topographic scenarios for Himalaya-Tibet (TBT) and the Andes (ADS), while environmental boundary conditions are kept constant. The topographic scenarios are constructed by successively lowering modern topography to 0% of its modern height in increments of 25%. This results in a total of 5 topographic scenarios for TBT (tbt100, tbt075, tbt050, tbt025, tbt000) and ADS (ads100, ads075, ads050, ads025, ads000). TBT scenarios are then nested in ADS scenarios, resulting in a total of 25 experiments with unique topographic settings. The climate for each of those 25 scenarios is simulated with the GCM ECHAM5-wiso. We then explore possible synergies and distant impacts of topographic changes by testing the hypothesis that varying ADS has no effect on simulated climate conditions in the TBT region (c_tbt) and vice versa. This can be expressed as the null hypothesis c_tbt(ads100) = c_tbt(ads075) = c_tbt(ads050) = c_tbt(ads025) = c_tbt(ads000) for each of the 5 TBT scenarios, and vice versa. We conduct Kruskal-Wallis tests for a total of 10 treatment sets to address these hypotheses. The results suggest that ADS climate is mostly independent of TBT topography changes, whereas TBT climate is sensitive to ADS topography changes when TBT topography is high, but insensitive when TBT topography is strongly reduced. Analyses of atmospheric pressure fields suggest that TBT height acts as a control on cross-equatorial atmospheric transport and modifies the impact of ADS topography on northern hemisphere climate. These results dictate a more careful consideration of global (off-site) conditions in the interpretation of Earth surface records.</p>

scholarly journals On the Orographically Generated Low-Level Easterly Jet and Severe Downslope Storms of March 2006 over the Tacheng Basin of Northwest China

2018 ◽  
Vol 146 (6) ◽  
pp. 1667-1683 ◽  
Author(s):  
Guangxing Zhang ◽  
Da-Lin Zhang ◽  
Shufang Sun
Keyword(s):  
Large Scale ◽  
Inversion Layer ◽  
Dust Storms ◽  
Frozen Soil ◽  
Gradient Force ◽  
Mountain Range ◽  
Pressure Gradient Force ◽  
Low Level ◽  
Downslope Winds ◽  
The Impact

A high-latitude low-level easterly jet (LLEJ) and downslope winds, causing severe dust storms over the Tacheng basin of northwestern China in March 2006 when the dust source regions were previously covered by snow with frozen soil, are studied in order to understand the associated meteorological conditions and the impact of complex topography on the generation of the LLEJ. Observational analyses show the development of a large-scale, geostrophically balanced, easterly flow associated with a northeastern high pressure and a southeastern low pressure system, accompanied by a westward-moving cold front with an intense inversion layer near the altitudes of mountain ridges. A high-resolution model simulation shows the generation of an LLEJ of near-typhoon strength, which peaked at about 500 m above the ground, as well as downslope windstorms with marked wave breakings and subsidence warming in the leeside surface layer, as the large-scale cold easterly flow moves through a constricting saddle pass and across a higher mountain ridge followed by a lower parallel ridge, respectively. The two different airstreams are merged to form an intense LLEJ of cold air, driven mostly by zonal pressure gradient force, and then the LLEJ moves along a zonally oriented mountain range to the north. Results indicate the importance of the lower ridge in enhancing the downslope winds associated with the higher ridge and the importance of the saddle pass in generating the LLEJ. We conclude that the intense downslope winds account for melting snow, warming and drying soils, and raising dust into the air that is then transported by the LLEJ, generated mostly through the saddle pass, into the far west of the basin.

scholarly journals Geophysical Challenges for Future Satellite Gravity Missions: Assessing the Impact of MOCASS Mission

2021 ◽  
Author(s):  
T. Pivetta ◽  
C. Braitenberg ◽  
D. F. Barbolla
Keyword(s):  
Spatial Resolution ◽  
Large Scale ◽  
Cold Atom ◽  
Mountain Range ◽  
Cumulative Number ◽  
Mass Detection ◽  
Satellite Mission ◽  
Satellite Gravity ◽  
The Impact ◽  
Satellite Gravity Missions

AbstractThe GRACE/GRACE-FO satellites have observed large scale mass changes, contributing to the mass budget calculation of the hydro-and cryosphere. The scale of the observable mass changes must be in the order of 300 km or bigger to be resolved. Smaller scale glaciers and hydrologic basins significantly contribute to the closure of the water mass balance, but are not detected with the present spatial resolution of the satellite. The challenge of future satellite gravity missions is to fill this gap, providing higher temporal and spatial resolution. We assess the impact of a geodetic satellite mission carrying on board a cold atom interferometric gradiometer (MOCASS: Mass Observation with Cold Atom Sensors in Space) on the resolution of simulated geophysical phenomena, considering mass changes in the hydrosphere and cryosphere. Moreover, we consider mass redistributions due to seamounts and tectonic movements, belonging to the solid earth processes. The MOCASS type satellite is able to recover 50% smaller deglaciation rates over a mountain range as the High Mountains of Asia compared to GRACE, and to detect the mass of 60% of the cumulative number of glaciers, an improvement respect to GRACE which detects less than 20% in the same area. For seamounts a significantly smaller mass eruption could be detected with respect to GRACE, reaching a level of mass detection of a submarine basalt eruption of 1.6 109 m3. This mass corresponds to the eruption of Mount Saint Helens. The simulations demonstrate that a MOCASS type mission would significantly improve the resolution of mass changes respect to existing geodetic satellite missions.

scholarly journals Simulating the forest fire plume dispersion, chemistry, and aerosol formation using SAM-ASP version 1.0

2020 ◽  
Vol 13 (9) ◽  
pp. 4579-4593
Author(s):  
Chantelle R. Lonsdale ◽  
Matthew J. Alvarado ◽  
Anna L. Hodshire ◽  
Emily Ramnarine ◽  
Jeffrey R. Pierce
Keyword(s):  
Biomass Burning ◽  
Process Model ◽  
Large Scale ◽  
Trace Gases ◽  
Regional Scale ◽  
Process Models ◽  
Plume Dispersion ◽  
Aerosol Formation ◽  
Fire Plume ◽  
The Impact

Abstract. Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM), with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP version 1.0 presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

scholarly journals Simulating Forest Fire Plume Dispersion, Chemistry, and Aerosol Formation Using SAM-ASP version 1.0

2019 ◽  
Author(s):  
Chantelle R. Lonsdale ◽  
Matthew J. Alvarado ◽  
Anna L. Hodshire ◽  
Emily Ramnarine ◽  
Jeffrey R. Pierce
Keyword(s):  
Biomass Burning ◽  
Process Model ◽  
Large Scale ◽  
Trace Gases ◽  
Regional Scale ◽  
Process Models ◽  
Plume Dispersion ◽  
Aerosol Formation ◽  
Fire Plume ◽  
The Impact

Abstract. Biomass burning is a major source of trace gases and aerosols that can ultimately impact health, air quality, and climate. Global and regional-scale three-dimensional Eulerian chemical transport models (CTMs) use estimates of the primary emissions from fires and can unphysically mix them across large-scale grid boxes, leading to incorrect estimates of the impact of biomass burning events. On the other hand, plume-scale process models allow for explicit simulation and examination of the chemical and physical transformations of trace gases and aerosols within biomass burning smoke plumes, and they may be used to develop parameterizations of this aging process for coarser grid-scale models. Here we describe the coupled SAM-ASP plume-scale process model, which consists of coupling the large-eddy simulation model, the System for Atmospheric Modelling (SAM) version 1.0, with the detailed gas and aerosol chemistry model, the Aerosol Simulation Program (ASP). We find that the SAM-ASP version 1.0 model is able to correctly simulate the dilution of CO in a California chaparral smoke plume, as well as the chemical loss of NOx, HONO, and NH3 within the plume, the formation of PAN and O3, the loss of OA, and the change in the size distribution of aerosols as compared to measurements and previous single-box model results. The newly coupled model is able to capture the cross-plume vertical and horizontal concentration gradients as the fire plume evolves downwind of the emission source. The integration and evaluation of SAM-ASP presented here will support the development of parameterizations of near-source biomass burning chemistry that can be used to more accurately simulate biomass burning chemical and physical transformations of trace gases and aerosols within coarser grid-scale CTMs.

Impact of COVID-19 on Nuclear Medicine in Germany, Austria and Switzerland: An International Survey in April 2020

2020 ◽  
Vol 59 (04) ◽  
pp. 294-299 ◽  
Author(s):  
Lutz S. Freudenberg ◽  
Ulf Dittmer ◽  
Ken Herrmann
Keyword(s):  
Nuclear Medicine ◽  
Health Systems ◽  
Personal Protective Equipment ◽  
Large Scale ◽  
Diagnostic Procedures ◽  
Protective Equipment ◽  
Current Crisis ◽  
Web Based ◽  
Public Versus Private ◽  
The Impact

Abstract Introduction Preparations of health systems to accommodate large number of severely ill COVID-19 patients in March/April 2020 has a significant impact on nuclear medicine departments. Materials and Methods A web-based questionnaire was designed to differentiate the impact of the pandemic on inpatient and outpatient nuclear medicine operations and on public versus private health systems, respectively. Questions were addressing the following issues: impact on nuclear medicine diagnostics and therapy, use of recommendations, personal protective equipment, and organizational adaptations. The survey was available for 6 days and closed on April 20, 2020. Results 113 complete responses were recorded. Nearly all participants (97 %) report a decline of nuclear medicine diagnostic procedures. The mean reduction in the last three weeks for PET/CT, scintigraphies of bone, myocardium, lung thyroid, sentinel lymph-node are –14.4 %, –47.2 %, –47.5 %, –40.7 %, –58.4 %, and –25.2 % respectively. Furthermore, 76 % of the participants report a reduction in therapies especially for benign thyroid disease (-41.8 %) and radiosynoviorthesis (–53.8 %) while tumor therapies remained mainly stable. 48 % of the participants report a shortage of personal protective equipment. Conclusions Nuclear medicine services are notably reduced 3 weeks after the SARS-CoV-2 pandemic reached Germany, Austria and Switzerland on a large scale. We must be aware that the current crisis will also have a significant economic impact on the healthcare system. As the survey cannot adapt to daily dynamic changes in priorities, it serves as a first snapshot requiring follow-up studies and comparisons with other countries and regions.

HOME VISITS DURING THE FIRST MONTH OF DELIVERY FOR RECENTLY DELIVERED WOMEN IN UTTAR PRADESH, INDIA

2020 ◽  
Vol 6 (5) ◽  
pp. 1183-1189
Author(s):  
Dr. Tridibesh Tripathy ◽  
Dr. Umakant Prusty ◽  
Dr. Chintamani Nayak ◽  
Dr. Rakesh Dwivedi ◽  
Dr. Mohini Gautam
Keyword(s):  
Large Scale ◽  
National Level ◽  
Uttar Pradesh ◽  
Life Time ◽  
Structured Interview ◽  
The Other ◽  
Registration System ◽  
Action Group ◽  
Current Article ◽  
The Impact

The current article of Uttar Pradesh (UP) is about the ASHAs who are the daughters-in-law of a family that resides in the same community that they serve as the grassroots health worker since 2005 when the NRHM was introduced in the Empowered Action Group (EAG) states. UP is one such Empowered Action Group (EAG) state. The current study explores the actual responses of Recently Delivered Women (RDW) on their visits during the first month of their recent delivery. From the catchment area of each of the 250 ASHAs, two RDWs were selected who had a child in the age group of 3 to 6 months during the survey. The response profiles of the RDWs on the post- delivery first month visits are dwelled upon to evolve a picture representing the entire state of UP. The relevance of the study assumes significance as detailed data on the modalities of postnatal visits are available but not exclusively for the first month period of their recent delivery. The details of the post-delivery first month period related visits are not available even in large scale surveys like National Family Health Survey 4 done in 2015-16. The current study gives an insight in to these visits with a five-point approach i.e. type of personnel doing the visit, frequency of the visits, visits done in a particular week from among those four weeks separately for the three visits separately. The current study is basically regarding the summary of this Penta approach for the post- delivery one-month period.     The first month period after each delivery deals with 70% of the time of the postnatal period & the entire neonatal period. Therefore, it does impact the Maternal Mortality Rate & Ratio (MMR) & the Neonatal Mortality Rates (NMR) in India and especially in UP through the unsafe Maternal & Neonatal practices in the first month period after delivery. The current MM Rate of UP is 20.1 & MM Ratio is 216 whereas the MM ratio is 122 in India (SRS, 2019). The Sample Registration System (SRS) report also mentions that the Life Time Risk (LTR) of a woman in pregnancy is 0.7% which is the highest in the nation (SRS, 2019). This means it is very risky to give birth in UP in comparison to other regions in the country (SRS, 2019). This risk is at the peak in the first month period after each delivery. Similarly, the current NMR in India is 23 per 1000 livebirths (UNIGME,2018). As NMR data is not available separately for states, the national level data also hold good for the states and that’s how for the state of UP as well. These mortalities are the impact indicators and such indicators can be reduced through long drawn processes that includes effective and timely visits to RDWs especially in the first month period after delivery. This would help in making their post-natal & neonatal stage safe. This is the area of post-delivery first month visit profile detailing that the current article helps in popping out in relation to the recent delivery of the respondents.   A total of four districts of Uttar Pradesh were selected purposively for the study and the data collection was conducted in the villages of the respective districts with the help of a pre-tested structured interview schedule with both close-ended and open-ended questions.  The current article deals with five close ended questions with options, two for the type of personnel & frequency while the other three are for each of the three visits in the first month after the recent delivery of respondents. In addition, in-depth interviews were also conducted amongst the RDWs and a total 500 respondents had participated in the study.   Among the districts related to this article, the results showed that ASHA was the type of personnel who did the majority of visits in all the four districts. On the other hand, 25-40% of RDWs in all the 4 districts replied that they did not receive any visit within the first month of their recent delivery. Regarding frequency, most of the RDWs in all the 4 districts received 1-2 times visits by ASHAs.   Regarding the first visit, it was found that the ASHAs of Barabanki and Gonda visited less percentage of RDWs in the first week after delivery. Similarly, the second visit revealed that about 1.2% RDWs in Banda district could not recall about the visit. Further on the second visit, the RDWs responded that most of them in 3 districts except Gonda district did receive the second postnatal visit in 7-15 days after their recent delivery. Less than half of RDWs in Barabanki district & just more than half of RDWs in Gonda district received the third visit in 15-21 days period after delivery. For the same period, the majority of RDWs in the rest two districts responded that they had been entertained through a home visit.

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